Seymour and the laboratory's director, U-M cardiac surgeon Steven Bolling, M.D., caution that their results cannot be directly translated into humans. But they are encouraged by the positive signs seen in the new data.
"Rats fed tart cherries as 1 percent of their total diet had reduced markers of metabolic syndrome," says Seymour. "Previous research by other groups studied pure anthocyanin compounds rather than anthocyanin-containing whole foods, and they used concentrations of anthocyanins that would be very difficult if not impossible to obtain in the diet."
He continues, "We are interested in a whole-foods approach, using amounts of fruit that are relevant to human diets. We are enthusiastic about the findings that tart cherries conferred these beneficial effects at such a modest daily intake."
The potential for protective effects from antioxidant-rich foods and food extracts is a promising area of research, says Bolling, who is the Gayle Halperin Kahn Professor of Integrative Medicine, a professor of cardiac surgery, co-director of U-M Integrative Medicine and member of the U-M Cardiovascular Center.
"These data from whole tart cherries join other findings that suggest a correlation between anthocyanin intake and reductions in cardiovascular and metabolic risk factors," he says. "But there is still a long way to go before we can advocate any course of action for humans. Still, the growing body of knowledge is encouraging."
Bolling and Seymour performed the study using 48 male Dahl Salt-Sensitive rats, which are bred for their susceptibility to salt-linked high blood pressure, high cholesterol and impaired glucose tolerance.
For 90 days beginning in their sixth week of life, the rats were fed either a carbohydrate-enriched diet or a diet that, by weight, included 1 percent cherries or 10 percent cherries. The higher cherry dose was
Source:University of Michigan Health System