Diabetes independently imposes such stress upon the heart and vascular system that the diabetic frequently succumbs from a cardiovascular event rather than the disease itself.
Hyperglycemia and excesses of ineffective insulin cause rampant free-radical activity, lipid peroxidation, glycation (the pathological union of protein and sugar), and increased inflammation (Sears 1999). Impotence, depression, cataracts, glaucoma, atherosclerosis, and dementia often negatively impact a diabetic's quality of life.
Vitamin E's antioxidant properties and its ability to enhance insulin's responsiveness are but a few of the reasons the nutrient should be included in a diabetic protocol. This was clearly evidenced in a 4-month study reported in the American Journal of Clinical Nutrition with subjects receiving (approximately) 900 mg of vitamin E a day. The researchers assessed how well 15 Type II diabetics and 10 healthy controls tolerated glucose before and after vitamin E supplementation. In healthy subjects, glucose removal from the blood increased 17%. In diabetics, total glucose removal increased 47% and nonoxidative glucose metabolism increased 63%. The study established that pharmacologic doses of vitamin E in Type II diabetes improve insulin's action and reduce free-radical activity (Paolisso 1993b).
Vascular endothelial dysfunction (an early marker of atherosclerosis) has been demonstrated in Type II diabetes mellitus. It appears hyperglycemia is particularly destructive to endothelial cells because it increases oxidative stress and impairs the activity of nitric oxide, the endothelial derived relaxing factor (Giugliano et al. 1995). Oxidative injury may be increased in diabetes mellitus because of a weakened defense due to reduced endogenous antioxidants (vitamin E and reduced glutathione). With compromised nitric oxide activity, diabetic-cardiovascular complications (smooth muscle proliferation, platelet activation/aggregation, and leukocyte adherence to the endothelium) are compounded.
Some of the strongest recent evidence of a vitamin E-diabetes benefit comes from researchers at the University of Texas Southwestern Medical Center in Dallas. Scientists found that vitamin E (1200 IU daily) reduced the risk of heart failure in 75 diabetics by curtailing vascular inflammation in the heart. Left unchecked, inflammation can cause cardiac vessels to swell, promoting cardiovascular disease. Dr. Sridevi Devaraj, assistant professor of pathology and lead researcher, termed the end results of the study very encouraging (Devaraj 2001).
Last, elevated levels of CRP, an inflammatory marker, have recently been found to predict the development of Type II diabetes. A newer finding relating to the functions of vitamin E is that high dose vitamin E lowers CRP. Administering 1200 IU of alpha-tocopherol (daily for 3 months) lowered CRP levels by 30%. CRP levels remained reduced 2 months postsupplementation. By preventing vascular inflammation, many of the complications arising from diabetes are overcome (Devaraj et al. 2000).