Vitamin E and vitamin C are important cellular antioxidants in humans that have lipophilic and lipophobic properties, respectively. This allows the vitamins to function in different cellular environments, with vitamin E being found predominately in the phospholipid membranes of cells, while vitamin C is present mainly in the cytosol and extracellular fluid. Within the phospholipid membrane, vitamin E is able to prevent lipid peroxidation by donation of hydrogen atoms in reduction reactions that inhibit free radical propagation. The oxidised vitamin E is then recycled back to its reduced form by vitamin C, which in turn becomes oxidised. As such vitamin C and vitamin E show synergistic effects at protecting vital cellular components from oxidative damage. Both vitamins are thought to be protective of cardiovascular disease because of their antioxidant effects in vivo, as has been demonstrated in research.
For example, researchers1 have investigated mortality risk in 11 178 subjects aged 67 to 105 years taking dietary supplements of vitamin E and vitamin C. Diets and health were assessed at baseline, and associations with the vitamin E and vitamin C content of the diet were investigated during the follow up period in which there were 3490 deaths. The risk of all cause mortality and the risk of death by cardiovascular disease was reduced with the use of vitamin E supplements (relative risk = 0.66 and 0.53, respectively). The use of vitamin E at two separate time points was also associated with a reduced risk of total mortality compared with individuals who had never used vitamin E. Simultaneous intake of vitamin E and vitamin C supplements reduced the risk of total mortality and cardiovascular mortality still further (relative risk = 0.58 and 0.48, respectively).
These results support other studies in younger individuals that show a reduced risk of mortality with supplementation of vitamin C and vitamin E. Adjustment for other know factors that alter mortality risk such as alcohol, aspirin and smoking history did not substantially change the results. Interestingly in this study, vitamin C use alone did not reduce mortality, but did provide a synergistic effect when taken with vitamin E, as might be expected from their mechanism of action. Information in this study was not available for the dose of the supplements or their type, both of which would be expected to have an effect on the protective effects seen. Taken as a whole, these data suggest that the antioxidants vitamins C and E are protective of cardiovascular disease, possibly because of their beneficial effects against the perioxidation of low density lipoprotein membranes.
RdB
