Ingestion of red wine significantly increases plasma phenolic acid concentrations but does not acutely affect ex vivo lipoprotein oxidizability

Background: Reduced lipoprotein oxidizability by red wine phenols has been proposed as the basis for a relatively lower incidence of coronary heart di sease in red wine drinkers. We showed previously that caffeic and protocate chuic acids isolated from red wine exhibit antioxidant activity in vitro. H owever, there is no information in the literature on the absorption of thes e compounds after red wine ingestion. Objectives: We sought to determine whether certain phenolic acids can be de tected in the circulation after red wine consumption and if their presence has an acute effect on serum and LDL oxidation ex vivo. Design: Twelve healthy male nonsmokers consumed red wine, phenol-stripped r ed wine, dealcoholized red wine, or water, each at a separate visit, in ran dom order and 1 wk apart. Beverages were consumed over 30 min and blood was sampled just before beverage consumption and 1, 2, and 4 h after consumpti on. Plasma caffeic, protocatechuic, and 4-O-methylgallic acids were measure d by gas chromatography-mass spectrometry. We also measured copper-induced serum and LDL oxidizability ex vivo and serum uric acid. Results: Caffeic acid and 4-O-methylgallic acid concentrations increased si gnificantly (P < 0.025) after consumption of red wine and dealcoholized red wine compared with water or phenol-stripped red wine. Uric acid increased significantly (P < 0.001) after ingestion of red wine, phenol-stripped red wine, and dealcoholized red wine. There was no effect on ex vivo serum or L DL oxidation after any of the beverages. Conclusion: Although red wine and dealcoholized red wine consumption acutel y increase plasma phenolic acid and serum uric acid concentrations, the inc rease is insufficient to influence ex vivo lipoprotein oxidation.