Glycosylated hemoglobin concentrations and vitamin E, vitamin C, and beta-carotene intake in diabetic and nondiabetic older adults.

Studies indicate that large doses of all-rac-alpha-tocopherol in people with diabetes or ascorbic acid in nondiabetic subjects reduces protein glycosylation. The mechanisms by which these nutrients influence glycosylation are poorly understood but may be related to their ability to function as antioxidants. We examined the relationship between glycosylated hemoglobin (GHb) and intake of vitamins E and C and beta-carotene in a population-based sample of middle-aged and older adults participating in the Beaver Dam Eye Study. In people with diabetes, no significant associations were observed between GHb and intake of vitamins E and C and beta-carotene. In people without diabetes, energy-adjusted vitamin C intake was negatively associated with GHb after age and sex were controlled for (dietary, P = 0.02; total, P = 0.04). No significant relationships between GHb and intake of vitamin E and beta-carotene were observed.