Metabolic benefits deriving from chronic vitamin C supplementation in aged non-insulin dependent diabetics.
OBJECTIVE
Our study investigated the metabolic benefits deriving from chronic pharmacological vitamin C administration in aged non-insulin dependent (Type II) diabetic patients.


METHODS
Forty type II diabetic patients (age: 72 +/- 0.5 years) underwent placebo and vitamin C (0.5 g twice daily) administration in double-blind, randomized, cross-over fashion. All patients were treated by oral hypoglycaemic agents which continued throughout the study. After baseline observations, treatment periods lasted 4 months and were separated by a 30-day wash-out period.


RESULTS
Patients' antropometric data were unchanged throughout the study. Chronic vitamin C administration vs placebo was associated with a significant decline in fasting plasma free radicals (0.26 +/- 0.06 vs 0.49 +/- 0.07 p < 0.03) and insulin (90 +/- 4 vs 73 +/- 6 pmol/L p < 0.04), total- (7.3 +/- 0.5 vs 5.8 +/- 0.4 mmol/L p < 0.03), LDL-cholesterol (5.6 +/- 0.6 vs 4.1 +/- 0.3 mmol/L p < 0.05) and triglycerides (2.58 +/- 0.07 vs 2.08 +/- 0.04 mmol/L p < 0.04) levels. In 20 patients, chronic vitamin C administration improved whole body glucose disposal and nonoxidative glucose metabolism. Percent increase in plasma vitamin C levels correlated with the percent decline in plasma LDL-cholesterol (r = 0.44; p < 0.007) and insulin levels (r = 0.42; p < 0.006). Finally percent increase in plasma vitamin C levels was correlated with the percent decline in plasma free radicals and increase in GSH levels.


CONCLUSIONS
Chronic vitamin C administration has beneficial effects upon glucose and lipid metabolism in aged non-insulin dependent (type II) diabetic patients.
Paolisso
G
G
Department of Geriatric Medicine and Metabolic Diseases, II University of Naples, Italy.
Balbi
V
V
Volpe
C
C
Varricchio
G
G
Gambardella
A
A
Saccomanno
F
F
Ammendola
S
S
Varricchio
M
M
D'Onofrio
F
F
D000368:Aged; D001205:Ascorbic Acid / Q000494:pharmacology / Q000627:therapeutic use*; D018592:Cross-Over Studies; D003924:Diabetes Mellitus, Type 2 / Q000178:diet therapy* / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005260:Female; D005527:Food, Fortified; D005947:Glucose / Q000378:metabolism*; D015309:Glucose Clamp Technique; D006442:Glycated Hemoglobin / Q000032:analysis; D006801:Humans; D007328:Insulin / Q000097:blood; D008055:Lipids / Q000097:blood*; D008297:Male
D001205:Ascorbic Acid; D005947:Glucose; D006442:Glycated Hemoglobin; D007328:Insulin; D008055:Lipids