Polyphenols are a type of natural chemical compound, made up of different types of chemical units called phenols. They are found in high amounts in green tea, and also occur in dark chocolate, olives, celery, apples, plums and spinach. There are a few different types: catechins, tannins, isoflavones, stilbenes, lignans, and anthocyanidins.

Sustained scientific research has shown that polyphenols are essential for maintaining a healthy, nutritious diet. As an antioxidant, polyphenols protect the cells of your body from oxidation and help prevent them from dying.  Some evidence has suggested that they could even help to reduce the risk of cancers, cardiovascular disease (like heart disease) and osteoporosis.

Green tea contains the highest concentrations of polyphenols, potentially making them worthwhile to drink for a range of health benefits. The ones found in green tea are called catechins, of which there are believed to be 6 different compounds that can be found in the drink. Epigallocatechin gallate (EGCG) occurs in the highest levels in green tea and is the one that is thought to have the highest number of benefits.