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Unformatted text preview: REVIEW ARTICLE Effect of Cocoa and Tea Intake on Blood Pressure A Meta-analysis Dirk Taubert, MD, PhD; Renate Roesen, PhD; Edgar Scho mig, MD Background : Epidemiological evidence suggests blood pressurelowering effects of cocoa and tea. We under- took a meta-analysis of randomized controlled trials to determine changes in systolic and diastolic blood pressure due to the intake of cocoa products or black and green tea. Methods : MEDLINE, EMBASE, SCOPUS, Science Ci- tation Index, and the Cochrane Controlled Trials Reg- ister were searched from 1966 until October 2006 for stud- ies in parallel group or crossover design involving 10 or more adults in whom blood pressure was assessed be- fore and after receiving cocoa products or black or green tea for at least 7 days. Results : Five randomized controlled studies of cocoa ad- ministration involving a total of 173 subjects with a me- dian duration of 2 weeks were included. After the cocoa diets, the pooled mean systolic and diastolic blood pres- sure were -4.7 mm Hg (95% confidence interval [CI],-7.6 to -1.8 mm Hg; P =.002) and -2.8 mm Hg (95% CI,-4.8 to -0.8 mm Hg; P =.006) lower, respectively, com- pared with the cocoa-free controls. Five studies of tea con- sumption involving a total of 343 subjects with a me- dian duration of 4 weeks were selected. The tea intake had no significant effects on blood pressure. The esti- mated pooled changes were 0.4 mm Hg (95% CI, -1.3 to 2.2 mm Hg; P =.63) in systolic and -0.6 mm Hg (95% CI, -1.5 to 0.4 mm Hg; P =.38) in diastolic blood pres- sure compared with controls. Conclusion : Current randomized dietary studies indi- cate that consumption of foods rich in cocoa may reduce blood pressure, while tea intake appears to have no effect. Arch Intern Med. 2007;167:626-634 A N INCREASED CONSUMP- tion of fruits and veg- etables is recommended as a first-line therapeutic ap- proach in current hyper- tension control guidelines. 1,2 At least part of the reduction of blood pressure and low- ering cardiovascular risk has been attrib- utedtothepolyphenols(flavonoids)infruits and vegetables. 3-5 Tea and cocoa products account for the major proportion of total polyphenol intake in Western countries. 6,7 However, cocoa or tea are currently not implemented in cardioprotective or anti- hypertensive dietary advice, 8 although both have been associated with lower inci- dences of cardiovascular events. 9-11 A re- cent cross-sectional study suggests consid- erable hypotensive and cardioprotective effects of cocoa. 12 Observational studies of the association between consumption of black or green tea and blood pressure yielded mixed results; some have reported areductionofbloodpressure, 13-15 whileoth- ers found no effects....
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This note was uploaded on 02/07/2012 for the course BIO 152 taught by Professor Doyle during the Fall '08 term at Wisconsin.
- Fall '08