Alpha-lipoic acid protects beta-cell function and improves insulin sensitivity

A small clinical study shows improvements in insulin secretion and insulin sensitivity and prevention of oxidative stress with the use of alpha-lipoic acid in obese persons with impaired glucose tolerance (IGT), according to Chinese researchers.

Obese patients often have elevated levels of free fatty acids, which may increase the formation of reactive oxygen species, says Ping Han, MD, department of endocrinology, Shengjing Hospital, Liaoning, China. Oxidative stress plays an important role in insulin resistance, leading to beta-cell dysfunction.

Alpha-lipoic acid is a powerful antioxidant and a scavenger of reactive oxygen species and has been prescribed in Germany for more than 30 years for the treatment of diabetes complications, mostly diabetic polyneuropathy, notes Dr. Han.

In this study, alpha-lipoic acid was investigated in a dosage of 600 mg daily, given intravenously for 14 days, in 10 obese patients with IGT. Six obese patients with normal fasting glucose served as controls.

First-phase insulin secretion and second-phase insulin secretion were evaluated with a 2-hour hyperglycemic clamp before and after the completion of therapy in the obese IGT patients. First-phase insulin secretion increased by 42% (p<0.01) and second-phase insulin secretion increased by 33% (p<0.01) after the 14 days of therapy.

The insulin sensitivity index and glucose disposition index also increased significantly (p<0.05 for both) after treatment. Alpha-lipoic acid also prevented oxidative stress and inflammation, as evidenced by decreases in levels of interleukin-6 and tumor necrosis factor-alpha.