18 Best Vitamins and Supplements for Immune Support in 2026

11. Vitamin A - Epithelial Barrier Integrity and Immune Regulation

Vitamin A has gained renewed appreciation in 2026 for its fundamental role in maintaining immune system integrity and function, particularly in supporting the epithelial barriers that serve as the body's first line of defense against pathogens. This fat-soluble vitamin exists in two primary forms: preformed vitamin A (retinol) from animal sources and provitamin A carotenoids (beta-carotene) from plant sources, both of which contribute to immune health through different mechanisms. Vitamin A is essential for the development and differentiation of immune cells, particularly T-cells and B-cells, and plays crucial roles in antibody production and immune memory formation. The