A chemical called resveratrol is thought to be at least partly responsible for red wines’ health benefits, as it has been shown to exert a range of both cardioprotective as well as chemoprotective mechanisms in animal studies. Resveratrol is produced naturally by grape skins in response to fungal infection, which includes exposure to yeast during fermentation. As white wine has minimal contact with grape skins during this process, it generally contains lower levels of resveratrol. Other beneficial compounds in wine include other polyphenols, antioxidants, and flavonoids.

Red wines from South of France (Bordeaux, Cotes du Rhone and Bourgogne) and Sardinia Italy have been found to have the highest levels of procyanidins ?€” the compounds in grape seeds responsible for making red wine good for the heart. Wines from France and Sardinia have between two and four times as much procyanidins as other red wines. Procyanidins suppress the synthesis of a peptide called endothelin-1 that constricts blood vessels.