Effects of high-dose vitamin E supplementation on oxidative stress and microalbuminuria in young adult patients with childhood onset type 1 diabetes mellitus

Introduction The aim of this study was to evaluate the effects of high‐dose vitamin E supplementation (1200 mg/day) on reducing both microalbuminuria (MA) and oxidative stress in patients with type 1 diabetes mellitus (T1DM) and persistent MA. Methods We performed a 12‐month, randomized, placebo‐controlled, double‐blind cross‐over trial in ten Caucasian young adults (7m/3f; mean age 18.87 ± 2.91 years) with T1DM and persistent MA. At baseline and at end of the treatment period, determination of albumin excretion rate (AER) and HbA1c and evaluation of the oxidant/antioxidant status were performed. Results At the beginning of the study, AER and HbA1c were not significantly different between the vitamin E and placebo group. No differences in terms of oxidant and antioxidant status were found between the two groups. This was associated with no significantly different urinary VEGF and TGF‐β levels. After 6 months, no significant differences in AER were observed between the two groups (p = 0.59). However, plasma and LDL‐vitamin E content were significantly higher in the vitamin E group compared to the placebo group (p = 0.0001 and p = 0.004, respectively). This was associated with a significantly longer lag phase (p = 0.002) and lower MDA (p = 0.049). However, no statistically significant differences were detected in terms of VEGF and TGF‐β urinary levels. Conclusion These data demonstrate that high‐dose vitamin E supplementation reduces markers of oxidative stress and improves antioxidant defence in young patients with T1DM. However, although it positively affects the oxidant/antioxidant status, vitamin E supplementation does not reduce AER in patients with T1DM and persistent MA. Copyright © 2007 John Wiley & Sons, Ltd.