Have you ever wondered if there’s a natural way to lower your high blood pressure, guard against Alzheimer's, lose weight, and feel better? Well as it turns out there is. Michael Greger, M.D. FACLM, founder of NutritionFacts.org, and author of the instant New York Times bestseller “How Not to Die” celebrates evidence-based nutrition to add years to our life and life to our years.

Let’s Call It…IBD

If you had inflammatory bowel disease you probably wouldn’t want to admit it.  Here’s how to prevent it.

This episode features audio from The Best Diet for Crohn’s Disease Treatment, Preventing Crohn’s Disease with Diet, and Does Nutritional Yeast Trigger Crohn’s Disease?. Visit the video pages for all sources and doctor’s notes related to this podcast.


Did you ever wonder if the food you eat has a direct effect on your health, well-being – and longevity?  Well, I’m here to end that mystery.  You ARE the foods you eat.  Welcome to the Nutrition Facts podcast – I’m your host, Dr. Michael Greger.

Today, we do the math on a condition – we call IBD.  And if we didn’t call it that – it would have to go by its longer – more embarrassing name – Inflammatory Bowel Disease. INTRO

Did you know that switching to a plant-based diet has been shown to achieve far better outcomes than those reported on conventional treatments for both Crohn’s disease and ulcerative colitis.  Let’s look at the facts.

Important to our understanding and prevention of the global increase of inflammatory bowel disease, we know that dietary fiber appears to reduce risk, whereas dietary fat, animal protein, and sugar may increase risk. “Despite the recognition of the Westernization of lifestyle as a major driver of the growing incidence of inflammatory bowel disease, no countermeasures against such lifestyle changes have been recommended, except that patients with Crohn’s disease should not smoke.” Look, we know consuming whole, plant-based foods is synonymous with an anti-inflammatory diet. So, how about putting a plant-based diet to the test?

Just cutting down on red and processed meat didn’t work, but what about cutting down on all meat? A 25-year-old guy diagnosed with Crohn’s disease, but failed to enter clinical remission despite standard medical therapy. But after switching to a diet based exclusively on grains, legumes (like beans, split peas, chickpeas, and lentils), vegetables, and fruits, he entered clinical remission, without the need for medication and showed no signs of Crohn’s disease on follow-up colonoscopy.

It’s worth delving into some of the details. The conventional treatment they started him on is infliximab, sold as REMICADE®, which can cause a stroke, and may increase your chances of getting lymphoma or other cancers—but it’s a bargain for only $35,000 a year. And it may not even work in 35 to 40 percent of patients. And that seemed to be the case here. So, they upped the dose, after 37 weeks and still suffering after two years on the drug—until he tried completely eliminating animal products and processed foods from his diet, finally experiencing a complete resolution of his symptoms.

Prior to this, his diet had been a typical American diet. But having experienced complete clinical remission for the first time since his diagnosis, he decided to switch to a whole food, plant-based diet permanently, severely reducing his intake of processed food and limiting animal products to one serving, or less, per week. And whenever his diet started to slip, symptoms started coming back. But he could always wipe them out by eating healthier. After six months of implementing these changes in diet and lifestyle, including stress relief and exercise, a follow-up demonstrated complete mucosal healing of the gut lining with no visible evidence of Crohn’s disease.

We know “[a] diet consisting of whole grains, legumes, fruits, and vegetables has been shown to be helpful in the prevention and treatment of heart disease, obesity, diabetes, hypertension, gallbladder disease, rheumatoid arthritis, and many cancers. Although further research is required …, this case report suggests that Crohn’s disease might be added to this list of conditions.” But that further research has already been done! About 20 patients with Crohn’s disease were placed on a semi-vegetarian diet, meaning no more than a half-serving of fish once a week and a half-serving of meat once every two weeks, and achieved 100 percent remission rate at one year and 90 percent at two years.

Some strayed from the diet though. After a year, half had relapsed, and at year two, only 20 percent remained in remission. But those that stuck with it had remarkable success. It was a small study with no formal control group, but represents the best reported result in Crohn’s relapse prevention published in the medical literature to date.

Nowadays, Crohn’s patients are often treated with so-called biologic drugs, expensive injected antibodies that suppress your immune system and have effectively induced and maintained remission in Crohn’s disease, but not in everybody. The current remission rate in Crohn’s with early use of REMICADE® is 64 percent. So, 30 to 40 percent of patients are likely to experience a disabling disease course even after treatment. What about adding a plant-based diet? Remission rates jumped up to 100 percent for those who didn’t have to drop out due to drug side effects. Even if you exclude the milder cases, 100 percent of those with serious—even severe—fulminant disease achieved remission.

But if you look at gold standard systematic reviews, they conclude that the effects of dietary interventions on inflammatory bowel diseases, Crohn’s disease and ulcerative colitis, are uncertain. This is because only randomized controlled trials were considered. Totally understandable, as that’s the most rigorous study design. “Nevertheless, people with inflammatory bowel disease deserve advice based on the ‘best available evidence’ rather than no advice at all . . .” And switching to a plant-based diet has been shown to achieve far better outcomes than those reported on conventional treatments in both active and quiescent stages in both Crohn’s and ulcerative colitis. For example, here are one-year remission rates in Crohn’s disease: 100 percent compared to budesonide, an immunosuppressant corticosteroid drug; a half elemental diet, meaning like at-home tube feedings; the $35,000 a year drug REMICADE®; or the $75,000 a year drug Humira. Safer, cheaper, and more effective? Maybe we should recommend plant-based diets for inflammatory bowel disease.

It would seem clear that treatment based on treating the cause of the disease is optimal. Spreading the word about healthier diets could help halt the scourge of inflammatory bowel, but how are people going to hear about this amazing research without some kind of public education campaign? That’s what NutritionFacts.org is all about.

In our next story, we look at how diets centered around whole plant foods may help prevent Crohn’s disease through the benefits of fiber on the maintenance of intestinal barrier function.

Crohn’s disease is an autoimmune disorder that affects more than a million Americans, an inflammatory bowel disease in which your body attacks your own intestines. There is currently no cure for Crohn’s disease and current research focuses on just controlling symptoms. There is no definitive medical or surgical therapy. In fact, the best we have is a more plant-based diet, which has afforded the best result in relapse prevention to date. They got the idea to try it because diets rich in animal protein and animal fat have been found to cause a decrease in beneficial bacteria in the intestine, and so they designed this semivegetarian diet to counter that, and 100% stayed in remission the first year and 92% the second year. These results are far better than those obtained by current drugs, including these new so-called biological agents that can cost $40,000 a year, and cause side effects like progressive multifocal leukoencephalopathy, a disabling and deadly brain disease, whereas the diet doesn’t cost $40K, and the worst that could happen is that you may get greens stuck in your teeth or something, and diet appears to work better.

But what about preventing Crohn’s disease in the first place? Well, a systematic review of the scientific literature on dietary intake and the risk of developing inflammatory bowel disease found that high intakes of fats and meat were associated with an increased risk of Crohn’s disease, as well as ulcerative colitis, whereas high fiber and fruit intakes were associated with decreased risk of Crohn’s. This was supported more recently by the Harvard Nurses’ Health Study. Three million person-years of data revealed that long-term intake of dietary fiber, particularly from fruit, was associated with lower risk of Crohn’s disease. Women who fell into the highest long-term fiber consumption group had a 40% reduced risk leading the accompanying editorial to conclude that “Advocating for a high-fiber diet may ultimately reduce the incidence of Crohn’s disease.” The irony is that the highest fiber group wasn’t even eating the official recommended daily minimum of fiber intake, but even just being less fiber deficient has a wide range of benefits, including, evidently, a significant reduction in the risk of developing Crohn’s disease. But why? The authors suggest it’s because fiber appears to play a vital role in the maintenance of our intestinal barrier function.

Our skin keeps the outside world outside, and so does the lining of our gut, but in Crohn’s disease this barrier function is impaired. You can see it under an electron microscope; the tight junctions between the intestinal cells have all sorts of little holes and breaks. The thought is that the increase in prevalence of inflammatory bowel diseases may be that dietary changes lead to the breakdown of our intestinal barrier, potentially allowing the penetration of bacteria into our gut wall, which our body then attacks, triggering the inflammation.

We know fiber acts as a prebiotic in our colon, the large intestine, feeding our good bacteria, but what does fiber do in our small intestine, where Crohn’s often starts? We didn’t know, until this landmark study was published. They wanted to find out what could stop this Crohn’s-associated invasive bacteria from tunneling into the gut wall. They found that the invasion is inhibited by the presence of certain soluble plant fibers, such as from plantains and broccoli, at the kinds of concentrations one might expect from just eating them. They wonder if that may explain why plantain-loving populations have lower levels of inflammatory bowel disease. They also found that there was something found in processed foods that facilitated the invasion of the bacteria: polysorbate 80, found predominantly in ice cream, but also found in Crisco, Cool Whip, condiments, cottage cheese—you just have to read the labels.

What about maltodextrin? Found in artificial sweeteners like Splenda, snack foods, salad dressings, and fiber supplements. Maltodextrin markedly enhanced the ability of the bacteria to glom onto our intestinal cells, though other additives, carboxy-methyl cellulose and xanthan gum appeared to have no adverse effects.

This may all help solve the mystery of the increasing prevalence of Crohn’s disease in developed nations, where we’re eating less fiber-containing whole plant foods and more processed foods. What we need now are interventional studies to see if boosting fiber intake and avoiding these food additives can be effective in preventing and treating Crohn’s disease. But until then, what do we tell people? The available evidence points to a diet low in animal fat, with lots of soluble fiber-containing plant foods, and avoiding processed fatty foods that contain these emulsifiers, as well as making sure we’re not ingesting traces of dishwashing detergent, which could have the same effect, by just rinsing dishes well. They found that some people wash dishes and then just leave them to dry without rinsing, which is probably not a good idea. Now, do we have studies that show that avoiding polysorbate 80 and rinsing dishes well actually helps? No. Nevertheless, advice based on “best available evidence” is better than no advice at all.

Finally today, we look at Crohn’s disease patients – and their different reactions to baker’s, brewer’s, and nutritional yeast.

“Baker’s yeast in Crohn’s disease—Can it kill you?” Well, that’s an inflammatory title (no pun intended). Crohn’s disease is an inflammatory bowel disease. Might baker’s yeast, which is the same yeast as brewer’s yeast, which is the same yeast as nutritional yeast, play a role in Crohn’s disease?

It all started with this study published in 1988, showing that people with Crohn’s disease tend to have more antibodies to yeast than people without Crohn’s disease. Antibodies are like homing devices our immune system makes to attack foreign invaders. That’s one part of our immune system; another is cell-mediated immunity, where our white blood cells attack invaders directly. And, the same hypersensitive reaction to yeast was found in the white blood cells of Crohn’s disease patients, as well.

If you draw blood from healthy people, even bakers who are around yeast all the time, and you expose their peripheral blood leukocytes, their immune system white blood cells, to yeast, nothing happens. They just kind of ignore it, because it’s typically harmless. But, do the same thing with Crohn’s disease patients, and their white blood cells go crazy.

Now, when I say typically harmless, if you have cancer, or AIDS, or are immunocompromised, you could potentially get infected from like, home-brewed beer, or probiotic yeast supplements, but they don’t think the yeast is actually infecting Crohn’s patients. People with Crohn’s may just be hypersensitive to exposure to the inactive, dead yeast in typical food products, which may help explain why, when you rest their bowels, when you make Crohn’s patients fast, they get better.

In fact, that’s why we add yeast extracts and proteins to vaccines, as an adjuvant, an irritant like aluminum, to make the vaccines work better, by heightening the immune response. But, might that be raising the risk of autoimmune disease, boosting our immune response a little too much, especially in people who may be genetically susceptible, like with Crohn’s?

And, the greater the anti-yeast response, the more severe the disease, in both children and maybe adults too. So, maybe we should try a yeast-free diet for Crohn’s patients, and see if they get better. But, wait a second. Just because anti-yeast antibodies are associated with Crohn’s disease doesn’t mean the reaction to yeast is causing the Crohn’s disease. Maybe the Crohn’s disease is causing the reaction to yeast. What? Think about it. Crohn’s causes an inflamed, leaky gut; so, maybe the Crohn’s came first, allowing yeast particles to leak into the bloodstream, resulting in the anti-yeast reaction. So, instead of the yeast reaction triggering the Crohn’s, maybe the Crohn’s just triggers the yeast reaction. “Whether the…antibodies are actually triggering [inflammatory bowel disease] or are only…consequence[s] of gut inflammation…remains elusive.”

So, how could we test it? Well, if anti-yeast antibodies are just a consequence of food particles leaking through the gut, Crohn’s patients should have antibodies to all sorts of common foods. But, no. Higher anti-yeast antibodies in Crohn’s disease compared to controls, but no greater reaction in Crohn’s patients to milk, wheat, or egg proteins, which would presumably all leak through, too.

Or, you can look at it the other way; instead of other foods, what about other inflammatory bowel disorders—ulcerative colitis or acute gastroenteritis? There, you could get inflamed and leaky, too, yet no increased yeast reaction. So, there does appear to be something unique about the yeast-Crohn’s relationship. But, maybe inflamed Crohn’s intestines just uniquely and selectively allow yeast through? If you cut out the Crohn’s, can you stop the yeast reaction?

Crohn’s gets so bad that most patients have to go under the knife, and get sections of their intestines removed. So, when the inflamed segments are removed, does the yeast reaction go away? No; no change post-op. So, a change in Crohn’s activity does not lead to a change in the yeast reaction. But, we still have to prove that the yeast reaction comes first.

Thankfully, the Israeli military “systematically [draws blood] from [their] recruits,” follows their health for years; so, you can go back and check the blood of newly-diagnosed Crohn’s victims. And indeed, those who went on to have Crohn’s were years earlier disproportionately reacting to yeast. So, it’s not like yeast reactions were low until Crohn’s hit, and then they shot up; yeast reactivity crept up year after year, before the diagnosis. Now look, it’s possible that there was some subclinical gut leakiness in the years preceding diagnosis that led to the yeast reaction, but there doesn’t appear to be any association between yeast reactivity and gut leakiness.

So: “Do high [blood] levels of [anti-yeast] antibodies result from a leakiness of the gut barrier in Crohn’s disease?” No; that does not appear to be the case. So, if Crohn’s isn’t leading to the yeast reaction, does that mean that the yeast reaction is leading to the Crohn’s?

Any time you have two things that appear to be associated—in this case reacting to yeast and Crohn’s disease—they both can appear tied together because X causes Y, or because Y causes X. Well, in this case it appears that Y does not cause X. But, does that mean that X causes Y? Well, there’s another option. Maybe there’s a third factor that causes both of them independently. Maybe the only reason yeast reactivity and Crohn’s disease appear to go together is that there’s a third factor causing them both—like, for instance, candida.

We would love it if you could share with us your stories about reinventing your health through evidence-based nutrition.  Go to nutrition facts.org slash testimonials. We may share it on our social media to help inspire others.

To see any graphs charts, graphics, images or studies mentioned here, please go to the Nutrition Facts podcast landing page.  There you’ll find all the detailed information you need – plus links to all of the sources we cite for each of these topics.

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