Effect of oral vitamin E (alpha-tocopherol) supplementation on vascular endothelial function in Type 2 diabetes mellitus

Diabet Med. 1999 Apr;16(4):304-11. doi: 10.1046/j.1464-5491.1999.00049.x.


Aims: Vascular endothelial dysfunction, an early marker of atherosclerosis, has been demonstrated in Type 2 diabetes mellitus (DM). Vitamin E preserves endothelial function in animal models of diabetes and reduces cardiovascular risk. We examined endothelial function and the effect of vitamin E supplements in uncomplicated Type 2 DM.

Methods: Forty-eight subjects with Type 2 DM and 21 controls had endothelial function assessed using forearm venous occlusion plethysmography with endothelium-independent (sodium nitroprusside) and dependent (acetylcholine, bradykinin) vasodilators. Those with diabetes received 1600 i.u. daily oral alpha-tocopherol or placebo, double-blind for 8 weeks, and had endothelial function reassessed.

Results: The diabetic group had higher HbA1c (6.9+/-1.4 vs 4.8+/-0.6%; P<0.01) and systolic (145+/-15 vs. 130+/-16 mm Hg; P<0.01) but not diastolic blood pressure (79+/-8 vs. 76+/-9 mm Hg; P = 0.15). There was blunted vasodilation to acetylcholine (15 microg/min; P<0.01) in subjects with diabetes. Vasodilation to sodium nitroprusside and bradykinin was similar (all P>0.1). Alpha-tocopherol did not affect vasodilation to nitroprusside (P>0.1), acetylcholine (P>0.1) or bradykinin (P>0.1).

Conclusions: There may be receptor-specific endothelial dysfunction in subjects with uncomplicated Type 2 DM. This is not improved by treatment with alpha-tocopherol.

Publication types

  • Clinical Trial
  • Controlled Clinical Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Administration, Oral
  • Case-Control Studies
  • Diabetes Mellitus, Type 2 / drug therapy*
  • Diabetes Mellitus, Type 2 / physiopathology
  • Dietary Supplements*
  • Double-Blind Method
  • Endothelium, Vascular / physiopathology*
  • Female
  • Forearm / blood supply
  • Humans
  • Male
  • Middle Aged
  • Regional Blood Flow / drug effects
  • Vitamin E / therapeutic use*


  • Vitamin E