Grape-Enriched Diet

The researchers studied several groups of rats and assigned each group of 12 to various combinations of salty foods, grape powder, and hydralazine. All the rodents were fed the same weight of food daily, with powdered grapes making up 3% of the diet for the animals that received grapes as part of either a low-salt or high-salt diet. Rats receiving hydralazine lapped it up in their water supply.

After looking at various factors, including molecular indicators of cardiac stress, the researchers still found that the rats in the high-salt grape and high-salt hydralazine groups developed high blood pressure over time but had lower systolic blood pressures than the high-salt rats deprived of grape powder.

"Though it's true that your mom told you to eat all your fruits and your vegetables, and that we are learning a lot about what fruits, including grapes, can do ... we would not directly tell patients to throw all their pills away and just eat grapes," Bolling says.

The researchers say the study suggests that a grape-enriched diet can have broad effects on hypertension, but that more work is needed to see if the beneficial effects will apply to humans.

They write that the findings "may have particular importance to our aging population, which has reduced intake of both fruit and vegetables."

According to recent data, only 35% of women and 39% of men over age 60 consumed two servings of fruits per day, and only 6% of both women and men met the goal of three servings daily of vegetables.

The study was funded in part by the California Table Grape Commission, but the authors note that the commission had no involvement in study design, data analysis, or manuscript preparation.