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Low Plasma Ascorbate Levels in Patients with Type 2 Diabetes Mellitus Consuming Adequate Dietary Vitamin C
Author(s) -
Sinclair A.J.,
Taylor P.B.,
Lunec J.,
Girling A.J.,
Barnett A.H.
Publication year - 1994
Publication title -
diabetic medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.474
H-Index - 145
eISSN - 1464-5491
pISSN - 0742-3071
DOI - 10.1111/j.1464-5491.1994.tb00375.x
Subject(s) - medicine , fructosamine , ascorbic acid , dehydroascorbic acid , diabetes mellitus , vitamin c , endocrinology , vitamin , type 2 diabetes , vitamin e , food science , antioxidant , biochemistry , biology
Low ascorbate concentrations in diabetes may be secondary to inadequate dietary vitamin C intake or may relate to the varied metabolic roles of the vitamin. To determine whether inadequate dietary intake is a factor we calculated daily vitamin C intakes using both a vitamin C questionnaire and a 4‐day food diary in a group of 30 patients with Type 2 diabetes (mean age 68.8 ± 6.9 yr, 17M/13F) and in 30 community controls (mean age 68.0 ± 5.5 yr, 12M/18F)). Measures of plasma glucose, serum fructosamine, and plasma ascorbic and dehydroascorbic acid were obtained from 20 subjects in each group. There was no significant difference in daily vitamin C intake between the two groups using both methods: food diary, 61.4 ± 28.3 (patients) vs 69.5 ± 33.4 (controls) mg; questionnaire, 54.0 ± 28.9 (patients) vs 65.0 ± 30.9 (controls) mg. Vitamin C intake derived from both methods was significantly correlated ( p < 0.001). Plasma ascorbate (30.4 ± 19.1 μol l −1 ) and dehydroascorbate (27.6 ± 6.4 μmol l −1 ) levels were significantly lower in patients vs in controls (68.8 ± 36.0 and 31.8 ± 4.8 μmol l −1 , respectively), p < 0.0001 and p < 0.01. Plasma ascorbate levels were significantly correlated with vitamin C intake derived from the food diary ( p < 0.01) and questionnaire ( p < 0.01) methods in the diabetic group only. Low ascorbate levels in diabetes appears to be a consequence of the disease itself and not due to inadequate dietary intake of vitamin C. A short vitamin C questionnaire is a convenient and reliable estimate of vitamin C intake. Vitamin C supplementation of the diabetic diet deserves further consideration.