Research Article: Supplementation of Vitamin C Reduces Blood Glucose and Improves Glycosylated Hemoglobin in Type 2 Diabetes Mellitus: A Randomized, Double-Blind Study

Date Published: December 28, 2011

Publisher: Hindawi Publishing Corporation

Author(s): Ganesh N. Dakhale, Harshal V. Chaudhari, Meena Shrivastava.


No study has ever examined the effect of vitamin C with metformin on fasting (FBS) and postmeal blood glucose (PMBG) as well as glycosylated hemoglobin (HbA1c) in the treatment of type 2 diabetes mellitus (DM). The goal was to examine the effect of oral vitamin C with metformin on FBS, PMBG, HbA1c, and plasma ascorbic acid level (PAA) with type 2 DM. Seventy patients with type 2 DM participated in a prospective, double-blind, placebo-controlled, 12-week study. The patients with type 2 DM were divided randomly into placebo and vitamin C group of 35 each. Both groups received the treatment for twelve weeks. Decreased PAA levels were found in patients with type 2 diabetes mellitus. This level was reversed significantly after treatment with vitamin C along with metformin compared to placebo with metformin. FBS, PMBG, and HbA1c levels showed significant improvement after 12 weeks of treatment with vitamin C. In conclusion, oral supplementation of vitamin C with metformin reverses ascorbic acid levels, reduces FBS, PMBG, and improves HbA1c. Hence, both the drugs in combination may be used in the treatment of type 2 DM to maintain good glycemic control.

Partial Text

Diabetes mellitus (DM) is one of the major metabolic disorders associated with great deal of morbidity and economic cost. Apart from hyperglycemia, DM is also characterized by oxidative stress, inflammation, and insulin resistance [1]. Several investigators have implicated the role of free radical-mediated pathology in diabetes mellitus [2, 3]. The illness has poor outcome in spite of the best currently available treatments. Hence, development of novel strategies to improve the outcome will be of great benefit. Presently available oral hypoglycemic agents do not show marked improvement in oxidative stress in diabetic patients [4]. Ascorbic acid (vitamin C), an antioxidant vitamin, plays an important role in protecting free radical-induced damage. Previous study has shown decrease in basal vitamin C level in type 2 DM [5]. Vitamin C is structurally similar to glucose and can replace it in many chemical reactions and thus is effective for prevention of nonenzymatic glycosylation of protein [6].

The mean age of the patients with diabetes mellitus in vitamin C group (48.33 ± 1.39 years) and placebo group (45.88 ± 1.42 years) was not significantly different from each other (Table 1). Fasting, postmeal blood glucose, and plasma ascorbic acid levels did not differ among subjects before receiving placebo and vitamin C treatment (P > 0.05).