American Journal of Clinical Nutrition, Vol 27, 144-151, Copyright © 1974 by The American Society for Clinical Nutrition, Inc.

Plasma and leukocyte ascorbic acid levels in the elderly

¹ From the Medical Research Council Epidemiology Unit and the University of Wales Institute of Science and Technology, Cardiff, South Wales, United Kingdom

A survey of ascorbic acid blood levels was carried out in the elderly population of a South Wales town. Response rates of 88% for the men and 84% for the women were obtained, and 830 subjects were seen, 93% of whom were living at home. The ascorbic acid concentration was estimated in the plasma and leukocytes (including platelets) and found to decline significantly with advancing age. Mean plasma levels were 0.24 mg/100 ml and 0.37 mg/100 ml in 202 men and 429 women aged 75 years and over; their mean leukocyte levels were 16.6 µg/10⁸ cells and 21.4 µg/10⁸ cells, respectively. These values are considerably lower than those reported from studies of younger persons. Information was obtained about consumption of fresh fruit and green vegetables. Vitamin C blood levels were correlated with both, the effect of the fruit being the stronger. More fruit was eaten by women than by men and more by nonsmokers than by smokers. These differences did not seem to account for the fact that blood ascorbic acid levels were higher in women than in men, and higher in nonsmokers than in smokers. The clinical importance of the low ascorbic acid levels is being investigated by a randomized controlled trial.