The Benefits of a Modified Mediterranean Diet for Irritable Bowel Syndrome


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Dietary interventions, such as the low Fermentable Oligo-, Di-, Monosaccharides and Polyols (FODMAP) diet, which are low in many plant-based foods are considered by many IBS experts as first line treatments for IBS, even though they are bad for our overall health.

The low FODMAP diet focuses on the elimination of foods than can trigger symptoms. However, these interventions are restrictive, difficult to maintain, may lead to deficiencies of certain nutrients when maintained over a period of time, and importantly have a negative influence on the health of the gut microbial ecosystem. Furthermore, they also reinforce food-related fears that drive anxiety and IBS symptoms.

A wealth of evidence has demonstrated benefits of the Mediterranean diet for cardiovascular, metabolic and brain health as well as longevity (reviewed in The Gut Immune Connection). Some data suggest that a low adherence to the Mediterranean diet, in other words a low consumption of fruits and vegetables, is also associated with a higher prevalence of IBS and other disorders of gut-brain interactions.

There is no question, adherence to a Mediterranean-type diet is the best thing you can do for healthy aging, even if you have IBS. Our group at UCLA studied dietary habits, IBS symptoms and gut microbial compositions in 106 IBS patients and 108 healthy control subjects. Scores measuring the adherence to the Mediterranean diet were similar between IBS and healthy control subjects, and did not correlate with such cardinal IBS symptoms as abdominal pain or bloating.

However, amongst IBS participants, responses to individual food items were inconsistent. For example, fruits many of which are high in FODMAPs were associated with higher abdominal pain, bloating, and higher scores on the IBS symptom questionnaire, while vegetables were associated with higher scores on the visceral sensitivity index, an instrument measuring food related anxiety. However, surprisingly, higher consumption of beans, legumes, and soy was associated with lower overall and less severe IBS symptoms. On the other hand, higher consumption of butter, creams and margarine were associated with higher bloating and IBS severity scores.

A higher adherence to a modified Mediterranean diet was associated with relative abundances of health-promoting bacteria in the gut microbiome. The take home message from this study, consistent with my previous recommendations are the following:

  1.  A modified Mediterranean diet consisting of fruits and vegetables is not only essential for many aspects of your health, but it is generally NOT associated with worsening of IBS symptoms, as long as patients reduce the intake of certain food items.
  2.  Reducing or sometimes eliminating the intake of certain food items, such as lactose containing dairy products, certain fruits and non-nutritive sweeteners will result in a personalized Mediterranean diet that is good for many aspects of your health, including IBS symptoms.

Emeran Mayer, MD is a Distinguished Research Professor in the Departments of Medicine, Physiology and Psychiatry at the David Geffen School of Medicine at UCLA, the Executive Director of the G. Oppenheimer Center for Neurobiology of Stress and Resilience and the Founding Director of the Goodman-Luskin Microbiome Center at UCLA.