Dr. Cinque - C and E supplement users have lower five year mortality

C and E supplement users have lower five year mortality

An article published online on July 13, 2009 in the American Journal of Epidemiology reported the results of a study conducted by researchers at Seattle's Fred Hutchinson Cancer Research Center which found that vitamin C and vitamin E supplement users had a lower risk of dying over a five year period than those who did not supplement.

For their analysis, Gaia Pocobelli and colleagues evaluated data from 77,673 participants in the Vitamins and Lifestyle Study of men and women aged 50 to 76. Questionnaires completed between 2000 and 2002 provided information on the participants' supplement use over the previous ten years. Deaths that occurred over the following five years were classified as being due to cardiovascular disease, cancer, or other causes.

Over the follow-up period, 3,577 deaths occurred. Participants who reported using vitamin C and vitamin E supplements were found to have a lower risk of dying from any cause than those who did not use the supplements. Subjects whose vitamin C supplementation was in the top one-third of participants at an average daily dose of 322.1 milligrams per day or higher over the 10 year period had an 11 percent lower risk of dying than nonusers. Those whose vitamin E supplementation was among the highest third of participants at an average of 215.1 milligrams per day or more also experienced an 11 percent lower risk of dying over follow-up than those who did not supplement. When the analysis was restricted to those who never smoked, participants in the top third of vitamin C supplementation were found to have a 25 percent lower risk of dying than nonusers, and for those in the top third of vitamin E, the risk was 20 percent lower. A similarly decreased risk was shown for those whose body mass index was 30 or greater and those whose intake of fruit and vegetables was below the median.

"Our findings of stronger associations between total mortality risk and use of vitamins C and E among persons with greater body mass index and lesser fruit and vegetable consumption are consistent with the hypothesis that any impact of vitamins C and E on total mortality risk may be stronger among persons with greater levels of oxidative stress," the authors write. "On the other hand, the associations between use of vitamins C and E and total mortality risk were stronger among never smokers than among current/recent smokers, yet smoking is thought to increase oxidative stress."

When mortality was examined by cause, multivitamin use of 6 to 7 days per week was associated with a 16 percent lower risk of cardiovascular disease death and vitamin E use averaging over 215 milligrams per day was associated with a 28 percent lower risk. In their introduction to the article, the authors note that oxidative damage, which can be prevented, in part, by antioxidant vitamins, has adverse effects on DNA, proteins, and lipids that is associated with diseases such as cancer and atherosclerosis.

Dr. Cinque's comments: They also caution that supplement users tend to adopt other healthy lifestyle practices that reduce the development of major diseases and related mortality. They try to control for that by asking about body mass index, fruit and vegetable consumption, exercise, etc. Admittedly, it's hard to control for every variable. But one thing is certain: if this study had showed no advantage for vitamin users, it would have been all over the news. That's the way it goes: negative vitamin studies get hyped and postive ones get buried.

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