Transcript: Preventing Crohn’s Disease With Diet
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.
To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video. This is just an approximation of the audio contributed by Katie Schloer.
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