Diet Components, Immune Function and IgE-Mediated Food Allergy

Area of Science:

• Immunology
• Nutrition Science
• Microbiome Research

Background:

• Rising global food allergies present a significant public health issue.
• Complex interactions between diet, immune development, and environment contribute to allergies.

Purpose of the Study:

• To review cellular and molecular mechanisms of dietary components in promoting intestinal homeostasis.
• To highlight key signaling pathways involved in immune tolerance to food antigens.

Main Methods:

• Literature review focusing on cellular and molecular mechanisms.
• Analysis of microbiota-dependent and -independent pathways in the small intestine.
• Examination of retinoic acid (RA) and aryl hydrocarbon receptor (AhR) signaling axes.

Main Results:

• Dietary nutrients like vitamin A, fiber, indole compounds, and proteins enhance epithelial barrier integrity and tolerogenic immune responses.
• RA and AhR signaling converge to regulate RORγt-expressing immune cells (ILC3s, γδ IELs, Th17 cells) crucial for barrier function.
• These pathways also guide regulatory T cell subsets and CD4+ IELs, maintaining tolerance to dietary antigens.
• RORγt+ APCs play a role in inducing peripheral Tregs during early life, especially at weaning.

Conclusions:

• Dietary components and microbial metabolites critically shape intestinal immune responses and oral tolerance.
• Key signaling axes (RA, AhR) and specific immune cells are central to maintaining gut homeostasis and preventing allergies.
• Early life, particularly weaning, represents a critical window for establishing immune tolerance through diet-microbiota interactions.