The Functional Role of Polyphenols Across the Human Lifespan

Polyphenols are bioactive molecules that occur naturally in plants and exhibit a diverse array of properties, including antioxidant, anti-inflammatory, and anti-obesity effects, all of which have been supported by numerous studies. They are categorized into four main groups: flavonoids, phenolic acids, stilbenes, and lignans. Polyphenols demonstrate a wide range of health-promoting effects throughout human life, from the womb to old age. They can exert these effects by modulating signaling pathways, regulating gut microbiota, influencing gene expression, and regulating epigenetic pathways. This comprehensive review summarizes the evidence regarding polyphenol intake across various life stages, exploring their effects on immune function, cognitive development, cardiovascular health, and healthy aging. These findings highlight the potential role of polyphenol supplementation in supporting lifelong health. It also emphasizes the significant impact of polyphenols on mental health issues and obesity, which have become more prevalent in modern life. The review also highlights the distinct requirements for each age group, due to changes in metabolic and cellular functions, as well as the age-specific effects of polyphenols. Recent in vitro, in vivo and clinical studies were reviewed to evaluate the biological effects of polyphenols. In the current literature, there are limited studies that directly compare the effects of polyphenols specific to different life stages and comprehensively address the results. This review aims to provide a framework to guide future research by evaluating the effects of polyphenols used in early life, adulthood, and old age.