The use of vitamin E in type 2 diabetes mellitus.

Diabetes mellitus has assumed epidemic proportions in most parts of the world, and it is a major source of morbidity in developed countries. In addition, in several instances, diabetes is associated with a variety of metabolic abnormalities, including abdominal obesity, insulin resistance, hypertension, dyslipidemia, and hyperglycemia. There is considerable evidence that hyperglycemia causes the generation of reactive oxygen species (ROS), ultimately leading to increased oxidative stress in a variety of tissues. In the absence of an appropriate compensatory response by the endogenous antioxidants, such as vitamins C and E, catalase, glutathione, and superoxide dismutase, oxidative stress dominates, resulting in the activation of stress-sensitive intracellular signaling pathways. One of the major consequences is the generation of gene products that cause cellular damage and are ultimately responsible for the late complications of diabetes. The ability of antioxidants to protect against the effects of hyperglycemia in vitro, along with the clinical benefits often reported following antioxidant therapy, supports a causative role of oxidative stress in mediating and/or worsening these abnormalities. This review will focus on the critical assessment of the literature as it relates to the association between oxidative stress and diabetes, followed by the role of oxidative stress in the complications of type 2 diabetes mellitus. Finally, a review of the use of the antioxidant vitamin E will be provided in diabetic patients by assessing and evaluating some of the clinical trials in the literature.