Health Journal Online

Category: Nutrition

  • Do Potatoes Shorten Your Life?

    Do Potatoes Shorten Your Life?

    Do potato eaters live longer or shorter lives than non-potato eaters?

    Is there a link between potato intake and the incidence of hypertension? Harvard researchers followed the diets and diseases of more than 100,000 men and women for decades and found that those who ate potatoes on most days—not only French fries and potato chips, but even mashed, boiled, or baked—appeared to be at higher risk of developing high blood pressure. But what do people put on potatoes? Salt, not to mention butter, so might the potatoes just be innocent bystanders? The researchers made attempts to tease out the effects of salt and saturated fat, and there still seemed to be a link between potato consumption and high blood pressure.

    Maybe potato eaters are meat-and-potatoes people. After all, these same Harvard researchers found that meat, including poultry, seemed to be associated on its own with an increased risk of hypertension, and the same goes for even a moderate amount of canned tuna. So, in the potato study, they were careful to try to factor out any effects from the consumption of all types of animal flesh. Yet, they still found an increased risk and became concerned that associating potato intake with hypertension could be a “critical public health problem.” It was assumed potatoes might actually decrease high blood pressure, given their high potassium content, but they found evidence of the opposite effect.

    As I discuss in my video Do Potatoes Increase the Risk of High Blood Pressure and Death?, two similar studies performed in Mediterranean Europe did not find any association between potato consumption and high blood pressure, though. Perhaps this is because they don’t smother their potatoes in butter and sour cream in that neck of the woods and instead eat potatoes with other vegetables. Now, the Harvard researchers tried to control for the salty and fatty dietary components associated with eating potatoes in the West, just like these researchers tried to factor out all the extra vegetables, but you can’t control for everything.

    One of the main reasons we care about blood pressure is because we care about the consequences. In two studies done in Sweden, where they primarily eat their potatoes boiled, no evidence was found that potato consumption was associated with the risk of major cardiovascular disease. No relationship between potato consumption and risk of premature death was found in Southern Italy either. In the United States, however, potato consumption was associated with increased mortality: a whopping 65% increased risk of dying from heart disease, a 26% increased risk of fatal stroke, a 50% increased risk of dying from cancer, and an increased risk of dying from all causes put together. However, this association disappeared after adjusting for confounding factors. In other words, it wasn’t the potatoes at all. Potato eaters must just smoke more, drink more, or eat more saturated fat or something. Once you control for all these other factors, the link between potatoes and death disappears.

    This was confirmed in the NIH-AARP study, the largest such study of diet and health in human history. If you separate out just the potatoes, researchers find they are not associated with increased risk of death, with the possible exception of French fries, which are associated with an increased risk of dying from cancer. Put all the studies together—20 in all—and no significant association has been found between potato consumption and mortality, though again, fried potatoes may be the exception. Even just twice a week, fries may double one’s risk of dying prematurely, independently of other factors, but the consumption of unfried potatoes seemed to be neutral.

    I’ve talked a lot about how all plant foods are not created equal, as well as healthy versus unhealthy plant-based diets. To this end, researchers created not only an overall plant-based diet index (PDI)—just scoring plant versus animal foods—but also a healthy plant-based diet index (hPDI) and an unhealthy plant-based diet index (uPDI). The healthy index puts a greater emphasis on whole plant foods, whereas the unhealthy index scores how much low-quality plant foods you’re eating, grouping potatoes along with soda, cake, and Wonder Bread. When you run the numbers, the more plant-based you eat, the longer you live, and the lower your risk of cardiovascular disease. In other words, more plant foods and less animal foods are associated with a significantly lower risk of dying prematurely. This benefit was limited, though, to those eating the healthier plant-food diets. However, the researchers were surprised that those eating the less healthy plant-based diets with processed plant-based junk did not live significantly shorter lives. Maybe that’s just because they were eating fewer animal products, and that’s really the primary determinant of lifespan here, or maybe the lack of an association between less healthy plant-based diets and mortality is because potatoes were kind of coming to the rescue. And indeed, higher intake of potatoes did appear protective; so, given these conflicting results, future studies may consider just resigning fried potatoes to the unhealthy list.

    Now, in terms of mortality, fried potatoes may not be as bad as fried meat—fried chicken and fried fish—but that’s not really saying much. The French fry/death data gave the industry trade group Potatoes USA a bit of a chip on its shoulder, reminding readers that observational studies can only prove correlation, not causation, to which the authors replied, “Our data add to the pressing public health calls to limit fried potato consumption.” French fries may be so bad for you that it wouldn’t be ethical to do an interventional study and randomize people to eat them.

    Doctor’s Note

    This is the second in a five-part series on potatoes. The first installment was Do Potatoes Increase the Risk of Diabetes?.

    Aside from French fries, potato consumption is not associated with mortality. Potato eaters tend to live just as long as non-potato eaters. That’s actually bad news. A whole plant food that’s not associated with living longer? One that has a neutral effect on lifespan? That’s a lost opportunity. But what if you really like white potatoes? Then you should chill and reheat them, as I explain in my next video.

    Coming up:

    For more on preventing and treating high blood pressure, see related posts below.



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  • Potatoes and Diabetes: It’s Complicated

    Potatoes and Diabetes: It’s Complicated

    Does the link between white potatoes and diabetes extend to non-fried potatoes without butter or sour cream?

    The trouble for white potatoes began in 2006, when the Harvard Nurses’ Health Study, which had followed the diets and diseases of tens of thousands of women for 20 years, found that greater potato intake was associated with a greater likelihood of getting type 2 diabetes. However, of the hundred or so pounds of potatoes Americans eat every year, most are in the deep-fried forms of potato chips, french fries, or other processed products. What happened when they looked specifically at mashed or baked potatoes? They found the same link with diabetes. Okay, but what might potato eaters eat more of? Maybe I should rephrase that: What might meat-and-potatoes people eat more of? Indeed, people who ate more potatoes ate more meat, and we know that animal protein may be associated with increased diabetes risk. But the researchers tried to statistically adjust for that and still found increased risk with potatoes.

    Well, what do people put on baked and mashed potatoes? Butter and sour cream. Again, the researchers tried to adjust for other dietary factors like these as well as effectively looking at the ratio between plant and animal fats and whether potato eaters drank more soda or maybe skimped on other vegetables. Yet, still, there seemed to be this association between potatoes and diabetes.

    Okay, but that was just one study. By 2015, Harvard researchers had also looked into other cohorts, including the all-male Health Professionals Follow-up Study to complement the all-female Nurses’ studies, and they continued to find a small increased diabetes risk associated with baked, boiled, or mashed potatoes, though french fries do indeed appear nearly five times worse. The authors concluded that potatoes are considered to be a healthy vegetable in dietary guidelines, but the current evidence “casts serious doubts on this classification.” Walter Willett, the chair of Harvard’s nutrition department at the time, went a step further, suggesting potatoes should be siloed up there with candy, as you can see below and at 2:18 in my video Do Potatoes Increase the Risk of Diabetes?.

    A meta-analysis of potato consumption and risk of type 2 diabetes published in 2018 combined all six of the prospective studies that had been done to date, and the researchers found about a 20% increase in diabetes risk associated with each serving of potatoes a day, concluding “[l]ong-term high consumption of potato…may be strongly associated with increased risk of diabetes.” But, again, the great majority of the potatoes consumed were fried, and we know deep-fried foods contain all sorts of nasty things, like advanced glycation end-products. The researchers weren’t able to assess french fries versus non-fried potatoes. Even just three servings of fries a week is associated with nearly 20% greater risk of type 2 diabetes, whereas there was only a tiny associated risk with potatoes in general, and that included the fries mixed in.

    The world’s largest manufacturer of frozen french fries took issue with this conclusion. Claiming to make one in three fries eaten on planet Earth to the tune of billions of dollars, the company has the money to fund reviews to cast doubt on the science. One review said that the scientific literature should be read with caution because the impact of potatoes on disease risk factors may depend on the foods they’re grouped with as part of a dietary pattern. Indeed, they do have an actual point. Observational studies can never prove cause and effect, and maybe potato consumption—even baked potato consumption—may just be a marker for an unhealthy diet in general. As much as researchers try to adjust for these other factors, as the journal of the Potato Association of America is quick to remind us, it’s not possible to separate the effects of potatoes and fries from the effects of the overall crappy Standard American Diet.

    Is there a country where potato consumption is associated with a healthy diet? If potato consumption was still associated with diabetes there, then that would be concerning. Enter a seventh study, but this time out of Iran, where most potato consumption is of boiled potatoes. In fact, those who ate potatoes had the healthiest diets and ate the most whole plant foods—fruits, vegetables, legumes, and whole grains. And though the researchers tried to tease out those other dietary factors, those eating the most boiled potatoes had only half the odds of developing diabetes. This supports the notion that it may be hard to completely separate out just the potatoes. The bottom line, this systematic review concluded, is that we really don’t have “convincing evidence” that the intake of potatoes in general is linked to type 2 diabetes, but we should still probably hold the fries.

    Doctor’s Note

    This is the first in a five-part series on potatoes. Stay tuned for:

    Interested in a sampling of diabetes videos? Check out the related posts below.



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  • Prunes: Nature’s Answer to Constipation

    Prunes: Nature’s Answer to Constipation

    Prunes, figs, and exercise are put to the test as natural home remedies for constipation.

    The act of defecation is very private and the object of cultural taboos, so much so that it’s rarely thought of, even by physicians—but it should be. Constipation accounts for three million annual visits to doctors in the United States and 800,000 emergency room visits. Depending on how you define it, up to 80% of the population may be suffering. Even people who don’t think they’re constipated may very well be clinically constipated. A quarter of so-called healthy study participants reported experiencing “incomplete emptying,” and about half “indicated increased straining.” In fact, more than half had found blood on their toilet paper within the past year. In severe cases, the blood pressure spike associated with straining while passing stool can even trigger a heart attack or a stroke.

    There are drugs for it. There are always drugs, resulting in side effects like nausea, diarrhea, headache, and abdominal pain, leaving most patients unsatisfied. So why not instead just try to treat the cause? Common causes of chronic constipation include a lack of whole plant foods containing fiber or insufficient water intake, so changing one’s diet and lifestyle is the preferred method for constipation relief. Such nonpharmacological, clinically effective interventions include engaging in physical activity for about 30 minutes a day.

    A systematic review and meta-analysis found that aerobic exercise interventions help, starting at about 140 minutes a week. And then, of course, a diet centered around whole plant foods—the only naturally concentrated sources of fiber—helps as well. Any plants in particular?

    When elderly women with severe constipation were given about a dozen prunes a day, they experienced significant improvement within the first week. The control group in the study wasn’t told to do anything, though. When one group does something while the other does nothing at all, you can’t discount the placebo effect. And, indeed, the placebo effect for constipation trials can range up to 44%, meaning up to nearly half of the people given a sugar pill claimed to experience an improvement.

    That’s why we need studies like this: Participants were randomized to about 8 prunes a day plus a large glass of water, 12 prunes and water, or just the water alone. So, even the control group got an intervention (the water), which might help with constipation. Previous studies mostly assigned about 10 prunes a day, so the researchers wanted to see if more prunes provided greater benefit or whether fewer would work just as well. They found a significant improvement in stool bulk on the prunes and a significant increase in bowel movement frequency, as you can see below and at 2:45 in my video Prunes: A Natural Remedy for Constipation, though there was no real difference between 8 and 12 prunes. So, 8 a day seems sufficient.

    Prunes even seem superior to psyllium, sold as Metamucil, beating it out in terms of improved stool frequency and consistency.

    We used to think it was just all the fiber in prunes that was helping, but prune juice evidently works too, which, like most juices, has had the fiber removed. Other potential active components include a natural sugar alcohol known as sorbitol that’s used in some sugar-free gums. Once you eat more than a dozen or so large prunes a day, however, the dose of sorbitol could start reaching laxative levels in susceptible individuals. So, be careful.

    If you don’t have constipation, should you avoid prunes? That question has been put to the test, and the answer appears to be no—most people should be able to eat a dozen or so a day without any issues. In fact, it’s interesting to note that prunes have been traditionally used as a laxative and an antidiarrheal remedy.

    What about dried figs, one of the few medicinal plants mentioned explicitly in the Bible? Researchers took patients with the type of irritable bowel syndrome (IBS) characterized by constipation and randomized them to one fig with breakfast and one fig with lunch, each with a glass of water, and there was a significant improvement in frequency of defecation and a significant drop in the frequency of hard stools, compared to the control. But what was the control? The control group was just asked to continue their normal diet. In other words, do nothing special. The placebo response for irritable bowel is infamous. Give people with IBS a fake sugar pill, and sometimes 72% say they magically feel better.

    That’s why we need this kind of study: a randomized, double-blind, placebo-controlled trial. Researchers made a gross-sounding fake fig paste placebo that supposedly had the same taste, smell, and appearance as the real deal. Those who got the real figs, about six a day, seemed to experience “a significant reduction in colon transit time and a significant improvement in stool type [consistency] and abdominal discomfort,” compared to the placebo. Researchers measured transit time by having people swallow little beads that would show up on X-rays so they could track the progress through their digestive system. They found that those eating the real figs sped up their gut movement by a full 24 hours. Defecation frequency per week didn’t beat out placebo, though. In fact, they tested so many different outcomes, even the stool consistency and abdominal discomfort results may have been statistical flukes. So, it looks like prunes would be the better treatment choice.

    Doctor’s Note

    What about carbonated drinks? See Club Soda for Stomach Pain and Constipation.

    I previously discussed prunes and constipation in Prunes vs. Metamucil vs. Vegan Diet.

    What else can prunes do? See Prunes for Osteoporosis.

    Can we do anything else for IBS? Check out the related posts below.



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  • The DNA-Damager in Fried Foods

    The DNA-Damager in Fried Foods

    Glycidol may help explain why people who eat fried foods get more cancer.

    “The main purpose of frying is to produce foods with good consumer acceptability. However, not all acceptable foods are safe.” Food chemists have been very interested in the newly discovered toxic compounds produced by frying.

    We’ve been refining vegetable oils for more than a century, but only recently have we discovered that this can produce concerning compounds such as 3-MCPD and, even worse, glycidol. 3-MCPD is considered a nongenotoxic carcinogen with a tolerable daily intake, while glycidol is a known genotoxic carcinogen, meaning it can cause cancer by directly damaging our DNA, as I discuss in my video The Carcinogen Glycidol in Cooking Oils.

    If a compound is not directly DNA-damaging, it’s assumed that it acts through a mechanism that exhibits a threshold; a so-called no-effect level may exist, a level below which it may not be harmful. But if a compound does damage DNA, it’s generally assumed to follow “a non-threshold mechanism…and no ‘safe level of intake’ can be derived,” because it may only take DNA mutation to start the march towards cancer. So, such substances are not allowed to be added intentionally to foods. For so-called unavoidable contaminants, the “ALARA” principle is followed, meaning that the level should be as low as reasonably achievable or as low as reasonably practicable. Since that’s what glycidol appears to be, we should try to avoid it as much as possible.

    A lifetime cancer risk of 1 in 100,000 is “often used as a figure for acceptable risk in the population.” Based on lab animal data, this might be exceeded if someone weighing about 150 pounds consumed less than a microgram a day. However, thanks to the use of refined oils in so many food products, the average glycidol exposure may be more than 50 micrograms. And in children, the level of intake may exceed acceptable cancer risk by 200-fold.

    So, do people who eat more fried food get more cancer? There is said to be strong evidence that there may be a higher risk of developing chronic disease among frequent consumers of fried foods, but that’s talking largely about cardiovascular health. For example, in a study of more than 100,000 women, frequently consuming fried foods, especially fried chicken and fried fish, was associated with a higher risk of all-cause mortality, meaning such consumers lived, on average, significantly shorter lives. But that was due largely to cardiovascular mortality, whereas fried food consumption was not generally associated with dying from cancer. In men, however, a larger intake of fried food was associated with a 35% increased risk of prostate cancer. Therefore, perhaps men with an increased risk of prostate cancer should, as a precaution, limit their consumption of fried foods.

    These refined oils are also used in infant formulas, which presents a problem for babies who aren’t breastfed. The German Federal Institute for Risk Assessment has come to the conclusion that “infants who are fed exclusively industrially prepared infant milk formula would take in harmful levels of glycidol.” It should be noted that U.S. formulas contain levels of glycidol contamination comparable to those found in Europe—yet another reason that breast is absolutely best. Meanwhile, there are calls on the manufacturers of these products to do everything they can to reduce levels as low as possible.

    But, evidently, the industry has yet to find a way to refine vegetable oils without creating these kinds of by-products, “while at the same time maintaining the quality of the refined product.” It was therefore concluded that this problem has no simple solutions, but I disagree. We can choose to avoid the use of oils and fried foods.

    Doctor’s Note

    I previously talked about 3-MCPD in The Side Effects of 3-MCPD in Bragg’s Liquid Aminos and 3-MCPD in Refined Cooking Oils.

    There is no substitute for human breast milk. Adoptive families or those who use surrogates may want to look for a nearby milk bank.



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  • Building an Anti-Inflammatory Diet

    Building an Anti-Inflammatory Diet

    What does an anti-inflammatory diet look like?

    “Intervention studies to enhance healthy ageing need appropriate outcome measures, such as blood-borne biomarkers, which are easily obtainable, cost-effective, and widely accepted.” We need blood-borne biomarkers of mortality risk. For example, having higher levels of C-reactive protein in your blood may increase your risk of dying prematurely by 42%. C-reactive protein is one of the most widely used inflammatory biomarkers for predicting mortality, but those with the highest levels of interleukin-6 (IL-6), another marker of inflammation, may increase premature death risk by 49%. What can we do to bring it down?

    I’ve previously talked about foods that can contribute to inflammation, like meat and sugar, versus foods like nuts that don’t. But what about anti-inflammatory foods that actually attenuate that inflammation?

    What happens when blueberries are added to a high-fat, high-glycemic-load meal consisting of white potatoes, white bread, ham, cheese, and butter? Adding a single cup of blueberries caused a significant drop in IL-6 from that meal, as you can see below and at 1:15 in my video Which Foods Are Anti-Inflammatory?.

    What about raspberries? People were fed eggs, butter, white potatoes, white flour biscuits, and sausage with or without two cups of frozen raspberries blended with water into a smoothie, compared to giving others the same amount of calories and carbs in banana form. Bananas were no match for meat, eggs, dairy, and crappy carbohydrates; that meal resulted in a tripling of IL-6 levels within four hours. But by drinking those two cups of raspberries instead, their bodies were able to hold the line, as you can see below and at 1:45 in my video.

    Why did raspberries work but bananas didn’t? Maybe it’s the antioxidants.

    Well, antioxidant supplements failed miserably. There was no benefit from antioxidant vitamins and minerals like vitamins C or E, beta-carotene, or selenium. Maybe it’s those special antioxidant pigments, the anthocyanins, that give berries those bright red, blue, and purple colors? Indeed, that’s what dozens of randomized controlled trials have demonstrated, whereas a half-dozen studies combined show pomegranates, a fruit packed with anthocyanin pigments, can bring down inflammation over time.

    What about adding spices to meals as an approach to cool down inflammation? Supplementation with grape and turmeric extracts did not affect the inflammatory response to a milkshake. But giving people one teaspoon a day of actual turmeric—that is, the whole spice, not purified curcumin supplements—resulted in a significant drop in IL-6 levels.

    Garlic powder reduced IL-6 levels as well, starting at about half a teaspoon a day. Ginger powder (ground ginger) had the same results with doses ranging from half a teaspoon to one and a half teaspoons.

    Of course, another way to mediate the inflammation caused by a Sausage and Egg McMuffin is to not eat it in the first place. What about just eating a plant-based diet? To my surprise, the drop in IL-6 did not reach statistical significance. Whenever a dietary intervention doesn’t have the result you expect, you always have to ask, “What exactly was the diet they actually ate?” The study mostly looked at the Mediterranean diet, which certainly has more plants, but maybe the diets didn’t go far enough? For more clarity, we turn to Dr. Turner-McGrievy’s famous New DIETs study, where people either continued to eat their fully omnivorous diets or were randomized to eat a vegan diet, a vegetarian diet, a pesco-vegetarian diet, or a semi-vegetarian diet that, for example, limited red meat. So, whereas the vegan might eat red beans and brown rice with chopped tomatoes and roasted peppers for dinner, the vegetarian might add some cheese, the pesco-vegetarian might add shrimp, and the semi-vegetarian might add some turkey sausage. Below is a more in-depth look at the five diet patterns, which you can also see at 4:01 in my video.

    What happened within two months to their Dietary Inflammatory Index scores? The Dietary Inflammatory Index is a measure of how inflammatory your diet is. Negative scores mean your overall diet is anti-inflammatory, and the lower, the better, whereas positive scores mean your overall diet is on balance pro-inflammatory, which is exactly where the people in the study started. That comes as no surprise, given that they were eating regular diets and our nation is awash with inflammation-related disease.

    But when the study participants switched to strictly plant-based nutrition, their diet flipped to become an anti-inflammatory diet. That was the case even if they just cut out meat or all meat except fish. But if they instead switched mostly to poultry or only limited their meat intake, their diet remained inflammatory. You can see the results below or at 4:47 in my video.

    Now, not all plant foods are anti-inflammatory. If all you do is boost your intake of less healthy plant foods, like juice, white bread, white potatoes, soda, and cake, you can end up even more inflamed. But if you eat a really clean diet of whole plant foods, you get significant reductions in lipoprotein(a)—Lp(a)—which we didn’t even think was possible with diet—as well as drops in LDL cholesterol and even the most dangerous form of LDL cholesterol. Also, nearly across the board, you get a drop in inflammatory markers; we’re talking a 30% drop in C-reactive protein and a 20% drop in IL-6. So, maybe previous studies with plant-centered diets were unsuccessful because they weren’t plant-based enough, with animal products still being substantially consumed. Therefore, the total “elimination of animal products and processed foods…may be a more prudent dietary strategy” to combat inflammation.

    Doctor’s Note

    Hungry for more? See Foods That Cause Inflammation.

    For more on plant-based diets, see related posts below.



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  • What Foods Trigger Inflammation?

    What Foods Trigger Inflammation?

    Inflammatory markers can double within six hours of eating a pro-inflammatory meal. Which foods are the worst?

    Excessive inflammation may play a role in a number of leading causes of death and disability, including type 2 diabetes, obesity, and heart disease. “But what are the stimuli that jumpstart the destructive inflammatory cascade?” You typically hear about the pro-inflammatory nature of a chronic high-fat diet, but the inflammatory effect “may not be limited to chronic intake but may be evident after the consumption of a single meal.”

    Within hours after eating an unhealthy meal, inflammatory markers like interleukin-6 (IL-6) can skyrocket, doubling within six hours. The majority of studies show an increase in IL-6 after consuming a high-fat meal. But the meals they tested weren’t just filled with meat, eggs, dairy, and oil, but also junky refined carbohydrates like white flour and added sugar.

    When people are given essentially straight butter fat and no carbs, they can still get a spike in inflammation within hours, proving the added fat itself is pro-inflammatory. But when people are given straight sugar water without any fat, the result is the same, proving the added sugar is pro-inflammatory, too, as you can see below and at 1:26 in my video Foods That Cause Inflammation.

    Why should we be concerned with the inflammatory responses after unhealthy meal ingestion? Because extensive research points to the idea that “persistent low-grade inflammation is an underlying factor in several high-mortality chronic diseases and that diet can contribute to, or attenuate, that inflammation.”

    You’ll note in the graph below that IL-6 levels jumped up to about 3 pg/mL after the meal. (You can also check it out at 1:55 in my video.)

    When levels start regularly getting up to about 3 pg/mL, that’s associated with twice the risk of death. That increased risk was found across the board, compiling eight other similar studies, likely because it’s linked with increased risk of heart disease, the number one killer of men and women, even as strongly as some other major well-known risk factors like high cholesterol.

    Now, not all high-fat foods cause inflammation. More than a dozen studies combined show that whole plant foods such as nuts do not increase inflammatory markers, even when eating up to handfuls of nuts a day. In fact, spread half an avocado on a beef burger, and you may be able to blunt some of the inflammation caused by the meat—even lean meat—as you can see below and at 2:35 in my video.

    There are reviews purporting to show a drop in inflammatory markers after eating wild game, which is about as lean a meat as you can get, but that’s only compared to store-bought meat. Give people some really fatty meat and their IL-6 shoots up, as do their tumor-necrosis factor and C-reactive protein. Inflammatory, inflammatory, inflammatory—within hours of consumption. But what if you instead eat a kangaroo steak, which is extremely low in fat, similar to elk or moose? You’ll get the same strong inflammatory response within hours of eating it, as you can see below and at 3:15 in my video.

    Now, certainly less inflammatory than conventional meat you might get at the store, but pro-inflammatory nonetheless, increasing markers of inflammation within mere hours.

    Doctor’s Note

    Stay tuned for Which Foods Are Anti-Inflammatory?, up next.

    For more on diet and inflammation, see related posts below.



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  • Do Pomegranates Live Up to Health Claims?

    Do Pomegranates Live Up to Health Claims?

    Pomegranates are put to the test for weight loss, diabetes, COPD, prostate cancer, osteoarthritis, and rheumatoid arthritis.

    The case of POM Wonderful (the pomegranate juice company) vs. Federal Trade Commission made it all the way up to the U.S. Court of Appeals before being denied review by the Supreme Court. In that landmark case, a panel of judges concluded that many of POM’s ads made false or misleading claims and the company “touted medical studies ostensibly showing that daily consumption of its products could treat, prevent, or reduce the risk of various ailments, including heart disease, prostate cancer, and erectile dysfunction.” The U.S. First Amendment does not protect misleading and deceptive ads. Striking a blow to its billionaire owners, the Court ruled that at least one randomized clinical trial would be required to substantiate claims of treating or preventing disease.

    If you look at the medical literature on pomegranate in general, you’ll see reviews touting its many benefits, with diagrams like the one below on the medicinal effects of pomegranates (which you can also see at 1:01 in my video Pomegranate: A Natural Treatment for Rheumatoid Arthritis).

    But if you dig a little deeper, you see this is based on studies like one that talks about the “antiobesity effects of pomegranate leaf extract in a mouse model.” First of all, who eats pomegranate leaves? And second, who’s a mouse?

    Does pomegranate consumption affect weight in humans? If you look at all the randomized controlled clinical trials (meaning human trials), pomegranates have no significant effect on body weight, BMI, belly fat, or even body fat percentage in those randomized to consume pomegranate products. What about the prevention and treatment of cardiovascular diseases? Researchers reviewed 25 clinical trials, looking at cholesterol, blood pressure, artery function, atherosclerotic plaque formation, and platelet function, and did not find significant indications of benefit even in the best studies.

    POM Wonderful helped fund a study on pomegranate juice and erectile dysfunction, but it failed as well. Other studies found no benefit for diabetes markers and observed no benefit for chronic obstructive pulmonary diseases, such as emphysema. They were banking on the antioxidant activity of pomegranate juice to help, but that’s antioxidant activity in vitro (meaning in a test tube or petri dish). To my surprise, a meta-analysis of data from 11 randomized controlled trials “did not support convincing evidence” of pomegranate intake having a significant effect on increasing the total antioxidant capacity in the bloodstream because some of the most potent antioxidants don’t even seem to be absorbed into the human body. No wonder pomegranate supplementation didn’t seem to affect oxidative stress in tissue samples taken from prostate cancer patients. But, of course, what we care about is whether it affects the cancer itself.

    The strongest evidence for the anticancer activity of pomegranates is said to come from studies on prostate cancer. Unfortunately, early promising results were not confirmed when they were actually put to the test. For example, daily pomegranate intake was found in a randomized controlled trial to have no impact on PSA levels, a marker of tumor progression. Additionally, a randomized, double-blind, placebo-controlled trial found essentially no difference when it came to prostate cancer disease progression, as you can see below and at 3:19 in my video.

    They were banking on the anti-inflammatory activity of pomegranate juice to help, but again, that had been demonstrated in vitro. In people, a meta-analysis based on five randomized controlled trials published in 2016 concluded that pomegranate juice did not have a significant effect on C-reactive protein levels, a key marker of inflammation. If you look at the forest plot, though, you’ll see all five trials tended towards lower C-reactive protein levels such that the data combined almost reached statistical significance, as you can see below and at 3:53 in my video.

    Indeed, an updated meta-analysis published in 2020 based on seven studies crossed the threshold into statistical significance and found a significant drop in two other inflammatory markers as well.

    Perhaps pomegranate juice could help in the control of inflammatory diseases after all. But you don’t know until you put it to the test.

    Osteoarthritis involves the degeneration of the cushioning cartilage within joints, particularly the knees. Dripping a pomegranate extract on human osteoarthritic cartilage samples appears to show cartilage-protective effects. As you can see below and at 4:43 in my video, compared to baseline levels of cartilage disintegration, adding inflammation triples the damage. However, with increasing amounts of pomegranate extract, the breakdown starts to calm down.

    But again, that’s in a petri dish. How do we know that when we eat pomegranates, the active components actually get into our bloodstream so they can find their way into our joints? Cartilage-protecting components were found to be bioavailable (at least in rabbits), raising the possibility that pomegranates could be a safe and non-toxic treatment with no side effects, as opposed to the drugs currently in use. But is it effective?

    The first clinical trial on pomegranate juice and osteoarthritis was not a placebo-controlled trial, but instead randomized people to pomegranate juice or nothing at all. Those drinking the juice did report less stiffness and impairment of physical function, but not significantly better than just doing nothing. Shoot.

    Just as I was about to give up on pomegranates, I saw a study titled “Consumption of Hydrolyzable Tannins-Rich Pomegranate Extract Suppresses Inflammation and Joint Damage in Rheumatoid Arthritis.” But it turned out to be from the POM “Not-So-Wonderful” company, inducing joint damage in a mouse as a model of rheumatoid arthritis. Come on!

    There was an open-label study, where the patients knew what they were getting. Eight people with active rheumatoid arthritis took pomegranate extract every day, and the six who stuck with it reported fewer tender joints. But as we learned from the osteoarthritis study, if you don’t have a control group, you have no sense of what role, if any, the treatment actually plays.

    Finally, we come to this randomized, double-blind, placebo-controlled trial. It’s about time! Half the study participants unknowingly got some pomegranate extracts; the other half unknowingly got the equivalent of a sugar pill. There appeared to be a significant improvement in the number of swollen joints, tender joints, pain intensity, a disease activity score, a health assessment questionnaire, and morning stiffness compared to placebo. So, if you have rheumatoid arthritis, I would indeed recommend you start eating pomegranates. Why not just pop pomegranate pills? After all, it was a pomegranate extract that alleviated disease activity. One good reason to stick to the fruit is that when 19 pomegranate supplements were tested in a laboratory, most didn’t actually appear to have any pomegranate in them at all! Only 6 out of 19 appeared to be authentic.

    Doctor’s Note

    I previously reported on POM Wonderful back in 2011 in my video Is Pomegranate Juice That Wonderful?. My other video on this fruit is Flashback Friday: Pomegranate vs. Placebo for Prostate Cancer.

    What’s one way you can eat them? Check out my cooking video for Cran-Chocolate Pomegranate BROL Bowl.



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  • Beyond Elimination Diets | Dietitian Connection

    Beyond Elimination Diets | Dietitian Connection


    Welcome to a special Gut Health Month episode of The Dietitian Connection Podcast. This March, we’re celebrating Gut Health Month 2026 by bringing dietitians together to deepen our knowledge, strengthen our confidence, and amplify our voice to create meaningful impact in practice and beyond.

    In this episode, we’re joined by leading gut health dietitian Nicole Dynan to explore how dietitians can build confidence in this rapidly growing space. Tune in for practical insights and inspiration to help you feel empowered in your gut health practice.

    Hosted by Kate Agnew

    Biography

    Nicole Dynan is the founder of The Gut Health Dietitian (established in 2014) and one of Australia’s leading gut health experts. After a decade in corporate chronic disease management, Nicole saw first-hand how gut health impacts energy, stress, mood, and overall well-being. Since then, and together with her team, she’s helped over 40,000 people improve their gut health, feel more comfortable, and regain control of their overall health through science-backed nutrition. 


    In this episode, we discuss:

    • How dietitians can build confidence and credibility in gut health through targeted upskilling and staying across emerging research and trends
    • The shift in gut health care from restriction to focusing on foundations
    • Why it’s important for dietitians to raise their voice, strengthen their influence and work together to lead evidence-based gut health conversations
    • The importance of recognising what stage of behaviour change a client is in and adapting your approach to meet them where they are

    The content, products and/or services referred to in this podcast are intended for Health Care Professionals only and are not, and are not intended to be, medical advice, which should be tailored to your individual circumstances. The content is for your information only, and we advise that you exercise your own judgement before deciding to use the information provided. Professional medical advice should be obtained before taking action. The reference to particular products and/or services in this episode does not constitute any form of endorsement. Please see  here  for terms and conditions.


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  • Fighting Cancer with Whole Plant Foods

    Fighting Cancer with Whole Plant Foods

    The foundation of cancer prevention is plants, not pills.

    “The vast majority of cancer research is devoted to finding cures, rather than finding new ways to prevent disease. The results of these skewed priorities are plain to see.” It’s been nearly 55 years since President Richard Nixon declared war on cancer, yet deaths from the most common cancers in the United States have continued unabated.

    “We have been looking at the very nature of cancer in the wrong way. Breast cancer doesn’t begin when a lump is first felt or detected by a mammogram. All the common epithelial cancers (lung, colorectal, breast, prostate, pancreas and ovary), which account for the majority of deaths, have a long latency period—often 20 years or more.” So, it’s not like you were healthy one day, then got cancer the next. You haven’t been healthy—you’ve had cancer growing in you for decades. Indeed, there’s a “bizarre misperception that people are ‘healthy’ until they have actual symptoms of invasive cancer,” but “the barn in which hay is smoldering before it bursts into flames is not a safe place.”

    So, what does this professor of pharmacology I’ve been quoting recommend? Drugs, of course. Chemoprevention—putting people on drugs to prevent cancer. The pharmaceutical industry spends tons of money promoting chemoprevention of heart disease and strokes with statins and blood thinners, so why shouldn’t people take drugs every day for the rest of their lives to protect against cancer?

    There has to be a better way.

    What about using diet and nutrition to prevent and treat cancer? Well, what kind of cancer? There are more than 200 types. But here’s the key: They all share the same hallmarks. In a series of papers cited more than 40,000 times in the biomedical literature, 10 hallmarks of cancer have been identified:

    • Increased sensitivity to growth factors
    • Evading your body’s tumor suppressors
    • Dodging your immune system
    • Being able to grow forever
    • Tumor-promoting inflammation
    • The ability to invade and spread
    • The ability to hook up its own blood supply
    • The accumulation of DNA mutations
    • Disarming the self-destruct mechanisms in place
    • Hijacking the cell’s metabolism

    And, of course, there are classes of drugs to try to counter each one—chemotherapy agents designed to target each piece of the cancer puzzle. You can see them below and at 2:27 in my video Fighting the Ten Hallmarks of Cancer with Food.

    Now, ideally, there would be drugs able to target multiple hallmarks at one time, but that’s not how drugs tend to work. Indeed, “this need to target multiple hallmarks is one of the major reasons why, in the context of cancer research, there are many proponents of investigating plant foods as they can deliver a cocktail of bioactive compounds” that may target most, if not all, of the hallmarks of cancer. Below and at 3:00 in my video, you can see a sampling of compounds found in fruits and vegetables—such as berries, greens, and broccoli—shown to be able to target each of the 10 hallmarks of cancer, at least in a petri dish.

    Furthermore, they have the qualities of an ideal chemopreventive agent. If you were to design the perfect candidate, you’d want them to be selective to cancerous or precancerous cells while leaving normal cells alone, be side-effect-free, target most types of cancers, be able to be consumed in a daily diet, be conveniently available almost everywhere, and be relatively inexpensive to boot. Plants meet all these criteria. No wonder people who eat more plant-based foods tend to have lower cancer rates.

    To be clear, we aren’t talking about taking supplements containing extracts or purified phytochemicals, but rather eating whole plant foods themselves—more of a food system–based approach to targeting the hallmarks of cancer. Foods contain thousands of substances that result in vast numbers of possible interactions, yet much of nutritional science “has long been directed towards the impact of single dietary components.” Yes, this kind of reductionist approach can uncover the role of foods or even individual nutrients in disease development, but let’s think about what the optimal research strategy would be to study the effects of bioactive natural plant compounds on disease prevention. Instead of using isolated phytochemicals to manage cancer, why not try whole foods? Sometimes the whole can be greater than the sum of its parts, a concept known as food synergy.

    Check out this study involving the simultaneous inhibition of a series of cancer stages in breast cancer cells using a phytochemical supercocktail. Two breast cancer cell lines were treated with six different plant compounds individually, and then all together, at levels typically found in the bloodstream after eating foods like broccoli, grapes, soybeans, and turmeric. And while the compounds were ineffective individually, together they significantly suppressed breast cancer cell proliferation by more than 80%, inhibited cancer cell invasion and migration, stopped the cancer cells in their tracks, and eventually killed them all off. The plant compounds did all this without having any deleterious effects on the normal noncancerous cells used as control.

    No wonder the foundation of cancer prevention—based on an update of the most extensive report on diet and cancer ever published—is not pills, but plants, as you can see below and at 5:28 in my video.

    In other words, cut down on alcohol, soda, meat, and processed junk, and center your diet around whole grains, vegetables, fruits, and beans.

    Doctor’s Note

    I have dozens of videos on cancer prevention and treatment. Check the related posts below. 



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  • Can It Lower Your Cancer Risk?

    Can It Lower Your Cancer Risk?

    Does choosing organic over conventional foods protect against cancer? What are the effects of pesticides on cancer risk?

    In a review updating the evidence on human exposure and toxicity of pesticides, the body of evidence linking pesticide exposure and cancer is said to be so massive that pesticides’ role in the development of cancer “cannot be doubted.” However, most of the evidence that shows DNA damage from pesticides is from occupational exposure among farmers and workers in the fields, the pesticide industry itself, or those living in high-spray areas, as you can see at 0:35 in my video Pesticides and Cancer Risk.

    There is evidence linking non-occupational pesticide exposure to DNA damage—in this case, single- and double-stranded DNA fragmentation in the sperm of men with higher levels of pesticides flowing through their bodies—but that was in China, where the average pesticide concentrations are as much as four times higher than in some other parts of the world.

    Another way pesticides could potentially facilitate tumor growth is through adverse effects on anticancer immunity. Natural killer (NK) cells are our body’s first line of white blood cell defense against cancer cells and virus-infected cells. Pesticides have been shown to induce harmful effects on these defender cells, reducing their ability to kill off tumor cells. For example, if you put a bunch of NK cells in a petri dish along with human leukemia cells without any pesticide, your natural killer cells can clean house and wipe out more than half the cancer. But if you drip a tiny bit of pesticide on them, the NK cells are so disabled that the cancer wins the day, as you can see below and at 1:37 in my video.

    But how much pesticide are we talking about? The researchers used the maximum level found in people actively spraying pesticides. But what about looking at just the residual pesticides left on conventional produce? Is choosing organic for cancer prevention worth the investment?

    Pesticides are detectable in the blood and urine of more than 90% of the U.S. population, regardless of where they work or live. We know it’s from the food we eat because crossover trials where people are switched between consuming conventionally grown foods and organic foods show you can turn on and off urinary concentrations of pesticide metabolites like a light switch. But that doesn’t necessarily mean the pesticides are harming us.

    The health consequences of ingesting pesticide residues from conventionally grown foods remain unknown, but a recent study did find that people who self-reported the highest frequency of organic food consumption had about a 25% lower risk of getting cancer. The study is the first of its kind to evaluate the association between frequency of organic food consumption and cancer risk, controlling for a wide array of other factors. Doesn’t it matter that consumers eating organic are younger? The researchers controlled for that and still found significantly lower cancer risk. But maybe organic consumers get less cancer because they are more affluent or more highly educated or skinnier, or maybe they exercise more or eat less meat or smoke less. No, the researchers controlled for all that and still found significantly lower cancer risk in organic consumers. Maybe their diets were different in other ways, though—more fruits and vegetables overall, or less junk food? No, they still found significantly lower cancer risk. The researchers concluded, “Our results indicate that higher organic food consumption is associated with a reduction in the risk of overall cancer.”

    That was the most sophisticated study of its type to date, but there was an earlier study that was even bigger, and little evidence was found for a decrease in the incidence of all cancers except for perhaps one kind of blood cancer—non-Hodgkin lymphoma. You can see the data below and at 3:59 in my video.

    The data show no difference in cancer overall between those who never choose organic and those who usually or always do; the only significant findings were a lower risk of non-Hodgkin lymphoma and an increased risk of breast cancer. Is it possible that women who choose organic food are more conscientious about getting screened for breast cancer, and that explains the higher diagnosis rate? We really don’t know.

    Of course, what we care about the most is not just cancer but all-cause mortality—the risk of dying prematurely. As it turns out, higher blood levels of a pesticide known as beta-hexachlorocyclohexane are associated with living a significantly shorter life. How do we cut down on our levels? Decades ago, there was a study that found that the breast milk of a vegetarian mother had less beta-hexachlorocyclohexane than the milk of her non-vegetarian sister, who was also breastfeeding at the time. The vegetarian sister apparently had levels of that pesticide that were lower by about a third, compared with her omnivorous sibling, as you can see below and at 4:48 in my video.

    That’s no surprise, since this class of chlorinated pesticides is fat-soluble, so they’re found most frequently in foods of animal origin.

    A more recent study failed to look at beta-hexachlorocyclohexane, but it examined polychlorinated biphenyls (PCBs) and found that they were linked to increased mortality risk. Again, the toxins were found in the same kinds of foods: eggs, dairy products, and animal fats. So, it’s no surprise that the blood of those eating vegan was found to be “significantly less polluted than omnivores” in terms of a whole series of PCBs, including those found in the study to be associated with increased mortality; but the vegans did not have lower levels of beta-hexachlorocyclohexane.

    The bottom line: If you’re worried about the adverse health effects of pesticides and pesticide-type compounds, you may want to lower your intake of animal products. But when it comes to fruits and vegetables, the benefits of eating conventionally grown produce likely outweigh any possible risks from pesticide exposure. So, concerns about pesticide risks shouldn’t discourage us from stuffing our faces with as many fruits and vegetables as possible. That would give us a huge health benefit, whereas the potential lifelong damage of any pesticides on those same fruits and veggies has been estimated to cut only a few minutes off a person’s life, on average, which is nothing compared to the nutritional benefits of eating more fruits and vegetables.

    Doctor’s Note

    For more on organic foods, see related posts below.



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