The effect of consumption of red or white wine (11% alcohol) with meals on the propensity of plasma and low-density lipoprotein (LDL) to undergo lipid peroxidation was studied in 17 healthy men who were divided into two groups: 8 received 400 mL red wine/d for 2 wk, and 9 received a similar amount of white wine. Red wine consumption for 2 wk resulted in a 20% reduction in the propensity of plasma to undergo lipid peroxidation (in the presence of a free-radical-generating system) as determined by the thiobarbituric acid reactive substances (TBARS) assay. In parallel, red wine consumption reduced the propensity of the volunteers' LDL to undergo lipid peroxidation (in response to copper ions) as determined by a 46%, 72%, and 54% decrease in the content of TBARS, lipid peroxides, and conjugated dienes in LDL, respectively, as well as by a substantial prolongation of the lag phase required for the initiation of LDL oxidation. On the contrary, dietary consumption of white wine for 2 wk resulted in a 34% increase in plasma's propensity to undergo lipid peroxidation and also in a 41% increased propensity of the LDL to undergo lipid peroxidation. The antioxidant effect of dietary red wine on plasma lipid peroxidation was not secondary to changes in the plasma vitamin E or beta-carotene content but could be related to the elevation of polyphenol concentration in plasma and LDL. Thus, some phenolic substances that exist in red wine, but not in white wine, are absorbed, bind to plasma LDL, and may be responsible for the antioxidant properties of red wine.

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