Probiotics for the prevention or treatment of allergic diseases.

This review addresses the effects of probiotic bacteria on immune development and the role in the treatment and prevention of allergic disease. Although there is a sound theoretical basis for anticipating benefits, there are currently insufficient data to recommend probiotics as a part of standard therapy in any allergic conditions. Although there have been studies showing a benefit in prevention of atopic eczema, other studies have failed to support this. None of the studies has shown any clear preventive effect on sensitisation, nor any allergic disease other than eczema. The term “probiotic” is often used loosely to include bacterial strains with little documented immunomodulatory capacity or controlled studies to support claims. It is not known whether effects in experimental systems have any clinical relevance. Explanations for varied results between studies include host factors and other environmental factors, such as general microbial burden, individual microbiota, diet, and treatment with antibiotics. As more studies are completed, these factors are likely to make robust meta-analyses problematic to perform. J Allergy Clin Immunol. 2007;120(2):255-62.