Vitamin E supplementation and oxidative damage to DNA and plasma LDL in type 1 diabetes.
OBJECTIVE
To determine the effect of 400 IU/day of the antioxidant vitamin E on the susceptibility of plasma LDL and lymphocyte DNA to oxidative damage in type 1 diabetes.


METHODS
We studied 42 patients with type 1 diabetes and 31 age- and sex-matched control subjects in a randomized prospective double-blind placebo-controlled trial by using 400 IU/day of oral vitamin E for 8 weeks. Measurements were made of single-strand breaks in lymphocyte DNA at baseline and after hydrogen peroxide-induced stress (comet assay) and of copper-induced LDL oxidization and plasma antioxidant profiles.


RESULTS
Plasma LDL and lymphocyte DNA were more resistant to induced oxidative change in the type 1 diabetes group than in control subjects. Vitamin E supplementation reduced LDL oxidizability in the control subjects but not in the type 1 diabetes group and had no effect on oxidative DNA damage in either group. The type 1 diabetes group had a significantly poorer plasma antioxidant profile with lower mean serum concentrations of alpha-tocopherol and most carotenoids than control subjects.


CONCLUSIONS
Plasma LDL and lymphocyte DNA appear to be more resistant to oxidative change in type 1 diabetic subjects than in control subjects, and there was no evidence of oxidatively induced DNA or LDL change in type 1 diabetes. This study does not support the hypothesis of oxidative damage in these patients, and a dose of vitamin E (400 IU/day) that reduced LDL oxidative susceptibility in control subjects did not do so in patients with type 1 diabetes.
Astley
S
S
Institute of Food Research, Norwich, U.K.
Langrish-Smith
A
A
Southon
S
S
Sampson
M
M
D000284:Administration, Oral; D000328:Adult; D000975:Antioxidants / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000627:therapeutic use; D001786:Blood Glucose / Q000378:metabolism; D002784:Cholesterol / Q000097:blood; D008076:Cholesterol, HDL / Q000097:blood; D020552:Comet Assay; D004247:DNA / Q000097:blood; D004249:DNA Damage; D003922:Diabetes Mellitus, Type 1 / Q000097:blood* / Q000188:drug therapy*; D019587:Dietary Supplements; D004311:Double-Blind Method; D005260:Female; D006442:Glycated Hemoglobin / Q000032:analysis; D006801:Humans; D008077:Lipoproteins, LDL / Q000097:blood*; D008214:Lymphocytes / Q000187:drug effects / Q000378:metabolism; D008297:Male; D011446:Prospective Studies; D012016:Reference Values; D014280:Triglycerides / Q000097:blood; D014810:Vitamin E / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000627:therapeutic use*; D014815:Vitamins / Q000097:blood*
D000975:Antioxidants; D001786:Blood Glucose; D002784:Cholesterol; D008076:Cholesterol, HDL; D004247:DNA; D006442:Glycated Hemoglobin; D008077:Lipoproteins, LDL; D014280:Triglycerides; D014810:Vitamin E; D014815:Vitamins; C099252:oxidized low density lipoprotein