A plant chemical found in both green and black tea, polyphenols are strong antioxidants. Although most of the research on tea has been done in the laboratory and on animals, there is strong evidence that tea offers positive health benefits to humans. Herbal teas do not contain polyphenols in any significant amount.

Polyphenols, particularly the flavonoids, are among the most potent plant antioxidants, and they protect and recycle other antioxidants, for example vitamin E. Many epidemiological  studies have found that a high dietary intake of polyphenols is strongly associated with a low incidence of cancer. Results of one study found that theaflavin-3’-monogallate (TF-2), a polyphenol found in tea, triggers cell death in cancer cells while leaving healthy cells unharmed. Thus suggesting that polyphenols protect against cancer in a number of different ways. They are also known to protect against heart disease. One of the ways by which polyphenols protect the heart is by lowering the production of the protein endothelin-1, which causes blood vessels to constrict and reduces the flow of oxygen to the heart. They also chelate metal ions such as iron, lead, and copper, this prevents them from being absorbed by the body where they would promote free radical generation.

DEFICIENCY SYMPTOMS: Not applicable

Fruits and vegetables have significant variations in polyphenol content, depending on the part of the plant used (leaves are highest), cultivation and harvesting methods, degree of ripeness, storage conditions etc. A flavonoid intake of about 150-300 mg per day would be obtained from eating the recommended 5 portions of fruit and vegetables each day, thus supplemental intake should also be in this range. Refer to packaging, as dosages will vary in different preparations.

MAXIMUM SAFE LEVEL: Not established

SIDE EFFECTS/CONTRAINDICATIONS: None known