The Association Between Short-Chain Fatty Acids and the Incidence of Food Allergies-Systematic Review.

BACKGROUND/OBJECTIVES: There is a constant increase in the incidence of food allergies. Short-chain fatty acids (SCFAs), responsible for maintaining the intestinal barrier and immune balance, are produced by the intestinal microbiota through the fermentation of dietary fibre. The aim of this systematic literature review was to analyse the association of SCFAs with the occurrence of food allergies. METHODS: The analysed data were obtained by searching the PubMed and Scopus databases with the keywords "short-chain fatty acids and allergy", "SCFA and allergy", "SCFA and food allergy", and "acetic acid or propionic acid or butyric acid or 3,4-methylvaleric acid and allergy". Exclusion criteria were as follows: retracted articles, articles not freely accessible, and incomplete/insufficient data (conference reports). Two authors independently searched the literature. RESULTS: Patients with food allergies show lower levels of SCFAs, especially acetic, butyric and propionic acids. 3,4-methylvaleric acid may be associated with intestinal inflammation in infants and intestinal leakage. CONCLUSIONS: Based on studies, there appears to be an association between lower stool levels of SCFAs-particularly butyric, propionic, acetic, and isovaleric acids-and the occurrence of food allergies in both children and adults. A proper diet that strengthens fibre, probiotics, and prebiotics and limits antibiotics, xenobiotics, pesticides is crucial for maintaining adequate SCFA levels and thus reducing allergy-related symptoms. 3,4-Methylvaleric acid and the activation of inflammatory processes contributing to intestinal leakage may provide a new diagnostic path.