Washington: Vitamin E supplementation may extend the lifespan of restricted groups of men, depending on their vitamin C intake and the level of smoking, according to a new study.
Several large randomized trials of humans found that vitamin E supplementation does not reduce mortality.
However, the average effect on mortality in a group of people with a wide age range may mask an effect of vitamin E on the lifespan.
Dr. Harri Hemila, and Professor Jaakko Kaprio, of the University of Helsinki, Finland, studied the age-dependency of vitamin E effect on mortality in the large randomized trial (Alpha-Tocopherol Beta-Carotene Cancer Prevention Study), which was conducted in Finland between 1985-1993. Their study was restricted to follow-up period over 65 years and 10,837 participants contributed to the analysis.
Among all analyzed participants, vitamin E had no effect on mortality when participants were 65 to 70 years old, but reduced mortality by 24 percent when participants were 71 or older.
Among 2,284 men with dietary vitamin C intake above the median who smoked less than a pack of cigarettes per day, vitamin E extended lifespan by two years at the upper limit of the follow-up age span. In the other participants, consisting of 80 percent of the cohort, vitamin E did not affect mortality, which shows that vitamin E is no panacea for extending life expectancy.
The researchers concluded, "If vitamin E influences the life-span, it is possible that a benefit on the oldest participants might be camouflaged by the large middle-aged majority of study participants".
Therefore, they propose that it might be useful to analyze the effect of vitamin E supplementation in large controlled trials by the age of the participant at the follow-up and not just by the time after randomization that has been customary.
The study has been published in the Age and Ageing.