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

Abstract

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.

Glycemic control, micronutrients and some metabolic enzyme activity in type 2 diabetes

“…28 High but physiologic concentrations of ascorbic acid can directly inhibit erythrocyte aldose reductase thus preventing intracellular accumulation of sorbitol, or its sequelae, thereby inhibiting the progression of chronic diabetic complications; this is the rationale for the use of oral vitamin C supplements in diabetes. 9 Vitamin C as a result of its structural similarity to glucose can compete with it to reduce haemoglobin glycosylation in patients with type 2-diabetes. The reduction of glycosylated haemoglobin can reflect the decrease of total glycosylation of proteins.…”

“…9 interconnecting systems of antioxidant micronutrients (minerals) and enzymes are also present to accomplish the body's defence against oxidative stress. Vitamin C is structurally similar to glucose and can replace it in many chemical reactions, and thus is effective in prevention of non-enzymatic glycosylation of proteins.…”

Vitamin C in the Treatment and/or Prevention of Obesity

“…Moreover, it has been reported that a chronic VC administration improved whole body glucose disposal and nonoxidative glucose metabolism (63). Besides, additional positive effects of VC on these carbohydrate metabolism markers have been demonstrated in patients following pharmacological treatments in comparison with those in the placebo group, suggesting a possible use of this vitamin in combination with drugs (86).…”

Dietary antioxidant capacity and risk of type 2 diabetes in the large prospective E3N-EPIC cohort

“…Increasing evidence from both experimental and clinical studies suggests that oxidative stress plays a major role in the pathogenesis of type 2 diabetes: abnormally high levels of free radicals and the simultaneous decline of antioxidant defence mechanisms can lead to damage of cellular organelles and enzymes, increased lipid peroxidation and development of insulin resistance [3][4][5]. Moreover, previous studies have highlighted how increased intake of common dietary antioxidants such as vitamin E and vitamin C increase insulin sensitivity, reduce fasting and post-meal blood glucose and improve HbA 1c levels [6,7]. Other authors have reported a statistically significant decrease in total antioxidant status and increase in levels of oxidative stress markers in individuals with type 2 diabetes compared with healthy individuals, and have suggested that these levels could be considered markers of early disease and predictors of type 2 diabetes complications [8].…”