Effects of tea consumption on nutrition and health.

Title
Effects of tea consumption on nutrition and health.

Source
Journal of Nutrition. 130, (10): 2409-2412, 2000.

Effects of tea consumption on nutrition and health are discussd. Aspects considered include chemical composition of tea (including presence of catechols, theaflavins); results of studies investigating the absorption, tissue distribution, metabolism and elimination of tea polypenols with emphasis on pharmacokinetic studies using catechols; possible mechanisms underlying the putative association between tea consumption and reduced risk for cardiovascular disease (protection against low density lipoprotein (LDL) oxidation, hypocholesterolaemic activity, antithrombotic activity); examination of the results for animal and human studies demonstrating an association between tea consumption and decreased risk for cancer; mechanisms underlying the proposed ability of tea to reduce cancer risk (antioxidative activity, antiproliferative activity); and effects of tea consumption on nutrition (increase in energy expenditure, potential modulation of nutritional status due to the ability of tea polyphenols to bind proteins and minerals, increase in bone mineral density, and reduction in severity and incidence of arthritis in an animal model).

The possible beneficial health effects of tea consumption have been suggested by some epidemiologic studies and supported by some laboratory studies. Other studies, however, are not consistent with such beneficial effects. A difficulty in human studies is the possible confounding factors related to life style, such as smoking, coffee intake and fat intake. In animal studies, the doses required for demonstrating the disease prevention effects are usually higher than the amounts consumed by humans who drink tea. Caution is required, however, in the use of high concentrations of tea for disease prevention. Ingestion of large amounts of tea may cause nutritional and other problems because of the strong binding activities of tea polyphenols and the caffeine content, although no solid data exist concerning harmful effects of tea consumption.