A new German study suggests that eating a small amount of dark chocolate every day could lower blood pressure without increasing weight or other health risks.
The study is published in today's issue of the Journal of the American Medical Association (JAMA).
Eating large amounts of cocoa often increases other risk factors because of the higher intake of sugar, fat and calories. So the researchers, who are based at the University Hospital of Cologne, thought they would test the effects of a small daily portion of polyphenol-rich cocoa on blood pressure, since this should not increase the other risks.
The researchers recruited 44 adults aged from 56 to 73, comprising 24 women and 20 men, who had untreated upper range prehypertension (blood pressure ranging from 130/85 to 139/89) or stage 1 hypertension (140/90 to 160/100) to take part in the trial which lasted from January 2005 to December 2006. They had no other associated risk factors. All participants were attending one primary care clinic in Germany.
The participants were randomly assigned to take 6.3 g (30 calories) per day of dark chocolate (about the size of a Hershey's Kiss) containing 30 mg of polyphenols, or a matching dose of white chocolate that did not contain polyphenols for 18 weeks.The results showed that:
Eating dark chocolate for 18 weeks reduced average systolic blood pressure (the top reading) by 2.9 mm of mercury.
It also reduced the average diastolic blood pressure by 1.9 mm of mercury.
These reductions were not accompanied by changes in body weight, plasma levels of lipids or glucose.
The proportion of participants with hypertension who ate dark chocolate went down from 86 to 68 per cent.
The dark chocolate group also had increased levels of plasma biomarkers: cocoa phenols and vasodilatory S-nitrosoglutathione.
The systolic and diastolic blood pressure of the participants who ate white chocolate did not change.
S-nitrosoglutathione is a precursor of nitric oxide, a compound that causes relaxation and dilation of blood vessels and is linked to decreased blood pressure. It is used as a biomarker for vasodilative nitric oxide.
The researchers concluded that:
"Data in this relatively small sample of otherwise healthy individuals with above-optimal BP indicate that inclusion of small amounts of polyphenol-rich dark chocolate as part of a usual diet efficiently reduced BP and improved formation of vasodilative nitric oxide."
| Tags: Nutrition |
Labels: Nutrition, Women's Health