Enjoying small amounts of polyphenol-rich dark chocolate daily appears to lower blood pressure, according to a report in this week's Journal of the American Medical Association.

Previous reports have linked cocoa-containing foods with reduced blood pressure, but the effect of regular, low-level cocoa intake on blood pressure was not known, Dr. Dirk Taubert, from University Hospital of Cologne in Germany, and colleagues point out.

The researchers' study involved 44 subjects with "high normal" blood pressure or early hypertension who were randomly assigned to eat about 6 grams (about one-fifth of an ounce) of either dark chocolate or polyphenol-free white chocolate for 18 weeks.

The team found that dark chocolate reduced blood pressure by about 2 points, with no accompanying changes in body weight or in blood glucose or cholesterol levels.

The percentage of participants who were classified as having hypertension fell from 86 percent to 68 percent.

This effect was not seen with white chocolate, the researchers note.

"The most intriguing finding of this study is that small amounts of commercial cocoa confectionary convey a similar blood pressure-lowering potential compared with comprehensive dietary modifications," Taubert and colleagues write.

"Future studies should evaluate the effects of dark chocolate in other populations and evaluate long-term outcomes," they say.