The effects and practical applications of polyphenols on the human gut microbiome

要旨

Abstract: Polyphenols, dietary compounds, play a key role in the human gut microbiome. These bioactive compounds are commonly found in fruits, vegetables, coffee, wine, and chocolate, all of which promote gut health. These compounds demonstrate potent antioxidant and anti-inflammatory effects by interacting with the gut microbiome and modulating microbial composition. Foods rich in polyphenols are often colorful, with the highest levels within the skins of produce. Because they reduce oxidative stress, regulate cellular signaling, and protect mitochondria, they have been associated with the prevention of neurodegenerative diseases and cardiovascular disorders. This is due to their ability to cross the blood-brain barrier and improve overall metabolic functioning within the human body. However, their bioavailability is often low due to limited absorption, prompting further research that has led to the discovery of alternative delivery methods. Recent studies have shown that greater habitual polyphenol intake may support a balanced gut microbiome by inhibiting pro-inflammatory bacteria. Diets rich in fresh and minimally processed foods provide greater polyphenol intake than ultra-processed food diets, which are associated with lower overall intake. These findings highlight the therapeutic potential of polyphenols, which may improve overall human health by altering the gut microbiome.

Novelty: This comprehensive review uniquely synthesizes current understanding of dietary polyphenols' multifaceted roles, emphasizing their critical interaction with the human gut microbiome and their ability to cross the blood-brain barrier for systemic health benefits. Specifically, this review moves beyond general associations to detail the mechanistic role of the flavonoid subclass. We emphasize the precise pathway: 1) flavonoid intake, 2) its specific modulation of gut microbial communities, and 3) the resulting downstream health consequences. It particularly highlights emerging alternative delivery methods to overcome inherent low bioavailability and contrasts polyphenol intake from fresh versus ultra-processed foods, providing a nuanced perspective on dietary patterns. Furthermore, it uniquely explores novel applications of polyphenols beyond direct health benefits, including their potential as natural preservatives in food and cosmetics, and as agents for developing hypoallergenic products.

Keywords: Polyphenols, Human Gut Microbiome, bioactive compounds, Functional Foods