The review article authored by Taubert and colleagues described the results of their meta-analysis of published reports on the effects on cocoa and tea on blood pressure (Taubert 626). This investigation was prompted by earlier suggestions that cocoa and tea could serve as supplemental treatment regimens for lowering the blood pressure of hypertensive individuals. From an initial collection of reports published between 1996 and 2006, the investigators identified 3,106 potentially relevant reports on cocoa and tea.
These reports were further screened according to their inclusion criteria, including the employment of at least 10 normotensive, as well as hypertensive study participants, at least 7 days for the duration of the study, specific identification of tea or cocoa effects on blood pressure and the completeness of information on their studies. The final list of reports was thus composed of 10 publications, which were further subjected to statistical analysis for determination of correlation, heterogeneity, regression and significance.
The review article concluded that based on the 10 publications analyzed, cocoa was effective in lowering blood pressure, while tea did not generate any effect. The review paper’s conclusions may not be reliable as each of the published reports included in the study indicated different amounts of the active ingredients that were solely responsible for the reduction in blood pressure. Specifically, most of the reports only show that 5 cups of tea were consumed each day by the study participants, but this did not indicate the actual amount of polyphenol that was present in the beverage.
It is thus highly unlikely to believe that tea did not show any effect in the reduction of the blood pressure in hypertensive individuals as it may be possible that a single teabag was used for preparing 2 or 3 cups of tea. In addition, the inclusion criteria of the review were not as stringent as could be expected, as the minimum duration of a study should be at least 7 days. Using such variable criteria for inclusion may thus not convince me, as a reader, to change my diet to follow what the investigators suggest.
The review article could be more robust if they screened for reports that described the effects of the active ingredients in tea and cocoa, namely the specific polyphenol that is present in each beverage. A modification in the inclusion criteria may also be necessary to improve the selection process of the published reports. Work Cited Taubert, D. , Roesen, R. and Schomig, E. “Effect of Cocoa and Tea Intake on Blood Pressure: A Meta-analysis. ” Archives in Internal Medicine 167(2007): 626-634.