Black and green tea consumption and the risk of coronary artery disease: a meta-analysis.

Am J Clin Nutr. 2011 Jan 19
Wang ZM, Zhou B, Wang YS, Gong QY, Wang QM, Yan JJ, Gao W, Wang LS.
Department of Cardiology, First Affiliated Hospital of Nanjing Medical University, Nanjing, China.

BACKGROUND: Epidemiologic studies are inconsistent regarding the association between tea consumption and the risk of coronary artery disease (CAD).

OBJECTIVE: The objective was to perform a meta-analysis to determine whether an association exists between tea consumption and total CAD endpoints in observational studies.

DESIGN: We searched PUBMED and EMBASE databases for studies conducted from 1966 through November 2009. Study-specific risk estimates were combined by using a random-effects model.

RESULTS: A total of 18 studies were included in the meta-analysis: 13 studies on black tea and 5 studies on green tea.

For black tea, no significant association was found through the meta-analysis [highest compared with lowest, summary relative risk (RR): 0.92; 95% CI: 0.82, 1.04; an increment of 1 cup/d, summary RR: 0.98; 95% CI: 0.94, 1.02].

For green tea, the summary RR indicated a significant association between the highest green tea consumption and reduced risk of CAD (summary RR: 0.72; 95% CI: 0.58, 0.89). Furthermore, an increase in green tea consumption of 1 cup/d was associated with a 10% decrease in the risk of developing CAD (summary RR: 0.90; 95% CI: 0.82, 0.99).

CONCLUSIONS:

Our data do not support a protective role of black tea against CAD.

The limited data available on green tea support a tentative association of green tea consumption with a reduced risk of CAD. However, additional studies are needed to make a convincing case for this association.

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