A randomized, double-blind, placebo-controlled, pilot study to evaluate the effect of whole grape extract on antioxidant status and lipid profile

The health benefits of grapes, which contain polyphenols, are well documented. The antioxidative and cardioprotective effects of a whole grape extract (WGE) were studied in a single-centre, randomized, double-blind, placebo-controlled, 6-week pilot study conducted on 24 pre-hypertensive, overweight, and/or pre-diabetic subjects. Blood and urine biomarkers of antioxidant status were assessed at the beginning and end of the study. WGE subjects had significantly lower superoxide dismutase concentrations (P = 0.032) and total cholesterol/HDL-C ratios (P = 0.037), and significantly higher HDL-C levels (P = 0.001) compared to the placebo subjects after 6 weeks. The concentration of 8-isoprostane and oxidized LDL decreased by 5% and 0.5%, respectively, for WGE subjects, but increased by 50% and 5%, respectively, for the placebo subjects. This is the first North American study to report efficacy of WGE on antioxidant status and lipid profile.