Spermidine in food and health: biosynthesis, dietary sources, production, and biological functions.

Spermidine, a ubiquitous natural polyamine in living organisms, has gained growing attention for its diverse biological functions and translational potential. This review systematically summarizes recent research progress on spermidine, including its biosynthesis, production strategies, analytical methods and emerging applications. Dietary spermidine has become a key research focus, with evidence linking its intake to multiple health benefits such as lifespan extension, anti-inflammation and metabolic regulation, sparking interest in its use in functional foods and nutritional interventions. It also serves as a promising biomarker for evaluating food freshness and disease-related metabolic status. Current research is shifting from mechanistic studies to application development. Future work should validate molecular mechanisms via in vivo models and clinical trials, develop sustainable production and targeted delivery systems, thus promoting spermidine's translation from basic research to industrial and societal applications.