A new review on inflammatory bowel disease, entitled “Diet and Inflammatory Bowel Disease: Review of Patient-Targeted Recommendations” and published in October issue of Clinical Gastroenterology and Hepatology summarizes the scarce data on the role of diet in this syndrome and highlights the need for patient-targeted dietary information and advice from the medical community.

Researchers are recognizing that environmental factors can impact the severity of IBD. In agreement with this hypothesis, several studies have linked diet to gut inflammation on many levels, such as with direct dietary antigens, alterations to the micro biome in the gut, and higher permeability in the gastrointestinal wall. Specifically, IBD was associated with high fatty acids and protein content diet; on the contrary, a diet rich in fibers was associated with lower risks for Crohn’s disease (one of the most common types of IBD); the second most common type of IBD, Ulcerative Colitis was associated with increased red meat consumption, eggs, protein and alcohol. Notably, exclusion diets were shown to improve IBD symptoms and to increase the period to relapse.

In this review, the authors compiled data related to three types of diet commonly referred to the literature — the specific carbohydrate diet (SCD); the fermentable oligosaccharides, disaccharides and monosaccharides (FODMAP) diet; and the Paleolithic diet.

All diets’ regimens are based on restrictive measures — while SCD diet restricts carbohydrates in general and the monosaccharides’ glucose, fructose, and galactose, FODMAP restricts many fruits and vegetables. Both share the reasoning that many types of carbohydrates are poorly absorbed by the intestine and thus lead to bacteria overgrowth.

The Paleolithic diet restricts lean game meats and non cereal plant-based foods, since these foods were introduced later during human evolution, and so the human gut is not as evolutionarily prepared to handle this type of plant-based food.

Without studies to support any of these diets’ regimens, the authors underscore the urgent need for comprehensive studies addressed to IBD patients: “There is scientific evidence that dietary factors may influence both the risk of developing IBD and intestinal mucosal inflammation. However, there is a lack of large prospective controlled trials to provide the dietary recommendations patients desire. Taken together, studies of exclusive enteral nutrition, exclusion diets, and semivegetarian diets suggest that minimizing exposure of the intestinal lumen to selected food items may prolong the remission state of patients with IBD. Even less evidence exists for the efficacy of the SCD, FODMAP, or Paleo diets.”