Vitamin C is an important antioxidant in human, capable of scavenging oxygen-derived free radicals. 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. In addition, vitamin C acts as a regulator of catabolism of cholesterol to bile acid in guinea pig and has been demonstrated to be an important factor in lipid regulation. Ness et al showed beneficial effects of vitamin C on lipids in human.
Several studies showed decreased basal vitamin C level in diabetic patients and also it is suggested that oxidative stress is increased in diabetes. Most patients with diabetes have lipid metabolism disorders; most prevalent forms are decreased high density lipo-protein (HDL) and increased triglyceride. High doses of ascorbic acid (2 g/day) have been shown to improve blood glucose regulation and reduce serum cholesterol and triglyceride in type 2 diabetes patients.