Dark Chocolate, Other Cocoa-Rich Foods May Lower Blood Pressure Better Than Tea
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Reviewed By Louise Chang, MD
April 9, 2007 -- A chocolate treat may be better than green or black tea at keeping high blood pressure in check.
A new study suggests that dark chocolate and other cocoa-rich products may be better at lowering blood pressure than tea.
Researchers compared the blood pressure-lowering effects of cocoa and tea in previously published studies and found eating cocoa-rich foods was associated with an average 4.7-point lower systolic blood pressure (the top number in a blood pressure reading) and 2.8-point lower diastolic blood pressure (the bottom number). But no such effect was found among any of the studies on black or green tea.
Cocoa and tea are both rich in a class of antioxidants known as polyphenols. But researchers say they contain different types of polyphenols, and those in cocoa may be more effective at lowering blood pressure.
Polyphenols Help Blood Pressure
Current guidelines call for people with high blood pressure to eat a diet rich in fruits and vegetables, which are also high in polyphenols. These compounds are thought to contribute to their beneficial effects on protecting against heart disease and high blood pressure.
But researchers say there are no current recommendations for people at risk for high blood pressure or heart disease to include polyphenol-rich cocoa and tea products in their diet, despite the fact that tea and cocoa products account for the bulk of people's total intake of polyphenols in Western countries.
In their review, researchers reviewed the effects of cocoa-rich products, such as dark chocolate or specially formulated polyphenol-rich milk chocolate, and blood pressure in five studies, which totaled 173 participants and lasted on average two weeks.
They also reviewed black and green tea and blood pressure in five different studies that totaled 343 participants and lasted on average four weeks. All studies were published between 1966 and 2006.
The results showed four of the five cocoa studies reported a reduction in both systolic blood pressure and diastolic blood pressure. The reduction was an average of 4.7 points systolic and 2.8 points diastolic.
Researchers say those effects are similar to those found using one-drug therapy with common blood pressure-lowering medications such as beta-blockers and ACE inhibitors.
None of the five studies on green or black tea were associated with any significant reduction in blood pressure.
Cocoa to the Rescue
Applied to the population as a whole, researchers estimate that the blood pressure-lowering effect associated with cocoa would be expected to reduce the risk of stroke by about 20%, coronary heart disease by 10%, and death from all causes by 8%.
However, they say their findings should not be interpreted as a widespread recommendation to raid the candy counter.
But they say it appears reasonable to substitute polyphenol-rich cocoa products like dark chocolate for other high-calorie or high-fat desserts, such as having a piece of dark chocolate rather than a slice of cheesecake.
"We believe that any dietary advice must account for the high sugar, fat, and calorie intake with most cocoa products," write researcher Dirk Taubert, MD, PhD, of the University Hospital of Cologne in Germany, and colleagues, in the Archives of Internal Medicine. "Rationally applied, cocoa products might be considered part of dietary approaches to lower hypertension risk."
SOURCES: Taubert, D. Archives of Internal Medicine, April 9, 2007; vol 167: 626-634. News release, Archives of Internal Medicine.
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