The Latest in Nutrition Research Thu, 20 Apr 2023 12:08:23 +0000 en-US hourly 1 Ten (Free!) Ways You Can Support the Work of Dr. Greger and NutritionFacts Thu, 20 Apr 2023 12:00:11 +0000 You’ve asked, and we’ve listened. Massive thanks to each one of you who wants to help spread our work to disseminate the latest in nutrition research. With more than ten years’ worth of informational content, several books and cookbooks, and our newer resources, including guides and infographics, we have plenty of ways for you to share in whatever way works best. Here are some suggestions: 

1. Share a Video

Watch our Traffic Light Dining System video in which Dr. Greger explains his traffic light system for ranking the relative healthfulness of Green Light vs. Yellow Light vs. Red Light foods, and share it with others. 


2. Download the Evidence-Based Eating Guide and the Daily Dozen Meal Planning Guide

Check out our Evidence-Based Eating Guide, and share it with others to help them simplify making the switch to a healthier lifestyle. You can download it for free in English, Spanish, and Chinese, and request a print version here. And don’t forget about our Daily Dozen Meal Planning Guide. This resource will help you incorporate the Daily Dozen checklist into your meal planning.


3. Share Our Infographics 

Read through our infographics on vitamin B12, vitamin D, plant-based meat, and sweet potatoes, and share any (or all) of them.


4. Share Dr. Greger’s Daily Dozen App

What are some of the healthiest foods that we should eat every day? Check out Dr. Greger’s free Daily Dozen app, and share it with friends and family. You can even encourage others to start a challenge to see how many streaks they can achieve. 

5. Start Cooking

Cook a dish from The How Not to Die Cookbook or The How Not to Diet Cookbook, and share with friends and family. For more Green-Light recipes, check out our recipe page


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7. Donate Copies of Dr. Greger’s Books

Leave copies of How Not to Die, How Not to Diet, or any of his cookbooks in places with public bookshelves, such as Little Free Libraries or a shelf in your favorite cafe.


8. Host a Book Club or Screening

Are you a part of a book club or interested in starting one? Suggest How Not to Die as the next title to read! Learn more about the book here. Why not consider hosting a screening of Dr. Greger’s “How Not to Die” or “Evidence-Based Weight Loss” presentation? Happy viewing!


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We hope these are helpful ways you can encourage healthy habits and share potentially life-changing information with others you know. As usual, everything on our website and platforms is free, and all of the proceeds from Dr. Greger’s book sales are donated to charity. Thank you for your support!

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Is It Safe to Consume Cannabis Edibles? Tue, 18 Apr 2023 12:00:18 +0000 What do we need to know about the safety of marijuana edibles?

You may recall from my video Smoking Marijuana vs. Using a Cannabis Vaporizer that smoking cannabis can create respiratory problems, so using a vaporizer is an alternative. What about eating it? I discuss that in my video Are Cannabis Edibles Safe?.

“Vaping is likely less harmful than smoking marijuana,” and edibles are another alternative, but they may carry increased risks to children and increased risk of overdosing. I’d add a third risk—to pets. “Since the legalization of recreational marijuana in Colorado in January 2014, edibles comprise almost half of total cannabis sales,” and a “significant correlation” has been found between the rise in use and the rise in marijuana toxicosis cases at veterinary hospitals, thought to have contributed to two dog deaths in the state.

“There have been no reported deaths in young children from marijuana exposure,” thankfully, though some have ended up on life support because an edible marijuana overdose can lead to severe respiratory depression. As you can see in the graph below and at 1:09 in my video, Colorado regional poison control cases increased significantly after recreational pot became legal and at a higher rate than the rest of the United States, which is one reason the American Academy of Pediatrics continues to oppose legalization.

At the very least, cannabis edibles shouldn’t be packaged to look like popular candy, as you can see below and at 1:29 in my video. (Keef Kat, Buddahfinger, and Munchy Way, to name a few.) Some states have since banned selling marijuana-infused candy with that kind of imagery, but, to play it safe, maybe we shouldn’t be making cannabis candy at all.

How big of a problem is this, really? “To put this in perspective, the Rocky Mountain Poison and Drug Center reported…that 2,700 children in Colorado required treatment after accidentally ingesting cosmetics or personal care products, and 739 after eating large amounts of vitamins…Compare that with the dozen or so reports of kids accidentally eating marijuana edibles last year.” And if you want to talk about poisoning deaths, how about alcohol? “More than 2,200 alcohol poisoning deaths occur among adults in the United States every year, or about six per day,” whereas deaths attributed to marijuana are few and far between, though there have been a few.

The problem is that you may not feel an effect from edibles for an hour or two after consumption and may not know how much to take, so you might then “overconsume, thinking in the first hour or so after initial consumption that [you] have not ingested enough product to feel an effect.” As you can see in the graph below and at 2:22 in my video, it takes about three hours for cannabis compounds to peak in your bloodstream compared to just ten minutes when you smoke it and at least a full hour before you feel much at all.

This happened right after legalization in Colorado: A 19-year-old died after consuming a marijuana cookie. He had one piece. “Approximately 30–60 minutes later, not feeling any effects, he consumed the remainder of the cookie.” Two-and-a-half hours later, he jumped to his death from a fourth-floor balcony. A month later, a “second man developed hallucinations and rambling speech…and in the midst of an apparent psychotic break, fatally shot his wife while she was calling 911 for help.”

These kinds of cases, as you can see below and at 3:10 in my video, commonly involved someone eating the recommended serving size, feeling nothing, deciding to eat the rest, then ending up restrained in the psych ward, claiming they’re God or mutilating themselves because “friends wanted their energy back.”

The cannabis industry responded by blaming the victims. “No one buys a bottle of Jim Beam and thinks they should consume it all in one sitting.” Maybe not, but people do expect to be able to eat a whole cookie. Who eats just one-tenth of a cookie?

Other over-the-counter products “are required to carry specific labeling for dosing and adverse events. It seems odd, to say the least, that edible cannabis, which contains a known psychoactive substance, is not held to the same standard as a bottle of acetaminophen tablets,” like Tylenol. In 2016, Colorado regulators enacted new rules for labeling edibles, including mandating their THC content be listed right on the label. How accurate are those labels, though? We didn’t know until they were put to the test. Of 75 products purchased, involving 47 different brands of edibles, only 17 percent were accurately labeled, and only about one in six came within 10 percent of the labeled value. The greatest likelihood of obtaining more-than-you-bargained-for products was in Los Angeles, whereas Seattle seemed to tend to overinflate its labels.

It’s hard to study cannabis of any kind due to illegality, but according to a hundred thousand tweets about edibles, most people express a positive opinion. One unexpected benefit arose in a focus group of teens on marijuana edibles: Several students in a high school culinary class were “there to learn how to cook in order to be able to produce edibles.”

I have a whole treasure chest of cannabis videos. If you want to see them all, I put them in a digital DVD that you can stream now.

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Does the Science Say That Butter Is Really Back? Thu, 13 Apr 2023 12:00:47 +0000 Are butter and other saturated fats bad for you or not?

My video Friday Favorites: Is Butter Really Back? What the Science Says explores the uses and misuses of research on butter consumption and health. Time magazine famously exhorted people to “Eat Butter” and no doubt sold a lot of magazines, but perhaps at the cost of selling the public short. The publication followed up with an article that doubled down, saying that “the case for eating butter just got stronger.” It was based on the study “Is Butter Back? A Systematic Review and Meta-Analysis of Butter Consumption and Risk of Cardiovascular Disease, Diabetes, and Total Mortality” and claimed: “Pooling these studies, each daily serving of butter (14g/d) was associated with a 1% higher risk of death.” Hold on. One percent? That’s the study that’s supposed to make the case to eat butter stronger? Further, the study suggests that swapping just a spoonful or so of oil in place of butter every day might drop the risk of diabetes by 8 percent. “Thus, even with the absence of major health associations in the present investigation, healthier (and less healthy) alternatives may be available.” A 1 percent increase in death is pretty tiny, though. Why didn’t the researchers find a larger effect? Well, butter is just a tiny part of people’s overall diets. It’s illustrative to review the candy literature.

The National Confectioner’s Association is fond of contracting with scientists-for-hire like those at Exponent Inc., a company infamous for shilling for Big Tobacco and chemical companies. As you can see below and at 1:22 in my video, it encourages people to eat candy every day—but “in moderation,” like 15 to 25 jelly beans a day. Parents who restrict foods “in an effort to moderate a child’s intake of calories” are just going to make their kids fat, argue such scientists-for-hire.

See, parents use “coercive practices…to limit children’s access to palatable, energy-dense, or low-nutrient foods, which may include when, how often, or how much can be consumed.” Isn’t it outrageous that parents have the gall to tell their kids when, how often, or how much candy can be consumed? Don’t they know that butter(scotch) is back? “Evidence suggests that it [candy] is not associated with adverse health effects.” Don’t believe me? Ten thousand kids surveyed in one study were asked if they had eaten candy within the last 24 hours, and, after researchers compared those who said yes to those who said no, they concluded: “Current levels of candy consumption were not associated with adverse health parameters in children or adolescents.” And, this was a study in which the authors declared no conflicts of interest—even though it was a study about candy funded by the candy industry. Seems like interests were a bit conflicted.

Do you see how it would be hard to tease out the specific health effects of candy with such a blunt instrument? We don’t need a study, though, because we already know what candy is: It’s candy. It’s mostly pure sugar. We already eat too much sugar and certainly don’t need more. You don’t need to pay off researchers to come up with a study like this about candy or devise one about butter. We already know what butter is: It’s butter. It’s mostly pure saturated fat. We already eat too much saturated fat and certainly don’t need more. Anyway, it gets even wilder. Claimed the scientists-for-hire, “Candy consumers were…less likely to be overweight and obese than non-candy consumers.” Really? Maybe the candy company was right. Pass the Peeps!

“Is candy eating a way to control body weight?” What’s an alternative explanation of why obese children eat less candy? Reverse causation. Perhaps it’s not that cutting down on candy led to obesity, but rather obesity led to cutting down on candy. In other words, the “reported candy consumption…reflects consequences of obesity, not causes,” just like people with heart disease may cut down on butter, clouding the association. And, remember, it was reported candy consumption, which brings up the specter of reporting bias. “In other words, overweight children or adolescents may underreport their intake of confectionery [candy] to a greater extent than do those of normal weight.”

Otherwise, “what would the implications of the finding” be? Do we want to randomize kids to eat more candy to see if it makes them lose weight? “It is doubtful that any ethical committee would be happy about this kind of a proposal,” but you don’t know until you put it to the test. Feed folks extra candy or the same number of extra calories in the form of peanuts, and surprise, surprise: Those who ate all of that extra candy gained more weight.

There was an interventional trial that showed that candy can improve ADHD symptoms, though. What’s the story with that? If you’re the Mars candy bar company and want to fund a study showing that candy bars help kids focus, what would you do? The “parents were sent a formal letter instructing them not to feed their child after 10 p.m. and to send them to school without breakfast,” then the children were given a candy bar or an aspartame beverage, basically nothing. And, what do you know? Feeding kids something rather than nothing “enhanced [their] ability to stay on task.” That reminds me of a Frosted Mini-Wheats ad that you can see at 5:08 in my video that boasted the cereal was “clinically shown to improve kids’ attentiveness by nearly 20 percent” with the really fine print explaining that this was compared to kids who ate no breakfast at all.

Butter has been put to the test, too. As you can see at 5:29 in my video, give people a single meal with butter, and you see a boost of inflammatory gene expression within just hours of consumption, significantly more than you’d see after they ate the same amount of fat in olive oil or walnuts. You can randomize people to foods made with all sorts of different fats, and butter has been shown to be the worst in terms of LDL cholesterol. Those were short-term studies, though. It’s not as if you can randomize people to eat or avoid butter for years—unless they’re patients in a mental hospital, and that was the case for one study where researchers showed that you can raise or lower their cholesterol and cut coronary events by about 40 percent just by switching diets. The study participants also cut down on meat and eggs, however, so it wasn’t only butter.

You can’t get a whole country to cut down on butter, or can you? A 75 percent drop in butter consumption in Finland helped create an 80 percent drop in heart disease mortality, which was driven largely by the countrywide drop in cholesterol levels, which was largely driven by the countrywide dietary changes to lower saturated fat intake, such as moving away from butter.

The bottom line is that researchers have put it to the test in randomized, controlled trials involving more than 50,000 people and found that the more you decrease saturated fat content, the more your cholesterol drops, and the greater the protection. “Lifestyle advice to all those at risk of cardiovascular disease…should continue to include permanent reduction of dietary saturated fat…” The American Heart Association got so fed up with industry attempts to confuse people that it released a Presidential Advisory in 2017 to make it as clear as possible. “The main sources of saturated fat to be decreased” include butter.

This is the second time I’ve address the obfuscation surrounding saturated fat, part of an industry-wide scheme. Check out The Saturated Fat Studies: Set Up to Fail and The Saturated Fat Studies: Buttering Up the Public.

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Is Laetrile (Amygdalin or Vitamin B17) an Effective Alternative Cure for Cancer? Tue, 11 Apr 2023 12:00:01 +0000 The Mayo Clinic puts laetrile to the test to see if it is an effective cancer treatment.

My video Does Laetrile (Amygdalin or Vitamin B17) Work as an Alternative Cancer Cure? looks at amygdalin and whether it is “quackery or cure.”

A cyanide-containing compound found in apple seeds, amygdalin is ten times more concentrated in the seeds of peaches, apricots, and bitter almonds. It can be sold as a derivative called laetrile, which has been advertised with the misnomer “vitamin B17.” “Amygdalin gained high popularity among cancer patients in the 1970s” as an alternative treatment, but the reason researchers published a review of amygdalin in 2016 and why I’m doing videos about it is that it has “experienced a renaissance,” thanks to the internet.

Back in the 1970s, the FDA could only send out its Bulletin to a million doctors and other health professionals, warning them that laetrile is not only worthless, but dangerous. About ten thousand copies of the alert were posted in U.S. post offices, and The New York Times editorialized that we should be able to choose our own placebo. But laetrile was killing people. Finally, as the New England Journal of Medicine reported it, the “Supreme Court stops the nonsense” with Justice Thurgood Marshall writing the unanimous court opinion that terminally ill patients deserve the same FDA protections against unsafe drugs. At last, laetrile was banned on a federal level.

Rational argument failed to dissuade people, though, so the State stepped in, but that had the opposite effect. “Cancer victims and their families almost universally respond[ed] by accusing organized government and organized medicine of conspiracy.” At an FDA meeting, for example, a physician from M.D. Anderson Cancer Hospital rhetorically asked: “‘You surely cannot believe that the quarter of a million of American physicians are sitting on a cancer cure just so they can get rich?’ He was answered with a chorus of yeses from the audience, many of whom had been borne to the hearings on chartered buses.” Some laetrile advocates were getting rich, though, like the head of the “Committee for Freedom of Choice in Cancer Therapy.” More like committed to the freedom of pocketing millions a year in laetrile sales.

“Laetrile’s proponents consider it to be a ‘natural cancer cure’; whereas opponents consider it ‘the slickest, most sophisticated, and certainly the most remunerative [lucrative and profitable] cancer quack promotion in medical history.’” Which is it? You don’t know until you put it to the test.

“The National Cancer Institute, in response to widespread public interest, undertook a retrospective analysis of Laetrile treatment.” In other words, it sent out a letter to every physician in the country and tens of thousands of other health professionals, and contacted all of the pro-laetrile groups, basically saying, send us the best you got. Although at least 70,000 Americans are estimated to have used laetrile, only 93 cases were submitted for evaluation, and, of those, only six appeared to be legitimate, where taking laetrile was associated with at least some partial improvement.

Now, of course, the people sending in those reports may have gotten things wrong or falsified data, but, maybe those six actually did respond to the treatment. If that’s out of 70,000 treated, though, you’d think maybe that’d just be by chance. Regardless, the fact that so many people tried it should count for something. They may have all just been boondoggled, but maybe there’s something to it. Certainly, the fact that it didn’t seem to help with any of the laboratory animal cancers doesn’t mean it couldn’t work in people. The only way to know for sure is to put it to the test: “a tightly controlled clinical trial performed in competent and experienced hands.” The Mayo Clinic accepted the challenge.

One hundred seventy-eight cancer patients were treated with it and all of the patients died rapidly. “No substantive benefit was observed in terms of cure, improvement, or stabilization of cancer, improvement of symptoms related to cancer, or extension of life span.” There were only adverse effects of cyanide toxicity.

The conclusion? “Amygdalin (Laetrile) is a toxic drug that is not effective as a cancer treatment.”

The books have been closed on this for more than 30 years. “Laetrile doesn’t work.” It is unsafe and ineffective. Researchers “found no sound evidence that laetrile is effective as an anticancer agent.” So, the label “unproven” cancer remedy may be too generous at this point; “it is time to vehemently assert that laetrile cancer therapy has been ‘disproven.’”

What about eating apricot seeds directly? In case you missed my previous video, check out Do Apricot Seeds Work as an Alternative Cancer Cure?.

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Are Apricot Seeds an Alternative Cancer Cure? Thu, 06 Apr 2023 12:00:20 +0000 If you choose alternative cancer treatments, do you live longer?

In addition to conventional therapies, “does the use of alternative medicine predict survival from cancer?” Even if the alternative therapies themselves were useless, one might predict users would live longer because they tend to have more hope and a greater “will to live,” and are nearly three times as likely to believe their cancer is curable even if it isn’t. But, researchers found that death rates were actually higher in alternative medicine users. When they followed up with them years later, they found that 79 percent of the alternative medicine users had died, compared to 65 percent of non-users. If the alternative medicine users started out sicker, though, that could certainly explain why. And, in fact, they did tend to be sicker, but the difference didn’t reach statistical significance. The bottom line is that the association between the use of alternative medicine and shortened survival is not necessarily cause and effect, but it’s possible some of the alternative modalities may have indeed been harmful, as I discuss in my video Do Apricot Seeds Work as an Alternative Cancer Cure?.

Thanks to the internet, there has been a resurgence of older complementary and alternative cancer treatments, such as laetrile, which is a compound derived from amygdalin, a natural cyanide-containing substance concentrated in apricot kernels, the seeds inside the pits. To skirt regulations, it was branded as “vitamin” B17, but it’s not a vitamin at all. What’s more, the “lack of laetrile’s effectiveness [against cancer] and the risk of side effects from cyanide poisoning led the Food and Drug Agency (FDA) in the US and the European Commission to ban its use” decades ago. However, you can still buy it on the internet, just as you can still purchase the apricot kernels themselves. Is there any harm in just giving them a try? Yes, because of cyanide intoxication.

In a typical case report, a woman ate some apricot seeds. She had gotten them from a health food store, so they had to be healthy, right? Twenty minutes later, she had trouble breathing and slipped into a coma. Some calculations were made, and it appears an eight-ounce bag of apricot kernels is enough to kill six people if consumed in one sitting. Therefore, “the continuing sale of apricot kernels as health food is troubling.”

In another case, a person had been consuming a quarter-teaspoon of ground apricot kernels daily and had just switched brands the day before she ended up in the ICU. Thankfully, she survived, but others are not so lucky. For instance, a 17-year-old was dead within a day from severe cyanide poisoning, which can result in coma, convulsions, and cardiovascular collapse. That’s why calling laetrile a vitamin is so insidious. In yet another example, a 32-year-old woman arrived at the emergency room in a coma. Was she on anything? No, she had just taken some “vitamin supplements.” Thankfully, a relative showed up to the ER with them: so-called vitamin B17. The patient was given a cyanide antidote and survived. But, had that relative not brought the B17 or not shown up at all, the case “could have proved fatal.”

So, “cancer patients should be informed about the high risk of developing serious adverse effects due to cyanide poisoning after laetrile or amygdalin,” the natural compound in apricot seeds. Especially at risk may be those taking mega-doses of vitamin C or those not getting enough vitamin B12. The body has two major ways to detoxify cyanide. It can attach it to vitamin B12 to form the supplement form cyanocobalamin, which can be harmlessly eliminated when we pee, or it can use the amino acid cysteine, which is also used to metabolize vitamin C. So, if you take too much vitamin C, your levels can drop and you can end up more vulnerable to cyanide toxicity.

Conventional cancer treatments, such as chemotherapy, can be toxic, too. It’s all about benefits versus risks. Yes, amygdalin can block the growth of certain cancer cells in a petri dish, although it doesn’t appear to have any anti-cancer effects against tumors in laboratory animal. But you don’t know what happens in people until you put it to the test and do a clinical trial of amygdalin in the treatment of human cancer. For those results, see my video Does Amygdalin or Vitamin B17 Work as an Alternative Cancer Cure?.

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Can Oxidized Cholesterol 27HC Explain Three Breast Cancer Mysteries? Tue, 04 Apr 2023 12:00:13 +0000 Oxidized cholesterol, which is concentrated in products containing eggs, processed meat, and parmesan cheese, has cancer-fueling estrogenic effects on human breast cancer.

In 1908, the presence of cholesterol crystals was noted “in the proliferating areas of cancers,” suggesting that cholesterol “may, in some way or other, be associated with the regulation of proliferation.” A century later, we now recognize that the “accumulation of cholesterol is a general feature of cancer tissue, and recent evidence suggests that cholesterol plays critical roles in the progression of cancers, including breast, prostate, and colorectal cancers.” I discuss this in my video Oxidized Cholesterol 27HC May Explain Three Breast Cancer Mysteries.

Might this explain why egg consumption is associated with increased risk of breast cancer? Indeed, a systematic review and meta-analysis of the evidence “suggest that dietary cholesterol intake increases risk of breast cancer,” and the more cholesterol you eat, the higher the risk appears to rise, as you can see in the graph below and at 0:52 in my video. Why is that?

One thought is the “prolonged ingestion of a cholesterol-enriched diet induces chronic, auto-inflammatory responses resulting in significant health problems including colorectal cancer,” and we know that “chronic nonresolving inflammation leads to the initiation, promotion, and progression of tumor development.” As you can see in the graph below and at 1:12 in my video, sprinkling some cholesterol on white blood cells in a test tube can trigger the release of inflammatory compounds, and LDL cholesterol can induce breast cancer proliferation and invasion, but that’s in vitro. In a petri dish, you can show that breast cancer cells can migrate nearly twice as far within a day in the presence of LDL cholesterol, but what happens in people?

The level of LDL cholesterol in the blood of women diagnosed with breast cancer does appear to be a predictive factor of tumor progression. About two years after surgery, chemotherapy, and radiation, not a single one of the women in the lowest third of LDL cholesterol levels had a cancer recurrence. The same could not be said for women with higher cholesterol. We know cholesterol can cause inflammation in our artery walls. Might it also have an effect on breast cancer initiation and progression? Researchers speculate that high cholesterol levels may have a “cancer-fuelling effect,” and, indeed, women with breast cancer who happen to be taking cholesterol-lowering statin drugs appear to live about 40 percent longer before the cancer comes back. The data aren’t good enough to ensure the drug benefits outweigh their risks, though. Lowering cholesterol with diet may be able to give us the best of both worlds.

Animal studies show that if you feed cholesterol to mice, you can accelerate their cancers, “but extrapolation to humans is difficult as dietary cholesterol has limited effect on blood cholesterol levels in humans.” Thus, dietary cholesterol might just be “indicative of a lifestyle prone to health-related problems, including cancer”—that is, maybe people are just more likely to have an after-meal cigarette if that meal is bacon and eggs compared to oatmeal. It was difficult to imagine how dietary cholesterol alone could promote cancer development, but that changed recently with the discovery that 27-hydroxycholesterol, “27HC, a metabolite of cholesterol, can function as an estrogen and increase the proliferation of estrogen receptor-positive breast cancer cells.”

So, it’s not the cholesterol itself, but what the cholesterol turns into inside our body.Scientists have long struggled to understand why women with heart disease risk factors are more likely to develop breast cancer.” Now, perhaps, we know. “The discovery that the most abundant cholesterol oxidized metabolite in the plasma,” in our bloodstream, can have estrogenic effects may explain the link between high cholesterol and the development and progression of breast cancer and prostate cancer. And, 27-hydroxycholesterol also stimulates the proliferation of prostate cancer cells, boosting growth by about 50 percent, as you can see in the graph below and at 3:58 in my video.

I’ve previously explored the “role for oxysterols in mediating pro-oxidative and pro-inflammatory processes in age-related degenerative diseases such as Alzheimer’s disease and atherosclerosis,” heart disease, but it now looks like oxidized cholesterol can play a role in all three stages of tumor development, as well: initiation, promotion, and then the progression of the cancer, as you can see below and at 4:14 in my video. It doesn’t just promote the growth of breast cancer cells, but also “induces invasion and migration of breast cancer cells,” potentially facilitating breast cancer metastasis through suppressing anti-cancer immunity and then inducing angiogenesis, helping breast tumors hook up their blood supply.

“Several lines of evidence support a pathologic role” for this cholesterol metabolite. We know that when you feed cholesterol to mice, their oxysterol levels go up and their tumors accelerate, but it “also appears to dramatically hasten the spread, or metastasis, of breast tumors to other organs.” But, when researchers “turned to human breast tissue samples, they found that more aggressive tumors had higher levels of an enzyme…which converts cholesterol into 27HC.” In breast cancer patients with estrogen receptor-positive tumors, the 27-hydroxycholesterol content in their breast tissue is increased overall and especially within the tumor itself—so much so that circulating oxysterol levels in the blood may one day be used as a prognostic factor. And “breast cancer patients with low tumor levels of…[the] enzyme that breaks down 27HC…did not live as long as women with the highest levels” who can detoxify it better. “The bottom line…is that some estrogen-driven breast tumors may rely on 27HC to grow when estrogen isn’t available.” And that may explain a second breast cancer mystery.

More than 80 percent of breast cancers start out responding to estrogen, so we use hormone blockers—either aromatase inhibitors to stop the formation of estrogen in the first place or the drug tamoxifen to block its action. Despite the efficacy of these drugs, many patients relapse with resistant tumors, and that’s where oxidized cholesterol can come in. 27HC can fuel breast cancer growth without estrogen, which could explain why these estrogen blockers sometimes don’t work.

And, finally, 27HC may explain why breast cancer patients with higher vitamin D levels appear to live longer. Vitamin D supplementation decreases 27HC levels in the blood.

The best way to reduce our risk of getting breast cancer—and surviving it if we do get the diagnosis—may be to just lower our overall cholesterol. If you lower your cholesterol, you lower your oxidized cholesterol. So, discovering this role of cholesterol is actually really good news, since “cholesterol is a highly amenable risk factor, either by lifestyle, dietary, or pharmacologic interventions.” One of the implications of these findings, according to the principal investigator, is that “lowering cholesterol with dietary changes or statins [drugs] could reduce a women’s breast cancer risk or slow tumor growth.”

Since vitamin D supplementation decreases 27-HC levels in the blood, you may be interested in the best way get Vitamin D. See my videos The Best Way to Get Vitamin D: Sun, Supplements, or Salons? and The Risks and Benefits of Sensible Sun Exposure.

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Dr. Greger’s Top Takeaways on Brain Health, Erythritol, and Gluten-Free Diets Thu, 30 Mar 2023 12:00:38 +0000 Every month, we publish around eight new videos, four Friday Favorites, eight blogs, and four podcasts on We are bursting at the seams with all sorts of health and nutrition info that we don’t want you to miss, so we wanted to wrap up the juiciest bits into a nice, bite-sized blog as an end-of-month recap in case you missed anything or just want a refresher. So, what were some highlights from March?

The Role of Endotoxins in Alzheimer’s and Dementia

Assortment of seafood, meat, and eggsEndotoxins are highly pro-inflammatory components of bacteria like E. coli that can be absorbed through our gut wall and circulate in our bloodstream. Elevated endotoxin levels are associated with a host of health conditions, such as obesity, type 2 diabetes, depression, and heart disease. Researchers have found a higher abundance of endotoxins in the brains of patients with Alzheimer’s disease on autopsy. The highest levels of these components are found in foods like meat, perhaps helping to explain why those eating more plant-based may be as much as three times less likely to develop dementia.


The Impacts of Plant-Based Diets on Breast Cancer and Prostate Cancer

Round bowl of beans, greens, and other whole foods on a white surfaceWe know there appears to be a significant protective effect of a vegetarian diet for heart disease and all cancers combined, particularly for those eating vegan, but what about breast cancer and prostate cancer specifically? Studies have shown that more plant-based eating is associated with a significant reduction in breast cancer risk, and when it comes to prostate cancer, plant-based foods are associated with either decreased or neutral risk and animal foods are associated with either an increased or neutral risk. We shouldn’t only look at foods to avoid, like meat, eggs, and dairy products; we should also look at foods to embrace, such as vegetables, especially greens, and pulses, like beans, lentils, and chickpeas—foods that Dr. Greger includes in his Daily Dozen to encourage people to add to their meals each day.


How Much Erythritol Sweetener Is Too Much?

Wooden spoon with sweetenerErythritol, a sugar alcohol naturally found in small quantities in certain fruits and vegetables, is mass-produced commercially for use as a sweetener. It has a role in actively preventing tooth decay and has been reported to be “totally safe,” with almost no calories. It also has the highest digestive tolerance of all of the sugar alcohols and appears to have anti-oxidant properties and protective effects on the cells that line our arteries. Unfortunately, as I will detail on April 3 in the follow-up Update on Erythritol Sweetener: Are There Side Effects?, a new study published interventional data in mice and in vitro that suggests erythritol may be harmful, and so (*spoiler alert*) I urge everyone to stop consuming it until we know more.

Is Light or Dark Roast Coffee Healthier? and Less Acid Reflux from Low-Acid Coffee?

Coffee is more than just a drink to put some pep in your step. It may influence cholesterol, body weight, your blood sugars, and more, and light and dark roasts have different effects and their own pros and cons, depending on your own health priorities. One example is that dark roasting may destroy up to about 90 percent of chlorogenic acids, the antioxidant and anti-inflammatory phytonutrients thought to account for many of coffee’s benefits, so light roast would be better in this respect.

Don’t be fooled by “low acid” coffee. It doesn’t help with the acid reflux, heartburn, or stomach upset that plagues some coffee drinkers. The low acid is a reference to low chlorogenic acid—which is exactly what we don’t want. Low-acid coffee producers use a slow roasting process that destroys the beneficial compounds. That’s like an orange juice company going out of its way to destroy the vitamin C and then branding its OJ as “low acid.” Technically true, since vitamin C is ascorbic acid, but the OJ maker would be bragging about destroying some of the nutrition, and that’s exactly what low-acid coffee companies are doing.

This month included a bunch of coffee content! In addition to this pair of blogs, we also released a new video about coffee and iron absorption and a Friday Favorites video that asks, Do the Health Benefits of Coffee Apply to Everyone?.


Fight Aging with Brain-Healthy Foods and Can Lutein Supplements Benefit Our Brain Function?

Two major risk factors that impact brain aging are chronic, low-grade inflammation and oxidative and nitrosative stress, so antioxidant and anti-inflammatory foods may be helpful. Researchers investigated eight different dietary antioxidants, including vitamins A and E, and only lutein, the major carotenoid concentrated in the brain, was “significantly related to better cognition.”

Dark green leafy vegetables are lutein superstars: A half cup of kale has 50 times more lutein than an egg, and adding just 60 grams of spinach a day for a month can significantly boost macular pigment for most. Based on lutein/zeaxanthin supplement trials, greens may improve visual processing speed in young healthy people and significantly improve cognitive function in young adults and seniors. The earlier we start loading up, the better. Eat your greens!

Do You Need to Be Gluten-Free?

You’re probably familiar with the buzz around “gluten-free diets,” but is going gluten-free safe and beneficial for everyone? Until recently, the scientific world largely maintained that the wheat protein gluten would provoke negative effects only in people with rare conditions, such as celiac disease. Now, an expert panel recognizes gluten sensitivity, which may affect about 1 percent of the population.

There is no evidence to suggest that following a gluten-free diet has any significant benefit in the general population, however, and indeed  there is some evidence that a gluten-free diet may adversely affect gut health in those without celiac or gluten sensitivity. For the overwhelming majority of those who don’t have issues with gluten, whole grains—including the gluten grains of wheat, barley, and rye—are health-promoting and consumption is linked to the reduced risk of chronic disease. Dr. Greger includes two of these grains in his popular Basic BROL, which you can find on our recipes page.

This has been a wrap-up of just a small sampling of our recent content. To see everything from the past month, be sure to check out the video, blog, and podcast pages.

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Is Dietary Cholesterol in a Relationship with Cancer? Tue, 28 Mar 2023 12:00:18 +0000 What is the relationship between the consumption of eggs and other cholesterol-rich foods and cancers of the colon, breast, endometrium, pancreas, and throat?

In 1969, a correlation analysis was performed by a Dr. Gregor—no relation, and he spelled it wrong—and his colleagues. They found a rather tight correlation between animal protein intake and intestinal cancer mortality. You can see a graph of these results at 0:15 in my video Friday Favorites: Dietary Cholesterol and Cancer. In the 1970s, this relationship was extended to include breast cancer, too, and animal fat was implicated as well. Animal protein and dietary cholesterol kind of travel together in the same foods. So, it isn’t surprising that “there is significant correlation between high consumption of cholesterol-containing food items and the world-wide distribution of colon cancer.” A “large and highly significant” correlation exists, even after controlling for other dietary factors, such as animal fat and fiber, “supporting the possibility of a causal relationship between cholesterol intake and colon cancer.”

So, is dietary cholesterol co-carcinogenic for human colon cancer? Researchers decided to try to find out by feeding some to rats. In one study, researchers injected rats with a carcinogen, and the cholesterol-eating rats got tumors in half the time and they all died, whereas most of the rats in the cholesterol-free group survived. But “the relevance of animal data to the human situation is debatable.” How would the cholesterol and cancer link even work?

As humans, we don’t need to consume any cholesterol, since our body makes all that it needs. When we do consume extra cholesterol, there’s a limit to the amount our body can absorb. So, “where does the excess go?” Down to our colon. In this way, the cells lining our colon, where colon cancer arises, “are therefore constantly exposed to fecal cholesterol.” Should a cancerous or precancerous polyp arise, might all of that extra cholesterol help it grow faster? Indeed, the amount of cholesterol we eat “could thus be a factor determining the rate of development, growth, or spread of such a tumor.” Back in the 1970s, this was all just speculation, but the researchers realized that if it were true, that would be good news, since a low-cholesterol diet, cutting down on meat, dairy, eggs, and junk—the only foods that really have cholesterol—would be a “feasible, inexpensive, and without risk” way to help prevent and treat colon cancer. So, what’s the 40-year update?

Country-by-country correlation can never do more than just inspire studies like this: “the largest nationwide population-based case-control study [to date] to assess the association between cholesterol intake and several types of cancer.” The researchers found that “dietary cholesterol intake was positively associated with risk of cancers of the stomach, colon, rectum, pancreas, lung, breast (mainly postmenopausal), kidney, bladder and NHL,” non-Hodgkin’s lymphoma, or bone marrow. The flipside? “A diet low in cholesterol may play a role in the prevention of several cancers.” This means cutting down on meat, dairy, and eggs, the very foods that may increase risk of cancer.

“Thus, the findings of this study should essentially be viewed as an indication that a diet rich in meat, dairy products, eggs (and hence animal fat) is an unfavorable indicator of the risk of several common cancers…” Two cancers the study didn’t investigate, though, were endometrial cancer and throat cancer. When all of the studies on cholesterol consumption and the risk of endometrial cancer (cancer of the lining of the uterus) were put together, researchers found a dose-response, meaning more cholesterol consumption was associated with more cancer: 6 percent for every extra 100 mg of cholesterol each day. So, something like a daily omelet might increase endometrial cancer risk by about 20 percent. This may be because the extra cholesterol is converted into estrogen, or it may just be because the increased oxidative stress is reflected in higher levels of oxidized cholesterol. I talk about this in my video Oxidized Cholesterol as a Cause of Alzheimer’s Disease.

There also appears to be a dose-response relationship with pancreatic cancer, “one of the most dismal malignancies.” A compilation of studies found the risk of pancreatic cancer increased by 8 percent for every 100 mg of cholesterol, so that would be about a 30 percent higher risk for a daily omelet.

And throat cancer? Increased risk was observed by researchers for elevated cholesterol intake—about 85 percent higher odds, which is consistent with other studies. Yes, maybe it’s the oxidation, or maybe it’s the inflammation. We can’t, however, be sure the cholesterol itself is to blame. “Elevated cholesterol intake could be an indicator that a diet rich in meat, eggs, and dairy products may have unfavorable effects.”

The optimal intake of cholesterol? Zero. See Trans Fat, Saturated Fat, and Cholesterol: Tolerable Upper Intake of Zero.

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Lipstick Contaminated with Lead? Thu, 23 Mar 2023 12:00:07 +0000 Dozens of lipsticks and lip glosses are put to the test.

“Over the past years, using cosmetic products has increased worldwide at an alarming rate due to unending pursuit for individual beautification…” There’s nothing necessarily wrong with that unless cosmetic products contain ingredients that may be linked to disease—ingredients such as toxic heavy metals like lead.

As you can see at 0:28 in my video Flashback Friday: Is Lipstick Safe Given the Lead Contamination?, lead has been found in a wide range of cosmetic products, from eye shadow to skin cream, and foundation to blush. You may recall that I talked about lead in henna in my video Is Henna Safe?, but in looking at the data, “important warnings can be recognized”: the presence of lead in lipsticks. This is concerning because lipstick wearers may actually swallow a little bit of it. In fact, it has “been estimated that a woman inadvertently ingests 1.8 kg [about 4 lbs] of lipstick during her lifetime.” “Moreover, lipsticks can be used by pregnant women or women of child bearing age.” (I mean, obviously.) Yes, lead is highly toxic, but how much lead can there be in lipstick? Surely, it is “a very minor source….Nonetheless, one should not exclude the fact that lead accumulates in the body due to over time and repetitive lead-containing lipstick or hair dye application, which lead to significant exposure levels.” You don’t really know, though, until you put it to the test.

Thirty-two lipsticks and lip glosses were tested, and lead was detected in 75 percent of the products, which “suggests potential public health concerns.” But how much lead did the researchers actually find? About half of the samples exceeded the FDA-recommended maximum level set for candy.

That limit is set for something kids may eat every day, though. Kids are not going to eat tubes of lipstick each day. “Nevertheless, it is generally accepted that there is no safe level of Pb

intake,” and, ideally, we should get contaminant levels down to zero. As a consumer group pointed out, a quarter of the lipsticks were lead-free, so we know it can be done. Maybe we should better regulate toxic metals in cosmetics to protect women’s health in the United States, as has already been done in Europe. Fair enough, but it wasn’t well-received.

The billion-dollar lipstick industry wasn’t happy. In an article that tried to downplay the risks, the scientists-for-hire firm that once played villain in the real-life Erin Brockovich case concluded that, even though lipstick may contain lead, the concentrations are so low that they “are not expected to pose any health risks to adults or children.” Children’s blood lead levels are influenced more by background lead exposures, such as lead in the air, dust, water, and food, than by lipstick exposures, but just because our environment is so contaminated doesn’t mean we need to add to the problem. In fact, because there’s so much lead around anyway, maybe there’s that much more reason to cut down on additional exposures. But in that article, the scientists-for-hire calculated that an adult would need to apply lipstick more than 30 times a day to raise their blood lead level to even the most stringent limits and 695 times a day to get blood levels up to more concerning levels.

However, as you can see at 3:13 in my video, this was based on an assumption that lipstick would only have about one part per million lead or, at the extreme end, maybe two or three parts per million (ppm). But by 2016, about ten times more lipsticks were tested, and they averaged nearly 500 ppm—with 10 percent exceeding 1,000 ppm—going all the way up to 10,000 ppm, with more than one out of five exceeding FDA and even Chinese safety limits on lead in cosmetics.

As you can see in the graphs below and at 3:42 in my video, lip gloss was worse than lipstick; orange and pink colors had more lead than brown, red, or purple; and all of the really contaminated cosmetics were the cheaper ones, sold for less than five dollars each.

Hold on. The highest concentration found was 10,185 mg/kg. That’s 10 grams per kilogram, which means the lipstick was 1 percent pure lead. That means a single application could expose a grown woman to perhaps 12 times the tolerable daily intake.

And if a woman is interested in having children, that poses a “particular concern,” as lead accumulates in our bones and “may be released into the bloodstream during pregnancy,” where it can slip through the placenta or into breast milk.

The good news is that the FDA is considering lowering the maximum allowable lead levels in lipstick from 20 ppm to 10 ppm, something Canada arrived at a decade ago. But without enforcement, it doesn’t matter. As you can see in the graph below and at 4:39 in my video, moving the legal limit from 20 ppm down to 10 ppm would just mean that instead of 23 percent of lip products exceeding legal levels, 27 percent would be exceeding legal levels. Right now, the limit’s 20 ppm, but what does it matter if there still may be products on store shelves that violate the legal limits?

Is Henna Safe? is the video I mentioned.

I think the only other cosmetic safety videos I have are Flashback Friday: Which Intestines for Food and Cosmetics? and Avoiding Adult Exposure to Phthalates.

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Fiber: An Effective Anti-Inflammatory? Tue, 21 Mar 2023 12:00:53 +0000 Most Americans get less than half the recommended minimum daily fiber intake, which is problematic as the benefits of fiber go way beyond bowel regularity.

“Hippocrates, the father of western medicine, believed that all disease begins in the gut.” Of course, he also thought women were hysterical because of their “wandering uterus.” So much for ancient medical wisdom.

Even though a condition like constipation can have a “major impact…on physical, mental and social well-being,” it’s “often overlooked in health care.” This may be because poop-talk is “taboo,” but constipation can have “a severe influence on…everyday living,” both psychologically and physically. Constipation can literally hurt, causing “abdominal discomfort and pain, straining, hard stool, infrequent bowel movements, bloating and nausea.”

No wonder “laxatives are among the most commonly used drugs…Most are quite safe when used judiciously, intermittently,” but because people use them so frequently, laxatives end up being one of the most common causes of adverse drug reactions. Perhaps treatment should instead address the underlying problem that causes constipation, such as lack of dietary fiber. You probably don’t need a meta-analysis to demonstrate that “dietary fiber can obviously increase stool frequency in patients with constipation.” I discuss this in my video Friday Favorites: Is Fiber an Effective Anti-Inflammatory?.

“Populations in most Western countries must be considered on world standards to be almost universally constipated.” In the Western world, constipation is an epidemic among the elderly, but among those centering their diets around fiber-rich foods, it’s simply not a problem.

Where is fiber found? As you can see at 1:37 in my video, a patient summary in the Journal of the American Medical Association sums it up with an illustration of whole, unrefined plant foods. For those of us who may be smug about our hearty intake of fruits and vegetables, we need to realize that “fruits and leafy vegetables are the poorest source of plant fiber.” Why? Because they’re 90 percent water. Root vegetables have more fiber, but the real superstars include legumes, such as beans, split peas, chickpeas, and lentils, and we can’t forget whole grains. What about fruits? Gram for gram, fiber from fruits does not seem to have the same effect. It may take 25 grams of fruit fiber to double stool output, something just 10 grams of whole-grain fiber or vegetable fiber can do, as you can see in the graph below and at 2:08 in my video.

And that’s not all fiber can do. If you eat some whole-grain barley for supper, your good gut bacteria are having it for breakfast the next morning. This releases butyrate into our bloodstream, a compound that seems to “exert broad anti-inflammatory activities.” This could help explain why researchers found that “significant decreases in the prevalence of inflammation were associated with increasing dietary fiber intakes for all group.” As you can see at 2:44 in my video, the group with the highest fiber intake in the study had decreased inflammation—and that was with getting just the minimum recommended daily intake of fiber. So, if you have knee pain, for instance, should you eat more fiber-rich foods?

“Dietary Fiber Intake in Relation to Knee Pain Trajectory” is a study that followed thousands of patients. Researchers found that a high intake of dietary fiber, which is to say just the minimum recommended intake, was “associated with a lower risk of developing moderate or severe knee pain over time.” What’s more, two Framingham studies found that higher fiber intake was related to a lower risk of having symptomatic osteoarthritis in the first place.

Don’t a variety of diseases have an inflammatory component, though? How about “fiber consumption and all-cause, cardiovascular, and cancer mortalities”? Researchers found that, compared with those who consumed the least amount of fiber, those who consumed the most had 23 percent less cardiovascular disease mortality, a 17 percent lower risk of dying from cancer, and 23 percent lower mortality from all causes put together. “Unfortunately, most persons in the United States consume less than half of the recommended intake of dietary fiber daily.”

Researchers suggest all sorts of potential mechanisms for which fiber could be life-saving, such as improving cholesterol, immune function, and blood sugar control, but it may also have more of a direct cause. If you ask people to bear down as if they’re straining on stool, they can experience a rapid increase in intracranial pressure—that is, pressure inside your skull. And, if you look at trigger factors for the rupture of intracranial aneurysms and ask hundreds of people who had strokes or bleeds within their brains, one of the biggest trigger factors noted was “straining for defecation,” multiplying your risk by seven-fold.

This is one of the reasons legumes and whole grains are emphasized in my Daily Dozen checklist, which compiles all of the healthiest of healthy foods to ideally fit into your daily routine. It’s available (for free, of course!) as an app (Dr. Greger’s Daily Dozen) on [iPhone] and [Android], and you can learn all about it in my video Dr. Greger’s Daily Dozen Checklist.

If you buy processed grain products, how do you know they contain enough fiber? Check out The Five-to-One Fiber Rule.

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Can Lutein Supplements Benefit Our Brain Function? Thu, 16 Mar 2023 12:00:55 +0000 Avocados, greens, and lutein and zeaxanthin supplements are put to the test for improving cognitive function.

Dark green leafy vegetables are packed with a brain antioxidant called lutein, so increasing our greens intake “could be an important public health strategy for reducing the risk of visual or cognitive impairment.” Lutein is the dominant dietary pigment in the retina of the eye, as well as the brain. So, “it is not surprising that macular pigment density”—the concentration of lutein in the center of the eye called the macula—“was found to be significantly correlated with their levels in matched brain tissue.” This may explain the link between cognitive function and how much of these nutrients from greens you can see in the back of the eye. It’s assumed the neuroprotection is thanks to lutein being such a powerful antioxidant, but it has anti-inflammatory properties, too.

“This relationship between lutein and zeaxanthin [another greens nutrient] and visual and cognitive health throughout the lifespan is compelling.” That statement, however, was based on observational studies, where you observe that higher lutein levels and brain function seem to go together.

You don’t know if it’s actually cause and effect, though, until you put it to the test. As I discuss in my video Friday Favorites: Do Lutein Supplements Help with Brain Function?, “Could L [lutein] and Z [zeaxanthin] be supplemented as part of a lifestyle intervention to both improve central neural [brain] function and reduce the probability of progression through the various stages of dementia?” There’s a reason everyone is so excited about the possibility. Hopeful data from eye health studies have convinced many ophthalmologists to start recommending people to increase their intakes of lutein and zeaxanthin to prevent and treat macular degeneration, a leading cause of age-related vision loss. You don’t have to take pills, though. Adding as little as 60 grams of spinach a day for a month can significantly boost macular pigment in most individuals. That’s only about one-fifth of a ten-ounce package of frozen spinach.

Greens aren’t good for just treating diseased eyes. A randomized, placebo-controlled study found that the goodies in greens can improve visual processing speed in young healthy people—like when you’re trying to hit a fastball and your body has to begin reacting even before you consciously register that the ball is coming towards you. There are also real-world benefits outside of the Major League, though, such as improving visual performance during driving.

What about cognition? A randomized, double-blind, placebo-controlled trial gave adults with an average age of 73 the equivalent of either a daily half cup of cooked kale or a full cup of cooked spinach, and found significant improvements in cognitive function compared to those randomized to the placebo.

It may even work in young adults averaging around age 21. In one study, daily supplementation with that same amount of lutein and zeaxanthin not only increased their macular pigment, but it resulted in significant improvements in brain function, including spatial memory, reasoning ability, and complex attention.

Have researchers ever tried putting whole foods to the test? It’s hard to get Americans to eat greens every day, but not so hard to get them to eat green guacamole. A six-month, randomized, controlled trial tested the effects of the intake of avocado on cognition. What was the control? Study participants either ate a daily avocado, potato, or cup of chickpeas, and those in the avocado group had a significant improvement in cognitive function. But, to the Hass Avocado Board’s chagrin, so did the subjects in the potato and chickpea groups. That’s the problem with having healthy placebos! Maybe they should have used iceberg lettuce as the control.

What about the impact on cognition of those who really need it, like Alzheimer’s disease patients? Researchers found that their vision got better, so that’s good, but their cognitive function didn’t change significantly. Now, it’s possible that eating whole foods, like dark leafy greens, might have worked better than just the pigments in pill form.

Yes, “oxidation and inflammation appear to be key to both diseases [Alzheimer’s and macular degeneration], and neither seems particularly amenable to late-stage treatments.” That’s why prevention is critical. Reducing oxidation and inflammation in the earliest stages may be our most promising approach.

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Fight Aging with Brain-Healthy Foods Tue, 14 Mar 2023 12:00:49 +0000 What is the best source of lutein, the primary carotenoid antioxidant in the brain?

“An extensive [scientific] literature describes the positive impact of dietary phytochemicals [plant compounds] on overall health and longevity…However, it is now becoming clear that the consumption of diets rich in phytochemicals can influence neuro-inflammation”—that is, brain inflammation—“and mediate the activation of signaling pathways, leading to the expression of cytoprotective [cell protective] and restorative proteins.” As I discuss in my video Friday Favorites: Brain-Healthy Foods to Fight Aging, just “over the last decade, remarkable progress has been made to realize that oxidative and nitrosative stress (O&NS) and chronic, low-grade inflammation are major risk factors underlying brain aging,” so it’s no wonder that antioxidant and anti-inflammatory foods may help.

“The brain is especially vulnerable to free radical attack,” oxidative stress, due to its high fat content and cauldron of high metabolic activity. You don’t want your brains to go rancid. You’d think that one of the major fat-soluble dietary antioxidants would step in, like beta-carotene, but the major carotenoid concentrated in the brain is actually lutein. Our brain just preferentially sucks it up.

For example, look at the “oldest old,” like in the Georgia centenarian study. Recognizing that “oxidative stress is involved in age-related cognitive decline,” researchers figured that “dietary antioxidants…may play a role in the prevention or delay in cognitive decline,” so they looked at eight different ones: vitamin A, vitamin E, and on down the list. Only lutein was “significantly related to better cognition.” Now, in this study, researchers looked at brain tissue on autopsy, but by then, it’s a little too late. How could you study the effects of diet on the brain while you’re still alive? If only there were a way we could physically look into the living brain with our own two eyes. There is. With our own two eyes.

The retina, the back of our eyeball, is actually an extension of our central nervous system, an outpouching of the brain during development. And, as you can see at 2:02 in my video, there’s a spot right in the middle. That is what the doctor sees when looking into your eye with that bright light. That spot, called the macula, is our HD camera, where we get the highest resolution vision, and it’s packed with lutein.

And, levels in the retina correspond to levels in the rest of our brain so our eyes can be a window into our brain. So, now we can finally do studies on living people to see if diet can affect lutein levels in the eyes, which reflects lutein levels in the brain, and find out if that correlates with improvements in cognitive function. And, indeed, significant correlations do exist between cognitive test scores and the amount of macular pigment, these plant pigments like lutein in your eye. You can demonstrate this on functional MRI scans, suggesting lutein and a related plant pigment called zeaxanthin “promote cognitive functioning in old age by enhancing neural efficiency”—that is, the efficiency by which our nerves communicate. Researchers conducted a fascinating study on white matter integrity using diffusion tensor imaging, which “provides unique insights into brain network connectivity,” allowing you to follow the nerve tracts throughout the brain. As you can see at 3:14 in my video, researchers were also able to show enhanced circuit integrity based on how much lutein and zeaxanthin they could see in people’s eyes; this is “further evidence of a meaningful relationship between diet and neural integrity” of our brains, “particularly in regions vulnerable to age-related decline.”

So, do Alzheimer’s patients have less of this macular pigment? One study found significantly less lutein in their eyes, significantly less lutein in their blood, and a higher occurrence of macular degeneration, where this pigment layer gets destroyed. As you can see at 3:45 in my video, the thickness of this plant pigment layer in our eyes can be measured and may be a potential marker for the beginnings of Alzheimer’s. Let’s not wait that long, though. We know macular pigment density is related to cognitive function in older people, but what about during middle age?

“One apparent consequence of aging appears to be loss of some aspects of cognitive control,” which starts out early, in mid-adulthood, but not in everybody. This suggests that “it is possible that behavior, such as one’s diet, could drive some of these differences.” As you can see at 4:16 in my video, a measure of cognitive control showed that, on average, younger adults do better than older adults, but older adults who have high macular pigment, a lot of lutein in the back of their eyes, do significantly better. These results suggest that the “protective role of carotenoids” like lutein within the brain “may be evident during early and middle adulthood, decades prior to the onset of older age” and more apparent cognitive decline later in life.

You can take 20-year-olds and show superior auditory function, or hearing, in those with more macular pigment in their eyes. “The auditory system, like the rest of the central nervous system, is ultimately constructed and maintained by diet and it is therefore, not surprisingly, sensitive to dietary intake throughout life”—all the way back to childhood.

Higher macular pigment is associated with higher academic achievement among schoolchildren. You can look into a kid’s eyes and get some sense of how well they may do in subjects like math and writing. “This finding is important because macular L [lutein] is modifiable and can be manipulated by dietary intake in most of the population.” And where is lutein found? The avocado and egg industries like to boast about how much of these macular pigments they have in their products, but the real superstars are dark green leafy vegetables. A half cup of kale has 50 times more lutein than an egg. So, a spinach salad or a 50-egg omelet? You can see a chart of lutein/zeaxanthin content of some common foods at 5:33 in my video.

When should we start loading up on lutein? It seems the earlier, the better, and pregnant and breastfeeding women especially should definitely be checking off my Daily Dozen greens servings. But, it’s also apparently never too late to start. “While some age-related cognitive decline is to be expected in healthy aging…these effects may be less pronounced” among those eating more leafy greens, but you don’t know for sure until you put it to the test, which I explore in my next video Friday Favorites: Do Lutein Supplements Help with Brain Function?.

What was that about my Daily Dozen? Check out Dr. Greger’s Daily Dozen Checklist.

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Bacteria and Kosher and Organic Chicken Thu, 09 Mar 2023 13:00:25 +0000 How do contamination rates for antibiotic-resistant E. coli and ExPEC bacteria that cause urinary tract infections compare in kosher chicken versus organic chicken?

Millions of Americans come down with bladder infections or urinary tract infections every year, including more than a million children. Most cases stay in the bladder, but when the bacteria creep up into the kidneys or get into the bloodstream, things can get serious. Thankfully, we have antibiotics, but there is now a pandemic of a new multidrug-resistant strain of E. coli. Discovered in 2008, this so-called ST131 strain has gone from being unknown to now being a leading cause of bladder infections the world over and is even resistant to some of our second- and third-line antibiotics. What’s more, it’s been found in retail chicken breasts sampled from across the country, “document[ing] a persisting reservoir of extensively antimicrobial-resistant ExPEC isolates,” or bacteria—that is, the extra-intestinal pathogenic E. coli, including the ST131 strain—“in retail chicken products in the United States, suggesting a potential public health threat.” I discuss this in my video Friday Favorites: What About Kosher and Organic Chicken?.

Urinary tract infections may be foodborne, predominantly from eating poultry, such as chicken or turkey, so maybe we shouldn’t be feeding antibiotics to these animals by the tons in poultry production. Hold on. Foodborne bladder infections? What are you doing with that drumstick? Indeed, eating contaminated chicken can lead to the colonization of the rectum with these bacteria that can then, even months later, crawl up into the bladder to cause an infection.

“The problem of increasing AMR [anti-microbial resistance] is so dire that some experts are predicting that the era of antibiotics may be coming to an end, ushering in a post-antibiotic era…in which common infections and minor injuries can kill” once again. More than 80 percent of E. coli isolated from beef, pork, and poultry exhibited resistance to at least one antibiotic, and more than half isolated from poultry were resistant to five different drugs. One of the ways this happens is that viruses, called bacteriophages, can transfer antibiotic-resistant genes between bacteria. About a quarter of these viruses isolated from chicken were found to be able to transduce antibiotic drug resistance into E. coli. And one of the big problems with this is that “disinfectants used to kill bacteria are, in many cases, not able to eliminate bacteriophages,” these viruses. Some of these viruses are even resistant to bleach at the kinds of concentrations used in the food industry; likewise, alcohol, which is found in many hand sanitizers, is also unable to harm most of them.

The irony is that the industry has tried to intentionally feed these viruses to chickens. Why would it do that? They can boost egg production in hens and increase bodyweight gain in broiler (meat-type) chickens to get them to slaughter weight faster. The only thing that seems to dissuade the industry is any practice that affects the taste of the meat. That’s why the industry stopped spraying chickens with benzene to try to kill off all of the parasites. The meat ended up with a “distasteful flavor,” described as “strong, acidic, musty, medicinal, biting, objectionable, and good.” Good?!

What about organic chicken? For another type of bacteria, Enterococcus, antibiotic-resistant bugs were found in both conventional and organically raised chicken but were less common in organic. A study found that only about one in three organic chickens were contaminated with drug-resistant bugs compared to nearly one in two conventionally raised birds. But in a study of hundreds of prepackaged retail chicken breasts tested from 99 grocery stores, carrying the organic or antibiotic-free label did not seem to impact the contamination levels of antibiotic-resistant E. coli from fresh retail chicken. Purchasing meat from natural food stores appeared to be safer, however, regardless of how it was labeled.

Kosher chicken tested to be the worst, with nearly twice the level of antibiotic-resistant E. coli contamination compared to conventional chicken, which goes against the whole concept of kosher. As you can see in the graph below and at 4:17 in my video, there was no difference in drug resistance between the E. coli swabbed from conventionally raised chickens versus chickens raised organically and without antibiotics, but, either way, kosher chicken tested worse. But how could organic and raised-without-antibiotics chickens not be better? Well, it could be cross-contamination at the slaughter plants, so bugs just jump from one chicken carcass to the next.

Or it could be the organic chicken loophole. USDA organic standards prohibit the use of antibiotics in poultry starting on day two of the animal’s life. “This is an important loophole” because even antibiotics “considered critical for human health” are routinely injected into one-day-old chicks and eggs, which has been directly associated with antibiotic-resistant foodborne infections.

What’s more, there was no difference in the presence of ExPEC bacteria—the bacteria implicated in urinary tract infections—between organic and conventional chicken. “These findings suggest that retail chicken products in the United States, even if they are labeled ‘organic,’ pose a potential health threat to consumers because they are contaminated with extensively antibiotic-resistant and, presumably, virulent E. coli isolates.” Indeed, even if we were able to get the poultry industry to stop using antibiotics, the contamination of chicken meat with ExPEC bacteria could still remain a threat.

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Less Acid Reflux from Low-Acid Coffee? Tue, 07 Mar 2023 13:00:47 +0000 What is low-acid coffee? Does it help those who suffer from acid reflux, heartburn, and indigestion?

“Dark roast coffee is more effective than light roast coffee in reducing body weight,” but what is the effect of different roasts on heartburn and stomach upset? I discuss this in my video Does Low-Acid Coffee Cause Less Acid Reflux?.

We know that “coffee consumption sometimes is associated with symptoms of stomach discomfort,” so researchers put pH probes into people’s stomachs to measure the amount of stomach acid generated by different types of coffee. A gastrogram is a way to chart acid secretion in the stomach, as you can see at 0:30 in my video. You give people some baking soda so their stomach starts out alkaline, then measure the pH in the stomach to see how long it takes the body to restore the stomach to an acid bath—about 15 to 20 minutes. If you mix that same amount of baking soda with dark roast coffee, however, it takes longer, which means the dark roast coffee is suppressing stomach acid secretion because it takes longer to normalize the pH. If you give people more of a medium roast coffee, though, there is a dramatically different effect—an acceleration of stomach acid secretion, returning the stomach to acidic conditions three times faster than drinking dark roast coffee. Thus, dark roast coffee is less effective at stimulating stomach acid secretion than medium roast coffee. But you don’t know if that translates into symptoms, or clinical effects, until you put it to the test.

“The most commonly used coffee bean roasting process is referred to as convection or ‘flash’ roasting,” which usually takes less than ten minutes. “An alternative method is conduction roasting….[which] roasts the coffee beans at a lower temperature for a longer time, typically over 3 – 4 h,” and results in so-called low-acid coffee. “Anecdotal evidence from coffee-sensitive individuals has suggesting that this latter roasting method [for low-acid coffee] does not precipitate or aggravate heartburn.” However, when you look up the citation for this finding, the paper just cites data from the Puroast Coffee Co., makers of low-acid coffee. It should therefore come as no surprise that it was the same company that funded the study.

At one point, the Puroast Coffee website claimed, “The health benefits associated with drinking Puroast Low Acid coffee will become almost immediately obvious to those who suffer from acid reflux, heartburn, or indigestion,” with more than 90 percent of customers surveyed receiving symptom relief. So, the company decided to put its money where its mouth was. Before I get to the results, though, it’s important to realize that when they say “low acid,” they aren’t talking about stomach acid, but about roasting coffee beans so long that they destroy more of the chlorogenic acid within them. That’s the antioxidant, polyphenol, phytonutrient chlorogenic acid—that is, the “anti-diabetic, anti-carcinogenic, anti-inflammatory and anti-obesity” antioxidant.

That’s like an orange juice company going out of its way to destroy the vitamin C in its orange juice and then branding the juice as “low acid.” Vitamin C is ascorbic acid, so it would technically be true, but it would be bragging about destroying some of the nutrition, and that’s exactly what low-acid coffee makers are doing. But, if low-acid coffee causes less stomach discomfort, might it be worth it?

In the Puroast Coffee-funded study, 30 coffee-sensitive individuals completed a “randomized, double-blind, crossover study in which the symptoms of heartburn, regurgitation and dyspepsia [stomach upset] were assessed following coffee consumption” of Puroast brand low-acid coffee versus regular, conventionally roasted Starbucks coffee. To the study funder’s chagrin, no benefit whatsoever was found with the low-acid coffee, as you can see at 3:39 in my video. “Consumption of both coffees resulted in heartburn, regurgitation, and dyspepsia in most individuals.” So much for that ridiculous 90-percent-of-customers claim. “No significant differences in the frequency or severity of heartburn, regurgitation, or dyspepsia were demonstrated between the two coffees either in the fasting state or after the test meal.” The researchers couldn’t find any way to make the low-acid coffee look better.

They initially thought that a difference in coffee acidity might explain the company’s claims; however, when put to the test in a randomized controlled study, they found no difference in symptoms, suggesting that coffee acidity does not explain the sensitivity some people have. This, I think, further acts as a reminder that we should never believe claims made by anyone trying to sell us something.

Isn’t that amazing!? I love that Puroast’s own study did it in, but good for the company for allowing it to be published and not just quietly buried. Though, maybe it tried to make it disappear but the researchers held strong. Either way, this is how science is supposed to work, and I’m excited to bring it to you.

If you missed the previous video where I talked about that weight-loss finding, check out Which Coffee Is Healthier: Light vs. Dark Roast.

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Is Light or Dark Roast Coffee Healthier? Thu, 02 Mar 2023 13:00:00 +0000 When it comes to reducing body weight, dark roast coffee is more effective than light roast coffee. If you drink non-paper-filtered coffee, such as boiled, French press, or Turkish coffee, you should know that the amount of cholesterol-raising compounds in the lightest roast coffee beans may be twice as high as in very dark roast coffee beans, as you can see at 0:07 in my video Which Coffee Is Healthier: Light vs. Dark Roast. It appears some of the cholesterol-raising compounds are destroyed by roasting, so, in this case, darker is better. (Alternatively, as I described in Does Coffee Affect Cholesterol?, you can use a paper filter and eliminate 95 percent of the cholesterol-raising activity of coffee regardless of the roast.)

You may be familiar with another video of mine—Friday Favorite: Does Adding Milk Block the Benefits of Coffee?, which showed that dark roasting may also destroy up to nearly 90 percent of the chlorogenic acids, the antioxidant, anti-inflammatory phytonutrients purported to account for many of coffee’s benefits. In that case, light roast would be better, as you can see at 0:39 in my video. However, dark roasting can wipe out up to 99.8 percent of pesticides in conventionally grown coffee and more than 90 percent of a fungal contaminant called ochratoxin, a potent kidney toxin found “in a wide range of unprocessed and processed food including coffee”—foods that can get moldy.

What about the polycyclic aromatic hydrocarbon (PAH) products of combustion that are suspected to be carcinogenic and DNA damaging? As you can see in the graph below and at 1:16 in my video, darker roasts may have up to four times more than light roasts. “Thus, roasting conditions should be controlled to avoid the formation of PAHs due to their suspected carcinogenic and mutagenic properties.” To put things in perspective, benzopyrene is considered to be “the most toxic and the most carcinogenic” of these compounds, and even the darkest roast coffee might only max out at a fraction of a nanogram of benzopyrene per cup, whereas a single medium portion of grilled chicken could have over 1,000 times more, as you can also see in the graph below at 1:39 in my video.


Overall, you don’t know if light versus dark roast is better until you put it to the test. A study found that “dark roast coffee is more effective than light roast coffee in reducing body weight” and even said so in the paper’s title. Folks were randomized to a month of drinking two cups a day of light roast coffee or dark roast coffee, roasted from the same batch of green coffee beans. In normal-weight participants, it didn’t seem to matter—there were no significant weight changes either month—but overweight study participants ended up about six pounds lighter drinking dark roast coffee than light roast coffee, as you can see at 2:05 in my video. They lost more than a pound a week just drinking a different type of coffee.

What about light versus dark in relation to blood sugars? We’ve known since 2015 that even a single cup of coffee can affect the blood sugar response. As you can see at 2:33 in my video, after drinking a cup of coffee with more than a dozen sugar cubes in it, which is about a quarter cup of sugar in one cup of coffee, blood sugar spikes higher over two hours compared with the spike from the same amount of sugar in just plain water. “What is not known is whether this statistically significant increase in blood glucose [sugars] is physiologically relevant,” clinically meaningful. After all, coffee consumption does not seem to increase the risk of diabetes, and if you compare drinking light roast coffee with dark roast coffee 30 minutes before “a 75-g oral glucose tolerance test,” that is, drinking about 20 teaspoons of sugar, there didn’t appear to be any difference. Perhaps the take-home message is that regardless of whether the coffee is light or dark, maybe we shouldn’t be adding 20 spoonsful of sugar to it.

Finally, what do we know about the effect of different roasts on heartburn and stomach upset? We find out in my video Does Low Acid Coffee Cause Less Acid Reflux?.

How Much Added Sugar Is Too Much? Check out the video!

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Dr. Greger’s Top Takeaways on Parkinson’s, Fibromyalgia, and Tea Tree Oil Tue, 28 Feb 2023 13:00:05 +0000 Every month, we publish around eight new videos, four Friday Favorites, eight blogs, and four podcasts on We are bursting at the seams with health and nutrition information! Starting now, we are taking all of that information and wrapping up the juiciest bits into a nice, bite-sized blog as an end-of-month recap in case you missed anything or just want a refresher. So, what were the highlights in February?

Treating Parkinson’s Disease with Velvet Beans and Fava Beans

Fava beans in an enameled bowlOur two new videos on Parkinson’s disease released this month addressed the question, If we have known for decades that Parkinson’s is manifested by a dopamine deficiency in the brain, why not eat a dopamine diet? The dopamine in foods can’t actually cross the blood-brain barrier, but its precursor, levodopa (L-dopa), can and is then able to be converted into dopamine. Dr. Greger found interesting data on velvet and fava (or broad) beans, which both contain L-dopa. The information on velvet beans looked promising at first, but there are some hurdles to its use—including its nasty taste.

What about fava beans? They contain less L-dopa than velvet beans, but they are tasty—so you can eat more of them—and can be consumed as a whole food. Substantial clinical improvements were noted in patients after they ate fava beans, similar to that of receiving a standard drug. Overall, the research is ongoing, and, until we know more, Parkinson’s combo drugs like Sinemet should remain the first-line therapy, but adding beans to our diet can only help. Even just one and a half spoonsful’s worth of roasted soybeans (“soynuts”) led to a significant improvement in symptoms as an adjunct treatment.


The Best Diet for Fibromyalgia and Other Chronic Pain Relief

Woman holding upper shoulder as if in painFibromyalgia has long been dismissed as a psychological phenomenon, but it’s now understood to be a disorder of pain regulation and sensitization. If pain is typically caused by inflammation, does an anti-inflammatory diet help reduce the effects of fibromyalgia? A recent study found that on a plant-based diet, perceived pain decreased an average of three points (on a ten-point scale), falling from an average of five or six points down to just two out of ten. The study didn’t have a control group, but there’s no downside to giving healthier eating a try—not only to help with fibromyalgia pain, but for a whole host of other concerns.


Vinegar for Blood Sugar Control and Polycystic Ovary Syndrome (PCOS) Treatment

Gloved hand doing a finger prick on another person’s handVinegar has been shown to help accelerate weight loss, reduce cholesterol, act as a disinfectant, and blunt spikes in blood sugar and insulin after meals. Since insulin resistance has been suggested as one possible cause of polycystic ovaries and we know vinegar can improve insulin resistance, could it also benefit those suffering from PCOS? A tiny study using one tablespoon a day showed improvement for about half of the participants. The jury is still out, but this suggests that vinegar may help, so why not give it a try? Whatever your reason for taking a daily dose of vinegar, remember to never drink it straight, as it can cause second-degree caustic burns down your throat.

It has been suggested that insulin resistance is one of the causes of polycystic ovaries and we know that vinegar can improve insulin resistance, so researchers decided to study the effect of vinegar for PCOS. Seven patients seeking a non-pharmacological treatment for PCOS were given a beverage containing a tablespoon of apple cider vinegar every day for a few months. The insulin resistance did improve in most, but did their cycles return? Yes, in four out of seven. Before the study, they were either having their periods every 50 or so days or not at all, or they were not ovulating, but most resumed within 40 days on the vinegar. Now, this doesn’t prove anything, but it’s at least sufficient to indicate the possibility that it may help. And, what’s the downside? A tablespoon of vinegar would cost less than 10 cents a day. (Another reminder to never drink vinegar straight.)


Dr. Greger in the Kitchen: Groatnola

Dr. Greger holding cooking tray with groatnolaTwo years ago, Dr. Greger made a video about his then-favorite breakfast, the Cran-Chocolate Pomegranate BROL Bowl. He still loves it, but with pomegranate season waning once again, he’s on a new kick: groatnola! What’s that? Whole-food granola made with buckwheat groats, sweet potatoes, and spices. Give it a try, and let us know what you think!


Tea Tree Oil for Cold Sores and Warts?

Tea tree oil has antifungal and antibacterial properties, as shown in videos such as Does Tea Tree Oil Work for Dandruff and Athlete’s Foot? and Do Natural and DIY Tea Tree Oil Cleaning Products Disinfect as Well as Bleach?. Warts and cold sores, on the other hand, are caused by viruses, so does tea tree work on those conditions? Maybe on warts (at least in a singular case report), but not on cold sores.


Vegetarian Athletes

In this three-blog series, starting with What Is the Gladiator Diet and How Do Vegetarian Athletes Stack Up?, Dr. Greger looked at the history of vegetarian athletes and how they stacked up to their omnivorous competition. Top groups of athletes, from ancient Romans and Greeks to modern-day Olympic runners, have been known to eat largely plant-based diets. Overall, most studies have found little difference between vegetarian and omnivore athletes when it comes to cardio or strength fitness. Since extensive research has shown that a plant-based diet has the benefit of greater long-term health outcomes, it seems like a winning choice. 

Healthy Bones

This month’s spotlight is all about bone health. Do people eating plant-based have greater bone loss? Does animal protein intake lead to bone loss? What is the relationship between milk consumption and rates of hip fractures? Check out the podcast for answers to those questions and more. In a nutshell, though, for the strongest bones, eat plenty of phytonutrient-packed plant foods and incorporate weight-bearing exercise.


This has been a wrap-up of just a small sampling of our recent content. To see everything from the past month, be sure to check out the video, blog, and podcast pages.

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Explore African Cuisines with Chef Marie Kacouchia Thu, 23 Feb 2023 13:00:24 +0000

Meet Chef Marie Kacouchia. We had the pleasure of interviewing her about food history, health, culture, and her cookbook, Vegan Africa. Read on and enjoy her recipe for Sautéed Spinach and Mushrooms with Plantains.



In your experience, how have you found food to tell a story and shape culture?

Food is both created by history and creates history. Cuisines are created by history because they mix with invasions and population movements. It shows the movements of people and the introduction of new ingredients, cooking methods, and recipes. Sometimes these cuisines are impoverished–think of the globalization of cuisine and fast foods–but often they come out richer. In my book Vegan Africa, for example, I highlight the Indo-Chinese influence on the cuisine of East Africa and the Lebanese influence on all of West Africa. These result in unique dishes that are consubstantial with the history of these parts of the world.

On a personal level, the way we eat says a lot about who we are, where we come from, and all of the people who came before us.

And, finally, cooking creates history because it brings people together. It creates bridges between people through commonality. In fact, it is often the first introduction we have to another culture.


How do you educate people about the intersection of food, history, health, and culture?

This book is the materialization of my personal journey. As a young adult, I began to question my identity and naturally my relationship with food was at the center of this reflection. I made the work of becoming more intentional about food because it plays such a big part in our lives. I began to ask myself more systematically: Why am I eating what I am eating? How was this food produced? By whom? How can I live fully without inflicting suffering on other beings? And, finally, How can I reclaim my ancestral culinary heritage?

I wanted to share the fruit of my research to shed light on African cuisines and to encourage others to want to know and appreciate them better. I hope to inspire others to see food for what it is: a sacred fuel for our bodies and a central component of our identity.


Please tell us a little bit about your cookbook Vegan Africa. What countries and cultures are highlighted in it?

Africa is a huge continent and the culinary cultures are very diverse. With my book, I humbly wanted to represent the whole continent, from North to South and from East to West. Vegan Africa includes recipes from Ivory Coast, Senegal, Mali, South Africa, Ghana, Kenya, and many other countries! It is, of course, more of an initiation or, as I like to say, an invitation to discover these rich African culinary cultures. During the writing of the book, I had the pleasure of exchanging recipes with many people from different African countries, and they entrusted me with recipes from their countries of origin.

In addition, some of the recipes in my cookbook are my own creations, the result of my travels and my experiments, such as Cassava Tabbouleh with radishes and Herbs and Red Cabbage Salad with Mango and Raw Okra. My book is also full of personal anecdotes, cooking tips, and family cooking secrets.


As a chef, what do you envision as the way forward to encourage people to include more fruits and vegetables into their diets?

Often, fruits and vegetables are seen as boring side dishes. We need to reverse this narrative and really put them back at the center of the plate. I believe this necessarily involves education. We have to make people aware of the need to eat a nutrient-dense diet for good health. I am also convinced that it involves kindness and curiosity. Often, people are resistant to change because they are afraid of changing their routines. That’s why, in my cooking, I make it a point of honor to use ingredients that are accessible everywhere and by nearly everyone. Then I try to show that with a few spices, it is possible to totally transform everyday foods and give them a new dimension. For example, the next time you cook carrots, why not try roasting them instead of boiling them? And have fun with flavors! Try citrus zest, cumin, sumac, cardamom, ginger, or smoked paprika. Open up the field of possibilities.


Please tell us a little bit about your work and career.

By day, I work in the health and wellness sector. I help companies whose mission is to help people take care of themselves to improve their Customer Experience. In addition to this, I run workshops and cooking classes.

I am also occasionally a chef for individuals and companies for very intimate dinners. And on top of that, one thing I never stop doing is developing new recipes that I share on my Instagram account @thespicysoul.

I have a very holistic approach to health, and bringing wellness to others is what motivates everything I do.


Sautéed Spinach and Mushrooms with Plantains

SERVES 4 ✦ PREP TIME: 15 minutes ✦ COOK TIME: 35 minutes

Dishes made with leafy greens are very popular in sub-Saharan Africa, particularly in South and Central Africa. Any leafy green will do—such as taro, cassava, sorrel, or sweet potato leaves—but here I opted for spinach leaves since they’re easy to find in most parts of the world.

2 tablespoons water
1 onion, chopped
4 tomatoes, diced
8 ounces (225 g) button mushrooms, chopped
31⁄3 pounds (1.5 kg) fresh spinach
1 tablespoon curry
1 teaspoon smoked paprika
2 teaspoons garlic powder
Black pepper (to taste)
4 firm plantains, peeled and cut into large chunks


  1. Heat a large pan over medium heat. Add the water and onion, and cook until the onion is translucent, about 5 minutes. 
  2. Add the tomatoes, and cook for about 5 more minutes, stirring regularly.
  3. Add the mushrooms, and stir to combine. 
  4. Gradually add the spinach, stirring until it wilts.
  5. Stir in the curry, smoked paprika, garlic powder, and black pepper (to taste). Bring to a simmer, cover, and cook, stirring occasionally, until thickened, about 10 minutes. If the mixture sticks to the pan, stir in a splash of water.
  6. Meanwhile, place the plantains in a large pot, cover with water, and bring to a boil. Cook until easily pierced with a fork, about 15 minutes.
  7. Serve the spinach and mushrooms along with the plantains.

TIP: The greener the plantains, the less sugar they have. To steam the plantains, make a small cut halfway through each piece. Place in a steamer, and steam until easily pierced with a fork, about 10 minutes.

You can find Chef Marie Kacouchia on Instagram @thespicysoul

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The Muscle Power, Strength, and Endurance of Vegetarians Tue, 21 Feb 2023 13:00:22 +0000 Randomized controlled trials put plant-based eating to the test for athletic performance.

Historical examples of successful plant-based athletes range from the gladiators in ancient Rome to the Tarahumara Indians who run 160-mile races for the fun of it. That’s six back-to-back marathons. But, they weren’t put to the test until the last century or so in a study purporting to show “without reasonable doubt that the flesh-eating group of athletes was very far inferior in endurance to the abstainers, even the sedentary group” of vegetarians—meaning it isn’t that the veg athletes won simply because they had trained harder or something. Indeed, there certainly are advantages to plant-based eating, like more antioxidants to combat exercise-induced oxidative stress and the anti-inflammatory nature of many plant foods that may accelerate muscle repair and strength recovery. But, do you have to eat this way for years, decades, or even your whole life to get these apparent benefits? I discuss this in my video Vegetarian Muscle Power, Strength, and Endurance.

What if you took some Texas men, eating their regular Texan diet, put them through a maximal exercise test, and then asked them to cut out meat for four days. Then, after those four days without meat, you tested them again to measure time to exhaustion, ramping up the treadmill to see how many minutes could they go without collapsing? A researcher did this and found a significant difference favoring the vegetarian diet, which boosted the time to exhaustion by about 13 percent, as you can see at 1:28 in my video. Of the five participants, “each subject had a higher time to exhaustion after following a vegetarian diet.” But there was a fatal flaw to the study. Did you catch it? They were all in the same sequence—meat first, then veg—and any time you take a test a second time, you may do better just because you’re more familiar with it. If the Texans went back to eating meat after being on the vegetarian diet and their performance tanked during a third test, then you might be onto something, but this isn’t very convincing. And, even if the effect is real, it may not be the meat reduction per se, but a function of improved glycogen stores from eating more carbohydrates or something.

What about putting athletes on a vegetarian versus omnivorous diet before a 621-mile race? (You’ve heard of a 5K? This is a 1,000K!) And, what if you made sure to design the two diets so all of the athletes got about the same percentage of carbs? As you can see at 2:16 in my video, researchers did this and found that the finishing rates of the athletes were identical and their total times were within just a few hours of each other whether on the vegetarian diet or the omnivorous one.

Same with sprinting. As you can see at 2:44 in my video, a study randomized people into vegetarian or mixed diet groups, and there was no significant difference in sprint power between the two groups. The researchers concluded that “acute vegetarianism has no acute adverse effects on adaptations to sprint exercise,” but no apparent performance benefits either.

Same with strength training, too. A study measured maximum voluntary contraction of both biceps and quadriceps before and after each dietary period, and no significant difference was seen either way. When you put together all of the studies that compare physical performance in these kinds of randomized, controlled trials, where you have folks eat more plant-based for just a few days or weeks, “there appeared to be no differences at least acutely between a vegetarian-based diet and an omnivorous diet in muscular power, muscular strength, anaerobic or aerobic performance.” Long-term, though, a plant-based diet can be conducive to both endurance performance and health. “Whereas athletes are most often concerned with performance, vegetarian diets also provide long-term health benefits and a reduction in risk of chronic disease” and are “associated with a reduced risk of developing coronary heart disease”—the number one killer of men and women—“breast cancer, colorectal cancers, prostate cancer, type 2 diabetes, insulin resistance, hypertension, cataracts, and dementia.” Doesn’t matter how you shred if you’re dead.

I was honored to be a scientific consultant for the amazing documentary about diet and athleticism called The Gamechangers. Check it out at

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The First Studies on Vegetarian vs. Meat-Eating Athletes Thu, 16 Feb 2023 13:00:33 +0000 Meat-eating athletes are put to the test against vegetarian athletes and even sedentary plant-eaters in feats of endurance.

“In 1896, the aptly named James Parsley led the Vegetarian Cycling Club to easy victory over two regular clubs. A week later, he won the most prestigious hill-climbing race in England….Other members of the club also turned in remarkable performances. Their competitors were having to eat crow with their beef.” Then, a Belgian researcher put it to the test in 1904 and found that those eating more plant-based reportedly lifted a weight 80 percent more times. (I couldn’t find the primary source in English, though.) I did find a famous series of experiments at Yale, published more than a century ago, on “the influence of flesh eating on endurance,” which I discuss in my video The First Studies on Vegetarian Athletes.

The Yale study compared 49 people: meat-eating athletes (mostly Yale students), vegetarian athletes, and sedentary vegetarians. “The experiment furnished a severe test of the claims of the flesh-abstainers.” And, “much to my surprise,” wrote the researcher, the results seemed to vindicate the vegetarians, suggesting that those eschewing meat “have far greater endurance than those who are accustomed to the ordinary American diet.”

As you can see at 1:12 in my video, the first endurance test measured how many continuous minutes the participants could hold out their arms horizontally: “flesh-eaters” versus “flesh-abstainers.” The meat-eating Yale athletes were able to keep their arms extended for about ten minutes on average. (It’s harder than it sounds. Give it a try!) The vegetarians did about five times better. The meat-eater maximum time was only half the vegetarian average. Only two meat-eaters hit 15 minutes, while more than two-thirds of the meat-avoiders did. None of the meat-eating athletes hit half an hour, while nearly half of the plant-eaters did. This included nine who exceeded an hour, four who exceeded two hours, and one participant who kept going for more than three hours.

How many deep knee bends can you do? One meat-eating athlete did more than 1,000, with the group as a whole averaging 383, but the plant-eating athletes creamed them, averaging 927. Even the sedentary vegetarians performed better than the meat-eating athletes; they averaged 535 deep knee bends. That’s wild! “Even the sedentary [meat] abstainers surpassed the exercising flesh-eaters” in performance. In most cases, the sedentary plant-eaters were physicians who sat on their butts all day. I want a doctor who can do a thousand deep knee bends! As you can see at 2:15 in my video.

Then, in terms of recovery, all of those deep knee bends left everyone sore, but much more so among those eating meat. Among the vegetarians, of the two who did about 2,000 knee bends each, one went straight off to the track to run and the other went on to their nursing duties. Among the meat-eaters, one athlete “reached his absolute limit at 254 times, and was unable to rise from a stooping posture the 255th time. He had to be carried downstairs after the test, and was incapacitated for several days.” Another meat-eating athlete was impaired for weeks after fainting.

“It may be inferred without reasonable doubt,” concluded the once skeptical Yale researcher, “that the flesh-eating group of athletes was very far inferior in endurance to the abstainers,” the vegetarians, “even the sedentary group.” What could account for this remarkable difference? Some claimed that flesh foods contained some kind of “fatigue poisons,” but one German researcher who detailed his own experiments with athletes offered a more prosaic answer. In his book, Physiologische Studien über Vegetarismus—looks like Physiological Studies of Uber-Driving Vegetarians, doesn’t it? (I told you I only know English)—he conjectured that the apparent vegetarian superiority was due to their tremendous determination “to prove the correctness of their principles and to spread their propaganda.” If we believe him, vegetarians apparently just make a greater effort in any contest than do their meat-eating rivals. The Yale researchers were worried about this, so “special pains were taken to stimulate the flesh-eaters to the utmost,” appealing to their college pride. Don’t let those lousy vegetarians beat the “Yale spirit”!

The Yale experiments made it into The New York Times. “Yale’s Flesh-Eating Athletes”—sounds like the title of a zombie movie so far, doesn’t it?—“Beaten in Severe Endurance Tests.” “Prof. Irving Fisher of Yale believes that he has shown definitely the inferiority in strength and endurance tests of meat eaters to those who do not eat meat…Some of Yale’s most successful athletes took part in the strength tests for meat eaters, and Prof. Fisher declares they were obliged to admit their inferiority in strength.” How has the truth of this result been so long obscured? One reason, Professor Fisher suggested, is that vegetarians are their own worst enemy. In their “vegetarian fanaticism,” they jump from the premise that meat-eating is wrong—“often bolstered up by theological dogma”—to meat-eating is unhealthy. That’s not how science works. Such leaps in logic get people dismissed as zealots, “preventing any genuine scientific investigation.” A lot of science, even back then, was pointing to “a distinct trend toward a fleshless dietary,” towards more plant-based eating, yet the word vegetarian, even 110 years ago, had such a bad, preachy rap “that many were loath” to concede the science in its favor. “The proper scientific attitude is to study the question of meat-eating in precisely the same manner as one would study the question of bread-eating” or anything else.

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What Is the Gladiator Diet and How Do Vegetarian Athletes Stack Up? Tue, 14 Feb 2023 13:00:00 +0000 I compare the diets of the Roman gladiator “barley men” and army troopers to the modern Spartans of today.

The remains of dozens of Roman gladiators were recently discovered in a mass grave in ancient Ephesus (Turkey). The clue to their identities was the rather distinct types of mortal injuries the researchers found, like being speared in the head with a trident, as you can see at 0:15 in my video The Gladiator Diet: How Vegetarian Athletes Stack Up. Just by examining the skeletons, the researchers were able to reconstruct the deathblows, show just how muscular and buff the gladiators really were, and even try to reconstruct their diet “of barley and beans.” You can look at carbon isotopes and see what kinds of plants they ate. Nitrogen isotopes reflect intake of animal protein, for example, and looking at the sulphur in their bones and the amount of strontium led commentators to submit that the best athletes in ancient Rome ate largely plant-based diets.

The legionnaires, the Roman army troopers famed for their fighting abilities, also ate a similar kind of diet, suggesting the “best fighters in the ancient world were essentially vegetarian.” So, if the so-called perfect fighting machines, the great sports heroes of their day, were eating mostly grains and beans, what does that tell us about sports nutrition and the preferred diets of elite athletes? “The diet of most Greeks and Romans was basically vegetarian,” centered on grains, fruits, vegetables, and beans, so maybe the gladiators’ diets weren’t that remarkable. Ancient Greek philosopher Plato pushed plants, for instance, preferring plant foods for their health and efficiency.

The Roman gladiators were known as the “barley men.” Did they eat barley because it “gave them strength and stamina,” or just because barley was a common, “basic food” people ate at the time—not necessarily for performance, but because it was cheap?

Let’s look at the modern Spartans, the Tarahumara Indians, who run races where they kick a ball for 75 miles just for the fun of it. They run all day, all night, and all the next day for “as much as 150 miles and more” if they’re feeling in the mood. What do they get if they win? “Interestingly, a traditional prize of victory is said to be a special popularity with the women (although how much of a reward that would actually prove to be for a man who had been running for two days and a night is questionable, to say the least!).” Though, maybe their endurance extends in other arenas, as well.

“Probably not since the days of the ancient Spartans has a people achieved such a high state of physical conditioning.” So, what do they eat? They eat the same kind of 75 to 80 percent starch diet, based on beans, corn, and squash, and have the cholesterol levels to prove it, with total cholesterol levels down at 136 mg/dL, which is essentially heart attack-proof. They don’t have special genetics, either, because data show that if you feed them enough egg yolks, their cholesterol levels creep right up, as you can see at 2:52 in my video.

Modern day Olympic runners eat similarly. What are they eating in Kenya? They’re following a 99 percent vegetarian diet centered mostly on various starches. But, as in all of these cases, is their remarkable physical prowess because of their diets or in spite of them? Or, does their athleticism have nothing to do with what they’re eating? You don’t know until you put it to the test.

“In spite of the well-documented health benefits of vegetarian diets, less is known regarding the effects of these diets on athletic performance.” Researchers compared elite vegetarian and omnivore endurance athletes for aerobic fitness and strength by comparing oxygen utilization on the treadmill and quad strength with leg extensions. The vegetarians beat out their omnivore counterparts for cardiorespiratory fitness, but their strength didn’t differ. This suggests, at the very least, “that vegetarian diets do not compromise performance outcomes and may facilitate aerobic capacity in athletes.” But, this was a cross-sectional study. Is it possible the vegetarian athletes were just more fit because they trained harder? The National Runners’ Health Study looked at thousands of runners, and, as you can see at 4:06 in my video, vegetarian runners were recorded running significantly more on a weekly basis. Maybe that explains their superior fitness, though perhaps their superior fitness explains their greater distances.

Other cross-sectional studies have found no differences in physical fitness between vegetarian and non-vegetarian athletes, while another one found even worse performance among vegetarian athletes, but there could have been socioeconomic or other confounding factors. That’s why we need interventional studies to put different diets to the test and then compare physical performance.


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Plant-Based Meat Fact Sheet Thu, 09 Feb 2023 13:00:40 +0000 We can address human health and climate crises at the same time by increasing consumption of plant-based foods, including animal-free meat substitutes, and substantially reducing our intake of meat, eggs, and dairy.

What does the latest research on plant-based meat alternatives say? This fact sheet is a summary of the main takeaways.

plant-based meat infographic

plant-based meat infographic

Get this fact sheet as a downloadable PDF here.

For more details about these studies, watch the free videos on the’s YouTube channel or on the website’s Meat Substitutes topic page.

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Tea Tree Oil for Cold Sores and Warts? Tue, 07 Feb 2023 13:00:32 +0000 Does tea tree oil have enough antiviral activity to combat HSV-1 and papilloma viruses, the causes of cold sores and common warts, respectively?

“It has been reported that essential oils show not only anti-bacterial and anti-fungal activities but also antiviral activity.” As well, it’s been reported that “Bigfoot Kept Lumberjack as Love Slave,” according to in a headline in the Weekly World News. What does the science show?

How about pitting essential oils against HSV-1, the herpes virus that causes cold sores? There’s a drug called acyclovir that helps, but now there are drug-resistant strains of the virus, so researchers have been looking for other alternatives. As you can see at 0:40 in my video Benefits of Tea Tree Oil for Warts and Cold Sores, researchers found that a variety of essential oils, including tea tree oil and peppermint, could totally suppress the replication of the virus at a concentration of just 1 percent, but that was in a petri dish. What about in people?

Recurrent cold sores affect as many as 20 to 40 percent of the population. Tea tree oil appeared to work in vitro, so researchers undertook a randomized, placebo-controlled study to evaluate the efficacy of topically applied tea tree oil in the treatment of recurrent cold sores. When comparing a 6 percent tea tree oil gel versus a placebo gel five times a day, researchers found that the average healing time seemed to be a few days shorter and the virus was wiped out a little earlier with the tea tree oil. However, “none of the differences between groups reached statistical significance,” meaning that a difference that small could have just been due to chance. They blamed the sample size, but maybe tea tree oil just didn’t work.

It would be interesting to put lemongrass oil to the test, since it was the only essential oil in the study still effective at wiping out viral activity at a dose that was ten times lower—0.1 percent—but it doesn’t look like that’s ever been done.

What about warts? They’re caused by viruses, too. Irish researchers reported a case of successful topical treatment of tea tree oil on hand warts in a pediatric patient. A seven-year-old girl had six warts on the tip of one of her fingers, so heavily clustered as to distort the appearance of her finger, interfering with her writing and piano lessons. She had undergone the standard caustic treatment of painting the warts with acid, but they just came back with a vengeance. So, her doctors figured, why not?, and suggested applying straight tea tree oil. After five days, all of the warts had “considerably reduced in size,” and, in another week, they were all gone, and they didn’t come back.

Not bad compared to conventional wart treatments, which can be really painful. Indeed, in this case, the tea tree oil appeared to work without any side effects, only affecting the warts, in contrast to the standard acid treatments that can damage the surrounding tissue. So, the researchers made an urgent call for randomized, controlled trials, but who’s going to fund those when tea tree oil costs only pennies per dose? The reason we’d particularly like to see randomized trials for wart treatments is that they tend to get better on their own, disappearing without any treatment typically within a year or two. That’s why, “Since antiquity it has been believed that warts can be removed by various magical processes.” You pay some witch doctor, your warts go away on their own, and they take the credit.

Surprisingly, such “charming” of warts was actually put to the test and had no effect on the warts. It’s interesting how they do those types of studies, though. For example, one study tested whether warts can be prayed away. The researchers used a placebo prayer, so the participants didn’t know whether they were in the prayed-for group or the placebo-prayer group. They did this to exclude the possibility that participants mind-over-mattered their own wart cure. That’s been put to the test, too. In another study, one from the 1960s, researchers used a “magic” wand secretly connected to a circuit such that it tingled when the wand touched the wart to maximize any placebo effect. And, wrote the scientists, the patients were predominantly “Negroes who were mostly unsophisticated and who had a very deep belief in magic.” Yet, despite the participants’ purported “deep belief in magic,” more warts actually disappeared spontaneously in the untreated group compared to the magic-wanded ones, with no hint of the mere suggestion of magical cures being effective.

I was surprised studies like this were not only performed but published in respected journals. Evidently publication followed a “considerable discussion” among the journal editors, who said they “promised to keep an open mind, but not so open that our brains fall out.”

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The Dairy Industry’s Misleading Study Designs Thu, 02 Feb 2023 13:00:44 +0000 How do the meat and dairy industries design studies that show their products have neutral or even beneficial effects on cholesterol and inflammation?

Observational studies like “Milk and Dairy Consumption and Risk of Cardiovascular Diseases and All-Cause Mortality: Dose-Response Meta-Analysis of Prospective Cohort Studies,” which suggests that dairy might not be so bad, can be confounded by extraneous factors, such as the fact that people who eat more cheese tend to be of “a higher socioeconomic status.” In that case, what about an interventional study? Researchers designed a randomized, crossover trial that compared a high-fat cheese diet to a high-fat meat diet to a “nondairy, low-fat, high-carbohydrate” control diet. Both the high-cheese and high-meat diets were loaded with saturated fat, but all of the study participants, including those on the low-fat diet, ended up with the same cholesterol levels. And, it should be noted that the study was overwhelmingly paid for by the dairy industry.

So, how did they do it? If you’re in the dairy industry and trying to design a study to show that a high-cheese diet does not raise cholesterol, how would you go about doing that? This is the topic of my video Friday Favorites: How the Dairy Industry Designs Misleading Studies.

Anyone remember my video BOLD Indeed: Beef Lowers Cholesterol? It’s one of my favorites. The beef industry was in the same pickle as the cheese industry: Beef has saturated fat, which raises cholesterol, which raises the risk of dying from our number one killer. What’s an industry to do? Well, as you can see at 1:20 in my video, it designed a study in which beef was added and cholesterol went down. How is that possible? It was achieved by cutting out so much dairy, poultry, pork, fish, and eggs that their overall saturated fat intake was cut in half. Indeed, saturated fat levels were cut in half, and cholesterol levels went down. Well, of course that happened. They could have swapped in Twinkies and claimed that snack cakes lower your cholesterol…or frosting…or anything.

So, now you know the trick. The way to get the same cholesterol levels is to make sure all three diets have the same amount of saturated fat. How are you going to get a high-fat cheese diet and a high-fat meat diet to have the same saturated fat level as a diet that has neither cheese nor meat? The researchers added so much coconut oil and cookies to the so-called low-fat diet that all three diets had the same amount of saturated fat and…voila! That’s how you can make it appear that a cheese- or meat-rich diet doesn’t raise cholesterol.

This reminds me of the desperation evident in a study that compared the effects of dairy cheddar cheese to a nondairy cheddar cheese called Daiya. Milk consumption has plummeted in recent years as people have increasingly discovered plant-based alternatives, like soymilk and almond milk, and now there are plant-based cheese alternatives. What’s the National Dairy Council to do? How are you going to design a study that shows it’s healthier to eat dairy cheese? Well, you design a study where dairy cheese causes less inflammation than the vegan alternative. They had their work cut out for them. Daiya is no health food by any stretch, but it definitely has three times less saturated fat than cow’s milk cheese. So, how did they show the study participants got more inflammation from Daiya?

There is one fat that may cause more inflammation than milk fat: palm oil. In fact, palm oil may raise cholesterol levels as much as trans-fat-laden partially hydrogenated oil. And, you’ve probably guessed it: They slipped the Daiya group some extra palm oil on the side. Can you believe it? They compared cow’s milk cheese to Daiya nondairy cheese plus palm oil. In fact, there was so much extra palm oil that the vegan meal ended up having the same amount of saturated fat as the cheese meal. That’s like proving tofu is worse than beef by doing a study where they compared a beef patty to a tofu patty stuffed with lard. Oh, wait. The meat industry already did that! But, at least they had the decency to concede that “replacement of meat with tofu in the habitual diet would not usually be accompanied by the addition of butter and lard.”

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Cheese and the Comparison Challenge Tue, 31 Jan 2023 13:00:25 +0000 Dairy is compared to other foods for cardiovascular (heart attack and stroke) risk.

When studies funded by industries suggest their products have neutral health effects or are even beneficial, one question you always have to ask is, “Compared to what?” Is cheese healthy? Compared to what? If you’re sitting down to make a sandwich, cheese is probably healthy—if you compare it to bologna, but what if you compare it to peanut butter? No way. That’s the point made by Walter Willet, former Chair of Nutrition at Harvard, as I discuss in my video Friday Favorites: Is Cheese Harmful or Healthy? Compared to What?

 “To conclude that dairy foods are ‘neutral’…could be misleading, as many would interpret this to mean that increasing consumption of dairy foods would have no effects on cardiovascular disease or mortality. Lost is that the health effects of increasing or decreasing consumption of dairy foods could depend importantly on the specific foods that are substituted for dairy foods.”

Think about what you’d put on your salad. Cheese would be healthy compared to bacon, but not compared to nuts. “For example, consumption of nuts or plant protein has been inversely associated”—that is, protectively associated—“with risks of coronary heart disease and type 2 diabetes; in contrast, intake of red meat has been positively associated with these outcomes. Thus, it is reasonable to assume that the lack of association with dairy foods…puts these foods somewhere in the middle of a spectrum of healthfulness, but not an optimal source of energy or protein…More broadly, the available evidence supports policies that limit dairy production and encourages production of healthier sources of protein and fats.”

Willet wasn’t just speculating. His statements were based on three famous Harvard studies involving hundreds of thousands of men and women exceeding five million person-years of follow-up.

What was learned in the first large-scale prospective study to examine dairy fat intake compared to other types of fat in relation to heart attack and stroke risk? Replacing about 100 calories worth of fat from cheese with 100 calories worth of fat from peanut butter on a daily basis might reduce risk up to 24 percent, whereas substitution with other animal fats might make things worse. You can see a graph showing how it breaks down for heart disease at 2:07 in my video. Swapping vegetable oil for dairy fat would be associated with a decrease in disease risk, whereas swapping meat for dairy increases risk. Calories form dairy fat may be as bad as, or even worse than, straight sugar. The lowest risk would entail replacing dairy fat with a whole plant food, like whole grains.

Yes, “dairy products are also a major contributor to the saturated fat in the diet and have thus been targeted as one of the main dietary causes of cardiovascular disease (CVD),” the number one killer of men and women, but the dairy industry likes to argue that there are other components of dairy products, like fermentation by-products in cheese, that could counteract the effects of their saturated fat. This is all part of an explicit campaign by the dairy industry to “neutralize the negative image of milk fat among regulators and health professionals as related to heart disease.” If the Global Dairy Platform looks familiar to you, you may recall that it was one of the funders of the milk-and-dairy-is-neutral study, trotting out their dairy-fat-is-counteracted notion, to which the American Heart Association responded that “no information from controlled studies supports the hypothesis that fermentation adds beneficial nutrients to cheese that counteract the harmful effects of its saturated fat.”

We need to cut down on dairy, meat, coconut oil, and the like, no matter what their respective industries say. In fact, that’s the reason the American Heart Association felt it needed to release a special Presidential Advisory in 2017. It wanted to “set the record straight on why well-conducted scientific research overwhelmingly supports limiting saturated fat in the diet.”

Everything we eat has an opportunity cost. Every time we put something in our mouth, it’s a lost opportunity to eat something even healthier.

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Is Cheese Really Good for Our Health? Thu, 26 Jan 2023 13:00:02 +0000 What is the real story behind the recent studies that show cheese has neutral or positive health effects?

In my series of videos on saturated fat, I talked about a major campaign launched by the global dairy industry to “neutralize the negative image of milk-fat among regulators and health professionals as related to heart disease.” As you can see in my video Is Cheese Really Bad for You?, that campaign continues to this day with the publication of a meta-analysis demonstrating “neutral [non-harmful] associations between dairy products and cardiovascular and all-cause mortality,” that is, death.

How do we know the dairy industry had anything to do with this study? Well, it was published in a journal that requires authors to disclose financial conflicts of interest. So, what ties were divulged? As you can see at 0:47 in my video: Dairy, dairy, dairy, dairy, dairy, dairy, the fourth largest dairy company in the world, dairy, dairy, milk, beer, soda, McDonald’s, dairy, dairy, dairy, dairy, and more dairy. Oh, and the study itself was “partly funded by…the Global Dairy Platform, Dairy Research Institute and Dairy Australia.” So, there we have it.

The other big new study suggested that a little bit of cheese every day isn’t just neutral but actually good for you. And, researchers in that study make it clear that they have “no conflict of interest” despite some of the authors being employees of the Yili Innovation Center and the Yili R&D Center, with Yili being “China’s largest dairy producer,” which makes it one of the world’s largest dairy companies.

How can cheese consumption be associated with better health outcomes? Most of these studies were from Europe, where a “higher socioeconomic status was associated with a greater consumption of cheese.” In Europe, they aren’t eating Cheez Whiz and Velveeta. There, cheese is “generally an expensive product,” so who eats it? As you can see at 1:45 in my video, cheese consumers are those with higher paying jobs, those in a higher socioeconomic strata, and those with higher education levels, all of which are associated with better health outcomes, which may have nothing at all to do with their cheese consumption. Higher socioeconomic groups also consume more fruits and vegetables…and more candies. So, I bet you could do a population study and show that candy consumption is associated with better health. (Shh! Don’t tell the National Confectioner’s Association.) Too late! Did you know that candy consumers have lower levels of inflammation and a 14 percent decreased risk of elevated blood pressure? This information is brought to you by the candy industry and the U.S. Department of Agriculture from our very own government, which props up the sugar industry to the tune of a billion dollars a year.

It’s like when the government uses our tax dollars to buy up surplus cheese. Paul Shapiro, CEO of The Better Meat Co., wrote a great editorial on this: “Imagine the following CNN headline: ‘Government Buys $20 Million in Surplus Pepsi as Demand Plummets.’ The fictional article informs readers that our tax dollars will soon be buying up millions of unwanted cola cans, all as a favor to the flailing soda industry, which just kept producing drinks no one wanted. “As outrageous as such a government handout to the soda industry would be, that’s exactly what the U.S. Department of Agriculture is doing for the industrial dairy industry.”

Michele Simon, JD, MPH, produced a great report on how our government colludes with the industry to promote dairy junk foods. “The federal government mandates the collection of industry fees for ‘checkoff programs’ to promote milk and dairy.” In fact, “McDonald’s has six dedicated dairy checkoff program employees at its corporate headquarters” to try to squeeze in more cheese. That’s how we got double steak quesadillas from Taco Bell and 3-Cheese Stuffed Crust Pizza and the “Summer of Cheese” ad campaign from Pizza Hut. “These funds are used to promote junk foods, which contribute to the very diseases our federal government is allegedly trying to prevent. Does it make sense to tell Americans to avoid foods high in salt, sugar, and saturated fat, while engaging in the promotion of those same foods?” Look, “the meat and dairy industries can do what they like with their own money. The public power of taxation should be used for the public good,” though, not to support the dairy and candy industries.

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Testing Greens and Beets, Two of the Best Brain Foods Tue, 24 Jan 2023 13:00:39 +0000 Cocoa and nitrite-rich vegetables, such as leafy greens and beets, are put to the test for cognitive function.

“The production of NO in the brain and its role in the control of neuronal [nerve] functions has been comprehensively investigated in animals studies.” NO, or nitric oxide, is the “open sesame” molecule that dilates our blood vessels and is boosted by the consumption of nitrate-rich vegetables. “However, little evidence on the role of NO in brain function in humans exists”—until it was recently put to the test, that is.

As I discuss in my video Best Brain Foods: Greens and Beets Put to the Test, study participants ate a lot of green leafy vegetables with some beet juice, and then researchers measured their cerebral blood flow. At 0:36 in my video, you can see a spot with improved flow within a brain area “known to be involved in executive functioning.” Improved blood flow doesn’t necessarily translate into improved cognitive function, though. For example, when researchers fed people tart cherries, “despite some indication of improved blood flow,” it didn’t appear to manifest as improved cognitive performance.

And, indeed, some of the initial studies were disappointing. Researchers gave study participants more than a cup of cooked spinach, but saw no immediate boost in their ability to carry out simple tasks. When others were given a similar battery of simple tasks after consuming cocoa, again, researchers saw no significant effect. Might the tasks have been too simple? When individuals were put through a more demanding set of tasks, such as counting backwards in threes for minutes at a time, “acute improvements in mood and cognitive performance” were seen after consumption of cocoa. What if you tried doing that same challenge after drinking two cups of organic beet juice, which has about the same amount of nitrate as two cups of cooked arugula?

As you can see at 1:42 in my video, researchers found significantly improved performance in terms of more correct answers on the sustained subtraction task. “These results suggest that a single dose of dietary nitrate”—for example, nitrate-rich vegetables—“can modify brain function, and that this is likely to be as a result of increased NO [nitric-oxide] synthesis,” but how do we know it’s the nitrate? Beets are packed with all manner of phytonutrients, like the betalain red pigment. One way to tease it out would be to come up with a kind of nitrate-depleted beet juice that has everything in beets but the nitrate and see if that works just as well. Researchers did exactly that.

Indeed, researchers developed a nitrate-depleted beetroot juice placebo. Within two weeks of supplementation with real beet juice, a group of diabetic patients got “a significant improvement in simple reaction time” compared to the nitrate-free placebo. We’re only talking about 13 milliseconds, but other interventions, like balance training, which only increased reaction time by about 7 milliseconds, were associated with significantly lower fall risk, as you can see at 2:42 in my video. And, of course, in athletes, those fractions of a second can sometimes make a difference.

“At very high exercise intensities…, cognitive task performance deteriorates, with a pronounced detrimental effect on reaction time,” and that may be just when you need it the most—when you’re playing football, for instance, and need to quickly make appropriate decisions while simultaneously going all out. And, once again, beets come to the rescue—significantly reducing reaction time and not only improving physical performance, but mental performance, too.

Can it improve the structure of our brain? Indeed, cognitive training and aerobic exercise can actually affect the structure of the human brain. There’s something called neuroplasticity, where your brain can adapt, changing its configuration as you learn to play piano, for example.

We used to think only younger brains could do this, but now we know it can occur in the aging brain as well. Can’t “beet” that! Or, can you? We didn’t know…until now. As you can see at 3:45 in my video, researchers looked at the brain before and after participants engaged in a six-week exercise program and measured connectivity between various parts that control movement. They found no big changes at all. But, when the subjects drank beet juice before doing the same amount of exercise, researchers found a big difference. The exercise plus beetroot juice group developed “brain networks that more closely resembled those of younger adults, showing the potential enhanced neuroplasticity conferred by combining exercise” and nitrate-rich vegetables.

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Take the Daily Dozen Challenge! Thu, 19 Jan 2023 13:00:47 +0000 We just re-launched the Daily Dozen Challenge to help more people discover how easy it is to fit some of the healthiest of healthy foods into their meals. Join us on social media and show us how you Do the Dozen. 

  • Plan: Pick a day to eat the Daily Dozen. Download our free Daily Dozen app on iPhone and Android that features the checklist, as well as these valuable tools to help you prepare for a successful challenge: The Evidence-Based Eating Guide, The Daily Dozen Meal Planning Guide, and Daily Dozen Digest, our free 11-week email series.
  • Challenge: Use the Daily Dozen checklist in the app to guide you as you take the Challenge. Document your meals, snacks, and activities by taking photos and/or videos throughout your challenge day.
  • Post: Share your Daily Dozen Challenge experience to inspire and motivate others. Post your Challenge pictures or videos on social media, and use the hashtag #DailyDozenChallenge to build the community of participants. 
  • Encourage: The more, the merrier! Challenge others to take part in the Daily Dozen Challenge. Help spread the word!

For inspiration on how to Do the Dozen, check out these challenge videos:


Key Takeaways: Fasting 

Fasting has been branded the “next big weight loss fad” but has a long history throughout various spiritual traditions, practiced by Moses, Jesus, Muhammed, and Buddha. Today, about one in seven American adults report using some sort of fasting as a means to control body weight. There are various approaches to fasting, from intermittent fasting to weeks of only water. For more on fasting, check out the topic page and videos such as Is Fasting for Weight Loss Safe? and The Benefits of Fasting for Healing.


Recipe: Corn Chowder

Corn Chowder from The How Not to Diet Cookbook is a delicious comfort soup that’s perfect for the winter! This chowder can be as thick and creamy as you like, depending on how much of the soup you puree. Get the free recipe here and watch a video on how it’s made on our Instagram.




2022 Year in Review

Thank you for all of your support in 2022! To see what we accomplished last year, check out our 2022 Year in Review report. In addition to continuing to put out new videos and blogs each week, highlights include creating The Daily Dozen Meal Planning Guide, translating the Daily Dozen app into 14 languages, and launching the free Plant-Based Living email series. Download the full report here.





The Evidence-Based Eating Guide in More Languages

Our popular eating guide is now available in Spanish and Chinese. You can download these versions on our new Guides and Handouts page or buy hard copies on






How Not to Die Kindle Deals

How Not to Die is part of Amazon’s New Year, New You January Kindle deals. Kindle Unlimited subscribers can get the book through their subscription, and in the UK, it’s available for just .99p. 






Top Three Videos

Blue vitamin tablets on white surface

Vitamin D May Explain the Higher Bone Fracture Risk in Vegans: A combination of low calcium intake and low vitamin D exposure may explain higher bone fracture rates in British vegans.


Vitamin capsules on dark background

The Purported Benefits of Vitamin K2: Should You Take Supplements?: Our body can make vitamin K2 from the K1 in green leafy vegetables.



Digital drawing of plaque in arteries

Cholesterol and Heart Disease: Why Has There Been So Much Controversy?: Is the role of cholesterol in heart disease settled beyond a reasonable doubt?




Live Q&A

image of dr greger

Every month, I do a live Q&A right from my treadmill, and the next one is January 26! At 3 pm ET, tune in on our Facebook page, YouTube channel, or directly on

You can find links to past live Q&As here on And check out my recent conversation on Physicians Committee for Responsible Medicine’s Exam Room podcast.



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Testing Berries and Nuts, Two of the Best Brain Foods Tue, 17 Jan 2023 13:00:04 +0000 Randomized controlled studies put nuts, berries, and grape juice to the test for cognitive function.

When you read articles in Alzheimer’s disease journals about eating more berries to reduce cognitive decline in the elderly, the authors are talking about observational studies, like the Harvard Nurses’ Health Study that showed that berry intake appears to delay cognitive aging by up to two and a half years and the intake of nuts appears to delay brain aging by two years. These types of studies are just talking about associations, though, as I discuss in my video Best Brain Foods: Berries and Nuts Put to the Test.

Studies have found that, after trying to control for other lifestyle factors, berry eaters and nut eaters tend to have better brain function as they age, but you don’t know if it’s cause-and-effect…until you put it to the test. Thankfully, we now have “a growing number of human [interventional] studies” that have done just that. Randomized controlled trials have found that people who eat berries or nuts actually show improvements in cognitive performance, raising the “berry nutty” idea that “dietary supplementation with nuts, berry fruit, or both is capable of altering cognitive performance in humans, perhaps forestalling or reversing the effects of neurodegeneration in aging”—just with food.

For example, in a study on the effects of walnut consumption on cognitive performance, college students were split into groups, either eating walnuts for two months, followed by two months of placebo, or vice versa, and then they were switched. How do you make a placebo nut? The researchers gave the students banana bread with or without nuts—the same ingredients, just with or without walnuts. Those on the nuts showed a significant improvement in inference capacity, the ability to accurately draw conclusions from a set of facts—in other words, critical thinking. “On a practical level, maybe students or young professionals in…fields that involve a great deal of critical thinking or decision-making could possibly benefit and gain a slight advantage through regular consumption of walnuts.”

Another berry study randomized people to a smoothie made with blueberries, black currants, elderberries, lingonberries, strawberries, and…a tomato. Not only did their bad cholesterol drop about 10 points, but they also performed better on short-term memory tests. So, good for the heart, good for the brain. And, they were not just better on pencil-and-paper tests, but also in real-world applications. Give people Concord grape juice versus a fake grape Kool-Aid-type placebo, and you can get improved performance on everyday tasks, such as quicker response times in driving tests. Why not just give people Concord grapes instead of juice? It’s harder to create a placebo, and, of course, the study was paid for by Welch’s.

We talked about fruits and nuts. What about vegetables? “Consumers of cruciferous vegetables (cabbage, cauliflower, broccoli and Brussels sprouts) performed better in several cognitive tests than non-users.” And, in terms of cognitive decline with aging, women consuming the most leafy greens did better, effectively slowing brain aging by a year or two. This was the case not just with cruciferous vegetables, but also with other dark leafy greens, such as spinach, so it might be the nitrates.

As we age, our cerebral blood flow—the amount of blood flowing through our brain—drops, “which may be due to an age-related decrease in the production of NO,” nitric oxide, the “open sesame” molecule that dilates our blood vessels and is boosted by the consumption of nitrate-rich vegetables. “This reduction in blood flow to the brain has been indicated as a major risk factor for the impairment of cognitive function and development of neurodegenerative diseases, such as dementia.” We know nitrate-rich vegetables, such as leafy greens and beets, can improve physiological performance like beet juice does for athletes, but what about cognitive performance? We find out in my next video, Best Brain Foods: Greens and Beets Put to the Test.

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Can We Detoxify Lead from Our Body in a Sauna? Thu, 12 Jan 2023 13:00:05 +0000 How much does sweating from a sauna or exercise get rid of lead and mercury?

In my video Is Henna Safe?, I talk about a study that proved lead could be absorbed through the skin and into the body. Researchers applied lead to someone’s left arm and then measured the level of lead in the sweat from their right arm over the next few days. As you can see at 0:16 in my video Flashback Friday: Can Saunas Detoxify Lead from the Body?, there was a big spike, proving that lead can not only go into our body, but also out of it. If we can lose lead through sweat, can we sweat for detoxification?



“No person is without some level of toxic heavy metals in their bodies, circulating and accumulating with acute and chronic lifetime exposures.” Cultures around the world have viewed sweating as health-promoting. “Worldwide traditions and customs include Roman baths, Aboriginal sweat lodges, Scandinavian saunas…and Turkish baths,” but what does the science say?

When I looked up saunas, I was surprised to see a study on the detoxification of 9/11 rescue workers, with a regimen that “included exercise, sauna bathing and vitamin and mineral supplements.” As you can see at 1:00 in my video, the researchers reported on seven individuals. Evidently, during the month before the treatment, polychlorinated biphenyl (PCB) levels in their blood stayed about the same. Following the treatment, however, all rescue workers had measurable decreases in these PCBs and reportedly felt better, too. They had all sorts of symptoms—respiratory, neurological, musculoskeletal—and they all felt better after the treatment. These improvements were consistent with nearly 400 others treated with the same protocol.

Hold on. If 400 people were treated, why were the results from only seven individuals reported? That’s a bit of a red flag, but not as red as this: The detoxification regimen was developed by L. Ron Hubbard, the man who founded the infamous Church of Scientology. What’s more, the lead author of the detoxification paper appears to have failed to disclose his financial conflict of interest for presumably profiting off of the treatments.

Nevertheless, sweating does represent a “time-honored treatment” in the field of medicine for mercury poisoning, going back centuries. But other time-honored medical treatments include drilling open people’s skulls to release evil spirits or even giving people mercury itself. Remember mercurochrome? What do you think the “mercuro” stood for? In fact, some believe Mozart died of mercury poisoning trying to cure his syphilis, though all of the bloodletting he got probably didn’t help either. Bloodletting, another time-honored medical treatment that makes Scientology saunas look mild in comparison. There was a case report that described a person who apparently recovered from mercury poisoning “after six months of sweats and physical therapy,” though he might have gotten better anyway. You don’t know…until you put it to the test.

Mercury wasn’t formally studied, but lead was. Study participants stayed in a 200-degree dry sauna for 15 minutes, and, based on sweating rates, about 40 micrograms of lead were forced out of the body, with some people getting rid of 100 micrograms or more per 15-minute session. So, you could drink a gallon of chicken broth, and, even if you absorbed all of the lead in the bone soup, you could be back to baseline after just one sauna session.

Are saunas safe for children? “Based on the present scientific knowledge, sauna bathing poses no risks to healthy people from childhood to old age,” though medical supervision couldn’t hurt. This doesn’t mean it would be as effective in children because adults sweat a lot more than kids do, and, of course, kids are the ones who need lead detoxing the most, as you can see at 3:36 in my video. “There is a clear need for robust trials”—robust clinical trials—to test all of this, but even if it works, it’s not as though everyone who needs it—even those who need it most, like a child in Flint, Michigan—will have access to a sauna. That’s why I was so excited to find a paper that investigated the change in blood lead levels of basketball players after strenuous exercise. Saunas aren’t the only way to sweat. What about strenuous physical activity?

A study found that aerobic endurance training led to a drop in lead levels, with rowing more effective than cycling, but how long and how intense did the workout need to be? The paper was in German, but it seems the researchers ramped up the stationary bike by 50 watts every two minutes until the subjects reached exhaustion. So, it was probably just a few minutes with no significant before-and-after difference in blood or urine lead levels, whereas an hour-long endurance exercise row did seem to drop lead levels by about 12 percent.

I could read the basketball player study, though, since it was in English, and, as you can see at 4:38 in my video, college basketball players’ blood lead levels significantly increased—by nearly 300 percent—after a single intense training session on the court. The researchers suspected it was because it was so contaminated where they were playing. The study was done in Turkey, where the lead levels in the air are so high that all of that extra breathing by the athletes evidently made things worse, which I think underscores an important point.

All of the dietary tweaks I’ve talked about for lead poisoning and sweating it out could be thought of as more expedient and less costly than primary prevention—that is, getting at the root cause. However, “this represents a retreat of sorts from previous commitments to a clean environment and to abatement of hazardous pollutants” in the first place. Indeed, lifestyle “nutritional interventions should be thought of only as temporary solutions and continued emphasis must be placed on eliminating lead in children’s environments” in the first place.

How about diet instead? See How to Lower Heavy Metal Levels with Diet.

What about chelation therapy? Check out Heavy Metal Urine Testing and Chelation for Autism.

What about the non-heavy metal aluminum? See Antiperspirants and Breast Cancer.

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Benzoyl Peroxide or Tea Tree Oil for Acne? Tue, 10 Jan 2023 13:00:11 +0000 What happened when a 5 percent tea tree oil gel was pitted head-to-head against the leading over-the-counter treatment for pimples?

“Acne vulgaris remains one of the commonest diseases to afflict humanity.” As I discuss in my video Benzoyl Peroxide vs. Tea Tree Oil for Acne, according to some online surveys, tea tree oil appears to be “the second most commonly used topical treatment” for acne after benzoyl peroxide. “Crowdsourcing” may be “a novel research method for evaluation of acne treatments,” but before getting too enamored with popular wisdom, you should know information on facial application of “urine as a home remedy for acne” is also circulating on the internet.

“Urine therapy advocates cite historical use as proof of its therapeutic potential claiming urine not only as a treatment for numerous skin conditions, but also as a ‘free cure’ for many systemic diseases,” apparently forgetting all of the horrific skeletons crowding the closets of medical history. “While recycling what the body intentionally removes may seem counterintuitive to good health,” what about Premarin? (They’re talking about the hormone therapy drug made from PREgnant MARe’s urINe.) The best argument for putting pee on your face appears to be that some women swallow pills made from pregnant horse pee. I’m not exactly following the logic there.

Of course, there are drugs for acne. There are always drugs, as you can see at 1:18 in my video. Though, with drugs come side effects. Antibiotics that suppress the bacteria that cause acne “are the standard treatment…but are becoming less effective probably because of the emergence of antibiotic-resistant strains.” The prevalence of resistant strains has grown rapidly, such that antibiotics for acne are no longer recommended on their own as “mono-therapy” and re-evaluations are advised every six to eight weeks.

Bacteria do seem to be susceptible to tea tree oil in a petri dish, however, but many of these kinds of studies were performed with free-floating bacteria, whereas, in pimples, the bacteria form what’s called a biofilm, which generally makes them more difficult to eradicate. The bacteria form like a “biological glue” that plugs up the follicle, so petri dish studies can only tell you so much.

But, even if tea tree oil couldn’t kill off the bacteria, it has been shown to suppress skin inflammation. Indeed, if you inflame people’s skin with an allergen and then try to calm it down, tea tree oil does a decent job compared to an over-the-counter ointment or a moderate-potency prescription steroid cream. So, potentially, tea tree oil could help with acne either via an antibacterial mechanism or from an anti-inflammatory standpoint. You don’t know…until you put it to the test.

As you can see at 2:38 in my video, a 20 percent tea tree oil gel was applied twice a day in a study, and researchers saw a beautiful drop in acne lesions after one, two, and three months. About 24 pimples at the start of the study down to about 11. The researchers concluded that tea tree oil could “significantly improve mild to moderate acne and that the products were well tolerated,” but the study had fatal flaw. Did you guess? There was no control group.

How do we know the subjects wouldn’t have healed even faster without the tea tree oil? In a systematic review of randomized, clinical trials on tea tree oil, the “most striking finding” is that researchers could hardly find any randomized clinical trials on tea tree oil. Given “the widespread use” of tea tree oil, “this is both disappointing and important to note.”

Researchers finally conducted a randomized, double-blind, placebo-controlled trial of a 5 percent topical tea tree oil gel in mild to moderate acne. As you can see at 3:27 in my video, after six weeks, the tea tree oil group experienced a 40 percent drop in whiteheads and blackheads, a 40 percent drop in red and tender acne bumps, and a 47 percent drop in pus-filled pimples, compared to comparatively little change in the control group. Overall, in terms of total lesion count, the tea tree oil gel was three and a half times more effective than placebo—that is, three and a half times more effective than essentially doing nothing. But, most teens don’t do nothing for their pimples. How does tea tree oil compare to benzoyl peroxide, the gold standard?

By far, benzoyl peroxide is the most popular over-the-counter acne therapy—despite its side effects. It can be irritating, causing “erythema [redness], dryness, peeling, stinging, or burning.” However, the prescription option—the long-term use of topical or oral antibiotics—is discouraged due to the development and spread of antibiotic resistance. As a result, attention has turned to “non-antibiotic products such as tea tree oil.”

Compared to tea tree oil, benzoyl peroxide did cause more side effects, including “dryness, pruritus [itching], stinging, burning, and redness”—but it also worked better, cutting the number of inflamed pimples by two-thirds within three months versus only by half in the tea tree oil group, as you can see at 4:33 in my video. The most recent study found them to be more comparable, though.

Putting all of the studies together, tea tree oil products were not only found to outdo placebo, but they approximate more standard regimens, like benzoyl peroxide or topical antibiotics, suggesting tea tree oil products may be “an appropriate option for treating mild-to-moderate acne.”

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