Vitamin C status and nutrient interactions in a healthy elderly population.

Vitamin C status and interactions with other nutrients were studied in 677 healthy, noninstitutionalized elderly people aged 60-98 y. Although 6% of the males and 3% of the females showed marginal vitamin C status (plasma ascorbic acid 11 to less than 23 mumol/L), only one person had a plasma ascorbic acid (AA) level less than 11 mumol/L. At all levels of total vitamin C intake, mean plasma AA levels were higher in females than males. Vitamin C supplement use was associated with generally higher blood levels of vitamins B-6, B-12, and E and folate in both sexes and with higher levels of retinol in females. However, after both age and the total dietary intake of the specific nutrient being examined were controlled for, plasma AA levels were significantly correlated only with plasma levels of vitamin E and folate in females.