Consumption of grapes helped glucose metabolism in an animal model of prediabetes, according to preliminary findings in a study by Virginia Polytechnic Institute and State University.

The results were presented at the Experimental Biology annual meeting in Boston March 28 through April 1, according to a news release.

Lead investigator Andrew Neilson and his fellow researchers looked at the impact of grapes on blood glucose when the activities of glucagon-like-peptide, or GLP-1, a hormone type known to improve insulin response after meals, is impaired.

A reduced insulin response is partly responsible for high blood sugar levels. Prediabetes is defined as impaired glucose tolerance and other symptoms approaching clinically diagnosed diabetes. An estimated 35% of U.S. adults are prediabetic.

In the study, the group that was administered freeze-dried whole grape powder was able to keep blood glucose levels stable, and counteract the negative effect of the inhibited activities of GLP-1. In the group that did not receive grapes, blood glucose levels rose when GLP-1 activities were impaired.

"These findings demonstrate the potential for grapes to help prevent impaired glucose tolerance in a prediabetic population," Neilson said in the release. "This could have important implications for public health, in which the incidence of prediabetes is on the rise, and more study in this area is needed."