Understanding the role of probiotics and prebiotics in preventing allergic disease: evidence and methodological...

Research in the area of prevention of allergic disorders through modification of the intestinal microbiota by provision of probiotics and/or prebiotics is relatively new. This paper briefly summarizes evidence regarding the role of probiotics and/or prebiotics in reducing the risk of allergy. There are studies that show a protective effect, no effect or even a predisposing effect of using probiotics and/or prebiotics in preventing allergic disease. A variety of methodological issues are likely to contribute to current uncertainty. These include differences in the study population (high-risk vs unselected population), optimal strain selection (all probiotics are not equal), differences in definitions of outcomes, timing and duration of the interventions, and a lack of repeat studies.