Are adverse food reactions linked to irritable bowel syndrome?

We undertook to determine whether adverse food reactions play a role in irritable bowel syndrome (IBS).

A systematic review of the literature using Medline (1980-1996), targeting IBS and adverse food reactions, was performed. All clinical trials whereby dietary exclusion was followed by food challenge were selected. Each study was reviewed using a structured format to examine methodological issues and study outcomes.

Of the seven studies included, the positive response to an elimination diet ranged from 15% to 71%; double-blind placebo-controlled challenges identified problem foods in 6% to 58% of cases. Milk, wheat, and eggs were most frequently identified to cause symptom exacerbation; of the foods identified the most common trait was a high salicylate content. Foods high in amines were also identified. Studies of diarrhea-predominant IBS identified a higher percentage of adverse food reactions. However, all studies had major limitations in their trial designs, including inadequate patient selection, appropriateness of--and duration of--exclusion diets, and methods of food challenge.

Whether adverse reactions to foods are a key factor in exacerbating IBS symptoms or whether dietary manipulation is a valid treatment option is unclear. Carefully designed controlled clinical trials are now needed to specifically test the potential role of adverse food reactions in diarrhea-predominant IBS.