Tea Catechins and Polyphenols: Health Effects, Metabolism, and Antioxidant Functions
Authors: Jane V. Higdon1; Balz Frei1
Source: Critical Reviews in Food Science and Nutrition, Volume 43, Number 1, January-February 2003 , pp. 89-143(55)
Publisher: Taylor and Francis Ltd
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Abstract:
Increasing interest in the health benefits of tea has led to the inclusion of tea extracts in dietary supplements and functional foods. However, epidemiologic evidence regarding the effects of tea consumption on cancer and cardiovascular disease risk is conflicting. While tea contains a number of bioactive chemicals, it is particularly rich in catechins, of which epigallocatechin gallate (EGCG) is the most abundant. Catechins and their derivatives are thought to contribute to the beneficial effects ascribed to tea. Tea catechins and polyphenols are effective scavengers of reactive oxygen species in vitro and may also function indirectly as antioxidants through their effects on transcription factors and enzyme activities. The fact that catechins are rapidly and extensively metabolized emphasizes the importance of demonstrating their antioxidant activity in vivo. In humans, modest transient increases in plasma antioxidant capacity have been demonstrated following the consumption of tea and green tea catechins. The effects of tea and green tea catechins on biomarkers of oxidative stress, especially oxidative DNA damage, appear very promising in animal models, but data on biomarkers of in vivo oxidative stress in humans are limited. Larger human studies examining the effects of tea and tea catechin intake on biomarkers of oxidative damage to lipids, proteins, and DNA are needed. Referee: Dr. Jeffrey Blumberg, USDA HNRC on Aging, Tufts University, Antioxidants Research Lab, 711 Washington Street, Boston, MA 02111-1524 <kwdg><kwd>flavanol<kwd>theaflavin<kwd>thearubigin<kwd>cancer<kwd>cardiovascular disease<kwd>osteoporosis<kwd>epidemiology<kwd>LDL oxidation<kwd>plasma antioxidant capacity<kwd>TEAC<kwd>FRAP<kwd>ORAC<kwd>F2-isoprostanes<kwd>8-hydroxydeoxyguanosine<kwd>8-OHdGKeywords: flavanol; theaflavin; thearubigin; cancer; cardiovascular disease; osteoporosis; epidemiology; LDL oxidation; plasma antioxidant capacity; TEAC; FRAP; ORAC; F; 8-hydroxydeoxyguanosine; 8-OHdG
Document Type: Research article
DOI: 10.1080/10408690390826464
Affiliations: 1: Linus Pauling Institute, Oregon State University, Corvallis, OR 97331
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