RODALE NEWS, EMMAUS, PA—A digestive disorder present in nearly 20 percent of the population, irritable bowel syndrome (IBS) is often pegged to foods. But a new review of the scientific literature on the condition finds that dietary factors aren’t as guilty as doctors previously thought. Which means people with IBS may not need to give up their favorite foods or switch to a high-fiber diet.
THE DETAILS: Irritable bowel syndrome is most common in women, and in 50 percent of diagnosed cases, the person affected is under 35. The exact cause of IBS is unknown. Normally, the muscles in your intestinal walls contract and relax in rhythmic fashion as they move food through your stomach. In people with irritable bowel, the contractions are stronger and last longer, forcing food through the intestines either too fast, causing gas, bloating, and diarrhea, or too slowly, leading to hard, dry stools.
In the review published in this month’s issue of the Journal of the American Dietetic Association, researchers reviewed over 1,000 studies hoping to determine whether there’s a dietary trigger that causes the muscles to contract and relax out of sync. Conventional wisdom is that patients with irritable bowel aren’t getting enough fiber, and a primary treatment is switching to a high-fiber diet, says the review’s lead author William Heizer, MD, a retired professor in the division of gastroenterology and hepatology at the University of North Carolina School of Medicine, Chapel Hill. However, “The data indicate that [a high-fiber diet] really is of marginal benefit, and probably not useful at all in patients with diarrhea.” His review also found that scientific research has been unable to pin irritable bowel on other commonly blamed foods: coffee, alcohol, fatty foods, and diary products. They did, however, note that some carbohydrates found in sugars like fructose, common in fruit and honey and in prepared foods made with high-fructose corn syrup, and fructans, found in wheat, could trigger symptoms of IBS. “The amount of fructose in our diets has increased rather dramatically over the last 20 years,” says Dr. Heizer.
WHAT IT MEANS: Part of the difficulty in pegging IBS to a specific food trigger, says Dr. Heizer, is that people with the disease often blame the wrong foods. He cites studies finding that anywhere from 50 to 75 percent of patients who are convinced that a specific food is causing their IBS symptoms often have no reaction to that food when they eat it unknowingly. “We see people all the time who are unshakably convinced that certain foods trigger symptoms,” he says. “But when we give them the food without their knowing it, they don’t have those symptoms. That includes physicians.”
That doesn’t mean that IBS is all in your head, he adds, just that finding a trigger is difficult: it could be food, or it could be stress or hormonal changes. According to the Mayo Clinic, for example, women often notice an increase in signs and symptoms around their periods.
In many cases, controlling irritable bowel symptoms comes down to trial and error, Dr. Heizer says. Here are a few tips:
• Keep a food diary. In his review, Dr. Heizer suggests that patients keep a food diary and then notate any symptoms (gas, bloating, diarrhea, or constipation) that arise within one to three days after eating something. He says to pay particular attention to milk, sugars, gas-forming foods (including beans, brussels sprouts, onions, celery, carrots, raisins, bananas, prune juice, apricots, wheat germ, and bagels), foods containing wheat, fat, and coffee.
• Subtract and add back. If any of the foods noted above seem to trigger a reaction, he says to eliminate that food for two weeks, and then add it back in small amounts. If you notice that your symptoms come back with that particular food item, keep it out of your diet for three to six months. He says the same thing about larger changes to your eating habits; often the symptoms of irritable bowel mimic that of gluten intolerance and celiac disease, and it’s not uncommon for people to switch to a gluten-free diet. Those have been found to provide temporary relief from IBS, but again, he says, switch to the diet for a few weeks then go back to your normal diet to see if conditions change. Dietary changes don’t need to be permanent, he says.
• Try the peppermint cure. One interesting finding of his review was that peppermint oil seemed to be as effective as prescription drugs at relaxing the muscles in your intestinal tract. “Peppermint oil has proven to be very helpful,” he says. “No more helpful than drugs, but comparable in effect—and much cheaper.” You get the best benefit by using peppermint oil capsules or ingesting one to two drops of oil before each meal. Look for pure peppermint oil or capsules that contain 0.2 milliliter of peppermint oil per pill.