Effects of 3-month treatment with the antioxidant alpha-lipoic acid in diabetic peripheral neuropathy.

Alpha lipoic acid is a natural antioxidant that has been suggested to improve symptoms of diabetic neuropathy. To assess these potential benefits, a cohort of 26 type 2 diabetic patients with symptomatic peripheral neuropathy (stage 2) received a daily dose of 600 mg alpha-lipoic acid, and were followed for a 3 month-period. No dropout was noted. At the end of the follow-up period, in 20 subjects (76.9%) there was a 1-stage regression of somatic neuropathy (from symptomatic to asymptomatic neuropathy, and in 5 patients (19.2%) no signs of neuropathy were found. The nerve conduction velocity of motor fibers improved from 36.8 (95% Confidence Interval CI = 30.9-42.7) meters/second to 41.3 (95% CI = 39.5-43.0) meters/second (p = 0.049, paired t test). Mean blood glucose measured was significantly lower at 3 months than at baseline [197.9 (95% CI = 170.1-225.7) versus 162.2 (95% CI = 146.1-178.2 mg/dl, p = 0.02, paired t test)]. In a multiple linear regression model with age. sex, body mass index, diabetes duration and the difference between blood glucose values at 3 months and at baseline as explanatory variables, the increment in nerve conduction velocity was not accounted for by the improved glycemic control. Women, thinner and younger patients tended to benefit more from the treatment in terms of nervous conduction velocity improvement. In conclusion, alpha-lipoic acid seems to be efficient and safe in the treatment of diabetic peripheral neuropathy, improving both clinical manifestations and nerve conduction velocity. Placebo controlled clinical trials are needed to further define the role of this new medication in the treatment of diabetic neuropathies.