Indication: LDL oxidation

Source: Am J Clin Nutr December, 2002;76(6):1367-74.

Research: Subjects were randomly assigned to receive either 400 IU RRR-alpha-tocopherol/d or 10 ml Concord grape juice (CGJ) for two weeks. Serum oxygen radical absorbance capacity (ORAC), plasma protein carbonyls, urinary F(2)-isoprostanes and resistance of low density lipoprotein (LDL) to ex vivo oxidation were measured before and after supplementation as markers of antioxidant status and oxidative stress.

Results: After supplementation, plasma alpha-tocopherol increased 92% in subjects who received alpha-tocopherol; plasma total and conjugated phenols in­creased 17% and 22%, respectively, in subjects who received CGJ. There was a significant change in plasma triacylglycerols in both groups, but the concentrations were within the normal range. CGJ supplementation was associated with significantly higher triacylglycerols than was alpha-tocopherol supplementation. Both supplementation regimens significantly increased serum ORAC and LDL lag time and significantly decreased the LDL oxidation rate, with no significant difference in effectiveness. Protein carbonyl concentrations in native plasma decreased 20% after CGJ supplementation, which was a significantly different response than that after alpha-tocopherol supplementation. Researchers concluded that in healthy adults, 10 ml CGJ increased serum antioxidant capacity and protected LDL against oxidation to an extent similar to that obtained with 400 IU alpha-tocopherol/d but decreased native plasma protein oxidation significantly more than did alpha-tocopherol. CGJ flavonoids are potent antioxidants that may protect against oxidative stress and reduce the risk of free radical damage and chronic diseases.