Dairy-Gut Microbiome Interactions: Implications for Immunity, Adverse Reactions to Food, Physical Performance and Cardiometabolic Health-A Narrative Review

Background/Objective: Milk and fermented dairy products are widely consumed functional foods and beverages, offering not only essential nutrients but also bioactive compounds with potential to modulate host immunity, metabolism, and the gut microbiome. This narrative review aims to synthesize current knowledge on the relationship between dairy consumption, gut microbiome, immune modulation, adverse reactions to food, physical performance and cardiometabolic health. Methods: An extensive literature analysis was conducted to explore how milk and fermented dairy products modulate the gut microbiome and influence the immune and cardiometabolic health. This study synthesis focused on key dairy bioactive compounds, such as probiotics, miRNAs, milk-derived peptides and exosomes and on evaluating their proposed mechanisms of action in inflammation and metabolic regulation, and their possible influence on physical performance through gut–microbiome interactions. Additionally, advances in metagenomic and metabolomic technologies were reviewed for their potential to uncover host–microbiota interactions relevant to precision nutrition strategies. Results: Fermented dairy products have shown potential in promoting beneficial bacteria growth such as Lactobacillus and Bifidobacterium, short-chain fatty acid synthesis and reduction in proinflammatory biomarkers. Specific dairy-derived peptides and exosomal components may further support gut barrier integrity, immune regulation and improve physical performance and reduce cardiometabolic risk factors. Additionally, emerging evidence links individual gut microbiota profiles to specific metabolic responses, including tolerance to lactose and bovine milk proteins. Conclusions: Integrating microbiome science with traditional nutritional paradigms enhances our understanding of how dairy influences immune and cardiometabolic health. Overall, current evidence suggests that investigating dairy-microbiome interactions, alongside lifestyle factors such as physical activity, may inform future personalized nutrition strategies aimed at supporting metabolic and immune health.