European Heart Journal Advance Access originally published online on May 5, 2007
European Heart Journal 2007 28(11):1398-1399; doi:10.1093/eurheartj/ehm108
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Tea without milk: lifestyle advice based on a small lab study: reply
Medizinische Klinik mit Schwerpunkt
Kardiologie und Angiologie
Charité—Universitätsmedizin Berlin
CCM
Charitéplatz 1
D-10117 Berlin
Germany
Medizinische Klinik mit Schwerpunkt
Kardiologie und Angiologie
Charité—Universitätsmedizin Berlin
CCM
Charitéplatz 1
D-10117 Berlin
Germany
Medizinische Klinik mit Schwerpunkt
Kardiologie und Angiologie
Charité—Universitätsmedizin Berlin
CCM
Charitéplatz 1
D-10117 Berlin
Germany
Fax.: +49 30 450 513941, Tel: +49 30 450 513186, E-mail address: mario.lorenz{at}charite.de
We thank von Elm and Antes for their comments on our article ‘Addition of milk prevents vascular protective effects of tea’.
In the first section of the letter, the authors critically comment on the newspaper coverage of our study, particularly on one-sided and unbalanced reporting in the press. They also note that only a few agencies took the time to give a more complex view and that bad news sells better than good news. We agree with the authors that any one-sided coverage of a story—whatever the topic might be—should be avoided and does not necessarily lead to improved information of the public. However, we would like to point out to the authors that we are not the writers of those news articles and hence cannot be held responsible for one-sided press coverage. This criticism, although correct, would be better addressed to the journalists composing the headlines and press articles. We also would like to state that not all the citations from the press were original quotations from us.
On the basis of the results in the literature, and as quoted in our article as well as by the authors, there are conflicting data as to whether addition of milk has an adverse effect on the beneficial effects of tea and dark chocolate.1–3 Most of these studies determined antioxidative capacities. We therefore decided to measure flow-mediated dilation as a sensitive marker of endothelial function.4 We do not agree with the authors that the sample size in our study was rather small. We obtained highly significant results after measurement of FMD in 16 volunteers. Comparable studies measuring FMD in humans after consumption of beverages comprised a sample size similar to our study and yielded statistically significant results: e.g. after consumption of red wine5 and black tea.6
Nevertheless, we concur with the authors that a single study cannot replace larger studies involving a comprehensive cross-section of the population. The aim of our study was to evaluate the immediate impact that addition of milk to tea has on a single, cardiovascular relevant parameter, the endothelial function. The rationale for drinking tea in a lab setting was that only under these conditions could the influence of other beverages and food be controlled for. This setting accordingly allowed us to closely study the interaction of milk with tea. On the basis of our results and for the effects measured, addition of milk blunts the beneficial effects that tea has on its own, in vitro and in vivo, on endothelial function. Certainly, future trials are necessary to confirm these findings, and we do not claim that our conclusions are universally valid for all physiological outcomes.
References
- Reddy VC, Vidya Sagar GV, Sreeramulu D, Venu L, Raghunath M. Addition of milk does not alter the antioxidant activity of black tea. Ann Nutr Metab (2005) 49:189–195.[CrossRef][Web of Science][Medline]
- Serafini M, Ghiselli A, Ferro-Luzzi A. In vivo antioxidant effect of green and black tea in man. Eur J Clin Nutr (1996) 50:28–32.[Web of Science][Medline]
- Serafini M, Bugianesi R, Maiani G, Valtuena S, De Santis S, Crozier A. Plasma antioxidants from chocolate. Nature (2003) 424:1013.[CrossRef][Medline]
- Schachinger V, Britten MB, Zeiher AM. Prognostic impact of coronary vasodilator dysfunction on adverse long-term outcome of coronary heart disease. Circulation (2000) 101:1899–1906.
[Abstract/Free Full Text] - Agewall S, Wright S, Doughty RN, Whalley GA, Duxbury M, Sharpe N. Does a glass of red wine improve endothelial function? Eur Heart J (2000) 21:74–78.
[Abstract/Free Full Text] - Hodgson JM, Burke V, Puddey IB. Acute effects of tea on fasting and postprandial vascular function and blood pressure in humans. J Hypertens (2005) 23:47–54.[CrossRef][Web of Science][Medline]
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