Grapeseed Keeps Arteries Clear

A small amount of grapeseed extract added to animals' diets prevented aortic atherosclerosis and may well protect against heart disease in humans, say researchers Jun Yamakoshi, of the Research and Development Division of Kikkoman Corporation, and Takuro Koga, of the Noda Institute for Scientific Research, both institutions in Noda City, Japan.

Researchers added grapeseed extracts, rich in the class of polyphenols known as proanthocyanidins, to rabbits' diets. The animals were divided into groups of eight and fed either standard rabbit chow, chow with atherosclerosis-inducing cholesterol, chow with cholesterol plus 1 percent grapeseed proanthocyanidin, and chow with cholesterol plus 0.1 percent grapeseed proanthocyanidin.

When they examined the rabbits' aortas, researchers found that although grapeseed did not affect the animals' serum cholesterol levels it considerably lowered cholesterol in the aortic wall. Even more significantly, animals fed the proanthocyanidin supplement had less atherosclerotic plaque in their aortas. The aortas of the animals fed grapeseed also contained fewer oxidized smooth muscle cells—hallmarks of atherosclerosis.

Oddly, results were not significantly different for the 0.1 percent and the 1 percent proanthocyanidin groups, possibly because only a certain amount of the phytochemical is absorbed no matter how much is eaten.

Proanthocyanidins are powerful water-soluble antioxidants. They are thought to trap reactive oxygen compounds in the plasma and cells of the artery walls before they can damage low density lipoprotein (LDL) cholesterol.

Proanthocyanadins concentrate in artery walls, so small doses usually suffice—researchers suggest taking as little as 0.025 g/kg/day, or 1.25 g for a 110 lb person.

They conclude, "Proanthocyanidin-rich foods such as red wine and health foods containing grapeseed extract may be beneficial in lowering the incidence of atherosclerosis and coronary heart disease."

—Atherosclerosis 1999 Jan;142(1):139-49