Effect of vitamin C ingestion on the vascular endothelial function exposed to transient passive smoking

As well as active smoking, passive smoking is associated with a high risk of developing cardiovascular disease. The antioxidant vitamin C may inhibit the unfavorable effects of passive smoking. In this study, we investigated the effects of vitamin C ingestion on changes in the flow-mediated dilatation (FMD) at the brachial artery in patients exposed to transient passive smoking. The study participants included seven healthy adult males who were examined by high-resolution ultrasonography of the brachial artery before and after 15-minute of passive smoking. FMD was used to examine the endothelial function. Randomized crossover controlled trial, measurements were performed on two different days 120-minute after the oral administration of 1000mg of ascorbic acid (VC trial) or a placebo (P trial). Although the FMD values decreased after passive smoking in both trials, the FMD values of the VC trial were higher than those of the P trial, with significant differences between the trials observed immediately and 30-minute after passive smoking. The results of this study suggested that the ingestion of vitamin C may suppress the decrease in the vascular endothelial function caused by transient passive smoking.