Epidemiological observations and laboratory studies have indicated that polyphenolic compounds present in tea (Camellia sinesis) may reduce the risk of various diseases including cancer and coronary heart diseases.
However, most of these studies involved ‘green tea’. There are only a few studies which evaluated the beneficial effects of polyphenols present in black tea.
Results from studies in animals (rats, mice, and hamsters) proved that green tea consumption protects against cancers (especially lung, esophagus, duodenum, liver, pancreas, breast, colon, and skin) induced by chemical carcinogens. Some other studies showed that green tea consumption prevents atherosclerosis, coronary heart diseases, hyperlipidimeas and hypertension.
Similar studies involving humans are on to assess the beneficial effects of polyphenolic compounds present in tea. Researchers are also trying to combine these polyphenols with other food items and/or supplements to increase its efficacy and usefulness.