Epidemiological studies have linked consumption of polyphenol-rich foods with reduced cancer, stroke, coronary heart disease, and osteoporosis. Polyphenols are antioxidants and, in fact, are the most abundant antioxidants in our diets. Polyphenols are identified by their chemical structure. Polyphenols have several -OH groups attached to the ring structure. Phenolic acids are abundant in foods, especially coffee, whole grains, fruits, and vegetables.
Flavonoids are the most abundant polyphenols in our diets.
There are many classes of flavonoids. Resveratrol is one that has been studied. At first this compound was credited with the health benefits of red wine. However, new measurements show there is really very little resveratrol in red wine or anywhere else. So this class of compounds is not yet very important for human diets.