Plasma polyphenols and antioxidants, oxidative DNA damage and endothelial function in a diet and wine intervention study in humans

An intervention study was performed to evaluate the influence of a Mediterr anean diet, a high fat diet, and their supplementation with red wine in mod erate amounts, on biochemical, physiological, and clinical parameters relat ed to atherosclerosis and other chronic diseases. For 3 months two groups o f 21 male volunteers each, received either a Mediterranean diet or a high f at diet; during the second month, red wine was added isocalorically, 240 ml /day. Participants were kept under close medical and nutritional surveillan ce. Al days 0, 30 60 and 90, clinical, physiological and biochemical evalua tions were made. Plasma vitamin C was significantly decreased in the high f at diet group compared to the Mediterranean diet group. After wine suppleme ntation to the Mediterranean diet, a significant 13.5% increase in plasma v itamin C was observed. Furthermore, when wine was added vitamin E decreased significantly in plasma, 15% in the high fat diet and 26% in the Mediterra nean diet. Total plasma antioxidant capacity (total antioxidant reactivity) increased 28% above basal levels in the Mediterranean diet group, but not in the high fat diet group. In both groups, wine induced a marked increase in total antioxidant reactivity above basal levels, 56% and 23%, respective ly Oxidative DNA damage, detected as 8-hydroxydeoxyguanosine (8-OHdG) level s in blood leukocyte DNA, was markedly increased by the high fat diet; howe ver, it was strongly reduced, to approximately 50% basal values, after wine supplementation, both in the high fat diet and Mediterranean diet groups. Endothelial function evaluated noninvasively as flow-mediated vascular reac tivity of the brachial artery, was suppressed by the high fat diet and was normal after wine supplementation. These effects are attributed to oxidativ e stress associated with a high fat diet and to the elevated plasma antioxi dant capacity associated with wine consumption and the Mediterranean diet. The results presented support the following conclusions: a high fat diet in duces oxidative stress; a diet rich in fruits and vegetables enhances antio xidant defenses; wine supplementation to a high fat or a Mediterranean diet increases plasma antioxidant capacity, decreases oxidative DNA damage, and normalizes endothelial function.