“Low-FODMAP is not a new treatment, but we are now convinced that it really works.”—Shanti Eswaran, MD

If the quotation above is any indication, mainstream medicine is catching on to what nutritionists and functional medicine practitioners have known for quite a while now: elimination diets sometimes hold the key to helping people with otherwise “intractable” conditions. In fact, the title of the paper co-authored by Dr. Eswaran indicates just how powerful a dietary intervention can be for a condition that “can be highly debilitating, if not virtually paralyzing, and affect work, sleep and personal and family relationships” -- A Low FODMAP Diet Improves Quality of Life, Reduces Activity Impairment, and Improves Sleep Quality in Patients With Irritable Bowel Syndrome and Diarrhea: Results From a U.S. Randomized, Controlled Trial. This is pretty impressive, considering “most treatments initially rely on medications that are often expensive, usually ineffective and frequently cause unwelcome side effects.”

FODMAP stands for fermentable, oligo-, di-, monosaccharides, and polyols. These carbohydrates are found in a wide variety of foods, which makes sticking to a low-FODMAP diet no easy feat. High FODMAP foods include dairy products (particularly those that are high in lactose); vegetables and grains that are known to induce intestinal gas and bloating (artichokes, broccoli, cauliflower, cabbage, okra, wheat, rye, beans, and more); plus certain fruits (apples, cherries, grapes, bananas, watermelon, and more), coconut products (except oil); sugar alcohols (those ending in –ol, such as mannitol and xylitol); and sources of prebiotic fiber, such as inulin, chicory root, and additive gums (guar, xanthan). Fats and oils are virtually free of FODMAPs, as are pure animal proteins. (Meat-containing foods prepared with high-FODMAP ingredients and additives—such as breaded chicken nuggets—would be off-limits.)

Paleo-style diets and very low-carbohydrate/ketogenic diets naturally eliminate many high-FODMAP foods by default. But other foods, which some people consider to be staples of these dietary approaches, are high in FODMAPs, such as blackberries, mushrooms, broccoli, and onions. Therefore, some individuals who adopt these diets don’t experience the seemingly miraculous transformations they’ve read about on popular sites dedicated to these plans. It could be that they’re sensitive to FODMAPs, high histamine foods, or some other aspect of foods they’re still regularly consuming.

As for the study that evaluated the efficacy of a low FODMAP diet for IBS, of a cohort of approximately 90 IBS patients, roughly half were prescribed a low FODMAP diet, while the other half was a control group counseled to use a “common sense” approach, which included “cutting down on large meals, binges and known irritants such as caffeine and alcohol.” Both groups were coached and monitored by registered dietitians.

Among the low FODMAP group, over 50 percent of the patients experienced major improvement in their abdominal pain, compared to 20 percent in the control group. Patients also reported improvement in bloating, diarrhea, and stool urgency compared to the control group. After just four weeks, 61 percent of the low FODMAP group reported “meaningful improvement in IBS quality of life,” compared to just 27 percent in the control group.

These findings reinforce conclusions from earlier studies, including one from the UK, which determined that “a low FODMAP diet appears to be more effective than standard dietary advice for symptom control in IBS.” Another study investigating this type of elimination diet for IBS showed “a significant and large increase in the numbers of patients reporting satisfactory relief of symptoms between baseline (14/88, 16%) and low FODMAP diet (69/88, 78%),” with additional research suggesting that a low FODMAP diet typically improves symptoms in 68-76 percent of patients. A review of related medical literature concluded that “a low FODMAP diet should be the first dietary approach” for patients with IBS. (Emphasis added.)

Starting from a baseline of compromised gastrointestinal function, it should come as no surprise that many patients experience significant relief upon eliminating foods known to cause or exacerbate GI distress. And it’s refreshing when data from clinical trials support the efficacy of what some might otherwise be tempted to dismiss simply as anecdotes.

By Amy Berger, MS, CNS