The research, published in the American Journal of Clinical Nutrition, was done in a controlled study of a group of smokers and non-smokers, with diet and most other factors largely the same. By monitoring "labeled" vitamin E, it was found that the blood plasma levels of this essential nutrient dropped 13 percent faster among smokers than among the non-smokers, depleting it much more quickly. The study also demonstrated in humans an important interactive relationship between vitamins C and E, showing for the first time how inadequate levels of vitamin C can cause further and faster depletion of vitamin E.

Together, these scientists say, the research is providing significant insight into how smoking might cause cancer, and how the loss of protective antioxidant vitamins can play a role in this process.

"Cigarette smoke is an oxidant, creating free radicals that are associated with increased oxidative stress, cell mutations, and can lead to such diseases as cancer, heart disease and diabetes," said Maret Traber, a professor in OSU's Linus Pauling Institute and a national expert on vitamin E. "In lung tissue, vitamin E is one of the first lines of defense against the free radicals generated by cigarette smoke."

It has been known for some time that cigarette smoking reduced blood levels of vitamin C, Traber said, but the data were less clear on vitamin E it did not appear that there were significant differences in the blood plasma levels of vitamin E between smokers and non-smokers.

But researchers now believe what is happening is that vitamin E is being depleted from tissue concentrations in order to keep up its levels in the blood, leaving the tissues including those of the lungs particularly vulnerable to
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Contact: Maret Traber
maret.traber@oregonstate.edu
541-737-7977
Oregon State University
14-Apr-2005