Evidence of the effects of vitamin C and vitamin E on fat oxidation in live subjects is limited. Vitamin C protects membranes against oxidative damage in the water phase while vitamin E is considered the predominant fat-soluble, chain-breaking micronutrient antioxidant. Test tube studies suggest that vitamin C may enhance the effects of vitamin E. To the best of the researcher's knowledge, there is no documentation in humans that vitamin C enhances the antioxidant effect of vitamin E.
This study looks at whether, as previously believed, vitamins C and E work together and enhance each other's oxidation powers. The researchers looked at how vitamins C and E, alone or together, affected lipid oxidation in adults.
Why is oxidation an important process in the body?
Oxidation is a normal chemical reaction in the body, but the process can also damage cells. Lipid oxidation is believed to play a key role in the development of the artery-clogging disease atherosclerosis. Vitamin C and E have both been found to reduce oxidation.
How did the researchers determine their results?
The researchers found that both vitamins C and E lowered urine levels of a particular substance that is a byproduct of lipid oxidation. However, combining the vitamins was no more effective than either C or E alone.
When are antioxidants most effective in fighting atherosclerosis?
Antioxidants may be most effective in the earliest stages of atherosclerosis, when lipid oxidation is key.
The results of this trial have several implications pertaining to the use of antioxidant vitamins as a means to prevent hardening of your arteries, particularly with respect to primary prevention. First, supplementation of the usual diet with vitamin C up to 500 mg/day or vitamin E at 400 IU/day resulted in a reduction in a 10% reduction of fat oxidation.
Second, the extent of the reduction in lipid oxidation by each vitamin or the combination thereof was similar. A daily vitamin C dose of 500 mg is attainable through your diet, whereas it is virtually impossible to consume 400 IU vitamin E/day through food alone. Third, the lack of a synergistic interactive effect of these 2 vitamins suggests that, for the large number of Americans who consume antioxidant vitamins, supplementation with both vitamins may not confer additional benefit on fat oxidation beyond that by either vitamin alone.
American Journal of Clinical Nutrition September 2002;76:549-555
This is an interesting study that focuses on the use of vitamin C and E for prevention of fat oxidation. The study was well done and there doesn't appear to be any additional benefit in prevention of oxidation of your fats by taking both vitamin E and C at the same time.
As the authors point out in their study, data on the effects of vitamin E in protecting fat oxidation in food is somewhat challenging to find. I have tried a number of times to search the literature and come up empty-handed, so I really appreciate the results of this study.
It provides a major level of reassurance that if you are consuming the pound of green vegetables for every 50 pounds of body weight you will likely receive more than enough vitamin C to protect damage to the fish oils you are taking to improve your health.
It's virtually impossible to consume 400 units of vitamin E in a regular diet, but consuming the amount of vitamin C used in this study (500 mg) is relatively easy to do.
I previously felt that vitamin E is probably one vitamin that nearly everyone would benefit from taking. This study would suggest that it might not be necessary to take the vitamin E if you are consuming large amounts of vegetables. There are likely other benefits of vitamin E, but I am carefully reevaluating my position of taking a daily vitamin E supplement and may eventually phase it out of my personal program.
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