Tea polyphenols: prevention of cancer and optimizing health.
Am J Clin Nutr 2000 Jun;71(6 Suppl):1698S-702S; discussion 1703S-4S (ISSN: 0002-9165)
Mukhtar H; Ahmad N Department of Dermatology, Case Western Reserve University, Cleveland, OH 44106, USA. firstname.lastname@example.org.
The tea plant Camellia sinesis is cultivated in >30 countries. Epidemiologic observations and laboratory studies have indicated that polyphenolic compounds present in tea may reduce the risk of a variety of illnesses, including cancer and coronary heart disease . Most studies involved green tea , however; only a few evaluated black tea . Results from studies in rats, mice, and hamsters showed that tea consumption protects against lung , forestomach, esophagus, duodenum, pancreas, liver , breast , colon, and skin cancers induced by chemical carcinogens. Other studies showed the preventive effect of green tea consumption against atherosclerosis and coronary heart disease , high blood cholesterol concentrations, and high blood pressure. Because the epidemiologic studies and research findings in laboratory animals have shown the chemopreventive potential of tea polyphenols in cancer , the usefulness of tea polyphenols for humans should be evaluated in clinical trials. One such phase 1 clinical trial is currently under way at the MD Anderson Cancer Center in collaboration with Memorial Sloan-Kettering Cancer Center. This study will examine the safety and possible efficacy of consuming the equivalent of > or =10 cups (> or = 2 . 4 L) of green tea per day. The usefulness of tea polyphenols may be extended by combining them with other consumer products such as food items and vitamin supplements. This "designer-item" approach may be useful for human populations, but it requires further study.