Marta Raquel Araújo, Ana Mendes-Frias, Ricardo Silvestre
The immune system is central to maintaining homeostasis and orchestrating defense against infection and the regulation of inflammatory responses, yet its activity is far from uniform across individuals. Sex differences profoundly shape immune responses, with sex hormones driving distinct patterns of susceptibility to infectious diseases and inflammatory conditions. Nutrition further adds a powerful layer of modulation: vitamins, amino acids, and other bioactive compounds influence immune function and disease outcomes, often in a sex-dependent manner. The microbiome, whose composition is itself influenced by sex, is a critical regulator of both intestinal and systemic immune disorders, making it an attractive target for therapeutic intervention. In this review, we examine the dynamic interplay between sex, nutrition, and the immune system, emphasizing their combined impact on infection, inflammation, and immunomodulation. A deeper understanding of these interactions will be key to advancing personalized nutritional and therapeutic strategies designed to optimize immune health.