BACKGROUND: Vitamin C acts as a potent antioxidant; however, it can also be a 
prooxidant and glycate protein under certain circumstances in vitro. These 
observations led us to hypothesize that a high intake of vitamin C in diabetic 
persons might promote atherosclerosis.
OBJECTIVE: The objective was to examine the relation between vitamin C intake 
and mortality from cardiovascular disease.
DESIGN: We studied the relation between vitamin C intake and mortality from 
total cardiovascular disease (n = 281), coronary artery disease (n = 175), and 
stroke (n = 57) in 1923 postmenopausal women who reported being diabetic at 
baseline. Diet was assessed with a food-frequency questionnaire at baseline, and 
subjects initially free of coronary artery disease were prospectively followed 
for 15 y.
RESULTS: After adjustment for cardiovascular disease risk factors, type of 
diabetes medication used, duration of diabetes, and intakes of folate, vitamin 
E, and beta-carotene, the adjusted relative risks of total cardiovascular 
disease mortality were 1.0, 0.97, 1.11, 1.47, and 1.84 (P for trend < 0.01) 
across quintiles of total vitamin C intake from food and supplements. Adjusted 
relative risks of coronary artery disease were 1.0, 0.81, 0.99, 1.26, and 1.91 
(P for trend = 0.01) and of stroke were 1.0, 0.52, 1.23, 2.22, and 2.57 (P for 
trend < 0.01). When dietary and supplemental vitamin C were analyzed separately, 
only supplemental vitamin C showed a positive association with mortality 
endpoints. Vitamin C intake was unrelated to mortality from cardiovascular 
disease in the nondiabetic subjects at baseline.
CONCLUSION: A high vitamin C intake from supplements is associated with an 
increased risk of cardiovascular disease mortality in postmenopausal women with 
diabetes.