Grapes fight hypertension and combat inflammation

Eating grapes may help to lower the risk of cardiovascular disease by lowering high blood pressure and combating inflammation, new research suggests.

Mitchell Seymour, M.S, and colleagues at Michigan State University tested the effects of a powdered grape formula made from green, red, and black grapes on Dahl Salt-Sensitive (Dahl-SS) rats, which develop high blood pressure if they are fed a salty diet. The rats were fed one of five diets for 18-weeks: low-salt, low-salt plus grape powder, high-salt, high-salt plus grape powder, or high-salt plus the vasodilator hydralazine.

Results showed that rats fed the high-salt plus grape powder diet had lowered blood pressure, improved cardiac function, reduced levels of systemic inflammation, and fewer signs of heart muscle damage than rats fed the high-salt diet. The rats fed the high-salt diet plus hydralazine had lower blood pressure than rats fed a high-salt diet, however they did not have lower levels of systemic inflammation or fewer signs of heart muscle damage.

"Although there are many natural compounds in the grape powder itself that may have an effect, the things that we think are having an effect against the hypertension may be the flavanoids – either by direct antioxidant effects, by indirect effects on cell function, or both,” said study author Professor Steven Bolling, head of the University of Michigan Cardioprotection Research Laboratory, in a news release. “These flavanoids are rich in all parts of the grape - skin, flesh and seed, all of which were in our powder."

Seymour EM, Singer AAM, Bennink MR, Pariks RV, Kirakosyan A, Kaufman PB, Bolling SF. Chronic intake of a phytochemical-enriched diet reduces cardiac fibrosis and diastolic dysfunction caused by prolonged salt-sensitive hypertension. The Journals of Gerontology Series A: Biological Sciences and Medical Sciences. 2008;63:1034-1042.