BACKGROUND: Alpha-lipoic acid is a naturally occurring antioxidant widely sold over-the-counter as a dietary supplement in pharmacies and natural food stores. It has also been used in Germany for 45 years to treat diabetic polyneuropathy, a type of nerve dysfunction.
RESEARCH: Researchers analyzed four major clinical trials on alpha-lipoic acid in the treatment of diabetic polyneuropathy. In these studies, 716 people were treated with alpha-lipoic acid and 542 received placebos. Although alpha-lipoic acid is frequently taken orally, these studies administered alpha-lipoic acid intravenously (600 mg daily for three weeks). Researchers tracked the patients' symptoms, including their total symptom score, pain, burning, and numbness.
RESULTS: Overall, 52.7 percent of the patients responded to alpha-lipoic acid, compared with only 36.9 percent for placebo. Patients receiving alpha-lipoic acid had notable clinical improvements, including reductions in pain, after eight days. After three weeks, patients receiving alpha-lipoic acid had a 24.1 percent improvement in their total symptom score and a 16 percent improvement in pain and other symptoms in their legs compared to patients taking the placebos. Pain, burning, and numbness also decreased more in patients receiving alpha-lipoic acid than those getting placebos.
IMPLICATIONS: The researchers concluded from their collective analysis of four studies that alpha-lipoic acid is safe and may significantly improve nerve disease complications of diabetes.
Ziegler D, Nowak H, Kempler P, et al. Treatment of symptomatic diabetic polyneuropathy with the antioxidant alpha-lipoic acid: a meta-analysis. Diabetic Medicine, 2004;21:114-121.
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