Purpose of review
In the concept of food allergy prevention, no successful strategy could be identified until now. Although interventional trials using probiotics, prebiotics, hydrolyzed formula and bacterial lysates early in infancy were found to reduce the incidence of atopic dermatitis, no effect on food sensitization and allergy could be shown.
Studies in a farming environment showed that early contact to livestock, bacteria and moulds may upregulate the immune responses regulated via Toll-like receptors and thus prevent allergy. There is increasing evidence that the unbalanced composition of the human microbiome on human skin and mucosal surfaces may be a key player in the development of inflammatory diseases like allergy and asthma. However, during the last 5 years, this concept could not yet be verified in the interventional trials. There are few studies using bacterial lysates, for example, Escherichia coli plus Enterococcus faecalis in ProSymbioflor and heat-killed Bifidobacterium breve and Streptococcus thermophilus; however, food allergy prevalence could not be reduced by these interventions.
During the last 5 years, new interventional trials addressed the use of bacterial lysates. There was only an effect on eczema in the ProSymbioflor trial, whereas the trial using B. breve and S. thermophilus in a cow's milk formula showed a slight reduction of food sensitization at the age of 12 months. However, these strategies need further investigation and success seems to be restricted to certain subpopulations.