STUDY: A new study that provides in vivo evidence of vitamin C and E's ability to prevent lipid peroxidation

JOURNAL: American Journal of Clinical Nutrition

AUTHORS:

ABSTRACT: A new study that provides in vivo evidence of vitamin C and E's ability to prevent lipid peroxidation was published in the September 1 2002 issue of the American Journal of Clinical Nutrition.

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COMMENTARY: The researchers, from Johns Hopkins University in Baltimore and the University of Western Australia, sought to prove in humans what has been primarily demonstrated in vitro.

A trial of 184 smokers was conducted over a two month period, during which participants received either 500 milligrams vitamin C, 400 international units vitamin E, both vitamins, or a placebo. Subjects had blood samples and urine samples taken before receiving the supplements and at one and two months. The urine samples were analyzed for levels of 8-isoprostaglandin F2 alpha and MDA + 4-hydroxyalkenals, which are markers of lipid peroxidation.

Blood samples were analyzed for levels of serum ascorbic acid, serum alpha tocopherol, and serum oxygen-radical absorbance capacity (ORAC), which is a measure of the capacity of serum to resist oxidative damage.

Both vitamins were found to lower 8-isoprostaglandin F2 alpha, demonstrating a reduction in lipid peroxidation. Urinary levels of MDA + 4-hydroxyalkenals were not affected. Vitamin C caused an improvement serum ORAC values.

The group taking both vitamins did not have lower values than those taking either vitamin alone. The researchers speculate that the reason for this may be because there is a threshold effect as a result of endogenous processes at which a certain level of oxidative damage is inevitable.

This trial is the largest to date that rigorously assessed the effects of vitamin C and vitamin E on lipid peroxidation in vivo. The finding that vitamin C significantly increased ORAC is consistent with that from in vitro studies.

What we should gather from this is to include lot’s of foods containing vitamin E and A.

The doses used in this study can be obtained from just eating right and including lots of beneficial greens and neutral grain products.