Infants with greater diversity of bacteria in their stools are less likely to have allergies to foods such as egg, milk, or peanuts, researchers say.
The finding could lead to new approaches to preventing immunoglobulin E-mediated food allergy (IgE-FA), according to Christine Joseph, PhD, MPH, an epidemiologist in the Henry Ford Health System in Detroit, Michigan, and colleagues.
"Bacterial colonization is a potentially modifiable factor along the causal pathway to IgE-FA," they write in Pediatric Allergy and Immunology.
Food allergies can result when exposure to specific foods activate mast cells and basophils. The allergies may cause atopic eczema in infancy and rhinitis and asthma later in life.
In healthy infants, food proteins interact with antigen-presenting cells, but T regulatory cells suppress immune responses, preventing allergies, the researchers write.
The relationship between gut bacteria and allergy is complex. Oligosaccharides in human milk that induce the production of interleukin 10 and IgA also stimulate the growth of Bifidobacterium and Lactobacillus, according to the researchers. Clostridia activate the release of TGF-β, which helps induce T regulatory cells to suppress undesirable immune reactions. Gut bacteria also help ferment complex carbohydrates generating short-chain fatty acids, which influence B-cell and intestinal barrier function.
Previous studies have turned up associations between gut microbiota composition and food sensitivities.
