But the U-M study suggests that it may be possible that grape consumption can change the downhill sequence that leads to heart disease by prolonging the time between when symptoms begin to occur and a time of diagnosis.

"Reducing these risk factors may delay the onset of diabetes or heart disease, or lessen the severity of the diseases," says E. Mitchell Seymour, Ph.D., lead researcher and manager of the U-M Cardioprotection Research Laboratory. "Ultimately it may lessen the health burden of these increasingly common conditions."

Rats were fed the same weight of food each day, with powered grapes making up 3 percent of the diet. Although the current study was supported in part by the California Table Grape Commission, which also supplied the grape powder, the researchers note that the commission played no role in the study's design, conduct, analysis or preparation of the presentation.

Research on grapes and other fruits containing high levels of antioxidant phytochemicals continues to show promise. U-M will further its research this summer when it begins a clinical trial to test the impact of grape product consumption on heart risk factors.

"Although there's not a particular direct correlation between this study and what humans should do, it's very interesting to postulate that a diet higher in phytochemical-rich fruits, such as grapes, may benefit humans," Bolling says.

Bolling says that people who want to lower their blood pressure, reduce their risk of diabetes or help with weakened hearts retain as much pumping power as possible should follow some tried-and-true advice to eat a healthy diet low in saturated fat, trans fat and cholesterol, achieve a desirable weight and increase physical activity.

Source: University of Michigan Health System