A German study suggests there is evidence that cocoa but not tea is linked to blood pressure reduction.
The study is published in the American Medical Association journal Archives of Internal Medicine.
Dr Dirk Taubert and colleagues from the Department of Pharmacology at the University Hospital of Cologne, Germany, reviewed the medical literature for dietary effects of cocoa and black and green tea on blood pressure over the last 40 years.
They specifically searched for trials involving 10 or more adults that examined the before and after effects of consuming cocoa, black or green tea for at least 7 days on systolic (when the heart pumps, the higher reading) and diastolic (when the heart relaxes, the lower reading) blood pressure.
Looking at cocoa, they selected 5 randomized controlled trials on cocoa on a total of 173 people lasting for a median duration of 2 weeks. On analyzing the data from these trials they discovered that:
— The pooled mean systolic blood pressure for the cocoa consumers was 4.7 mm of mercury lower than for the non-cocoa consumers.
— The diastolic figure was 2.8 mm lower.
— These effects were sufficiently significant to show that cocoa was linked to reduced blood pressure.
Looking at tea, they selected 5 controlled trials covering a total of 343 people that lasted for a median duration of 4 weeks. The analysis on the tea trials showed that:
— The pooled mean systolic blood pressure for the tea consumers was 0.4 mm of mercury lower than for the non-tea consumers.
— The diastolic figure was 0.6 mm lower.
— These effects were not significant enough to show that tea was linked to decrease in blood pressure.
The researchers concluded that “Current randomized dietary studies indicate that consumption of foods rich in cocoa may reduce blood pressure, while tea intake appears to have no effect”.
Dr Taubert speculated that the flavonoid content of cocoa is probably the most likely explanation for the effect on blood pressure.
He was cautious to point out that the specific studies they investigated were of short duration, looking at before and after effects, under controlled conditions.
It does not necessarily mean that eating a little bit of chocolate every day will lower your blood pressure. There are many other factors to consider, for instance the calories consumed, and whether the chocolate that you eat or drink is rich in flavonoids.
Manufacturers of chocolate often remove the flavonoids because they make the chocolate taste bitter. Also, the effect of milk or sugar being present in the chocolate was not examined in this research.
“Effect of Cocoa and Tea Intake on Blood Pressure: A Meta-analysis.”
Dirk Taubert, Renate Roesen, Edgar Schömig.
Arch Intern Med. 2007;167:626-634.
Vol. 167 No. 7, April 9, 2007
Click here related article: Some Types Of Cocoa Could Improve Brain Function (Feb 2007).
Written by: Catharine Paddock
Writer: Medical News Today