Dietary treatment of irritable bowel syndrome: current evidence and guidelines for future practice

The aim of this literature review is to produce guidelines for dietetic practice in irritable bowel syndrome (IBS) by evaluating the research available. In this area randomized control trials (RCT) only account for a small proportion of the literature and have been concentrated in the modification of dietary fibre in patients with IBS. The bulk of the literature is mainly observational trials from which no indisputable conclusions can be extracted. In this review, the evidence available has been interpreted within the context of the current knowledge base. Conclusions are drawn to facilitate the development of guidelines, enabling a starting point for discussion and an evaluation of current practice. The literature available on therapeutic dietary manipulation in IBS patients is centred around non-starch polysaccharides (NSPs), mono and disaccharide sensitivity and food intolerance. The production of these guidelines has focused on research examining the role of dietary components in the therapeutic management of patients with IBS. However, where there is a deficiency in the literature directly relating dietary intake to management of IBS patients, physiological function in relation to dietary components has been relied upon to produce practical guidelines which can be applied realistically in a clinical environment. An interpretation of the evidence has revealed a limited role for exclusion diets, a move away from high-fibre diets towards the manipulation of fibre fractions in the diet, an evaluation of the effects of caffeine on gut function and the necessity for individual dietary assessment to identify dietary issues pertinent to the patient's symptoms. These guidelines outline a positive role for dietitians in the treatment of IBS patients which draws on the unique skills possessed by dietitians regarding the assessment of habitual eating habits and therapeutic dietary manipulation.