Oxidative stress during insulin resistance in prediabetes : a review on role of antioxidants

Abstract

Oxidative stress is one of the major causal factors behind insulin resistance during prediabetes. It can impair insulin signalling by triggering stress activated signaling pathways and can also directly oxidize and damage the proteins of these pathways. Although cells have impressive stock of antioxidant enzymes and minor antioxidant moieties, these agents may not be adequate to maintain the redox balance during oxidative stress. The important functional antioxidant vitamins for tissue protection from excess free radicals comprises vitamin C, E and A. Vitamin C can improve insulin resistance by altering endothelial function and reducing oxidative stress. Vitamin E is an excellent trap for peroxyl radicals which suppresses ROS production in the pancreas, preserves pancreatic β cell function and maintains structural integrity of pancreatic islet cells. Vitamin A prevents tissue oxidative damage as well as exhibits a regenerative role in the pancreas. Like vitamins,  minerals play  a crucial role during oxidative stress and insulin resistance. Zinc is crucial for insulin actions and carbohydrate metabolism. Chromium activates insulin receptors through the oligopeptidechromudulin, which occurs in the insulin sensitive cells that binds to the insulin receptor, thereby increasing insulin signal transduction and sensitivity. Selenium up regulates glutathione peroxidase activity can inhibit NF-kappa B activation. The risk of diabetes and its complications will be more with elevating oxidative stress. Interventions with these antioxidants have proven beneficial role in reducing oxidative stress which can be utilized for reduction of insulin resistance in prediabetes.