Low Blood Levels of Vitamin C Linked to Mortality in Older People

Source: Tufts University
December 12, 2003

The role of vitamin C as an antioxidant was established some time ago. But how this function affects health outcomes has been less clear. According to a new study, low blood levels of vitamin C in older adults (those over 75) may translate into an increased risk for death. The results are published in the American Journal of Clinical Nutrition.

Studying antioxidants and mortality

British researchers studied 1214 adults aged 75-84 years old to examine the association between blood levels of antioxidants and mortality. The participants provided blood samples and were interviewed about their usual diet by researchers using a food frequency questionnaire. After an average 4.4 years of follow-up, the researchers performed statistical analyses to determine what association, if any, existed between antioxidant levels in the blood and the risk of death.

They found that low blood vitamin C levels were associated with an increased death rates (both from cardiovascular disease and from any cause), and vice-versa. The group with the highest blood levels of vitamin C had a 46% lower mortality rate.

Vitamin C was the only nutrient studied that showed this association. Links between nutrient levels and mortality were not found for vitamin E, beta-carotene, and vitamin A.

Why vitamin C?

The exact mechanism behind why low vitamin C levels may be associated with increased risk for mortality is not known. It may be, of course, that high vitamin C levels are a marker for (i.e. an indication of) one or more other healthy behaviors that affect longevity.

For instance, the people in this study with the highest blood levels of vitamin C were also, not surprisingly, more likely to report eating at least five servings of fresh fruits and vegetables a day. Maybe the association found between vitamin C levels and mortality was partly due to other nutrients contained in a healthful diet. It could also be that people with high vitamin C levels led more healthy lives, in general.

The importance of nutrition in older age

While these results need corroboration from other studies, they underscore the importance of good nutrition throughout life and particularly for older adults, for whom there may be several barriers to eating a healthful diet, such as reduced appetite, financial difficulties, and lack of motivation to eat. Indeed, the researchers conclude by saying, "More attention needs to be given to addressing the barriers to the adoption of healthy diets in old age."

Source

• Antioxidant vitamins and mortality in older persons: findings from the nutrition add-on study to the Medical Research Council Trial of Assessment and Management of Older People in the Community. AE. Fletcher, E. Breeze, PS. Shetty, Am J Clin Nutr, 2003, vol. 78, pp. 999--1010

Related Links
Shopping for Longevity - Final Thoughts
Nutrition in the Elderly
Oxidative Damage, Part V: Should You Take a Vitamin C or E supplement?
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