Double-blind, randomised study of the effect of combined treatment with vitamin C and E on albuminuria in Type 2 diabetic patients.
OBJECTIVE
Elevated levels of urinary albumin excretion rate (AER) predict high risk for progressing to end-stage renal disease. In streptozotocin-induced diabetes, supplementation with vitamin C or E reduces albuminuria and glomerular hypertrophy. We tested the hypothesis that supplementation of both vitamin C and E in pharmacological doses lowers AER in Type 2 diabetic patients with persistent micro/macroalbuminuria.


METHODS
Thirty Type 2 diabetic patients with AER 30-300 mg/24 h were included in a double-blind randomised, cross-over trial. Patients received vitamin C (1250 mg) and vitamin E (680 IU) per day or matching placebo for 4 weeks with a 3-week wash-out period between treatment periods in random order.


RESULTS
Combined treatment with vitamin C and E reduced AER by 19% (95% CI 6-34%) (p = 0.04), geometric mean 197 mg/24 h (95% CI 114-341 mg/24 h) vs. 243 mg/24 h (146-404 mg/24 h). No changes were seen in serum creatinine, haemoglobin A1C or blood pressure. Fasting plasma concentrations of vitamin C and E increased in all patients during active treatment (mean vitamin C 79.4 micromol/L (SD 27.8) vs. 41.9 micromol/L (18.4) and vitamin E 47.0 micromol/L (19.8) vs. 29.5 micromol/L (15.3), P < 0.000001). Except for two patients that started additional blood pressure lowering treatment during the run-in period, no changes in medication, food and exercise habits or in the number of smokers occurred during the study.


CONCLUSIONS
Short-term treatment with vitamin C and E in pharmacological doses lowers AER in Type 2 diabetic patients with micro/macroalbuminuria. Further long-term, large-scale studies of this albuminuria reducing treatment modality are warranted.
Gaede
P
P
Steno Diabetes Center, Niels Steensens Vej 2, 2820 Gentofte, Denmark. p.gaede@dadlnet.dk
Poulsen
H E
HE
Parving
H H
HH
Pedersen
O
O
D000419:Albuminuria / Q000188:drug therapy*; D001205:Ascorbic Acid / Q000008:administration & dosage / Q000097:blood / Q000627:therapeutic use*; D018592:Cross-Over Studies; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy*; D004311:Double-Blind Method; D004359:Drug Therapy, Combination; D005215:Fasting; D005260:Female; D006442:Glycated Hemoglobin / Q000032:analysis; D006801:Humans; D008297:Male; D008875:Middle Aged; D010919:Placebos; D014810:Vitamin E / Q000008:administration & dosage / Q000097:blood / Q000627:therapeutic use*; D024502:alpha-Tocopherol / Q000008:administration & dosage / Q000097:blood / Q000627:therapeutic use*
D001205:Ascorbic Acid; D006442:Glycated Hemoglobin; D010919:Placebos; D014810:Vitamin E; D024502:alpha-Tocopherol