Tea polyphenols: prevention of cancer and optimizing health

The tea plant Camellia sinesis is cultivated in >30 countries. Epidemiologi c observations and laboratory studies have indicated that polyphenolic comp ounds present in tea may reduce the risk of a variety of illnesses, includi ng cancer and coronary heart disease. Most studies involved green tea, howe ver; only a few evaluated black tea. Results from studies in rats, mice, an d hamsters showed that tea consumption protects against lung, forestomach, esophagus, duodenum, pancreas, liver, breast, colon, and skin cancers induc ed by chemical carcinogens. Other studies showed the preventive effect of g reen tea consumption against atherosclerosis and coronary heart disease, hi gh blood cholesterol concentrations, and high blood pressure. Because the e pidemiologic 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 Cance r Center in collaboration with Memorial Sloan-Kettering Cancer Center. This study will examine the safety and possible efficacy of consuming the equiv alent of greater than or equal to 10 cups (greater than or equal to 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 populati ons, but it requires further study.