Lately, it seems as though gluten is being blamed for a vast host of ailments – everything from irritable bowel syndrome (IBS) to attention-deficit disorder – with an ever increasing number of people seeking relief through a gluten-free diet. While this strict regimen is absolutely critical for people with a confirmed diagnosis of celiac disease, doctors warn that inappropriately following the gluten-free diet can lead to a variety of nutrient deficiencies, among other unintended effects.

But some patients without the disease find a degree of relief with a gluten-free diet.  Researchers, medical professionals, and nutrition professionals have begun looking into another possible culprit, FODMAPs.

FODMAP is an acronym for “fermentable oligosaccharides, disaccharides, monosaccharides, and polyols.” This long, complicated phrase essentially refers to poorly absorbed carbohydrates found in dairy, wheat, legumes, and artificial sweeteners (among other places), and are therefore nearly impossible to avoid. When FODMAPs enter the small intestine, they can cause gas, bloating, and diarrhea – very similar GI symptoms that are associated with IBS. Symptom relief is often found by following a restrictive, low-FODMAP diet, but it is important to be aware of other unintended consequences, such as decreased calcium absorption and increased cholesterol levels. However, FODMAPs are not all bad, and do contribute to important physiologic processes.

Studies to assess the effectiveness of a low-FODMAP diet have varied considerably in their conclusions.  It is difficult to conduct “blind” food-related studies, of course, as patients are certainly aware of what they are eating and what they are not. Also, FODMAPs are found in so many different foods, it is difficult to pin down exactly which elimination might be responsible for an improvement in symptoms. The studies that have thus far been conducted have mostly had low sample sizes, short duration, and variable degrees of dietary restriction. All these differences make coming to a solid conclusion difficult, though some interesting and valuable insights have been made.

Through several studies, a low-FODMAP diet has been compared with a traditional IBS management diet and the mNICE diet (modified National Institute for Health and Care Excellence). In each case, the low-FODMAP diet seemed more effective, either for symptom relief, quality of life, or lowered anxiety, with approximately 70% of IBS patients experiencing improvement in a real-world situation. Quality of the data from these studies is still questionable however, and it is possible that the placebo effect has driven a great deal of the positive response.

So how do we determine who might benefit from a low-FODMAP diet? A couple of studies looked at different measures of gut and fecal bacteria in patients both before and after following the diet. Results suggest that individuals with the highest bacterial abundance at baseline were less likely to respond to the diet; bacteria numbers after the diet had been reduced in all participants, mostly correlating with lactose (dairy) ingestion. There was also evidence to suggest that taking a prebiotic while following the low-FODMAP diet was even more helpful to IBS sufferers.

There is much that is continuing to be discovered about our dietary choices and their effects on digestion and overall health; certainly more studies of FODMAPs are needed. In the meantime, the low-FODMAP diet is a step in a healthy direction for those who suffer with GI symptoms. It is important that each patient work closely with a medical team, including a dietitian, to develop an individualized strategy for selectively eliminating FODMAPs to most closely identify the exact source of difficulty, and to ensure that no nutrient deficiencies develop.

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Is a Low-FODMAP Diet the Next Big Thing?