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Research: ASTLEY and colleagues,
Listed in Issue 65
Abstract
ASTLEY and colleagues, Institute of Food Research, Norwich, UK investigated the effect of daily vitamin E supplementation on the susceptibility of plasma low-density lipoprotein (LDL) and lymphocyte DNA to oxidative damage in type 1 diabetes .
Background
Methodology
In this randomized, prospective, double-blind, placebo- controlle d trial, 42 patients with type 1 diabetes and 31 age- and sex-matched controls received oral vitamin E (400 IU) daily for 8 weeks . Measurements were made of single-strand breaks of 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 controls. Vitamin E supplementation reduced LDL oxidizability in control subjects but not in the diabetes group. Vitamin E supplementation 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 controls.
Conclusion
Plasma LDL and lymphocyte DNA appear to be more resistant to oxidative change in type 1 diabetic subjects than in controls. There was no evidence of oxidatively induced DNA or LDL change in type 1 diabetes. The results do not support the hypothesis of oxidative damage in type 1 diabetes . Furthermore, a dose of vitamin E (400 IU daily) that reduced LDL oxidative susceptibility in control subjects did not do so in patients with type 1 diabetes.
References
Astley S et al. Vitamin E supplementation and oxidative damage to DNA and plasma LDL in type 1 diabetes. Diabetes Care 22 (10): 1626-31. Oct 1999.
Comment
Again, these results disproved the hypothesis that oxidative damage to LDL and lymphocyte DNA could be alleviated by vitamin E supplementation. The surprise result was that Plasma LDL and lymphocyte DNA were in fact more resistant to oxidative change in the diabetes groups than the controls and that vitamin E had no effect upon oxidative damage in either group.