Michael Greger's Blog

International Life Sciences Institute, a nonprofit, is accused of being a front group for Coca-Cola and other junk food giants.

In 2019, a series of reviews was published in the Annals of Internal Medicine that concluded the same thing that past reviews have concluded: Adhering to dietary patterns that are lower in red or processed meat intake may result in decreased risks for premature death, cardiometabolic disease and mortality (meaning the risk of getting and dying of diseases like heart disease and type 2 diabetes), and getting cancer and dying from it. Therefore, they concluded in their Dietary Guideline Recommendations, “continue current unprocessed red meat consumption” and “continue current processed meat consumption.” Wait, what? Despite the increased risks of premature death, cancer, heart disease, and diabetes, the advice was essentially keep eating burgers and bacon?

To understand what happened, we have to go back to 2015. The Dietary Guidelines for Americans had just had the audacity to recommend people reduce their sugar intake. Imagine you work for the sugar industry. The evidence is overwhelmingly against you; so, what do you do? Well, what did the tobacco industry do? One method involved the tobacco industry’s “funding of and involvement in seemingly unbiased scientific groups to manipulate political and scientific debate concerning tobacco and health”—groups like the International Life Sciences Institute (ILSI), which “has enjoyed a long and serious collaboration with the tobacco industry.” That same industry group shapes food policy worldwide.

Technically a nonprofit “with an innocuous sounding name,” the International Life Sciences Institute “has been quietly infiltrating government health and nutrition bodies around the world.” The group was created by a top Coca‑Cola executive and “is almost entirely funded by Goliaths of the agribusiness, food and pharmaceutical industries.” “After decades largely operating under the radar, ILSI is coming under increasing scrutiny by health advocates in the United States and abroad who say it is little more than a front group advancing the interests of the 400 corporate members that provide its $17 million budget,” including Coca-Cola and PepsiCo.

So, when the 2015 U.S. dietary guidelines recommended eating less sugar, the soda-funded International Life Sciences Institute sponsored a review concluding that the sugar guidelines were simply not trustworthy. Who did they pick for this hatchet job? Bradley Johnston. The Annals of Internal Medicine published “The Scientific Basis of Guideline Recommendations on Sugar Intake,” which concluded there basically wasn’t one: “Guidelines on dietary sugar do not meet criteria for trustworthy recommendations and are based on low-quality evidence.”

“This comes right out of the tobacco industry’s playbook: cast doubt on the science,” said professor Marion Nestle. “This is a classic example of how industry funding biases opinion. It’s shameful.” Yes, the paper was paid for by the likes of Hershey, Red Bull, Coca-Cola, and the makers of Oreos, but the authors swore they “wrote the protocol and conducted the study independently from ILSI.” It turns out that was a lie, forcing the journal to publish a corrected version after the Associated Press obtained emails showing the industry front group “requested revisions,” as you can see below and at 4:00 in my video How Big Sugar Undermines Dietary Guidelines. It also came out that a co-author conveniently forgot to mention directly receiving a $25,000 grant from Coca-Cola.

You know it’s bad when candy bar companies criticize an industry-funded paper on sugar. Mars, the maker of Snickers, Skittles, and M&M’s, broke ranks with other food companies and denounced the industry-funded paper. What’s more, Mars itself was a member of ILSI, but telling people to ignore guidelines to cut down on sugar? That just makes us all look bad.

If you look at the relationship between funding sources and conclusions in nutrition-related scientific articles, there are about seven or eight times the odds that the conclusion will skew favorably compared to studies with no industry funding. For interventional studies, the proportion of industry-funded studies that reached unfavorable conclusions about their own products was a whopping 0%, which should not surprise anyone.

So, what can journals do to counter tactics industries often use to promote the safety of harmful products or “question the integrity of science that calls their products into question?” To push back against the tobacco industry’s influence over scientific discourse, leading journal editors have “refused to be passive conduits for articles funded by the tobacco industry.” They just won’t accept tobacco industry-funded studies, period. “Accordingly, high-quality journals could refrain from publishing studies on health effects of added sugars funded by entities with commercial interests in the outcome”—like soda and cookie companies. But they’re not, as evidenced by the ILSI-sponsored review on sugar intake that was published in the Annals of Internal Medicine.

Fast forward four years, back to the beginning of this blog: The next batch of Dietary Guidelines for Americans is on the way, and the last scientific report of the guidelines committee encouraged people to eat diets not just lower in sugar but lower in meat as well. So, Big Beef decided to follow in the footsteps of Big Butterfinger—the recommendations to continue eating processed and unprocessed meat were published in the same journal, with the same guy, scientist-for-hire Bradley Johnston, as lead author, and the rest is history. We’ll dig into exactly how he pulled it off next.

Doctor’s Note

This is the first in an eight-blog series on how industries impact dietary and health guidelines—stay tuned.

Sadly, sometimes corporate influence infiltrates the scientific Dietary Guidelines Advisory Committee itself. See Dietary Guidelines: Advisory Committee Conflicts of Interest. For a fascinating history, see The McGovern Report.

Please note: This blog and its accompanying video discuss the important and troubling issue of weight bias and discrimination, which may be a sensitive topic for some readers.

How might weight stigma be a vicious cycle?

Although total fasting can dramatically increase blood levels of the stress hormone cortisol, as much as doubling within five days, dieting alone does not. There is, however, a way stress and obesity could turn into a vicious cycle: weight stigma.

Across thousands of individuals followed for four years, those reporting discriminatory experiences had more than twice the odds of becoming obese. Those who started out obese had more than three times the odds of staying that way compared to those who started at the same weight but did not experience discrimination. Now, this could be from stress-induced eating on one side of the calorie-balance equation or stigma-induced exercise avoidance on the other.

Obese individuals with more frequent experiences with weight stigma report greater avoidance of exercising in public, feeling judged and embarrassed. These “too fat to exercise” fears may be well-grounded. Strong anti-fat biases have been documented in both fitness professionals and regular gym-goers, “which may translate into an unwelcoming environment at fitness centers and health clubs.”

Whichever side of the calorie equation that gets tipped, those who experience weight stigma can also end up suffering health consequences independent of any added weight. Those reporting more frequent weight-based discrimination exhibit higher levels of depression, show higher levels of inflammation, experience higher levels of oxidative stress, and have a shorter lifespan. Two studies following nearly 20,000 people both found about a 50% increase in mortality risk among those reporting greater daily discrimination. “[W]eight discrimination may shorten life expectancy.” Despite these hazards, some scholars advocate for even more fat-shaming.

The President Emeritus of the prestigious Hastings Center infamously advocated for “a kind of stigmatization lite,” using social pressures to compel people to lose weight without resorting to “outright discrimination.” After all, he argued, what else has the potential to counter the persuasive force of the billions spent in advertising every year by the food and beverage industries? It worked against tobacco. He recalls his own battle with addiction: “The force of being shamed and beat upon socially was as persuasive for me to stop smoking as the threats to my health.” The public health campaign to stigmatize cigarette smoking turned “what had been considered simply a bad habit into reprehensible behavior.”

When such campaigns have been tried, they have been met with fierce resistance, though. Georgia’s Strong4Life campaign featured billboards of morose-looking obese children with captions like “Warning: Chubby kids may not outlive their parents” or “It’s hard to be a little girl if you’re not,” which you can see below and at 3:16 in my video The Impacts of Weight Bias in Health Care.

The campaign sponsors defended the ads as an attempt to break through the denial in a state with some of the highest recorded childhood obesity rates. It’s only defensible, though, if it works.

Yale researchers found that when normal-weight women are provided with bowls of M&M’s, jelly beans, and chips to snack on after watching clips of stigmatizing material like clumsy, loud, lazy stereotypes getting teased about their weight, they eat about the same amount compared to watching neutral material, such as insurance commercials. But when overweight women watch the same two sets of videos, they triple their calorie intake after watching the stigmatizing scenes, as you can see below and at 3:56 in my video.

The researchers concluded, “This directly challenges the notion that pressure to lose weight in the form of weight stigma will have a positive, motivating effect on overweight individuals.” In other words, it could make matters worse. Being labeled “too fat” during childhood was associated with a higher risk of becoming obese, compared to children of the same weight who were never told that. But does that mean we should just ignore concerns about obesity? Many doctors apparently think so.

Just as veterinarians have been found to be reluctant to tell people their pets are obese, fewer than a quarter of parents of overweight children report having been told by pediatricians about their child’s weight status. One might think it would be obvious, but a Gallup Survey found that parents appear to be “notoriously poor judges of their children’s weight.” Similarly, the percentage of adults who describe themselves as overweight has remained essentially unchanged over the past few decades, despite skyrocketing obesity. “All of this helps ‘paint a picture of mass delusion in the United States about its rising weight,’” Gallup concluded.

I think patients have the right to be informed. Those told by their doctor that they are overweight have about four times the odds of attempting weight loss and about twice the odds of succeeding.

Just as smoking physicians are less likely to challenge their smoking patients, overweight physicians are less likely to bring up the subject of weight loss or even document obesity in their charts.

Ironically, overweight patients trust diet advice from overweight doctors more than from doctors of normal weight. Unfortunately, primary care physicians appear to have little to offer in terms of specifics. Fewer than half who were surveyed said they provide specific advice to their patients. Just telling patients to “watch what they eat” is unlikely to be particularly helpful, but many primary care physicians may not even go that far. Most physicians said they would spend more time working with patients on weight management if only their time was “reimbursed appropriately.” Maybe we could offer a bonus to refrain from blaming the victim. As one pair of commentators wrote in response to the pro-stigma camp, “If shaming reduced obesity, there would be no fat people.”

I want to end this weight stigma series with the jaw-dropping findings of a study that I think best illustrates how hard it is to live inside an obese body. If this doesn’t foster sympathy among my medical colleagues, I don’t know what will. Researchers talked to men and women who had lost and kept off more than 100 pounds to tap into their unique insight, having personally experienced what it was like to be morbidly obese and then, on average, 126 pounds lighter. Forty-seven people were interviewed.

They were asked to think back to when they were heavier and make a choice: “If someone offered you a couple of million dollars if you stayed morbidly obese forever, would you have chosen the money? Or would you have chosen to be normal weight no matter what?”

Option 1 was “I would have chosen no money and being normal weight. It would have taken me one second to decide.” Option 2: “I probably would have chosen being normal weight. But the possibility of having that much money would make me think about the choice.” Option 3: “I wanted to be normal weight, but I could really use the money. If I could be a multimillionaire, I think I could live with being morbidly obese.”

One of the 47 had to think about it, but the other 46 jumped at option 1. No one chose option 3. They all said they would give up being a multimillionaire to be normal weight.

If that shocked you, buckle your seatbelts. They were then asked about being obese compared to other disabilities. Normally, when you ask people to choose between living with their own disability or switching to a different one, there is a strong proclivity to prefer their existing condition. For example, even though most people would rather be deaf than blind, blind people prefer to remain blind by a large margin, rather than having sight without sound. They already know how to live with their own disability, so there’s safety in familiarity. However, the exact opposite happened when the 47 formerly obese individuals were asked to choose.

Every single one of the 47 said they’d rather be deaf, dyslexic, diabetic, or have very bad acne or heart disease for the rest of their lives than be obese. More than 90% said they’d rather have a leg amputated, and similarly, about 9 out of 10 said they’d rather be legally blind than be obese. Obesity appears to be the only handicap where nearly everyone wants to switch, no matter what the cost. To quote one person in the study: ”When you’re blind, people want to help you. No one wants to help you when you’re fat.”

Doctor’s Note

If you missed the previous installment in this two-part series, see Weight Bias in Health Care. The information is drawn from my book How Not to Diet. 

Please note: This blog and its accompanying video discuss the important and troubling issue of weight bias and discrimination, which may be a sensitive topic for some readers.

How common is weight stigmatization in health care?

Described as the last “acceptable” form of bias, weight stigma is the rampant discrimination and stereotyping of overweight individuals. Fifty overweight women were asked to keep a diary of all the times they felt they were being stigmatized for their weight. Over a single week, more than a thousand instances were recorded. An overweight woman may expect to be harassed (such as being called names or insulted), run into physical barriers (like being unable to fit into public seats), or discriminated against (such as receiving perceived poorer service at restaurants or stores) on average about three times a day. Obese men report three times less discrimination than women of the same size, so it may be only a daily occurrence for them.

They’re not just being paranoid. Studies using professional actors posing as job applicants made up with theatrical prostheses to appear overweight were significantly more likely to face discrimination than when appearing at their normal weight. This employment bias was found to be especially prejudiced against overweight women compared to men.

Attitudes can also be explored in surveys. In a comparison of 16 stigmatized social groups, such as people experiencing homelessness, “only drug addicts and smokers were seen as more disgusting than obese people,” as you can see below and at 1:42 in my video Weight Bias: Hating Their Guts.

The researchers did note, however, there was effectively a tie: “[O]bese people were rated just as disgusting as politicians.”

This weight stigma starts surprisingly young. Children as young as three years old describe overweight peers as “mean,” “stupid,” “lazy,” and “ugly.” The negative language increases with age, as you can see below and at 2:14 in my video.

Then, there was that famous study published in 1961. Children in summer camps and schools across a swath of different social, cultural, and ethnic backgrounds in California, Montana, and New York were shown pictures of different children and asked to rank who they liked best. The images included a child with crutches and a leg brace, a child in a wheelchair, a child missing a hand, a facially disfigured child, and an obese child. In every group of kids tested, there was “remarkable uniformity.” The obese child always came in dead last.

That was ages ago, though. In 2003, researchers published the 40-year follow-up. The study was repeated, and the title of the study gives it away: “Getting Worse: The Stigmatization of Obese Children.” The obese child was liked even less in the follow-up study than in 1961! This parallels trends throughout society, with a near 70% jump in perceived weight discrimination recorded in national surveys since the mid-1990s.

Attitudes among teachers may not be helping. More than a quarter of teachers and other school staff surveyed felt that becoming obese is “one of the worst things that could happen to a person.” Even parents can be biased, providing less support for college for their overweight daughters compared to thinner siblings, for example. As two prominent obesity researchers commented, “It is strong prejudice indeed when parents discriminate against their own children.”

What about doctors? One representative national survey found that more than half of physicians “viewed obese patients as awkward, unattractive, ugly, and noncompliant.” About a quarter of nurses agreed or strongly agreed with the statement: “Caring for an obese patient usually repulses me.”

This antagonism can have serious health consequences for those who may need it the most. For example, obese women are at higher risk for developing cervical cancer, as well as developing endometrial and ovarian cancers, yet they are less likely to be screened. Morbidly obese patients have only about half the odds of getting their recommended pelvic exams. Part of this may be avoidance on the part of the patient, but some doctors turn obese patients away. The Sun Sentinel polled OB/GYN practices in Florida and found that as many as one in seven refused to see heavier women and set weight cut-offs for new patients beginning at 200 pounds.

Even doctors who welcome obese patients have been found to give them short shrift. Physicians randomized to receive a medical chart of a migraine patient who was either presented as average weight, overweight, or obese said they would give the obese patient about 28% less of their time. And it’s less quality time. Recorded doctors’ visits found that physicians tend to build “less emotional rapport with overweight and obese patients.”

Even obesity specialists profess increasingly explicit anti-fat attitudes. Worsening in surveys taken between 2001 and 2013, obesity specialists “described fat people as significantly more lazy…stupid…and worthless…compared to thin people.” Even in the medical literature, you’ll find lines like this, an example from Annals of Internal Medicine: “Obesity is an aesthetic crime: it is ugly.”

The good news is that they appear able to hide their disdain. In a study entitled “Obese Patients Overestimate Physicians’ Attitudes of Respect,” despite the negative attitudes doctors harbored toward their obese patients, the same patients expressed their satisfaction with their providers. The researchers concluded, “While physicians may be successfully playing the part, the lack of true respect suggests…the authenticity of the patient-physician relationship should be questioned.”

Doctor’s Note

The next blog in this two-part series is The Burden of Weight Bias.

Both blogs in the series are drawn from my book How Not to Diet.

Do people who eat nuts live longer simply because they replace protein from animals with protein from plants?

The American Journal of Clinical Nutrition “is the highest-ranked peer-reviewed scientific journal in nutrition and dietetics.” That should tell you a lot about the field, since it’s published by the American Society of Nutrition, whose sustaining partners include The Sugar Association, soda companies, and the meat, dairy, and egg industries. This is the highest-ranked nutrition journal! The fact that the National Cattlemen’s Beef Association is a sustaining partner may help explain its publication of an article that claimed eating red meat “does not negatively influence cardiovascular disease risk factors.”

Imagine you’re in the pocket of Big Beef and Big Pork. How could you possibly pull off a meta-analysis of randomized controlled trials purporting to show that eating more versus less red meat does not influence cholesterol or blood pressure? Drs. Neal Barnard and Walter Willett pointed out the fatal flaw in their editorial “The Misuse of Meta-analysis in Nutrition Research” by asking the question: “Compared with what?” Of the 39 trials on LDL cholesterol that the authors of that meta-analysis had chosen, nearly 90% of them just swapped one meat for another, comparing red meat to white meat!

Indeed, the researchers used control diets of chicken or fish. And we know that when it comes to cholesterol, the impact of consuming beef is just as bad as fish or poultry. That’s how they pulled it off—they just swapped meats. That’s like publishing a study saying total Twinkie intake does not negatively influence risk factors by switching Twinkies with Ding Dongs. Those randomized to zero Twinkies didn’t do any better. Obviously, because they were eating Ding Dongs! It’s a classic drug industry trick: testing your drug against something known to be terrible.

Whereas if you swap out meat for plant-based meat—plant-based sausages, plant-based chicken patties, and veggie dogs—you end up with significantly lower cholesterol, as you can see below and at 2:31 in my video Are the Health Benefits of Nuts Limited to Those Eating Bad Diets?.

That shouldn’t be a surprise; there is less saturated fat in plant-based meats. But even independent of saturated fat content, you end up with higher LDL cholesterol when eating red meat or white meat—any kind of meat—compared to non-meat protein sources. The researchers conclude that this is “keeping with recommendations promoting diets with a high proportion of plant-based food,” but, based on cholesterol effects, white meat like chicken and turkey is just as bad as red meat. Fish may be even worse, though what they often did is try to standardize the saturated fat content by adding something like butter. But at the same saturated fat content, fish appears to be worse than beef, and chicken is just as bad as beef. Yet plant protein sources like soy, nuts, and legumes (beans, split peas, chickpeas, and lentils) did better, as you can see below and at 3:20 in my video.

Replacing a single serving of even lean beef with the same amount of calories of nuts or soybeans can lower LDL cholesterol, a key risk factor for the number one killer of men and women in the United States and around much of the world. Is that why a single serving of nuts a day is associated with 22% reduction in the risk of premature death? Why millions of deaths every year may be attributable to inadequate nut intake? Is the benefit just from eating nuts instead of meat? No. The drop in heart attacks amongst more frequent nut eaters is just as strong among nonvegetarians, as you can see below and at 4:10 in my video.

The reduced mortality associated with nut consumption is independent of health condition. It’s not just health nuts eating nuts. In fact, in a comparison of a dozen different food groups, nuts beat out even vegetables when it came to a lower risk of premature death.

Doctor’s Note

In my Daily Dozen Checklist, I recommend a quarter cup (about an ounce) of nuts a day. Check out some of my other videos on nuts in the related posts below to see why.

If you were intrigued by the industry hijinks of study manipulation, you’ll probably like:

A whole series is coming up soon, starting with The Corporate Playbook Behind Undermining Dietary Guidelines.

A micromort, a unit for comparing and communicating risk to patients, is equivalent to a one-in-a-million chance of dying.

Hundreds of millions of operations are performed every year, and the risk of death is typically around half a percent, to which patients might say things like, “I could die just as easily crossing the road,” making it clear they really don’t understand the difference in magnitude of risk. One way to communicate risk is by analogy. For example, just going under anesthesia carries about a 1-in-100,000 chance you won’t wake up. How much is that? Well, that’s about the same risk as an expert sky dive. But that still may be kind of tough to wrap your head around. It’s hard to think in terms of small numbers. Can you imagine a 0.0017 mile by 0.00227 mile rug? How big (or small) is that? We need more digestible units. Enter the micromort as a unit for comparing and communicating risk.

A micromort (mM) is a unit equivalent to a one-in-a-million chance of dying. That’s like the odds of flipping a coin and getting tails 20 times in a row, or a little less than the chances of getting a royal flush in poker. But the real utility is to help compare different risks to one another using the same metric. For example, driving 100 miles entails about a one-in-a-million chance of death, so that’s one micromort. Scuba diving is about five micromorts per dive, so each dive is as risky as driving 500 miles. So, now we have a way to directly compare the risk of surgical procedures and common activities.

Giving birth is as risky as driving from New York to Los Angeles and back again, but getting a Caesarean section is more than twice as risky. Even something like a simple hernia repair carries the same risk of dying as something like skydiving 200 times. Now, obviously, sometimes you have no choice, but death from varicose vein surgery or circumcision could probably be avoided, as you can see below and at 2:32 in my video Micromorts: How Risky Is It to Go Under Anesthesia?.I was surprised to learn that horseback riding is about four times deadlier than rock climbing, but getting chemotherapy and radiation for head and neck cancer is riskier than rock climbing for 500 years, driving 5 million miles, or skydiving 5,000 times.

One leading cause of death I didn’t really talk about in How Not to Die is accidental death. We have approximately a one-in-a-million chance of dying just by accident every day of our lives, and about half of that risk is dying in a car crash, based on U.S. averages. There are all sorts of other hazards, which you can see below and at 3:19 in my video.

I was surprised to learn Americans have about a 1-in-200,000 chance every year of dying from a foreign body entering an orifice other than the mouth.

Other things we may want to avoid include climbing Mount Everest, which is about 30 times riskier than coal mining or base jumping. Trains and planes are actually equivalent over the same distance, but riding a motorcycle is about 50 times deadlier than riding in a car, though cycling to a destination is riskier too, about 10 times as deadly as driving in the near term.

Here’s a good example of how one can use micromort comparisons to help put things in perspective. Certain types of breast implants can cause a rare type of cancer, a type of breast implant–associated lymphoma. You can imagine how scary this is for the millions of women who have implants, but check out that risk compared to the risk of other common activities in the table below and at 4:12 in my video.

Your risk of dying from that kind of cancer is less than a single day of skiing. Some might say it’s preferable to die quickly on the slopes than going through the slow suffering of cancer, and without the risk of bankrupting your family, but at least it can put the risk of the implant-cancer killing you in context.

Doctor’s Note

How dangerous are medical interventions in general? Surprisingly, physicians are a leading cause of death. See Why Prevention Is Worth a Ton of Cure. You can also check out .

Hot peppers, soy foods, and pumpkin seeds may help with hair loss.

Androgenic or androgenetic alopecia is one of the most common chronic problems seen by dermatologists. In men, it’s called male pattern hair loss, and in women, it’s called female pattern hair loss. It’s characterized by progressive hair loss, mostly of the central scalp. I’ve talked about hair-loss supplements and hair-loss drugs; what about foods for hair loss? What role might diet play in the treatment of hair loss?

Human experiments with fecal transplants offer a clue to how powerful our microbiome is, with reports of improvements in hair loss after a “fecal slurry made from freshly passed stools” from a donor was administered into another person’s colon. These weren’t just subtle improvements. As you can see below and at 1:14 in my video Food for Hair Growth, a totally bald guy started growing back hair a few months after a fecal transplant.

A little more than a year later, his hair had completely regrown, as you can see below and at 1:18.

The moral of the story is not to drink brown smoothies, but to keep your good gut bugs happy.

Population studies have found that male pattern baldness is associated with poor sleeping habits and the consumption of meat and junk food; whereas protective associations were found for the consumption of raw vegetables and fresh herbs, as well as frequently consuming soymilk. Drinking soy beverages on a weekly basis was associated with 62% lower odds of moderate to severe hair loss, raising the possibility that there may be protective compounds in plants.

Complementary and alternative medicine treatments “boast the ability to ‘cure’ hair loss ‘safely’ with ‘less side effects’ than conventional medicine. However, it is important…to look beyond the overarching claims and marketing to critically review the literature.” For example, many studies have little relevance because the evidence was obtained from shaved rodents. (Hey, let’s smear shaved mice with bee venom!) And even when researchers do clinical studies on actual people, sometimes there’s no placebo control, so there’s no way to know if the food had anything to do with the results.

But there has been a randomized, double-blind, placebo-controlled study of compounds in hot peppers and soy, showing significantly higher promotion of hair growth. Below are some before-and-after pictures of both men and women, which you can also see at 2:49 in my video.

What doses were they taking? They took 6 milligrams of capsaicin a day and 75 milligrams of isoflavones. What does that look like in real food? You can get 6 milligrams of capsaicin in just a quarter of a fresh jalapeno pepper. That sounds pretty doable. You can get 75 milligrams of isoflavones by eating ¾ of a cup of tempeh or just straight soybeans. Soy nuts (dry-roasted soybeans) are even more concentrated, but given the formation of advanced glycation end-products in high-fat, high-protein foods prepared at high temperatures, I’d suggest avoiding routinely eating roasted or toasted nuts, seeds, or soy.

There’s also been a randomized, double-blind, placebo-controlled trial of pumpkin seed oil. Where did that idea come from? In 2009, a study out of South Korea found that randomizing men with BPH—benign prostatic hyperplasia, also known as enlarged prostate glands—to just 320 milligrams of pumpkin seed oil a day (that’s about a 16th of a teaspoon, so just a few drops a day) improved urinary flow rates. Urinary flow continued to kink off and decline in the control group, but those taking the equivalent of eating just two single pumpkin seeds a day saw a significant improvement, as you can see below and at 4:18 in my video.

That would seem to be an anti-androgen effect, so maybe it would help with hair loss. It seems to work in mice when used topically, but what about in people just eating pumpkin seeds? Sadly, we often throw away pumpkin seeds, squash seeds, watermelon seeds, and they actually have a “rich repertoire” of nutrition. But you don’t know if they actually work for hair loss until you put them to the test.

In a study, 76 men with male pattern baldness received either 400 milligrams of pumpkin seed oil a day hidden in capsules or placebo capsules for a few months. (Again, 400 milligrams is like eating two or two and a half pumpkin seeds a day.) The researchers measured scalp hair growth with all sorts of objective and subjective measures, and after 24 weeks of treatment, self-rated improvement and satisfaction scores in the pumpkin seed oil group were higher, and they objectively had more hair—a 40% increase in hair counts compared to only 10% in the placebo group. Below are some representative before-and-after shots of the improvement in hair coverage on two and a half pumpkin seeds’ worth of daily oil, which you can also see at 5:25 in my video.

Show those pictures to investigators blinded to group assignment, and they rate the placebo groups as getting slightly worse over time but the pumpkin seed oil group getting significantly better. In the pumpkin seed oil group, 95% were rated as either unchanged or improved, whereas in the placebo control group, more than 90% were classified as unchanged or worsened. Given such a pronounced effect, might we be worried about sexual side effects? Researchers used an index of erectile dysfunction before and after the study and found no evidence of adverse effects.

Doctor’s Note

This is the last in a three-part series on hair loss and growth. The previous two blogs were Do Hair Growth Supplements Work? and The Benefits and Risks of Hair Loss Drugs.

A handful of pumpkin seeds would satisfy my Daily Dozen recommendation for nuts and seeds. See Dr. Greger’s Daily Dozen Checklist.

What are the pros and cons of Propecia and Rogaine for hair loss?

“Any consumer looking on the Internet for a treatment for hair loss is exposed to a multitude of remedies.” However, we only have good evidence for efficacy for drugs approved by the U.S. Food and Drug Administration: finasteride (sold as Propecia) and minoxidil (sold as Rogaine). It’s considered a myth that all the patented hair-loss supplements on the market will increase hair growth. And they may actually be more expensive, with over-the-counter supplement regimens costing up to more than $1,000 a year, whereas the drugs may cost between $100 and $300 annually. The drugs can help but can cause side effects. Propecia can diminish libido and cause sexual dysfunction, while the topical minoxidil can cause itching.

Below and at 1:12 in my video Pills for Hair Growth, you can see a list of some of the more common side effects of these FDA-approved drugs.

To understand why there are so many hormonal side effects for Propecia, like impotence, testicular pain, and breast enlargement, it’s important to understand how the drug works.

Androgens, male hormones like testosterone, are the principal drivers of hair growth in both men and women. We know this from studies half a century ago that show that castration of men stopped their hair loss. Why exactly were they being castrated? It was due to eugenics laws in the United States, when “mentally handicapped people” were castrated or forced to undergo tubal ligations against their will “to prohibit contribution to the genepool.” So-called “retarded persons were routinely sterilized without their consent or knowledge,” and the United States was the first country to introduce eugenic laws, which were later upheld by the U.S. Supreme Court. In the 1930s, a vocal proponent complained: “The Germans are beating us at our own game.”

Back to hair loss. Testosterone is the primary androgen circulating in the blood and can be converted to dihydrotestosterone, which is even more powerful, by an enzyme called 5-alpha reductase, shown below and at 2:28 in my video.

That’s the enzyme that is blocked by Propecia, so it inhibits the souping up of testosterone. That’s why women are not supposed to take it since it could feminize male fetuses; whereas for men, it has sexual side effects like erectile dysfunction, which can affect them for years. It’s something the drug companies had to disclose for the last decade: a “difficulty in achieving an erection that continues after stopping the medication,” a side effect that may even be permanent. Up to 20% of study participants reported “persistent sexual dysfunction” for six or more years after stopping the drug, suggesting the possibility that it may be permanent.

It’s possible that the drug may structurally change the part of your brain responsible for sexual function. Indeed, though blood levels of hormones in users with persistent effects appear normal, analysis of the cerebrospinal fluid surrounding the brain, obtained via spinal tap, shows that neurosteroid levels do appear to end up being altered. So, “it is recommended that prescribers of finasteride, as well as potential users, be aware of the potential serious long-term risks of a medication used for a cosmetic purpose.”

To date, no new interventions are used routinely in treating male or female pattern baldness. Given the side effects of the current drug options, “there is a need for alternative treatments.” So, what about food? Could what we eat help combat hair loss? That’s exactly what we’re going to explore next.

Doctor’s Note

This is the second in a three-part series on hair loss and growth. Do Hair Growth Supplements Work? is the first video, in case you missed it.

Antidepressants like Prozac can also cause sexual dysfunction, but there is something that may help. See Best Food for Antidepressant-Induced Sexual Dysfunction.

Might biotin or zinc supplements prevent hair loss in men and women?

By the time we’re 50, about half of us, men and women, will experience hair loss. No, it’s not caused by washing your hair too much or, for that matter, brushing it too much either—two of the many myths out there. Researchers found that the majority of hair loss with age is genetic for both women and men. And, based on studying twins, researchers discovered that the heritability of baldness in men is 79%, meaning about 80% of the differences in hair loss between men are genetically determined. But that still leaves some wiggle room.

Even when it comes to identical twins—in one case, identical twin sisters with the same DNA—one can have more hair loss than the other, thanks to increased stress, increased smoking, having more children, or having a history of high blood pressure or cancer.

Check out the two identical twin brothers below and at 1:24 in my video Supplements for Hair Growth. They have the same genes, but the twin on the right reported more stress in his life.

In this pair of twins, shown below and at 1:32, the identical twin on the right was a smoker and drank more alcohol.

Smoking can contribute to the development of both male and female pattern baldness because cigarettes’ genotoxic compounds may damage the DNA in hair follicles and cause microvascular poisoning in the base of the follicle. Other toxic agents associated with hair loss include mercury, because it seems to concentrate about 250-fold in growing scalp hair. In fact, the reason William Shakespeare started losing his hair may have been due to mercury poisoning from syphilis treatment. Thankfully, doctors don’t give people mercury anymore. These days, as the U.S. Centers for Disease Control and Prevention points out, mercury mainly enters the body through seafood consumption.

Often, women of reproductive age seek medical treatment for what is considered hormone-related hair loss, particularly at menopause. For example, a 43-year-old woman evaluated for early menopause was seen for hair loss, and blood tests indicated elevated mercury levels. No wonder—she had a diet high in tuna. But the good news is that her mercury levels fell after she stopped eating it. Within two months, her hair started to come back, and after seven months on a fish-free diet, her hair regrew completely. So, doctors should consider screening for mercury toxicity when they see hair loss, since it may be treatable. Advising patients to reduce fish intake and repeat blood tests could offer symptom relief and uncover dietary habits that may be a source of heavy metal–induced hair loss.

Can nutrient deficiencies cause hair loss? After bariatric surgery, the most frequent nutrient deficiency symptom is hair loss, but that’s because those individuals have had their anatomy rearranged to purposefully cause malabsorption. In general, there is little evidence to suggest that vitamin and mineral supplementation benefits people unless they are actually deficient.

For example, we’ve known for centuries that scurvy (severe vitamin C deficiency) can cause hair loss, but there are no data correlating vitamin C levels and hair loss once you have a certain baseline sufficiency of vitamin C (enough to keep your gums from bleeding, for example).

It’s also a myth that supplements containing zinc will increase hair growth, unless there is a zinc deficiency, which can occur in people who abuse alcohol. However, if blood zinc levels are normal, taking more zinc won’t help. In fact, it can have negative side effects. The same is true for iron supplements.

The most common ingredient in top-selling hair loss products is vitamin B7, also known as biotin. Yes, biotin deficiency causes hair loss, but there are no evidence-based data that supplementing biotin promotes hair growth. Severe biotin deficiency has never been reported in healthy people eating a normal diet, though deficiency can develop from eating raw egg whites since certain compounds attach to biotin and prevent it from being absorbed. But other than rare deficiency syndromes, it is a myth that biotin supplements increase hair growth.

Why not just have the attitude ‘‘can’t hurt, might help?” Because of the lack of regulatory oversight of the supplement industry and, in the case of biotin, interference with lab tests. Many dietary supplements promoted for hair health contain biotin levels up to 650 times the recommended daily intake of biotin. Excess biotin in the blood can interfere with a bunch of different blood tests, including thyroid function tests, other hormone tests (including pregnancy tests), and the test used to determine whether someone has had a heart attack, so the consequences could potentially be life or death.

In terms of poor regulation, I’ve talked a lot about all sorts of supplement manufacturer shenanigans. For example, there was an outbreak in which hundreds suffered selenium toxicity because an error resulted in a supplement containing 200 times the labeled dose, so it ended up causing hair loss. The same thing can happen with getting too much vitamin A.

Doctor’s Note

This is the first in a three-part series on hair loss and growth. Stay tuned for The Benefits and Risks of Hair Loss Drugs and What Foods Help Hair Growth?.

For more on what you can do about mercury exposure, see How to Lower Heavy Metal Levels with Diet.

Check the related posts below for some of my videos about the sketchy supplement industry.

I discuss a public health case for modernizing the definition of protein quality.

In 2019, Dr. David Katz and colleagues, including one of my favorite researchers, David Jenkins, published a “public health case for modernizing the definition of protein quality.” The prevailing definition seems to have more to do with biochemistry than the overall effects on human health. The common belief that protein is “good,” and the more the better, combined with a definition of protein quality that favors animal protein, gives the impression that eating more meat, eggs, and dairy is desirable and preferable. But this is directly opposed to nutrition guidelines that are instead trying to push more plants. Although protein malnutrition is still common in many areas of the world, it is extremely rare in the industrialized world, where “the most formidable public health threats…are from chronic diseases,” not something like kwashiorkor, severe protein and calorie malnutrition.

In 2016, a landmark study was published out of Harvard, involving more than 100,000 people, that found that replacing animal protein with plant protein was associated with lower risk of dying prematurely. The worst offenders seemed to be processed meat like bacon, as well as egg protein (the egg whites). But swapping in even just 3% plant protein for any of the animal proteins, such as processed meat, unprocessed meat, chicken, fish, eggs, or dairy, was associated with a significantly lower risk of arguably the most important endpoint of all: death. See below and at 1:32 in my video Animal Protein vs. Plant-Based Protein.

But how do we know it’s the protein? The researchers adjusted for factors such as saturated fat intake, which suggested it wasn’t just the animal fat. But how can our body differentiate between protein from a plant and protein from an animal? Isn’t protein…protein? No. Generally, plant protein is low in branched-chain amino acids, unlike animal protein, and decreased consumption of branched-chain amino acids improves metabolic health. It could be the IGF-1, a cancer-promoting growth hormone that is boosted by so-called high-quality animal protein intake, though. We suspect the IGF-1 connection is cause and effect, since people born with higher IGF-1 levels, regardless of what they eat, appear to suffer higher rates of killers like type 2 diabetes and heart disease. Or, it could be something the Harvard researchers didn’t control for, such as toxic pollutants like dioxins and polychlorinated biphenyls (PCBs), since they tend to accumulate up the food chain into cattle, pigs, chickens, and fish and therefore end up on our plates. So, “plant-based protein, besides other health benefits, stands as an important step to lower the body burden of harmful pollutants of dietary animal-protein origin.”

If you don’t think a study with 100,000 people is enough, how about 400,000 people? The U.S. National Institutes of Health–AARP Diet and Health Study is the largest diet cohort study in history, and, again, researchers found that simply replacing 3% of calories from animal protein with plant protein was associated with a 10% lower overall mortality—and you get even twice that benefit if you get rid of eggs, too. That’s not a surprise, since egg consumption is associated with a higher risk of developing cardiovascular disease.

Put all the studies together on dietary protein intake and mortality, and people who eat more protein tend to live shorter lives. But this is “mainly driven by a harmful association of animal protein.” Plant protein intake is actually inversely associated with mortality, meaning those who eat more plant protein tend to live longer lives. More animal protein may mean more mortality, whereas more plant protein is correlated with less mortality, as you can see below and at 3:30 in my video.

So, the best of both worlds would be to increase the intake of plant protein instead of animal protein. In other words, as another meta-analysis concluded, “Persons should be encouraged to increase their plant protein intake to potentially decrease their risk of death.”

Doctor’s Note

The benefits of calorie restriction may arise from the drop in animal protein intake. See Caloric Restriction vs. Animal Protein Restriction for more on this.

I also discuss branched-chain amino acids in Are BCAA (Branched Chain Amino Acids) Healthy?.

Do you need to combine plant proteins, like rice and beans? See The Protein Combining Myth.

How much protein do we need? See Do Vegetarians Get Enough Protein?.

What about plant-based meats? Are Beyond Meat and the Impossible Burger Healthy?

Healthy kidneys are required for potassium excretion. If you aren’t sure if you’re at risk, ask your doctor about getting your kidney function tested.

Based on how we evolved, the optimum dietary potassium intake likely greatly exceeds current and even recommended intakes. The problem is we replaced many of the potassium-rich plant foods that used to fill our diets—fruits, vegetables, leafy greens, roots, tubers—with calorie-dense junk heavy with added fats and sugars, and stripped not only of fiber but also potassium.

In a traditional, mostly plant-based diet, potassium intake is high and sodium intake is low. But now, high blood pressure is the second leading risk factor for death worldwide, killing more than 10 million people each year. Only unhealthy diets rank higher among global risk factors for death, as you can see below and at 0:41 in my video Potassium Chloride Salt Substitute Side Effects.

We can improve both by eating more whole, healthy plant foods like greens and beans, which are packed with potassium and help lower blood pressure. But since most of us are getting too much sodium along with too little potassium, what about using salt substitutes? Potassium chloride is the most common salt substitute, so you’d be swapping out sodium for potassium.

And it works. Based on a meta-analysis of more than a dozen randomized controlled trials, replacing sodium chloride with potassium chloride lowers blood pressure. Most of the trials involved swapping out regular salt for substitutes with less than 30% potassium chloride, and they still got results. And at less than 30% potassium chloride, most people can’t even tell the difference between regular salt and the potassium salt. So, it can taste the same yet still lower blood pressure? What’s the catch?

Potassium chloride is “generally regarded as safe” (GRAS) by the U.S. Food and Drug Administration. The only major concern for healthy people is that if you go 100% sodium-free and use potassium chloride salt substitutes exclusively, you may find it can taste kind of funny, adding a bitter or metallic taste. I’ve found that it depends on what I’m seasoning. Potassium chloride works perfectly well on some dishes and snacks, but I find it makes other foods inedible. When I learned about the sodium science and threw out my salt shaker for good, within a few weeks, my palate totally changed. Everything tasted fine without salt—except pesto. For some reason, pesto without salt didn’t have the same taste that I loved. So, I tried the potassium chloride salt substitute, and it worked perfectly. I couldn’t tell the difference at all! So, I had the best of both worlds. Then, I remembered how, as a kid, I used to put a tiny sprinkle of salt on watermelon like they do in the South to make it even sweeter. I tried it with the potassium salt and almost gagged. The salt substitute is definitely not for everything.

The reason healthy people don’t have to worry about getting too much potassium is that they just pee out the excess, thanks to the kidneys. But that’s with the potassium in food—what about supplements? No adverse effects have been shown with long-term potassium supplementation at doses as high as 3,000 mg a day. In fact, blood levels of potassium are maintained in the normal range by healthy kidneys even when potassium intake is increased to about 15,000 mg a day. That’s no surprise since we evolved eating so many potassium-rich plant foods that the natural intake of potassium for the human species may have been on the order of 15,000 mg a day.

Basically, the normal range for potassium levels in the blood is between 3.5 and 5.0 mmol/L; it becomes concerning when it starts creeping up towards 6 mmol/L. But give people potassium supplements—like the salt substitution trials where participants receive an average of about 2,000 daily milligrams—and blood levels only increase by 0.14 mmol/L. So, they might go from 4 to 4.14 mmol/L, not something that would push levels into the danger range.

Now, there is a limit. Someone with a “massive banana eating habit” could bump their potassium from a normal level to above 6 mmol/L, but this specific case was evidently the result of eating little else besides up to 20 bananas a day for years. Eating 10 pounds of carrots every day is also probably not a good idea. That’s like 75 carrots in one day—only really possible with a juicer, which is what one person attempted as part of a quack cancer cure. What about overdoing salt substitutes?

A 1940s report focused on lithium poisoning from the use of salt substitutes. Why? Because lithium chloride was used as a salt substitute. Yikes! But what about potassium chloride, which is what’s used today? There is one case where someone committed suicide by taking a little more than a tablespoon of a potassium chloride salt substitute. That doesn’t seem like a lot—just a tablespoon? I mean, how can we keep that on the shelves if only a tablespoon will kill you? Well, even smaller amounts of regular salt, if taken all at once, can kill you, too. In fact, ingesting salt water was evidently a traditional suicide method in ancient China.

Having said all that, a small number of the population may run into problems, primarily people with severely impaired kidney function. That’s why there’s been such a reluctance to push potassium‐based salt substitutes on a population level. If your kidneys can’t regulate potassium, then it can definitely become a serious issue. We’re talking about folks with known kidney disease, diabetes (since diabetes can lead to kidney damage), severe heart failure, those on medications that impair potassium excretion, older adults, and people with adrenal insufficiency. If you aren’t sure if you’re at risk, ask your doctor about getting your kidney function tested.

Ironically, potassium is so good at reducing deaths from high blood pressure—even among those with kidney disease—that using potassium chloride salt substitutes would probably still save more lives despite the risk, as you can see below and at 5:45 in my video.

Traditional dietary recommendations to kidney patients limited the consumption of fruits and vegetables because they were high in potassium. However, this paradigm is changing quickly given the many benefits of a fundamentally plant-based diet. A whole food, plant-based diet may even ameliorate chronic kidney disease. For example, there’s increasing evidence that a whole food, plant-based diet may help slow the progression of chronic kidney disease and delay kidney failure. So, the practice of restricting dietary potassium in kidney patients should really be reserved for patients with documented hyperkalemia, a potassium level of 6 or higher, because the key to halting the progression of chronic kidney disease might in fact lie in the produce aisle.

Doctor’s Note

If you are in crisis, you can call the National Suicide Prevention Lifeline 24 hours a day, seven days a week, at 800-273-8255.

This is the final blog in a three-part series. If you missed the first two, check out The Mineral Intake Recommendations Only 1 in 6,000 U.S. Adults Meet and Are Potassium Chloride Salt Substitutes Worth Trying?.