What Are Tannins?
Tannins are a class of chemicals found in plants. Specifically, they’re part of the family of polyphenols, many of which are celebrated for their amazing health benefits. Science has, so far, discovered about 8,000 polyphenols. I’m not going to name them all (as that would make for a very long and very boring article), but some of the most famous polyphenols include resveratrol (from red grapes, red wine, and cocoa), curcumin (in turmeric), and anthocyanins (found in blueberries and other dark berries).
Like many other polyphenols, tannins act as antioxidants, helping to prevent and reverse cellular damage caused when free radicals attack our cells.
Biochemists refer to the tannins in food as forms of tannic acid. There are two main classes of tannins: hydrolyzable tannins and proanthocyanidins. Proanthocyanidins are mostly found in red, blue, or purple fruit and flowers (not a coincidence — they actually give those plants their dark, rich hues). That’s one reason many dietitians encourage their clients to “eat the rainbow”; each color in plants delivers a different set of beneficial compounds to the body.
Like many other phytonutrients, tannins help protect plants from predators and fungi. And they may benefit us via a process known as “hormesis,” in which something harmful in large concentrations is actually beneficial in smaller doses, as it trains our body to handle stressors more effectively.
( Excerpt from The Food Revolution Network)