Armaghan Vaezlari,1,*
1. Physiology research center, Medical university of Jondi Shapour Ahvaz
Introduction: Diabetes is a chronic metabolic disorder that continues to present as a major health problem worldwide highlighting the importance of continued research and the need for novel methods to both prevent and treat this pandemic. This disease is characterized by absolute or relative deficiencies in insulin secretion and/or insulin action and is associated with chronic hyperglycemia and disturbances of carbohydrate, lipid, and protein metabolism. Recent evidence suggests that oxidative stress may contribute to the pathogenesis of type 2 diabetes mellitus by increasing insulin resistance or impairing insulin secretion. This has prompted investigations in the use of antioxidants as a complementary therapeutic approach. In this review we briefly summarize oxidative mechanisms implicated in diabetic complications.
Methods: In order to find relevant studies to the research question, a literature search using PubMed (last ten years) was performed using the following terms “Diabetes, “Reactive oxygen species (ROS),” “Oxidative marker,” “Oxidative stress (OS),” “Antioxidant”, “vitamin E”, “vitamin C” individually or/and in various combinations to retrieve the relevant literatures. This search was limited to human clinical trials.
Results: Results from previous studies showed that antioxidants may inhibiting the formation of ROS or scavenge free radicals or increase the antioxidants defense enzyme capabilities. In a prospective cohort study, vitamin C intake was found to be significantly lower among incident cases of type 2 diabetic patients. In three prospective observational studies, serum α-tocopherol levels were associated with lower risk of diabetes mellitus. In another prospective study cohort of more than 4000 non-diabetic subjects over 23 years, vitamin E intake was significantly associated with a reduced risk of type 2 diabetes mellitus. However, some clinical studies have failed to show a significant diabetes-related increase in oxidative stress markers and the beneficial impacts of antioxidants on the diabetes complications.
Conclusion: Antioxidants such as N-acetylcysteine, vitamin C, and α-lipoic acid are effective in reducing diabetic complications, indicating that it may be beneficial either by ingestion of natural antioxidants or through dietary supplementation. Therefore, routine vitamin or mineral supplementation is not generally recommended and the safety and efficacy of antioxidant supplementation in any future treatment, remains to be established.