They believe that the antioxidant polyphenols in grapes are responsible for this beneficial impact, confirming findings from epidemiological studies that have demonstrated lower risk of heart attack among wine drinkers.
Atherosclerosis develops when high blood cholesterol leads to the thickening and hardening of arteries. It is responsible for more than half the deaths in developed countries, according to the World Health Organisation (WHO).
A team from the Lipid Research Laboratory at the Rambam Medical Center in Israel standardized freeze-dried powder made from fresh California grapes.Thirty mice bred to develop the condition were assigned to consume either water alone (control), 150 mug total polyphenols per day in the form of grape powder or the equivalent amount of glucose and fructose (placebo) in drinking water for 10 weeks.
Consumption of grape powder reduced the atherosclerotic lesion area by 41 per cent compared to the control or placebo mice, report the researchers in the April issue of the Journal of Nutrition(vol 135, issue 4, pp722-8).
They said that the antiatherosclerotic effect was at least partly due to a significant 8 per cent reduction in serum oxidative stress, an up to 22 per cent increase in serum antioxidant capacity, and significant reduction in macrophage uptake of oxidized LDL.
"These processes can eventually reduce macrophage cholesterol accumulation and foam cell formation and hence attenuate atherosclerosis development," they report.
"Grapes contain an abundance of powerful antioxidants that appear to inhibit an array of critical factors that can cause atherosclerosis," said principal investigator Bianca Fuhrman, senior scientist at the Lipid Research Laboratory.