Mediterranean Diet & IBS

The effect of a Mediterranean diet on both gastrointestinal (GI) and psychological symptoms among people with irritable bowel syndrome (IBS) was recently published in Alimentary Pharmacology & Therapeutics. Designed as a pilot study to evaluate the feasibility of the Mediterranean diet (MD) for people with IBS, this was a 6 week unblinded study in which 59 adults with Rome IV IBS, as well as mild or moderate anxiety and/or depressive symptoms, were randomized to receive either 20-30 minutes of instructions to follow an MD or instructions to continue their typical diet.

Given that very little data exists for the use of an MD among patients with IBS, this study was also designed to determine how plausible this diet would be, with no well-done randomized trials existing for an MD diet among people with IBS. Forty-eight participants completed the 6-week study, which found the MD both feasible and acceptable. Additionally, 83% of people in the MD group reported improvement in global GI symptoms and 62% reported improvement in depressive symptoms. In contrast, only 37% of people on habitual diets reported GI improvement, and only 23% reported reduced depressive symptoms. Significant reductions in the severity of symptoms, such as pain, distention, bloating, etc., were observed with the MD diet.

This MD was not a low FODMAP diet (previously shown to reduce symptoms among people with IBS), and FODMAP intake increased in participants following the MD over the 6-week study. Additionally, a microbiome analysis conducted at baseline and again at study completion did not show any significant changes between the two groups, in terms of species abundance, alpha/beta diversity, etc. Thus, while the small sample size, short duration, unclear mechanism, and lack of a high-quality control group may limit the findings, this study suggests that more robust controlled trials should be done to evaluate MD effectiveness among people with IBS.