Polyphenols are a large class of plant-derived compounds with multiple phenol rings. They include flavonoids (quercetin, EGCG), anthocyanins (berries), stilbenes (resveratrol), lignans (flax), and hundreds more.
Mechanism — Bioavailability is variable but the molecules and their gut-microbiome metabolites have anti-inflammatory, antioxidant, and signaling effects (mTOR modulation, sirtuin activation, hormesis). The microbiome converts many polyphenols into the bioactive form.
Use case — Eat the rainbow. Berries, dark chocolate, green tea, red wine (in moderation), olive oil, coffee, herbs and spices. Diet-first; supplements as targeted boosters.
Caveats — Individual polyphenol supplements often underwhelm versus whole-food matrices. Gut microbiome variation creates large individual response differences.