Are Dietary FODMAPs a Cause of Irritable Bowel Syndrome?

The idea that dietary constituents called FODMAPs (Fermentable, Oligo-, Di-, Monosaccharides, And Polyols) might be responsible for some cases of irritable bowel syndrome (IBS) is gaining traction. FODMAPs are poorly absorbed, short-chain carbohydrates that include fructose, lactose, fructans (found in wheat), galactans, and polyol sweeteners.

In this randomized, crossover trial from Australia, 30 patients who met IBS criteria and 8 healthy controls consumed either a low-FODMAP diet (prepared by the researchers) or a “typical Australian diet” for 3 weeks, followed by the opposite diet for another 3 weeks; the two diet periods were separated by a 3-week washout. Patients were blinded to diet constituents.

At baseline, the mean symptom score fo…