Nutrition blog

Subscribe to Nutrition blog feed
The Latest in Nutrition Research
Updated: 1 day 1 hour ago

Our Black Friday Sale Is on Now!

Thu, 11/24/2022 - 07:00

Add some green to your Black Friday with 20 percent off all merchandise on The sale is site-wide, so it includes all clothing, video downloads, outreach materials, and more. If you’re heading into winter, cozy up with our sweatpants (back by popular demand!), hoodies, or a crewneck sweatshirt. Sale ends November 28. All proceeds go to keeping running! 


Key Takeaways: Walnuts

The Global Burden of Disease Study calculated that not eating enough nuts and seeds was the third-leading dietary risk factor for death and disability in the world. That is why I recommend a daily serving of at least ¼ cup nuts or seeds or 2 tablespoons of nut or seed butter in my Daily Dozen checklist. So, which nut is healthiest? Walnuts really seem to take the lead due to their high antioxidant and omega-3 levels, and they beat out other nuts in vitro in suppressing cancer cell growth. And, of all the nuts studied in PREDIMED, the largest dietary intervention trial to assess the effects of a Mediterranean-type diet on cardiovascular disease prevention, the researchers found the greatest benefits associated with walnuts, particularly for potentially preventing cancer deaths. Check out all of my videos on walnuts on the topic page


Recipe: Baked Apples with Walnuts and Goji Berries

After reading about the benefits of walnuts, I bet you’re ready to snack on some! Here’s a delicious fall treat from The How Not to Diet Cookbook that tastes like apple pie, but without all of the sugar and butter. And as a bonus, it will make your house smell divine while it bakes! Check out the recipe, and watch a video on how it’s made on our Instagram.



Volume 60 Is Out Now

I’m excited to release my 60th volume of videos! Sixty! I’ve created more than 2,000 videos in the lifetime of and have no plans of slowing down anytime soon! This new volume includes a series on tongue scraping, the controversy around cholesterol, whether vegans suffer more bone fractures, my popular webinar video on vitamin K2, and more. 

Each video in this new volume will be released online over the next few months, available for free, of course, but if you don’t want to wait, you can stream all of them right now

If you are a $15+ monthly supporter and opted in to our donor rewards, you’re likely an expert on these new topics by now, since you already received a complimentary link to the new download. If you’d like early access to new videos before they’re available to the public, please consider becoming a monthly supporter. Without your generosity, we wouldn’t be able to continue our work. Thank you!

And, remember, if you watch the videos on or YouTube, you can access captions in several different languages. To find yours, click on the settings wheel in the lower-right corner of the video and then “Subtitles/CC.” (You can also watch our new video about changing your settings.) Happy viewing!


Volunteer Spotlight: Laura McClanathan

I love everything about volunteering for Dr. Greger! I’m a part of the wonderful Article Retrieval Team where I help track down articles he needs for his books and videos. It’s incredibly fun detective work that really appeals to me as a reference librarian. What is most satisfying about it is that I feel I am making a tangible contribution to the body of evidence-based information about the incredible—and positive—power of plant-based eating. And it’s an honor to give back to someone who has helped me learn so much.

My favorite recipe is Dr. Greger’s ranch dressing. It is so delicious and versatile—cashews, unsweetened soy milk, a tasty spice blend, lemon, vinegar, red onion, dates, white miso, parsley, and dill.


Top Three Videos

The Side Effects of Burning Incense 

Burning incense has been found to generate about four times the particulate matter as burning cigarettes.


The Benefits of Fenugreek for Preventing and Treating Diabetes

The spice fenugreek contains 4-hydroxyisoleucine, a peculiar amino acid that may explain its benefits for controlling blood sugar.


Foods That Cause and Help Halitosis (Bad Breath)

Most bad breath is due to the decay of sulfur-containing proteins.



Thank you so much for the wonderful birthday messages and donations last month. My 50th felt truly special thanks to your kindness and your support. I enjoyed celebrating with the team at our annual staff retreat this year! If you missed my live Q&A last week, you can watch the recording by going to our Live Q&A page. And I recently did a fun interview with Tami of Nutmeg Notebook. Check it out!

What Is the Best Food for Gingivitis and Periodontal Disease?

Tue, 11/22/2022 - 07:00

What would happen if you stopped brushing your teeth but ate more healthfully?

 Experimentally, when study participants stop brushing their teeth, plaque starts to build up and, within a few days, their gums start to get inflamed. Though nothing may be visible just yet, if you take a biopsy at the gum line, you can see the inflammation beginning to spread. Within a few weeks, overt gingivitis becomes apparent with gums that can get red and swollen and bleed easily. If you don’t do anything about it, you can develop periodontal disease, where the inflammation creeps down into the supporting structures of the tooth—the bone and ligaments—setting you up for tooth loss.

How did we get along for millions of years without brushing our teeth? “Dental disease is almost universal” these days, but skulls from thousands of years before the invention of the toothbrush have perfect teeth. Admittedly, that was also thousands of years before the invention of candy bars. Does food play a role? You don’t know…until you put it to the test, as I discuss in my video Best Food for Periodontal Disease and Gingivitis.

How do you get people to stop brushing their teeth and also stop eating processed junk? Researchers designed a study where participants were forced to live under Stone Age conditions without “toothbrushes, toothpaste, dental floss, toothpicks, or other oral hygiene products” for a month, and “security guards ensured that all subjects maintained the appropriate lifestyle for Stone Age humans.” They could use a twig or other natural material to try to clean their teeth, but were pretty much on their own. (The participants didn’t get any candy bars either.) The researchers were attempting to replicate the diet from about 4000 BCE, so the subjects got a lot of whole grains with supplemental “salt, herbs, honey, milk, and meat from domestic animals (goats and hens),” and were allowed to pick berries or see what they could catch. What happened?

With no oral hygiene, their plaque built up, as you can see in the graph below and at 1:53 in my video, but their gums got healthier, as measured by bleeding on probing. (Gums bleeding when poked with a dental tool is a measure of gingivitis.) In almost every case, the participants’ gum health improved. How is it possible that their gums were actually healthier despite buildup of plaque? Many of the more disease-causing bacteria seemed to have disappeared from their mouths. The researchers suggested this could be from the lack of refined sugars, but the participants were eating honey, so they weren’t on a sugar-free diet. They were, however, eating a lot of whole grains and berries rich in antioxidant phytonutrients with anti-inflammatory properties. So, maybe it was restricted sugar intake combined with the intake of really healthy foods. Thus, all of those experimental studies where people stop brushing their teeth and their gums inevitably get inflamed “may only be applicable if the subjects maintain a Western diet rich in sugar and low in anti-inflammatory foods,” such as whole plant foods.

What about the role of nutrition in periodontal health? Gingivitis can lead to periodontitis, an inflammatory disease of the supporting tissues of the teeth, which, if left untreated, can lead to the progressive loss of the bone that holds our teeth in place. Part of the development of periodontal disease may involve oxidative stress, so not only do we need to reduce our intake of pro-inflammatory foods, such as refined carbohydrates and saturated fats, but it may also help if we seek out foods that are antioxidant-rich.

Is there an association between periodontitis and dietary vitamin C intake? Apparently so, as you can see in the graph below and at 3:34 in my video. Increased risk of periodontitis has been associated with lower levels of vitamin C intake. What effect might vitamin C depletion and supplementation have on periodontal health? Researchers provided controlled amounts of vitamin C to study participants for three months and found that measures of gum inflammation were directly related to the subjects’ vitamin C status. On about one orange’s worth of vitamin C a day, their gums improved; down around only 5 mg a day, though, their gums got worse. On ten oranges’ worth of vitamin C a day, they got better and then worse once again when the vitamin C level dropped down to five oranges’ worth, as you can see  in the graph below and at 4:01 in my video. The study was pretty convincing, though 5 mg a day is down at scurvy level. We know our gums start bleeding and our teeth can fall out if we have scurvy, but that doesn’t mean taking extra vitamin C helps.


Indeed, 1,500 mg of vitamin C a day did not seem to help prevent gingivitis and even 2,000 mg a day failed to help periodontitis sufferers. Is it possible that vitamin C is just too weak an antioxidant? What about lycopene, the powerful antioxidant pigment that makes tomatoes red? Lycopene worked! But that was from injecting it directly into the gum pocket with a syringe. Does it still work if you simply eat it?

A randomized, placebo-controlled, clinical trial investigated the efficacy of lycopene in the treatment of gingivitis. After two weeks of standard dental treatment with either a single daily tomato’s worth of lycopene or placebo, the placebo group had a 10 to 20 percent reduction in gingivitis, but the lycopene group had a nearly 30 percent improvement within just one week. How much lycopene? The amount found in just one and a half teaspoons of tomato paste a day. So, tomatoes may help with gingivitis, but what about periodontitis?

Another randomized, double-blind, placebo-controlled trial again treated subjects with a typical dental cleaning plus either one daily tomato’s worth of lycopene or a placebo for two months. Researchers found significant improvements in the lycopene group in plaque, gingivitis, and bleeding, though not probe pocket depth and clinical attachment. You can see the difference in how much better their gums looked as you can see below and at 5:59 in my video. The researchers concluded that “supplementation with lycopene seems to have augmented the healing sequence of inflamed gingival tissues,” but that was with a whole tomato’s worth a day. How about half a tomato’s worth or just three quarters of a teaspoon of tomato paste’s worth of lycopene a day? Neither worked. There was no difference. It looks like you have to go the whole tomato.

It should come as no surprise that healthy foods can benefit all parts of the body, but I still love to see the data!

I talk more about the red pigment in tomatoes in Lycopene Supplements vs. Prostate Cancer and Tomato Sauce vs. Prostate Cancer.

Is Cannabis a Cancer Cure?

Thu, 11/17/2022 - 07:00

Some studies on mice show that cannabis makes cancer better, while others show it makes cancer worse. What did the one and only human clinical trial to date find?

“Cannabis and cancer: reality or pipe dream quackery?” I tackle that question in my video Can Cannabis Cure Cancer?. “Among alternative cancer treatments, cannabis inhabits a peculiarly politicised position, hailed as a suppressed panacea by some, denounced as a psychosis-inducing and illegal drug by others….At the far end of the spectrum are those who insist cannabis…has helped cure their cancer.” “The promise, and even the hype, can reach hysterical proportions, with claims of cannabis cancer cures circulating in cyberspace at a furious pace.”

Sometimes, a patient will have a cancer that is curable with conventional therapies, such as surgically removing it before it spreads, but chooses to forgo that treatment in favor a purported cure that has a “large number of online testimonials.”

Yes, as you can see in the graph and at 0:54 in my video, cannabis compounds like THC can reduce brain tumor volume in mice or suppress cancer cell growth in a petri dish, but “mice and rats are not people, and what is observed in vitro does not necessarily translate into human clinical medicine.” Does it hurt to just give it a try, though? Well, there is other evidence that cannabis compounds “may encourage cancer cell growth.” Indeed, research indicates that THC may inhibit antitumor immunity or induce cancer cell proliferation, as well as enhance breast cancer growth and metastasis by suppression of the antitumor immune response—at least in mouse mammary tumors. You don’t know what happens in people…until you put it to the test. But, due to legal reasons, few human studies have been done. Thankfully, “after years of deep freeze on cannabis-related research, funding, and materials, a thaw is starting.” But, where do you even start?

Well, if cannabis compounds—cannabinoids—“are postulated to have a potential anticancer effect working through the CB1 [cannabinoid] receptors, it would follow that the brain—where the CB1 receptor is the most densely populated…receptor—would be a good place to start the investigation.”

“One of the most devastating forms of cancer is glioblastoma,” a fast-growing type of malignant brain tumor, and that’s the first cancer that was put to the test.

Cannabis compounds sometimes inhibit tumor growth in lab animals, but their anti-tumor effects hadn’t been tested in humans until recently. Finally, the first clinical study on cancer was conducted—a pilot study of nine patients with recurrent glioblastoma, meaning they had had their tumors cut out and then received radiation treatments, but their cancer returned and was growing. The researchers administered THC straight into their tumors. The study participants went back into surgery, had a scoop carved out of the center of their tumors. A catheter was inserted into the middle and the other end stuck out of their heads, and researchers dripped THC directly into the tumor with a syringe. THC had already been tested on biopsy specimens and showed it was able to kill off some of the cancer cells in a petri dish. What happened when it was tried on the patients themselves? The patients all died in a matter of months.

As you can see in the graph and at 3:39 in my video, in a few subjects, it seemed THC may have worked for a few weeks, but then their tumors began growing again despite repeated treatments. The patient with the most dramatic result was a 35-year-old man. At four weeks, his tumor had shrunk dramatically, but then it came back with a vengeance and, despite more infusions, his condition worsened and then he was gone. With no control group, the effect of the treatment on overall survival is unclear.

That was both the first clinical trial on cancer and the only clinical trial on cancer, and it was published more than a decade ago. There is some good news, though: There are more than 15 trials currently underway. The most exciting one may be a phase-two trial in Israel, once again looking at “advanced cancers that have progressed through all standard treatments.” In the meanwhile, if you are undergoing a standard treatment like chemotherapy, at least we know that cannabis may help with some of the side effects.

Doctor’s Note:

In case you missed it, check out my previous video, Does Marijuana Cause Lung Cancer?.

Does Smoking Cannabis Cause Lung Cancer?

Tue, 11/15/2022 - 07:00

On a puff-by-puff basis, cannabis smoke deposits four times more tar in the lungs than tobacco, but does that translate into increased cancer risk?

Does Marijuana Cause Lung Cancer? As I discuss in my video, “there are at least 33 carcinogens in marijuana smoke,” including polycyclic aromatic hydrocarbons, which are products of combustion. They are found in grilled meat and flow through the bodies of those who smoke marijuana, similar to what flows through the bodies of cigarette smokers, which is really remarkable, as you can see in the graph and at 0:17 in my video. Most tobacco users typically inhale much more smoke into their lungs over the course of a day than do cannabis users, so, on a puff-by-puff basis, is marijuana smoke really that much worse? 

Compared to unfiltered cigarette smoke, cannabis smoke does seem to contain more benzopyrene and benzanthracene, which are polycyclic aromatic hydrocarbon procarcinogens. However, cannabis users may just inhale more deeply and then hold in the smoke longer, which can end up depositing four times more tar in the lungs, “amplifying exposure of the lung to the carcinogens within the smoke.” What about bubbling the smoke through water, like in a bong? That does not appear to reduce the risks of tar buildup.

As you can see in the graph and at 1:11 in my video, the tar in marijuana smoke may have similar tumor-promoting effects as cigarette smoke—in mice. But what about in people?

Long-time marijuana users do have more cancers—more lung cancer, oral cancer, and voicebox cancer—but it seems that’s only because they also tend to be more likely to smoke tobacco, too. After cigarettes were taken out of the equation, no increased cancer risk was found.

The same holds for head and neck cancer. One study found increased risk, but five studies reported no association and one study even found decreased risk. “Regular use of marijuana causes airway injury leading to symptoms of chronic bronchitis in some smokers but no…evidence of emphysema,” long-term lung damage. And, despite the carcinogenic components in marijuana smoke, there is no apparent increased risk of lung cancer either. However, “evidence is mixed regarding the risk of heavy, long-term use”—and that may be the crux.

In terms of smoke exposure, smoking a joint every single day for ten years may only translate to six months of pack-a-day cigarette smoking. In most studies on tobacco smoke and lung cancer, six months in a lifetime might even classify you as “a never smoker.” It may take a couple of years of cigarette smoking to significantly bump up lung cancer risk, so that would be like smoking a joint every day of your adult life. It’s no wonder we can’t find a lung cancer link with casual marijuana use. There is also an alternative explanation: Maybe the anti-tumor effects of the cannabis plant counteract the tumor-promoting effects of the carcinogens in the smoke. Anti-tumor effects?

Indeed, the original demonstration of an anticancer effect, dating back to 1975, showed that THC can suppress the growth of lung cancer cells in a petri dish, as you can see in the graph and at 3:10 in my video. These kinds of data have led to wild claims of cancer cures on the internet, “extrapolating the results of preclinical work” (such as in petri dishes and test tubes) “to humans without any basis in fact.” Reportedly, cannabis has not been studied clinically as a treatment for malignancy in people—but that isn’t entirely accurate. A pilot study was performed on terminal brain cancer patients. Find out what they found in Can Cannabis Cure Cancer?.

Doctor’s Note:

Check out Can Cannabis Cure Cancer?, as well as a whole treasure chest of videos on cannabis that I’ve put together. If you want to see them all now, I put them onto a digital DVD.

Coffee Benefits Blocked by Adding Milk?

Thu, 11/10/2022 - 07:00

I open my video Does Adding Milk Block the Benefits of Coffee? with a graph from a study of mortality versus coffee consumption that suggests coffee drinkers live longer than non-coffee drinkers. Why might that be? Coffee may have beneficial effects on “inflammation, lung function, insulin sensitivity, and depression,” perhaps due in part to a class of polyphenol phytonutrients found in coffee beans called chlorogenic acids, which have been proven to have favorable effects in studies where it was given alone in pill form. Indeed, they have shown beneficial effects, such as “acute blood pressure-lowering activity,” dropping the top and bottom blood pressure numbers within hours of consumption, as you can see in the graph below and at 0:40 in my video. So, which coffee has the most chlorogenic acids? We know how to choose the reddest tomato and the brightest orange sweet potato, indicating that plant pigments are antioxidants themselves. So, how do you choose the healthiest coffee?

More than a hundred coffees were tested. Different ones had different caffeine levels, but the chlorogenic acid levels varied by more than 30-fold. “As a consequence, coffee selection may have a large influence on the potential health potential of coffee intake.” Okay, but if coffee can vary so greatly, what does it mean when studies show that a single cup of coffee may do this or that? Interestingly, coffee purchased from Starbucks had an extremely low chlorogenic acid content, which contributed significantly to widening the range.

The Starbucks coffee averaged ten times lower than the others. Could it be that Starbucks roasts its beans more? Indeed, the more you roast, the less chlorogenic acid content there is; chlorogenic acid content appears to be partially destroyed by roasting. Caffeine is pretty stable, but a dark roast may wipe out nearly 90 percent of the chlorogenic acid content of the beans. The difference between a medium light roast and a medium roast was not enough to make a difference in total antioxidant status in people’s bloodstreams after drinking them, and they both gave about the same boost. Other factors, such as how you prepare it or decaffeination, don’t appear to have a major effect either. What about adding milk?

You may remember Nutrient-Blocking Effects of Dairy, a video I produced ages ago, that showed that adding milk prevented the protective effects of tea on artery function. Drink black tea, and, within hours, you get a significant improvement in vascular function, “whereas addition of milk completely blunted the effects of tea.” Indeed, as you can see in the graph below and at 2:37 in my video, the study found that we get a big boost in artery function after drinking tea, but, if we drink the same amount of tea with milk, it’s as if we never drank the tea at all. It’s thought that the milk protein casein is to blame, by binding up the tea phytonutrients. “The finding that the tea-induced improvement in vascular function in humans is completely attenuated after addition of milk may have broad implications on the mode of tea preparation and consumption.” In other words, maybe we should not add milk to tea. In fact, maybe we shouldn’t put cream on our berries either. Milk proteins appear to have the same effect on berry phytonutrients, as well as chocolate, as you can see in the graph below and at 3:15 in my video. If you eat milk chocolate, nothing much happens to the antioxidant power of your bloodstream, but within an hour of eating dark chocolate, you get a nice spike in antioxidant power.


Is this because the milk in milk chocolate crowds out some of the antioxidant-rich cocoa? Milk chocolate may only be 20 percent cocoa, whereas a good dark chocolate may be made of 70 percent or more cocoa solids. That’s not all, though. How much of this cocoa phytonutrient gets into your bloodstream when you eat dark chocolate compared to milk chocolate? If you eat the same amount of dark chocolate with a glass of milk, it blocks about half of the antioxidant power, as you can see in the graph below and at 3:43 in my video.

What about coffee beans? When milk was added to coffee in a test tube, the antioxidant activity decreased by more than half with just a splash of milk and reduced by 95 percent in a latte or another preparation with a lot of milk. But, what happens in a test tube doesn’t necessarily happen in a human. You don’t know until you put it to the test. And, indeed, as you can see at 4:22 in my video, over the course of a day, significantly fewer chlorogenic acids made it into people’s bloodstreams when they drank their coffee with milk as compared to black. The added milk cut their absorption of chlorogenic acids by more than half.

What about soymilk? In a test tube, coffee phytonutrients appear to bind to egg and soy proteins, as well as dairy proteins. Computer modeling shows how these coffee compounds can dock inside the nooks and crannies of dairy, egg white, and soy proteins, but what happens in a test tube or computer simulation doesn’t necessarily happen in a human. Eggs haven’t been put to the test, so we don’t know if having omelets with your black coffee would impair absorption. And soymilk?

Soymilk has some inherent benefits over cow’s milk, but does it have the same nutrient-blocking effects as dairy? The answer is no. There is no significant difference in the absorption of coffee phytonutrients when we drink our coffee black or with soymilk. Soy proteins appear to bind initially to the coffee compounds in the small intestine, but then our good bacteria can release them so they can be absorbed in the lower intestine. So, “considering the reversible nature of binding,” it doesn’t seem to be as relevant if you add soymilk, but skip the dairy milk.

I explore the effects of dairy on the health benefits of berries in my video Benefits of Blueberries for Blood Pressure May Be Blocked by Yogurt.

Wondering about other milks? Almond, rice, and coconut-based milks have so little protein that I doubt there would be a blocking effect, but they have never been tested directly to my knowledge.

Blueberries to Benefit Mood and Mobility

Tue, 11/08/2022 - 07:00

The consumption of berries can enhance “beneficial signaling in the brain.” Plant foods are our primary source of antioxidant and anti-inflammatory compounds, but some plant foods may be better than others. As I’ve explored before, a randomized, double-blind, placebo-controlled trial showed us that one cup of blueberries a day can improve cognition among older adults, and the same happens in children after just a single meal with blueberries, though two cups of berries may work better than one.

As I discuss in my video Benefits of Blueberries for Mood and Mobility, that single hit of berries may also improve mood. In a double-blind, placebo-controlled, crossover study, young subjects were asked a series of questions, such as Are you very slightly or not at all, a little, moderately, quite a bit, or extremely interested? Excited? Strong? Ashamed? And so on. As you can see in the graph below and at 0:55 in my video, before and after drinking the placebo, there was no significant change in young adult participants aged 18 through 21. But, two hours after consuming about two cups of blueberries, their positive mood scores improved significantly. They felt more enthusiastic, alert, inspired, and attentive. The same results were found in seven- to ten-year-old children. Benefits achieved not with some dangerous new mood-enhancing drug or Ritalin, but blueberries—and after just a single meal.

Now, blueberries can’t do everything. Although a cup of berries certainly appears to improve brain function, no improvements in walking (gait) or balance were observed. What if you tried two cups of blueberries a day?Might six weeks of two cups of frozen blueberries a day affect the functional mobility in adults over age 60? Study participants were randomized to prepackaged blueberries or prepackaged carrot juice as a control, and researchers measured tasks, including one where “two bright yellow ropes on the floor outlined the narrow path, and participants were instructed to walk within the roped path.” The blueberries beat out the carrot juice control, and significant improvements suggest “blueberry supplementation may provide an effective countermeasure to age-related declines in functional mobility…” In retrospect, the researchers thought perhaps the control should have been “a true placebo (e.g., cucumber powder) without antioxidant properties,” since the carrots themselves may have offered some benefit, too. Had they used a different control, the blueberry results may have been even more impressive. “Overall, this study demonstrates the need for greater exploration of blueberry supplementation as a nonpharmacologic countermeasure to the public health issue of age-related declines in functional mobility and independence.” Or, to use the punnier version, “dietary interventions with polyphenol-rich [phytonutrient-rich] foods, such as blueberries, present a potentially fruitful strategy for combating some of the deleterious effects of age-related neurodegeneration.” (Emphasis added.)

Isn’t science grand! I love that these studies were conducted.

The video I referred to is Flashback Friday: Benefits of Blueberries for the Brain.

The Link Between Chicken Consumption and Urinary Tract Infections

Thu, 11/03/2022 - 07:00

Only about one in four people have heard of Campylobacter, compared to 90 percent who are familiar with Salmonella. “Although the incidence of these two…gastrointestinal infections is amazingly high,” infecting more than a million Americans every year, “it is even outranked by the incidence of infection caused by extraintestinal pathogenic Escherichia coli (ExPEC)”—a bug even fewer people have likely heard of.

Extraintestinal? That means outside of the intestines, as in causing bladder infections, and pathogenic, meaning disease-causing. Indeed, E. coli results in millions of infections annually. As I discuss in my video Friday Favorites: Urinary Tract Infections from Eating Chicken, “multiple lines of evidence indicate poultry as a major food animal reservoir for urinary tract infections”—that is, a source for the bacteria that cause UTIs in people. (You may recall I explored this several years ago, as discussed in my video Avoiding Chicken to Avoid Bladder Infections.) This is based not only on studies showing that blood infections, brain infections, and urinary tract infections in mouse models can be caused by these kinds of E. coli from commercial chicken meat and eggs, but also on studies of women with multidrug-resistant urinary tract infections reporting significantly more frequent consumption of retail chicken. Similarly, elderly consumers of chicken were significantly more likely to have Cipro-resistant bladder infections compared to those eating no chicken at all. Pork, but not beef, was also associated with increased risk, as you can see below and at 1:14 in my video.

“There have been few observed associations between beef cattle or retail beef and human ExPEC, suggesting that beef cattle are not a reservoir for human ExPEC” (bladder infections), whereas, in chickens, of the up to 90 percent of chicken carcasses harboring E. coli, about one in five isolates tested had the potential to cause urinary tract infections.

What about eggs? We know retail chicken meat “is contaminated with ExPEC isolates that resemble the strains that cause human infections,” but what about retail chicken eggs? Instead of one in five being ExPEC in chicken meat, it was more like just 1 in 20 among eggs, which is closer to levels for pork or beef.

Researchers are so sure that chicken is the primary reservoir that when they find the same kind of strain in a vegetarian, they interpret that “as consistent with human-to-human transmission or errors in reporting of poultry consumption rather than human strains being derived from a source other than chicken.” Someone may claim to be vegetarian but actually eat some chicken, for instance, or perhaps there was human-to-human or even shopping-cart-to-human transmission. (See my How to Shop for, Handle, and Store Chicken video.) Most people fail to sanitize their hands after picking up a package of poultry in the grocery store, so the “bacteria potentially left on the cart could affect other shoppers….A shopper who is not purchasing poultry, or is purchasing poultry and is following safety precautions, could still be exposed to poultry contaminates via the cart.”

“It’s difficult to estimate how much ExPEC exchange can be attributed to person-to-person contact” after the rectum of a poultry consumer has been colonized. Researchers swabbed public restrooms to try to quantify the risk, collecting more than a thousand samples from 56 public restrooms in 33 establishments. As you can see in the graph below and at 3:07 in my video, they found a lot of evidence of E. coli in general, but particularly in restrooms at public parks and fast-food joints—even more so than gas stations, which surprised me. What was really unexpected for me, though, was that women’s restrooms were worse than men’s!

Only about 1 percent of the samples the researchers took were positive for ExPEC bacteria, however, but they were recovered from sites that were not associated with toilets and were not visibly contaminated. So, one might come into contact with ExPEC bacteria with their bare hands after turning off a faucet after washing their hands, for example. In this way, the risk “could not be fully eliminated by careful hand washing or avoidance of fecal-appearing debris”—though it’s probably a good idea to avoid that anyway. Using hand sanitizers after exiting the restroom, not to mention in the meat aisle after touching a package of poultry, may offer additional protection.

What proportion of the seven million bladder infections—a common form of urinary tract infection (UTI)—every year in the United States is caused by chicken meat? “If no more chicken were consumed, how many E. coli UTIs would be prevented and how much would the prevalence decline?” It’s hard to tell because of the “time lag between the acquisition and asymptomatic colonization of the intestine with an ExPEC organism and the development of an infection.” You can eat some contaminated chicken today, but the UTI-causing ExPEC bacteria may hang out in your colon for months before making their way into your bladder and triggering an infection. The reason we know it can take that long is by studying the intestinal population dynamics of UTI-causing E. coli between partners. Increased rectum-to-rectum transfers “might be explained by the high levels of E. coli present in the urine of an infected woman, increasing the probability of transmission via direct contact.” That is, the E. coli could then be transferred to their partners, depending on certain intimate practices, such as cunnilingus.

The bottom line? There is “compelling evidence that retail meat, particularly poultry, serves as an important reservoir for human exposure to antibiotic-resistant E. coli that is causing UTIs. Thus, the term foodborne UTIs or FUTIs has been adopted to describe these infections.”

Certainly, we could decrease the burden of these foodborne bladder infections by developing some sort of ExPEC vaccine, but why not just reduce our contact with fresh or frozen poultry? No harm, no fowl.

Hold on. Who eats undercooked chicken? Typically, it’s a problem of cross-contamination, as I discuss in Food Poisoning Bacteria Cross-Contamination.

These days, there is particular concern about antibiotic-resistant infections. See Past the Age of Miracles: Facing a Post-Antibiotic Age and Friday Favorites: What About Kosher and Organic Chicken? to learn more about bacterial contamination.

Would buying organic be better? See my video Superbugs in Conventional vs. Organic Chicken.

What about treating UTIs? Check out Can Cranberry Juice Treat Bladder Infections?.

Treating Psoriasis with Aloe Vera

Tue, 11/01/2022 - 07:00

Psoriasis is a chronic, inflammatory skin disease that affects about one in 40 people, making it “one of the most frequent chronic skin diseases worldwide.” There are a lot of different drugs for it, some of which cost more than $100,000 a year to get a response. There are cheaper ones, like cyclosporine, but they carry long-term risks of kidney damage, hypertension, and malignancies. In fact, cyclosporine can cause cancer and kidney toxicity in more than 50 percent of the patients treated long-term, and, in terms of risk of malignancies, it carries up to 42 times the rate of cancer. And it doesn’t even work that well: It only keeps the disease at bay in a little more than half of the patients over a four-month period. There’s got to be a better way.

What about plants? “Topical botanical agents for the treatment of psoriasis?” As I discuss in my video Aloe Vera for Psoriasis, aloe vera gel is said to possess “anti-inflammatory, anti-pruritic [anti-itching], and wound-healing properties.” You may recall that it actually made things worse when it was put to the test for healing wounds. (See my earlier video Is Aloe Effective for Blood Pressure, Inflammatory Bowel, Wound Healing, and Burns?.) “The exploitation of aloe preparations has been accompanied too often by misinformation and exaggerated claims in advertising literature and commercially-inspired articles in the press and popular periodicals.” There is some impressive evidence, though. For example, to test its anti-inflammatory properties, it was tested head-to-head against steroids for exposure to mustard gas.

Mustard gas is probably the most widely used chemical warfare agent. It was first used in World War I, and the last widespread military use was in the 1980s during the Iran-Iraq war, with more than 100,000 military veterans and civilians exposed, “and many of them are still suffering from long-term complications,” predominantly itching. Even decades after surviving a gas attack, 70 to 90 percent of victims are still suffering.

Topical steroids, the most frequently administered medications, do help, but long-term use is associated with a variety of side effects and is not recommended. How about safer agents, like aloe vera?

Sixty-seven veterans injured by chemical warfare were randomized to apply either steroids or an aloe vera and olive oil cream, and the aloe vera mixture appeared to work as well as the drug, as you can see in the graph below and at 2:27 in my video.

So, researchers decided to give it a try for the management of psoriasis. By the end of a month-long study, the aloe vera-based cream had cured 83 percent of the patients, compared to the placebo’s cure rate of less than 10 percent, and resulted in “significant clearing of the psoriatic plaques,” the skin lesions.

That’s compared to an inactive placebo, though. How about compared to steroids? Aloe was found to be “more effective…in reducing the clinical symptoms of psoriasis,” as you can see in before-and-after photos below and at 3:02 in my video.

In a double-blind, placebo-controlled study of a commercial aloe vera gel for the treatment of slight to moderate psoriasis, conditions improved in 70 percent of the sites treated with aloe, compared with 80 percent of the placebo-treated areas improving. The placebo beat out the aloe. Indeed, “the high response rate of placebo indicated a possible effect…in its own right, which would make the Aloe vera gel treatment appear less effective.” The placebo was essentially xanthan gum and water, and the researchers figured that, instead of aloe failing, maybe xanthan gum works, too!

All in all, for psoriasis, the “results on the effectiveness of Aloe vera are contradictory,” but applying it on the skin appears safe, so why not give it a try?

You may be interested in my video Is Aloe Effective for Blood Pressure, Inflammatory Bowel, Wound Healing, and Burns?. I have many others in my extended series on aloe, and the most amazing one is probably Can Aloe Cure Cancer?.

Also check out Aloe Vera Gel: Best Treatment for Lichen Planus? and Aloe for the Treatment of Advanced Metastatic Cancer.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live, year-in-review presentations—2015: Food as Medicine: Preventing and Treating the Most Dreaded Diseases with Diet, and my latest, 2016: How Not to Die: The Role of Diet in Preventing, Arresting, and Reversing Our Top 15 Killers.

How to Eat to Reduce Cancer Risk

Thu, 10/27/2022 - 07:00

What does the best available balance of evidence say right now about what to eat and what to avoid to reduce your risk of cancer? 

In 1982, a landmark report on diet, nutrition, and cancer was released by the National Academy of Sciences. It was “the first major, institutional, science-based report on this topic.” The report started out saying that “scientists must be especially careful in their choice of words whenever they are not totally confident about their conclusions.” For example, by that time, it had become “absolutely clear” that cigarettes were killing people. “If the population been persuaded to stop smoking when the association with lung cancer was first reported, these cancer deaths would not be occurring.” If you wait for absolute certainty, millions of people could die in the meantime, which is why, sometimes, you have to invoke the precautionary principle.

For example, “emphasizing fruits and vegetables to reduce the risk of several common forms of cancer.” We’re not completely sure, but there’s good evidence—and what’s the downside? “There are no disadvantages for healthy people eating more fruits and vegetables,” as I discuss in my video The Best Advice on Diet and Cancer.

The 1982 National Academy of Sciences report continued: “The public is now asking about the causes of cancers that are not associated with smoking. What are these causes, and how can these cancers be avoided? Unfortunately, it is not yet possible to make firm scientific pronouncements about the association between diet and cancer. We are in an interim stage of knowledge similar to that for cigarettes 20 years ago. Therefore, in the judgment of the committee, it is now the time to offer some interim guidelines on diet and cancer.”

The committee raised concern about processed meats, for example, and, 30 years later, that concern was confirmed. Processed meat was officially declared “carcinogenic to humans.” Maybe if we had listened back in the early 1980s when the red flag first started waving, then we would have been spared Lunchables, about which a CEO of Philip Morris said: “One article said something like, ‘If you take Lunchables apart, the most healthy item in it is the napkin.’”

The findings of this landmark 1982 diet and cancer report “generated a striking level of disbelief from the cancer community and outright hostility from people whose livelihood depended on foods in question and the food industry whose products were being questioned.” In fact, one of the authors of the report was “accused of ‘killing more people than those being saved,’” and there were formally organized petitions to expel the researchers from their professional societies. Indeed, “clearly a very sensitive nerve was touched.”

The American Meat Science Association and other members of the Council for Agricultural Science and Technology criticized the report and released “Diet, Nutrition, and Cancer: A Critique” in 1982. They agreed that perhaps lives would be saved, but argued that the recommended “reductions in meat consumption would sharply reduce incomes to the livestock and meat processing industries….The fruit and vegetable industries would clearly benefit from the expanded demand for their products if consumers were to implement the guidelines. However, fruits and vegetables account for less than 15 percent of cash receipts for U.S. agriculture.” Most of the money is in “cattle, hogs, poultry products, feed grains, and oil crops.” This reminds me of the tobacco industry memo where Philip Morris spoke of the tobacco industry going bankrupt.

Maybe it’s not the meat that’s causing cancer, the industry critique continued, but all the marijuana people are smoking these days. “How then can one argue that such an abundant diet causes cancer? Or is this only some jealous attack on the goodness of our diet, like that of the Reverend Jonathan Edwards in Puritan times who condemned bear baiting, not because of the pain for the bear but because of the pleasure of the spectators.” You can’t tell us to cut down on meat, they argued, “one of mankind’s few remaining pleasures is that of the table.”

The day the National Academy of Sciences’ landmark report was published was “The Day That Food Was Declared a Poison” according to Thomas Jukes, the guy who discovered you could speed up the growth of chickens by feeding them antibiotics. How dare the National Academy of Sciences recommend people eat fruits, vegetables, and whole grains daily, which were said to contain “as yet unidentified compounds that may protect us against certain cancers. How can one select foods that contain unidentified compounds?…This is not a scientific recommendation; it sounds like ‘health food store’ literature.”

My favorite critique, though, told us to think about the human breast. How can animal fat be bad for us if breast-feeding women create so much of it? Women are animals, and their mammary glands make fat for breast milk. Therefore, we shouldn’t have to cut down on burgers. Huh?

Enough of that. What does the latest science tell us about nutrition and cancer? I’ve just talked about eating more fruits and vegetables. What are the other five recommendations that invoke the precautionary principle? Consumption of soy products may not only reduce the risk of getting breast cancer, but also increase chances of surviving it. In terms of dietary guidance suggestions on foods to cut down on, where evidence is sufficiently compelling, recommendations included “limiting or avoiding dairy products to reduce the risk of prostate cancer; limiting or avoiding alcohol to reduce the risk of cancers of the mouth, pharynx [throat], larynx, esophagus, colon, rectum, and breast; avoiding red and processed meat to reduce the risk of cancers of the colon and rectum; [and] avoiding grilled, fried, and broiled meats to reduce the risk of cancers of the colon, rectum, breast, prostate, kidney, and pancreas.” In this context, the researchers are talking about all meat, including poultry and fish.

Look, we all have to make dietary decisions every day and “cannot wait for the evolution of scientific consensus.” Until we know more, all we can do to protect ourselves and our families is “act on the best available evidence” we have right now.

The level of evidence required to make decisions depends on the level of risk. If we’re talking about a new drug, for example, given the fact that medications kill more than a hundred thousand Americans a year—which is Why Prevention Is Worth a Ton of Cure—you want to be darn sure that the benefits outweigh the risks before you prescribe or take a drug. But what level of evidence do you need to eat broccoli? Do you need randomized, double-blind, placebo-controlled trials? (How would you even design a placebo vegetable?) Even if all of the evidence suggesting how powerful broccoli is turned out to be some crazy cruciferous conspiracy, what’s the worst that could have happened? It’s healthy anyway! That’s the beauty of safe, simple, and side effect–free solutions provided by the lifestyle medicine approach. They can only help.

I have so many more videos on diet and cancer for you. How Not to Die from Cancer may be a good place to start before you check out some more in related videos.

How to Treat Canker Sores

Tue, 10/25/2022 - 07:00

Vitamin C, turmeric, beta-glucan fiber, and vitamin B12 are put to the test for recurring canker sores (aphthous ulcers).

Canker sores can be “a painful and often recurrent inflammatory process of the oral mucosa,” the lining of our mouths. Similar to other chronic inflammatory conditions, DNA damage due to oxidative stress caused by free radicals is thought to play a role.

Normally, free radical production is balanced with antioxidants, but if the concentration of free radicals gets too high and our antioxidant enzymes and the antioxidants we get in our diet “cannot compensate for these radicals, the balance changes in favor of the oxidants”—that is, in a pro-oxidant direction. This can lead to oxidative damage within our body. Does that mean that people who experience recurring canker sores—also known as recurrent aphthous stomatitis (RAS)—have fewer antioxidants, more oxidation, and more DNA damage? Yes, yes, and yes. As you can see in the graph below and at 0:51 in my video Best Supplement for Canker Sores, they exhibit more pro-oxidants and more oxidative stress in their bloodstream, lower antioxidant status, and more DNA damage. This suggests it might be possible for antioxidants to help improve the DNA damage caused by recurring canker sores, but you don’t know until you put it to the test.

Sixteen boys and girls around age 12 with recurring canker sores were given a whopping 2,000 mg (2 g) of vitamin C a day. That’s considered the tolerable upper daily limit for adults before you start getting diarrhea, and 1,200 mg may have that effect on a 12-year-old, but it’s all about risks versus benefits. How did they do? As you can see in the graph below and at 1:33 in my video, 15 out of the 16 kids cut the number of canker sores they were getting at least in half. In the three months before they started the vitamin C, they had averaged four canker sores each, but in the three months they were on it, they each had less than one on average. When they stopped the vitamin C for another three months, the ulcers started coming back. Then, when they once again added the vitamin C, the canker sore rate dropped again.

What about directly applying antioxidants, like a turmeric gel? Let’s find out. A turmeric gel containing 2 percent curcumin, the yellow pigment in the spice turmeric, was swabbed directly onto canker sores twice a day and “significantly reduced pain intensity and size of the aphthous ulcer [canker sore] compared to placebo,” which was a gel containing no active ingredient. Okay, but wouldn’t it be nice to see a comparison to an active treatment from an independent research group, rather than this study without an active treatment that was funded by the curcumin gel manufacturer?

Yes, and here we go. This randomized clinical trial compared a generic 2 percent curcumin gel to a prescription steroid gel and found that the curcumin worked just as well. This provides “strong evidence that [topical] curcumin gel can be used as an effective and safer alternative to steroids in treatment of RAS.” You may remember I’ve previously discussed that topical honey beat out the same steroid for both ulcer healing and pain reduction, as you can see in the graph and at 2:46 in my video. So, if you’re going to use something topically, honey seems better, but what if, instead of a topical application, you just want to swallow something like vitamin C but want something that doesn’t give you diarrhea?

Thirty-one patients with recurring canker sores were split into two groups and received either 20 mg a day of placebo or yeast beta-glucan fiber, which is the amount found in just an eighth of a teaspoon of brewer’s yeast or nutritional yeast. As you can see below and at 3:17 in my video, the placebo group experienced no significant change, whereas ulcer severity in the yeast group was cut nearly in half. So, now you have another useful alternative.

If it’s all about antioxidants, can’t you just treat recurring canker sores by eating a plant-based diet high in fruits and vegetables? That hasn’t been put to the test, but keep in mind a plant-based diet could also make things worse if one is not ensuring a regular reliable source of vitamin B12 through supplements or fortified foods. For example, a 30-year-old women had recurring canker sores for four years. She ate few animal products and didn’t supplement with vitamin B12, so she became B12-deficient and began experiencing weakness, tiredness, numbness, and tingling. She was immediately started on vitamin B12, and her deficiency symptoms got better. Her canker sores also improved and she experienced “a rapid and complete recovery” within weeks of starting vitamin B12 after years of suffering.

We’ve known since the 1970s that vitamin B12 deficiency can lead to canker sores—so much so that it’s recommended to consider B12 deficiency any time a patient has with recurring canker sores. In fact, a number of nutrient deficiencies may contribute. A study compared the lab tests of those with recurrent canker sores to those without and found that more than half of the canker sore group showed evidence of hematinic deficiencies—that is, blood-forming nutrient deficiencies. In contrast, less than one in ten in the non-canker sore group exhibited these deficiencies. In this case, we’re talking about iron and folate deficiency in addition to vitamin B12 deficiency. When the study participants were given supplements, their canker sores improved and this was more pronounced among those who had no family history of canker sore problems.

You can see how vitamin and mineral supplements might help people who are deficient, but might a supplement like vitamin B12 help people who are not vitamin B12 deficient? Apparently so. As the title of the study states, “cyanocobalamin”—the most common form of supplemental B12—“may be beneficial in the treatment of recurrent aphthous ulcers [canker sores] even when vitamin B12 levels are normal.” The researchers took a group of 72 patients with frequent canker sores and gave them vitamin B12, regardless of what their levels were. Ninety-six percent of the participants got better regardless of whether they started out vitamin B12–deficient or with normal vitamin B12 levels in their blood, as you can see below and at 5:37 in my video. In this case, there was no control group, though, so we don’t know how many would have gotten better without the vitamin B12 supplement. In addition, the researchers injected the vitamin B12, and injections can have an even greater placebo effect than pills—especially with something like a syringe of vitamin B12, which has a striking mad-scientist-looking ruby red color, as you can see below and at 5:57 in my video.

If only there were a randomized, double-blind, placebo-controlled trial of oral vitamin B12 for canker sores. And, here we go. In this case, 1,000 micrograms of sublingual vitamin B12 were taken every day for six months. It took five months, but, eventually, the duration of canker outbreaks, the number of ulcers, and the level of pain were significantly reduced, “regardless of initial vitamin B12 levels in the blood.” So, whether you are vitamin B12–deficient or not, B12 supplements seem to help. By the end of the study, twice as many in the vitamin B12 group appeared to have been cured. The researchers concluded that “vitamin B12 treatment, which is simple, inexpensive, and low-risk, seems to be effective,” but don’t forget that it appeared to take months before it started working. In another randomized, double-blind, placebo-controlled trial of a vitamin B12 ointment applied directly to the canker sores, a significant reduction in pain was demonstrated within only two days compared to placebo, regardless of whether the participant was vitamin B12–deficient or not.

Here’s a link to the video on the remarkable honey results I mentioned: Flashback Friday: Topical Honey for Canker Sores.

The Benefits of Broccoli and a New Recipe

Thu, 10/20/2022 - 07:00

If there were such a thing as a “superfood,” cruciferous vegetables like broccoli would certainly be wearing the cape. Along with kale, collards, cabbage, bok choy, cauliflower, and many others in that vegetable family, crucifers contain a relatively unique class of phytonutrients that can potentially help prevent DNA damage, metastatic cancer spread, and lymphoma; activate defenses against pathogens and pollutants; boost your liver detox enzymes; target breast cancer stem cells; and reduce the risk of prostate cancer progression. That’s why I include cruciferous veggies in my Daily Dozen healthiest-of-healthy-foods checklist. For more information and all of my videos on broccoli, check out the topic page.


Recipe: Mexican-Inspired Bowl

If you’ve found yourself with a sudden hankering for broccoli, try this recipe from Ángela, our Spanish Social Media and Program Coordinator. With broccoli, beans, whole grains, and a homemade salsa, her recipe will check off several of your Daily Dozen boxes for the day. Get the free recipe here, and watch a video on how it’s made on our Instagram.


  Host a Screening

Share the latest in evidence-based nutrition with your community by hosting a free screening of my “How Not to Die” or “Evidence-Based Weight Loss” presentation. Each video runs for approximately one hour. Your free Digital Event Kit will include the video, an introduction to NutritionFacts, a fun trivia game for attendees, and tips for hosting. For more information and to sign up, go here.



Volunteer Spotlight: Midge Constantino

I’ve been a volunteer for NutritionFacts for a couple of years. I assist on a variety of projects, but my primary role is to compile lists of videos that are added as YouTube cards accompanying the recordings of Dr. Greger’s Live Q&As. His mission of sharing evidence-based nutrition information to the general public is incredibly important, since misinformation sadly abounds. It’s been such an honor to help support NutritionFacts in my own little way.

I believe that breakfast is the most important meal of the day, and my favorite is Chocolate Oatmeal from The How Not to Die Cookbook. It’s yummy, very easy to prepare, and sustains me throughout the morning.


Top Three Videos

Do Vegans Have Lower Bone Mineral Density and Higher Risk of Osteoporosis?

Those eating plant-based tend to be so much slimmer that their bone mass may suffer.


The Best Diet for Healthy Aging

Swapping just 1 percent of plant protein in place of animal protein was associated with significantly less age-related deficit accumulation.


Antibiotic Resistance Genes in the Guts of Vegetarians vs. Meat-Eaters

Those eating plant-based have a reduced load of antibiotic resistance genes in their gut.


P.S. We hit 200 million lifetime YouTube views! As you know, I made it my life’s work to reach as many people as possible with health information that can change and save lives. I’m grateful to all of you for watching and sharing these videos, helping to spread the healthy-living message.



Every month, I do a live Q&A right from my treadmill, and the next one is today, October 20!

At 3 pm ET, tune in on our Facebook page, YouTube channel, or (new!) directly on

You can find links to past live Q&As here on If that’s not enough, remember, I have an audio podcast to keep you company, too.

Tea Tree Oil and Hormonal Side Effects

Tue, 10/18/2022 - 07:00

Do the estrogenic effects of tea tree oil get absorbed through the skin?

Concern has been raised about a “possible link between gynecomastia, topical lavender, and tea tree oil.” As I discuss in my video Does Tea Tree Oil Have Hormonal Side Effects?, gynecomastia is the abnormal development of breast tissue. (You can see a photo at 0:14 in my video.) You may recall that I’ve talked about lavender before, but what about tea tree oil?

It all started with a case series published in The New England Journal of Medicine. The researchers described three young boys in whom breast growth “coincided with the topical application of products that contained lavender and tea tree oils.” How do we know the products were to blame? “Gynecomastia resolved in each patient shortly after the use of products containing these oils was discontinued. Furthermore, studies in human cell lines indicated that the two oils had estrogenic and antiandrogenic activities,” that is, pro-female and anti-male hormone activities. The researchers concluded that “repeated topical exposure to lavender and tea tree oils probably caused prepubertal gynecomastia in these boys.”

A tea tree oil company representative pointed out that “only one of three boys (Patient 2) was exposed to any amount of tea tree oil,” while all three subjects were exposed to lavender oil. So, lavender oil may have been to blame in all three cases. How did the researchers respond? “There may be a valid argument that it was the lavender oil that caused the gynecomastia. However, the tea tree oil had activity similar to that of lavender oil with respect to the in vitro estrogenic and antiandrogenic effects.”

Let me walk you through that. As you can see below in the graph and at 1:24 in my video, if you drip a tiny amount of estrogen on human breast cancer cells in a petri dish, you can spike their growth more than twelve-fold. If you add an estrogen blocker along with the estrogen, though, it abolishes the effect. But, adding increasing amounts of tea tree oil to the breast cancer cells causes their growth to increase. The reason we know it’s an estrogenic effect is because the growth decreases when you add the estrogen blocker. This appears to be pretty convincing, but herbal proponents argue that “in vitro testing alone is not adequate grounds for indicting traditionally used products and may raise public fear.”

The Tea Tree Oil Industry Association specifically argued “that only 3 of more than 100 compounds” of pure tea tree actually make it through the skin, so the researchers should have just measured the hormonal effects of those three compounds—which they did later that year.

As you can see in the graph and at 2:25 in my video, dripping increasing concentrations of whole tea tree oil on breast cancer cells in a petri dish can increase their growth when compared to an oil with no estrogenic effect, like eucalyptus oil. However, if you only look at the three components of tea tree oil that actually make it into your bloodstream when you apply them on your skin, none appears to have any estrogenic effects. None of the components that penetrate the skin appears to act as an estrogen, “neither alone nor in combination,” so you can’t extrapolate the petri dish effects of the whole oil to what one might see when it’s applied on the skin. What you see in the petri dish may not be identical to what you see in a person.

This new data led European consumer safety officials to conclude that “the hypothesized correction…of gynecomastia to the topical use of Tea Tree Oil is considered implausible.” In fact, if the anti-male hormone components of tea tree oil remain on the skin, why not use it to treat women who feel they are affected by hirsutism, or excessive hairiness? A study was conducted on such women who were instructed to spray themselves with a dilute lavender/tea tree oil spray versus placebo twice a day, morning and evening, on “areas affected by hirsutism” for three months. Before and after the treatment, “hairs were taken from four different body areas: chin, chest, thigh and upper arms.” After three months, no change was detected in the hair diameter of the placebo group, as expected. But, in the lavender/tea tree oil group, all the hairs ended up thinner, as you can see in the graph and at 3:46 in my video.

This showed that the combination of lavender and tea tree oils applied locally on skin could be effective in reducing mild excessive hairiness, potentially representing “a safe, economic, and practical instrument in the cure of this disease.”

For additional information beyond potential hormonal effects, see my video Is Tea Tree Oil Safe?. I continue to add new tea tree videos, so keep an eye on the topic page.

To learn more about lavender specifically, see Lavender for the Treatment of Generalized Anxiety Disorder.

Safety Concerns with Tea Tree Oil?

Thu, 10/13/2022 - 07:00

What, if any, are the caveats for tea tree oil use and tips on safe storage?

Is tea tree oil toxic? That’s the topic of my video, Is Tea Tree Oil Safe?. “Anecdotal evidence…suggests that the topical use of the oil is relatively safe, and that adverse events are minor, self-limiting and occasional.” Published data, however, add some caveats: It can be “toxic if ingested in higher doses and can also cause skin irritation at higher concentrations.”

Normally, tea tree oil reduces skin inflammation. Researchers injected histamine into the skin of 27 volunteers, the equivalent of getting bitten by a fire ant. The application of tea tree oil significantly decreased the associated swelling and discoloration—the big, red, swollen mark. As you can see in the graph below and at 0:45 in my video, the swelling and discoloration continues to get worse after application of a placebo oil, before finally beginning to calm down at around 40 minutes. If you apply half of a single drop of pure tea tree oil at 20 minutes, though, it stops the inflammation in its tracks and it immediately starts to get better.

Some people are sensitive to tea tree oil, however, and it can trigger a rash, as you can see below and at 1:07 in my video. This is relatively rare, though, with only about 1 percent of older children or adults having such a reaction. None of the 40 younger children tested had a reaction, which is good, since tea tree oil may be found in about 5 percent of diaper wipes and lotions.

When they do occur, “most reactions are caused by the application of pure oil,” so there are recommendations to keep the concentration of tea tree oil products applied to the skin under 1 percent. “Moreover, manufacturers were advised to consider the use of antioxidants and/or specific packaging [such as dark bottles] to minimize exposure to light,” as aged oxidized oils are more likely to induce allergic reactions. Hundreds of different components have been identified in tea tree oil, but the composition changes when the oil is exposed to air, light, humidity, and higher temperatures. “With increasing age, the oil develops a green-brownish colour, the viscosity changes, and the smell becomes turpentine-like.” These are all bad signs.

Even “fresh” tea tree oil shouldn’t be ingested, though. Two hours before arriving at the pediatric critical care unit, a four-year-old’s “mother had given him approximately 2 teaspoons of 100% pure tea tree oil,” and, within 30 minutes, he had trouble walking and shortly thereafter fell into a coma. It was noted that the tea tree oil was in a bottle “without a childproof cap,” but it didn’t matter in this case because the cap wasn’t mother-proof either.

Similar cases have been reported at even less than two teaspoons, though the reported adult poisoning cases have tended to involve larger doses. Thankfully, no human deaths caused by tea tree oil have been reported, though it has been implicated in the deaths of pets when used inappropriately, such as trying to treat fleas. “Cats in particular are at risk because of their habit of licking their fur.”

In humans, though, it appears that tea tree oil can be used safely “by avoiding ingestion, applying only diluted oil topically and using oil that has been stored correctly.”

What about the reports of gynecomastia (abnormal breast development) among young boys exposed to tea tree oil? That’s the subject of my video Does Tea Tree Oil Have Hormonal Side Effects?.

Safety Concerns with Henna?

Tue, 10/11/2022 - 07:00

Is there risk of lead and PPD contamination of red and black henna?

The “average adult uses nine personal care products each day, with 126 unique chemical ingredients.” We used to think that anything applied to the skin would “always remain on the surface of the body,” and the only thing you had to worry about were problems like local skin irritation. But, over recent decades, “it was recognized that some topically applied substances can penetrate into or through human skin” and end up circulating throughout our bodies.

Take the toxic heavy metal lead (Pb), for example. As you can see in the graph below and at 0:38 in my video Is Henna Safe?, to see if lead could be absorbed through the skin into the body, researchers applied lead to a subject’s left arm and then measured the level of lead in the sweat coming off their right arm over the next few days. They observed a big spike, proving nearly 30 years ago that “lead can be absorbed through skin and rapidly distributed throughout the body.”

This led public health authorities “to recommend that parents avoid using cosmetics on their children that could be contaminated with Pb.” Which cosmetics might those be? Because it’s a natural constituent of many color pigments, lead has been found in a wide range of cosmetic products—from eye liner and lip gloss to hair cream and nail polish, as you can see below and at 1:07 in my video. The FDA has set an upper limit for lead at 20 parts per million. Though only some samples of henna exceeded this upper limit, because henna is “used for hair treatment, as a substitute for chemical hair dyes and also for temporary tattoos, these quantities of Pb that remain on the skin or hair for a long time cannot be safe.” Indeed, studies suggest that lead “may have no identifiable safe exposure level, with even the lowest levels shown to affect the fetus and the central nervous system in children.” “Thus, the use of henna especially among children may constitute a public health risk.” So, “increasing awareness of henna’s serious toxic implications seems to be the only reliable means of ending or at least reducing the use of such hazardous material especially when children are involved.”

Traditionally, henna was just the dried powdered leaves of a plant. More recently, though, other ingredients have been added to give it a stronger color, such as lead, said to be “one of the most common and egregious additives in henna.” But, lead is not as common as paraphenylenediamine (PPD), a coal tar derivative.

“The red paste traditionally used, known as ‘red henna,’ rarely produces adverse effects,” but to achieve a darker pigment, known as “black henna,” various additives may be used, including “animal urine.” Better pee than PPD, though, “a coal-tar hair dye” that can cause nasty skin reactions, such as blistering and scarring. Why add PPD at all? “In addition to achieving a darker and longer-lasting color, PPD helps shorten the duration of the tattooing process” from as long as 12 hours down to less than 2 hours. So, while the use of black henna may be “tempting,” it has the potential for both short- and long-term side effects.

How common are these reactions? The best estimate is about 2.5 percent, which means 1 in 40 kids who get a black henna tattoo may have an allergic reaction. Unfortunately, this practice “has become fashionable, ever since the Spice Girls decorated themselves with these body designs.” (Thanks a lot, Spice Girls!) There’s no such thing as natural black henna, so “perhaps it is best to respect the traditional practice of red henna, lest a temporary tattoo turn into a permanent scar.”

The problem is that “PPD can be found in products labeled as ‘red henna,’ too,” so just because it’s red doesn’t mean it isn’t risky. This is bad news for the $100 million industry.

Because henna of all colors is so often adulterated, under FDA guidelines, “henna should not be applied to the skin at all.”

Chlorella Put to the Test

Thu, 10/06/2022 - 07:00

Chlorella is put to the test for liver disease, cholesterol, and detoxifying carcinogens.

“Depression is a debilitating mental disorder with a severe impairment to quality of life,” but, as I’ve discussed before, the drugs don’t work particularly well and have a bunch of side effects. “For these reasons, searching for alternative antidepressant agents with proper efficacy and safety is necessary.” Well, there is a green algae called Chlorella that “has been used as a dietary supplement and alternative medicine in Far East countries for hundreds of years.” Why not put it to the test?

One of the studies I review in my video Friday Favorites: Detoxifying with Chlorella is a randomized controlled trial of Chlorella in patients with major depression. Subjects were randomized to either standard therapy or standard therapy plus 1,800 mg of Chlorella, which is about three-quarters of a teaspoon a day, and the researchers found that the subjects on Chlorella had significant improvements in “physical and cognitive symptoms of depression as well as anxiety…” Wow!

Okay, but what word is missing in the title of the study? “A randomized controlled trial of…Chlorella.” What we want is a randomized placebo-controlled trial. In the study, researchers compared Chlorella to nothing. Half of the subjects got a special treatment (the Chlorella) while the other half got nothing. That’s the perfect set-up for the placebo effect, particularly when the measured outcomes are primarily subjective feelings. Now, you could argue, “Look, that much Chlorella would only cost about 10 cents a day, it’s healthy for you anyway, and depression is such a serious disease. Why not just give it a try?” Excellent points, but I’d still like to know if it actually works or not.

You may recall another Chlorella study I’ve discussed before that suffered from a similar problem, but at least that one had an objective quantifiable outcome: a significant decrease in liver inflammation. Nevertheless, that study also didn’t have a control group, so it’s possible the subjects would have just gotten better on their own for some reason.

What we need is a randomized, double-blind, placebo-controlled trial of Chlorella for liver disease…and we finally got just that. And, not just any liver disease, but non-alcoholic fatty liver disease, which, thanks to the obesity pandemic, now affects one in four people on Earth. Let’s see if 1,200 mg of Chlorella  will help. (That’s just about a daily half-teaspoon, costing about nickel a day.) As you can see below and at 2:21 in my video, the researchers saw significant drops in liver inflammation, perhaps because the subjects lost significantly more weight—about a pound a week over the eight weeks—and that would explain the significant improvement in fasting blood sugars that was also found. The researchers conclude that Chlorella has “significant weight-reducing effects” with “meaningful improvements” in liver function.

How about a double-blind, randomized, placebo-controlled study of Chlorella for cholesterol? “Compared with the control group, the Chlorella group exhibited remarkable changes in total cholesterol…” How remarkable were the changes? Only 1.6 percent, which seems pretty unremarkable. And note that the study evaluated total cholesterol. If you look at what really matters—the so-called bad LDL cholesterol—there was no effect whatsoever, as you can see below and at 3:01 in my video. Thankfully, that’s not what other studies found. A meta-analysis of 19 randomized controlled trials of Chlorella for cholesterol, involving hundreds of subjects, found that those taking Chlorella did drop their LDL cholesterol by eight points on average and even dropped their blood pressure a few points. Four grams or more a day for at least eight weeks seems to be the magic formula, which would be about two daily teaspoons. That’s a lot of Chlorella, but if you can find a palatable way to take it, it might help.

In a more recent study, a double-blind, randomized, and placebo-controlled dietary cholesterol challenge, researchers had 34 study subjects eat three eggs a day (a total of 510 mg of dietary cholesterol) with either a few spoonful of Chlorella or a matched placebo for four weeks. As you can see below and at 3:57 in my video, the participants had a 14 percent rise in LDL cholesterol from just eating the eggs alone, but with the Chlorella, it was significantly less. Therefore, Chlorella can play “a useful role in maintaining healthy serum [blood] cholesterol levels,” though another way would be not to eat three eggs a day.

That reminds me of another study that was performed “to assess the ability of Chlorella vulgaris to detoxify carcinogenic HCAs,” which are heterocyclic amines, the cancer-causing chemicals created when you fry, bake, broil, or barbecue meat. The Chlorella did seem to lower the levels of one of the cooked meat carcinogens flowing through the subjects’ bodies but didn’t quite reach statistical significance, as you can see below and at 4:27 in my video.

What about polycyclic aromatic hydrocarbons (PAHs), another class of cancer-causing compounds found particularly in smoked meats and cigarettes that “includes numerous genotoxic [DNA-damaging] carcinogens”? Again, Chlorella did seem to lower levels but not significantly so. Still, if you’re going to have eggs and ham for breakfast, might as well try to add lots of Chlorella to make them green eggs and ham. 

How Might Ginger Help with Obesity and Fatty Liver Disease?

Tue, 10/04/2022 - 07:00

Ground ginger powder is put to the test for weight loss and nonalcoholic fatty liver disease (NAFLD).

Ginger has been used in India and China for thousands of years to treat illnesses, but so has mercury, so that doesn’t really tell you much. That’s what we have science for. But, when you see article titles in the medical literature like “Beneficial Effects of Ginger…on Obesity and Metabolic Syndrome: A Review,” for example, you may not be aware the researchers are talking about the beneficial effects of ginger on fat rats. Why don’t they just conduct human clinical studies? That may be attributed to “ethical issues” and “limited commercial support,” for instance. Limited commercial support I can see: Ginger is dirt cheap, so who’s going to pay for the study? But ethical issues? We’re just talking about giving people some ginger.

Cross-sectional studies in which you take a snapshot in time of ginger consumption and body weight are relatively inexpensive and easy to do. Researchers have found that people who are obese tend to eat significantly less ginger, so they suggest this “demonstrated that the use of ginger could have relevance for weight management.” You can see a chart below illustrating this and at 0:59 in my video Benefits of Ginger for Obesity and Fatty Liver Disease. But, maybe ginger consumption is just a marker of more traditional, less Westernized junk-food diets. You don’t know…until you put it to the test.

A randomized controlled trial was conducted to assess the effects of a hot ginger beverage made with two grams of ginger powder in one cup of hot water, so about one teaspoon of ground ginger stirred into a teacup of hot water. That’s about five cents’ worth of ginger. The findings? After drinking the ginger beverage, the participants reported feeling significantly less hungry and, in response to the question “How much do you think you could eat?” described lower prospective food intake.

Since the control was just plain hot water, the participants knew when they were getting the ginger so there could have been a placebo effect. The researchers considered putting the ginger into capsules to do a double-blinded study, but they thought part of the ginger’s effect may actually be through taste receptors on the tongue, so they didn’t want to interfere with that with a capsule.

Not all of the effects were just subjective, though. Four hours after drinking the hot beverage, the metabolic rate in the ginger group was elevated compared to control, as you can see in the graph below and at 2:12 in my video. Though, in a previous study, when fresh ginger was added to a meal, there was no bump in metabolic rate. The researchers of the hot ginger beverage study suggest this discrepancy is “likely due to the different method of ginger administration,” giving participants fresh ginger instead of dried ginger powder, and there are dehydration products that form when ginger is dried that may have unique properties.

“Although satiety and fullness were greater with ginger compared to control, [the researchers] have no objective measure of food intake.” They didn’t then go on to follow the participants to see if they actually ate less for lunch. The problem is there’s never been a randomized, double-blind, placebo-controlled study of that much ginger and weight loss…until now.

After 12 weeks of that same teaspoon of ginger powder a day, but this time hidden in capsules, consumption of ginger “significantly reduced BMI,” that is, body mass index. As you can see in the graphs at 3:12 in my video, there was no change in the placebo group, but there was a drop in the ginger group. Body fat estimates didn’t really change, though, but that was kind of the whole point.

What about using ginger to pull fat out of specific organs, like the liver? Evidently, “treatment with ginger ameliorates fructose-induced fatty liver…in rats.” You know what else would have worked? Not feeding them so much sugar in the first place. We aren’t rats, though. We didn’t have this type of study on humans…until now: “Ginger Supplementation in Nonalcoholic Fatty Liver Disease: A Randomized, Double-Blind, Placebo-Controlled Pilot Study” in which participants were given a teaspoon of ginger a day or placebo for 12 weeks.

All of the subjects were told to get more fiber and exercise, and to limit their dietary cholesterol intake. (My video How to Prevent Non-Alcoholic Fatty Liver Disease discusses why this is important.) So, even the placebo group should improve. And how did the ginger group do? Any better? Yes. Daily consumption of just one teaspoon of ground ginger a day “resulted in a significant decrease in inflammatory marker levels,” improvements in liver function tests, and a drop in liver fat. All for five cents’ worth of ginger powder a day. And what are the side effects? A few gingery burps?

I searched for downsides and didn’t find any other than ginger paralysis. What? Indeed, “in 1930, thousands of Americans were poisoned by an illicit extract.” Hold on. Who drinks ginger extract? The year 1930 was during the Prohibition, so some people bought ginger extract as a legal way to get their hands on alcohol. “It was the poor man’s way of getting a drink of liquor.” But, “bootleggers had taken advantage of the demand for this old household remedy as an alcoholic beverage” and swapped in a cheaper ginger substitute—a varnish compound—”in order to make greater money profits.” The moral of the story: Don’t drink varnish.

The video about the dietary cholesterol effect that I referred to is How to Prevent Non-Alcoholic Fatty Liver Disease. Oats might help, too, as you can see in Can Oatmeal Help Fatty Liver Disease?. And, for even more on fatty liver disease, check out The Best Diet for Fatty Liver Disease Treatment and How to Avoid Fatty Liver Disease.

Why I Don’t Recommend Melatonin Supplements

Thu, 09/29/2022 - 07:00

Over-the-counter melatonin (“anti-gonad hormone”) supplements tend not to contain what they say they do, and the contaminants could be dangerous.

If you’re crossing three or more time zones during a journey and plan to stay at your destination for a week or more, long enough to make it worthwhile, you can adjust your body clock to the new time by “using behavioural and, if desired, pharmacological methods.” The behavioral method is light exposure and light avoidance at specific times of the day based on which direction you’re going and how many time zones you cross. I feature a helpful table with “recommendations for the use of bright light to adjust body clock after time zone transitions” at 0:23 in my video Are Melatonin Supplements Safe?, which you can also see below. You may want to take a picture or screengrab it for future reference.

The pharmacological intervention is melatonin. “It is called the ‘darkness hormone’ sometimes because…it is secreted at the onset of darkness and is suppressed by light.” A little gland in the center of your head starts to secrete it as soon as it gets dark and shuts off when the sun comes up in the morning, thereby helping to set your circadian rhythm. A lot of research has been conducted on treating jet lag, but most of it has been on rats instead of people, as you can see below and at 0:53 in my video. But, of the handful of human trials that have been done, most have found that taking melatonin “close to the target bedtime at the destination” to try to sync your body to the new time can effectively decrease jet-lag symptoms after long flights “crossing five or more time zones.” It’s important to note that “melatonin differs from most or all other drugs in that the timing of the dose is critical and determines the effect; given at the wrong time it will delay circadian adaptation to local time,” making jet lag even worse. For example, if you were to take “melatonin at bedtime when traveling west,” it “actually could result in a phase advance” when a “phase delay is desired.”

Taking a daily dose of melatonin between 0.5 and 5 mg of melatonin seems to be “similarly effective” in terms of helping with jet-lag symptoms, but the higher dose does have more of a sleeping pill-type effect, allowing people to “fall asleep faster and sleep better after 5mg than 0.5mg,” but that appears to plateau at about 5 mg. Those are massive doses, though. Even taking only a 3 mg dose produces levels in the bloodstream 50 times higher than normal nightly levels. It works, but we don’t know how safe that is. After all, in the early days, melatonin “was known as an anti-gonadal hormone,” with human-equivalent doses of just 1 or 2 mgs reducing the size of sex organs and impairing fertility in laboratory animals. Now, obviously, rats aren’t people, but “considering the pronounced effects of…melatonin on reproductive physiology in these nonhuman mammals, to assume they would not have some sexual effects in humans would almost seem naive.” In fact, the researchers speculated that perhaps melatonin could one day play a role as some sort of a “contraceptive agent in both human males and females.”

Wouldn’t we know about these effects, though? Well, how? Melatonin is available over the counter (OTC) as a dietary supplement, so there isn’t any post-marketing surveillance like there is with prescription drugs. “Without a license, there is no obligation for undesirable side effects following melatonin use to be recorded.” And, let’s not forget about the purity problem. Supplements are so poorly regulated that that you never really know what’s actually in them. Indeed, the “purity of melatonin…cannot be guaranteed. For these reasons, melatonin cannot be recommended….”

Is the purity issue just theoretical though? You don’t know until you put it to the test.

Indeed, due to the “poor quality control of over-the-counter melatonin,” what the labels “say is often not what you get.” Melatonin is not only one of the most popular supplements among adults, but among children, too. An analysis of 31 different brands found that most had just a fraction of what was claimed. What makes that even more egregious is that actual melatonin content varied up to nearly 500 percent compared to what it said on the label. “The most variable sample was a chewable tablet (and most likely to be used by children). It contained almost 9 mg of melatonin when it was supposed to contain 1.5 mg,” which could result in a hundred times higher than natural levels. “In short, there was no guarantee of the strength or purity of OTC melatonin,” leading these researchers to suggest it should be regulated as a drug so that, by law, it would at least contain what it says on the bottle. Okay, but that’s regarding its strength. What about its purity?

“Four of six melatonin products from health food stores”—two-thirds—“contained impurities” that could not be characterized. But, with no exclusive patent, “no pharmaceutical company wants to pay for the toxicological studies and the data assembly required to obtain a product license because it cannot have exclusivity.” The stuff is just so dirt cheap to purchase. The researchers recommend “buying it from a large reputable pharmacy chain and hope for the best.” Is it worth the risk?

A study I discuss at 4:26 in my video suggests it’s not worth the risk at all. Contaminants present in tryptophan supplements were reported to be responsible for a 1980s outbreak of a disease that affected more than a thousand people and resulted in dozens of deaths. Given the structural similarities of tryptophan and melatonin, is it possible that those same toxic contaminants could be created when you’re trying to synthesize melatonin? Indeed, as you can see below and at 4:57 in my video, researchers found similarities between the contaminant blamed on the tryptophan epidemic and what they found in melatonin supplements. In fact, they are a little too close for comfort, suggesting melatonin supplements may just be “‘another accident [epidemic]… waiting to happen.’”


Jet Lag Treatment Cheat Sheet

Tue, 09/27/2022 - 07:00

Use cheat sheets to figure out exactly when and how to treat jet lag using light exposure and light avoidance at specific times of the day, based on which direction you’re going and how many time zones you cross.

“Jet lag is a blessing to circadian biologists because the disruption of mental and physical well-being immediately highlights the importance of our internal ‘body clock,’” the focus of their work. Much of the general malaise we may experience on long journeys may just be “so-called ‘travel fatigue,’” which can occur “regardless of the mode of transport and the number of time zones crossed,” leaving people feeling disorientated, generally weary, and headachy.

Dehydration has been blamed. The air circulated in the cabins of commercial airlines is pretty dry, but even though it can make your throat, skin, and eyes feel dry, the maximum loss of fluid through breath and sweat, for instance, wouldn’t be more than about an extra half cup if you actually did the math. So, it isn’t as though you’re in Death Valley or the Sahara when on a flight. “Further, the calculation assumes that the passenger would be nude,” and I’m sure the airline would charge you extra for that!

Of course, “airplane food—if any is served—tends to be starchy and sugary,” and giving passengers salty snacks like pretzels during a flight doesn’t help. “The vegetarian…special meals are sometimes an improvement, but you must order them in advance. BYOF—bring your own fruit—is a good rule to fly by. A small bag of unsalted almonds or walnuts is a healthy alternative to those skimpy bags of salted peanuts.”

The cabin air isn’t just dry, though; it’s also low in oxygen pressure, about what you’d get at 10,000 feet above sea level, which is about twice as high as Denver. That alone can make you feel lousy. Then, when you land, if you’ve crossed enough time zones, you can suffer from jet lag.

Jet lag is the temporary disconnect between the new time at your destination and that of your own internal body clock, which is still on home time. “This desynchrony is abnormal,” since our internal clock is normally synced to the outside world. Symptoms of jet lag do go away, though, as your body becomes hip to the new time. The “duration of jet lag in days can be calculated to be two-thirds the number of time zones crossed eastwards, compared with half the number of zones crossed westwards.”

Let’s look at an example. As you can see below and at 2:04 in my in my video How to Treat Jet Lag with Light, London is six time zones eastward from Chicago.

So, after flying there, it may take four days before you get back to normal—six eastward time zones multiplied by two-thirds. On the other hand, Londoners flying westward to Chicago should get over their jet lag in only three days—six westward time zones divided by two. The reason it’s easier to go westward, where the day is longer, than it is to go eastward, is because our internal clock is naturally set for longer than 24 hours—“closer to 25 h,” in fact—and has to be reset every day. “It is for this reason that the observed rhythms are called circadian (from the Latin: about a day.”

Interestingly, you can see this in Major League Baseball performance. Researchers churned through 40,000 games, mining 20 seasons, and found “surprisingly specific effects of circadian misalignment [jet lag] on athletic performance under natural conditions.” Indeed, the “jet-lag effects were largely evidence after eastward travel with very limited effects after westward travel, consistent with the >24-h period length of the human circadian clock.” Okay, so how do you treat it?

As you can see below and at 3:05 in my video, you first need to decide whether it needs to be treated at all. If you’re just traveling over one or two time zones, you don’t have to worry about it. If you’re crossing three or more time zones, for instance traveling coast to coast, jet lag “will be experienced,” so it then depends on how long you plan on staying. If only for a few days, it’s probably not worth treating, because you’ll then have to switch back as soon as you return home. “In these cases,” if you have control over your schedule, though, it’s better to “time appointments in the new time zone to coincide with daytime in the home zone that has been left, and to avoid times that coincide with night on ‘body time.’” So, it’s pretty much common sense: If you travel east, your body will still think it should be sleeping in the morning, so you should push your activities to later in the day, and vice versa. But, if you are going to be gone for a while, for a week or more, for example, you can adjust your body clock using behavioral methods and/or drugs, supplements, or foods.

“There is only one sure fire way to avoid jet lag altogether and that is to adapt to the new time zone before flight,” meaning before you leave on your trip. Changing your home sleep schedule more than two hours, however, can be “counter-productive,” because it will interfere with your pre-trip sleep and you don’t want to go into a long trip already sleep-deprived. In fact, before your trip, you want to maximize your sleep. In flight, as you can see below and at 4:12 in my video, the recommendation is for “immediate adjustment to destination meal and light schedule,” although this is easier said than done. Then, once you land, you want to “attempt to maintain destination sleep schedule.” Try not to nap for more than 15 to 30 minutes, and don’t drive around when your body thinks it’s the middle of the night.

The real key to treating jet lag, however, is light therapy. Traveling eastward, you expose yourself to the bright light in the morning and avoid bright light in the evening. The opposite is the case when traveling westward—“evening exposure to bright light; morning avoidance of bright light…” Seems simple, right? It’s actually a bit more complicated than that. “The advice changes…if you’ve traveling through more than six time zones—say from Boston to Athens. Your biological clock may adjust in the wrong direction, reacting to light in the morning as if it were afternoon.” Okay, but what if I tell you it’s even more complicated than that! “The effects of light acting upon the body clock” are actually only during a specific window around the time your body temperature bottoms out, which is usually around 4 AM. As part of our circadian rhythm, our body temperature typically drops from 98.6 degrees down to more like 97.6 degrees, even when we aren’t sleeping, as you can see below and at 5:02 in my video.

What’s the bottom line? I feature two cheat sheets at 5:12 in my video, which you can see below. Snap a picture or screengrab them for future reference. If you fly eastward across eight time zones from Los Angeles to London, for example, on day one, you should avoid light between 6 AM and noon local time and then expose yourself to light between noon and 6 PM. local time. The rest of that first day, your light exposure won’t matter and won’t affect you either way. “On subsequent days, the local times of light avoidance and exposure need to be advanced earlier by 1 – 2 h each day until light avoidance coincides with nocturnal sleep,” that is, when you’re sleeping at night.

But, on those first few days after traveling eastward, note that you’ll want to avoid morning light, which “can be difficult to achieve, particularly on the day of arrival, since many flights are overnight and land in the morning…” One thing you can do is wear really dark glasses until you get indoors. Of course, if they’re too dark, you can’t really drive, which is when those not-so-attractive orange lenses that block blue wavelengths can come in handy, as they prevent the dip in melatonin you can get with regular sunglasses, as you can see below and at 6:09 in my video. Regardless, the next day, you might have the urge to get “out and about,” but that could actually make your jet lag worse by taking you in the opposite direction.

What about if you’re flying eastward more than eight time zones? In that case, you subtract the number from 24 and treat it as travel westward. For instance, an eastward trip across ten time zones—New York to Delhi, say—should be treated as a westward flight, requiring a delay of the body clock across 14 time zones. In that case, it would be easy to get outside and get some sun, but what would you do if you just went four zones westward and needed to get light in the middle of the night?

One gadget company came up with light-emitting headphones, which you can see below and at 6:57 in my video. The theory is that you could bathe your brain in light directly through the ear canals. Researchers stuck them on the heads of cadavers and did seem to get some light penetration, but you don’t know…until you put it to the test. A randomized, double-blind, placebo-controlled trial demonstrated that “transcranial bright light exposure via the ear canals alleviates jet lag symptoms.” Or…you could just turn on a lamp.


Upcoming Webinar on Vitamin K and Recipe for Veggie Mac & Cheese

Thu, 09/22/2022 - 07:00

My next webinar is on vitamin K. It’s been touted for bone, brain, and heart health, but have vitamin K supplements been shown to help? To complicate matters, there are multiple types of vitamin K: Vitamin K1 is concentrated in greens, and a type of vitamin K2 is found in animal products. Do we need both? Do we have to rely on a healthy microbiome for conversion from one to the other? Do we have to eat a slimy, fermented food called natto? 

Join me for a 60-minute live webinar on October 7 at 2pm ET to learn everything you ever wanted to know about vitamin K.


Key Takeaways: Saturated Fat 

Saturated fat—the kind of fat that is solid at room temperature—is found mostly in animal products like fatty meats and dairy. We’ve known for a long time that saturated fat raises cholesterol, contributing to our number one killer, heart disease. It also impacts insulin resistance and can lead to other diseases. Hold on. I said it’s mostly found in animal products, but what about that jar of coconut oil in your cabinet that’s also solid at room temperature? Saturated fat. See what I have to say on the matter of both animal- and plant-derived saturated fats on the topic page.

  Recipe: Veggie Mac & Cheese

Dairy is the number one source of saturated fat in the United States, but, fortunately, there are many ways to make plant-based versions of traditionally dairy-laden dishes. A cruciferous spin on macaroni and cheese, this recipe takes comfort food to a whole new level and is a tasty way to check off a few servings on the Daily Dozen checklist. This recipe comes from Kristina, our director of Nutrition & Social Media Strategy. Get the free recipe here, and watch a video on how it’s made on our Instagram

    Evidence-Based Eating Guide Now in Spanish

I’m thrilled to announce that our popular Evidence-Based Eating Guide is now available in two new languages. This resource includes information on my Traffic Light eating system, the Daily Dozen, sample menus, and more. Read about it and download a digital copy here. You can also order hard copies in English and Spanish for only the cost of printing and shipping. Help us continue creating these fun and useful resources by making a donation today! Around the World

Did you know that every NutritionFacts video has subtitles in English and a variety of other languages, prepared by our volunteers? Learn how to access them and other playback settings. Also, see important information about our translated resources.

Consider helping make our free Daily Dozen app more accessible to people around the world by volunteering to contribute translations in your language.


Top Three Videos

The Role of Kimchi and H. pylori in Stomach Cancer 

What explains the Achilles’ heel in certain Asian diets?



Why Don’t Health Insurers Encourage Healthier Eating?

Why don’t more big payors in health care embrace plant-based eating?


The Best Diet for Treating Atrial Fibrillation

What foods should we eat and avoid to reduce our risk of Afib?



Live Q&A October 6 

Every month, I do a live Q&A right from my treadmill, and the next one is October 6!

At 3 pm ET, tune in on our Facebook page, YouTube channel, or (new!) directly on

You can find links to past live Q&As here on If that’s not enough, remember, I have an audio podcast to keep you company, too.

Paper-Filtered Coffee and Cholesterol

Tue, 09/20/2022 - 07:00

New data suggest even paper-filtered coffee may raise “bad” LDL cholesterol.

In my video from more than a decade ago called Is Coffee Bad for You?, I explained that the “cholesterol-raising factor from…coffee does not pass [through] a paper filter.” As I discuss in my recent video Does Coffee Affect Cholesterol?, if you give people French press coffee, which is filtered but without paper, their cholesterol starts swelling up within just two weeks, as you can see below and at 0:22 in the video. But, if you switch them to paper-filtered coffee, their cholesterol comes right back down. It’s the same amount of coffee, just prepared differently.

The cholesterol-raising factor from coffee beans has since been identified as the fatty substances in the oil within coffee beans. One reason it took us so long to figure that out is that they didn’t raise cholesterol in rats, hamsters, or even in monkeys, but did in human beings, as you can see below and at 0:45 in my video.

But, the fatty substances apparently get stuck in the paper filter. “This explains why filtered coffee does not affect cholesterol, whereas Scandinavian ‘boiled,’ cafetiere [French press coffee], and Turkish coffees do.” As you can see below and at 1:07 in my video, espresso, which has 20 times more cafestol, the cholesterol-raising substance, than paper-filtered drip coffee, also raises cholesterol, though French press, Turkish, and boiled coffees are progressively worse. Instant and percolated coffee are pretty low, even though neither is prepared with paper filters, but still not as low as paper-filtered drip coffee. Note, however, that if you make drip coffee with a metal mesh filter common in many machines and do not add a paper filter in the cradle, it would presumably be just as bad as French press coffee.

The studies in general “appeared to consistently find” that this fatty component was filtered out by paper, but “a small number of studies suggested that filtered coffee may also increase cholesterol levels, and began to cast some doubt into what appeared to be a fairly clear picture.” So, yes, “although the cholesterol-raising effects brought about by the consumption of filtered coffee may not be as strong as those of the boiled coffee, it is important not to discard the possibility that filtered coffee may also play a small but important role in explaining the cholesterol-raising effects of coffee.”

I had known about a study that found that three cups a day of filtered coffee raised total cholesterol, but the increase in “bad” LDL cholesterol was not statistically significant, as you can see below and at 2:10 in my video. Researchers got the same results in another study, finding that subjects who stopped consumption of filtered coffee reduced their total cholesterol, which suggests that perhaps paper coffee filters only achieve partial cafestol removal. Had anyone ever just measured the levels of the cholesterol-raising compounds found in the paper filters?

Indeed, researchers investigated just that and found most of the cholesterol-raising cafestol was retained by the coffee grounds, rather than actually getting stuck in the paper filter itself. In other words, “the principal function” of the paper filter is not necessarily blocking the compound itself, but blocking any fine particles that are carrying the compound. This is similar to when you make French press coffee. When you depress that plunger with its fine mesh screen, you’ll still get a little sludge at the bottom of the cup. That sludge is made up of the tiny particles that pass through the screen and can carry some of the risk. So, a little cafestol does get through the filter. As you can see below and at 3:07 in my video, you can cut out more than 90 percent of cafestol by switching from a French press or coffee maker with a metal mesh filter to one with a paper filter. If you use coffee that starts out with a high level of the cafestol compound, you’re still clearing out about 95 percent with the paper filter, but could there still be enough left to bump up your LDL? You don’t know until you…put it to the test.

As you can see below and at 3:38 in my video, study subjects started out drinking a high-cafestol coffee, and after a month of drinking two cups a day, their LDL cholesterol increased significantly, even though the coffee was paper-filtered. So, if you have high cholesterol despite eating a healthy diet, you may want to try cutting out coffee and then getting retested. Or, you can try switching to a lower cafestol coffee. There are all sorts of variables that may affect cafestol levels, including roasting degree or grind size, and one can imagine a smaller particle size would allow for greater extraction. Since roasting appears to destroy some cafestol, a really dark roast should have less, but no significant difference was seen between the rise in cholesterol after a medium light roast versus a medium roast; both raised bad cholesterol.

In the chapters on liver disease, depression, and Parkinson’s in my book How Not to Die, I discussed the benefits of coffee for the liver, mind, and brain. Coffee drinkers do seem to live longer and have lower cancer rates overall, but coffee may worsen acid reflux disease, bone loss, glaucoma, and urinary incontinence. The bottom line is that I don’t recommend drinking coffee, but mainly because every cup of coffee is a lost opportunity to drink something even more healthful, such as a cup of green tea, which wouldn’t have the adverse cholesterol consequences.