LONDON, UNITED KINGDOM. Researchers at the London School of Hygiene and Tropical Medicine report that older people with high blood levels of vitamin C live longer than people with low levels. Their study involved 1214 people between the ages of 75 and 84 years. All participants had a blood sample drawn for analysis of vitamin C (ascorbate), vitamin E, vitamin A (retinol), and beta-carotene levels. They also completed detailed food frequency questionnaires during a personal interview.
The researchers found that ascorbate concentrations decreased markedly with age and that participants with the highest blood levels of ascorbate (greater than 66 micromol/L) had about half the risk of dying during the 4-year follow-up period as did participants with the lowest blood levels (less than 17 micromol/L). Blood levels of the other antioxidants measured did not correlate with mortality.
Ascorbate levels correlated well with fruit and vegetable intake of at least 5 servings per day. Only 17% of
the participants took vitamin C supplements and doing so did not affect the correlation between blood levels
of ascorbate and mortality. Men, smokers, sedentary people, and people of a lower socioeconomic status
were more likely to be vitamin C deficient. The researchers conclude that an effort should be made to
increase ascorbate levels in older people preferably through an increased intake of fresh fruit and
Editor's comment: Other research has shown that supplementing with 400 mg/day of vitamin C yields an equilibrium ascorbate level of about 70 micromol/L in healthy young volunteers. It is likely that older people may require more, so 300-500 mg 3 times a day is probably a good aim. Vitamin C should always be taken in divided doses throughout the day as it is fairly rapidly excreted. It is also prudent to supplement with a combination of vitamin C and the bioflavonoids usually found with it in nature rather than with just pure ascorbic acid.