Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 9/1/2006
Publication Date: 1/1/2007
Citation: Harris, G.K., Baer, D.J., Clevidence, B.A. 2007. The effects of black tea on blood lipids and cardiovascular disease risk in humans. In: Hou, C.T., Shaw, J.F., editors. Biocatalysis and Biotechnology for Functional Foods and Industrial Products. Boca Raton, FL. CRC Press. p. 171-186. Interpretive Summary: This book chapter examines the ways in which black tea may affect blood lipids and cardiovascular disease risk. Blood lipids are fatty substances found in blood. Increases in the levels of certain types of blood lipids (triglycerides, LDL cholesterol, and total cholesterol) are known to increase the risk of two types of cardiovascular disease (heart attack and stroke). Epidemiological studies and clinical trials have been used to understand how black tea might affect a person’s risk of cardiovascular disease over their lifetime. The majority of epidemiological studies, which follow many people over a long period of time, suggest that people who drink black tea regularly may be less likely to suffer from cardiovascular disease. The majority of clinical trials, in which a certain amount of tea is given to individuals over a period of days or weeks, found that tea had no effect on blood lipids. Scientists are not sure why there seems to be a disagreement between these two types of studies. This chapter will be useful to individuals interested in understanding the degree of certainty to which tea can prevent cardiovascular disease.
Technical Abstract: This book chapter examines the ways in which black tea affects blood lipids and cardiovascular disease (CVD) risk by comparing the results of epidemiological and clinical studies. Black tea is produced by the complete fermentation of leaves from the plant Camelia sinensis. The majority of epidemiological studies examining the effects of black tea on CVD indicate a reduction in risk. In contrast, the majority of clinical trials report that tea has no effect on blood lipids, lipid oxidation, blood flow, or clotting factors. The reasons for this apparent disagreement between epidemiological and clinical data are not clear, but may relate to study population, experimental design and study length. In summary, black tea may reduce CVD risk, but the mechanisms by which it acts have yet to be determined.