After three to four weeks of the experiment, the researchers found that the presence of whole cinnamon or cinnamon extract in the diet reduced the systolic blood pressure of the rats.

“Addition to diets of cinnamon (eight percent w/w) reduced the systolic blood pressure of rats eating sucrose containing diets to virtually the same levels as SHR consuming non sucrose containing (only starch) diets,” wrote lead author Dr. Harry Preuss from Georgetown University Medical Center.

Interestingly, both whole cinnamon and the cinnamon extract also reduced the blood pressure of the non-sucrose diet group, “suggesting that cinnamon reduces more than just sucrose-induced systolic blood pressure elevations,” said Preuss.

The effects of cinnamon were dose-dependent, said the researchers, and the extract group also decreased levels of fructosamine, a marker of plasma glucose concentrations. Cinnamon's role in improving the control of blood sugar levels has been reported by several studies, but this is the first time that researchers have reportedly shown a beneficial effect on blood pressure.

“Research on cinnamon has pointed to its efficacy in maintaining favorable blood glucose levels and reducing serum cholesterol in people with type 2 diabetes,” explained lead researcher Dr. Richard Anderson from the US Department of Agriculture.

“This is the first time we have seen the positive effects of cinnamon on blood pressure levels, a common co-factor to diabetes and one of the risk factors associated with cardiovascular disease,” he said.

In the US, seven percent of the population lives with diabetes, while 34.2 percent of Americans suffered from some form of cardiovascular disease (CVD) in 2002, according to the American Heart Association.