The journal Diabetes & Metabolic Syndrome recently published a systematic review and meta-analysis on the use of alpha-lipoic acid (ALA) in the management of diabetic polyneuropathy (DPN). Fifteen randomized and controlled trials were included, and of the 23 outcomes evaluated, 19 showed a significant favorable effect of ALA versus placebo or other treatments, typically at either the 600 or 1200 mg daily dose. Overall, over 2200 participants were included in the analysis, with an average follow-up of nearly 10 months.ALA is well recognized for its antioxidant effects, but this review sought to tease out specific benefits to better elucidate its mechanisms and potentially personalize its use. For example, in addition to reducing oxidative stress, it also improves mitochondrial function and glucose utilization, enhances nitric oxide-mediated endothelium-dependent vasodilation, and inhibits inflammatory pathways, specifically the nuclear factor kappa B (NF-κB) pathway.
The primary outcomes were grouped into one of two categories: clinical manifestations of DPN, including Total Symptom Score (TSS) domains (e.g., burning, paresthesia, etc.), and metabolic indicators related to DPN, such as glycated hemoglobin and fasting glucose levels. A number of secondary outcomes were also evaluated, including oxidative stress biomarkers, neurophysiological measures (e.g., nerve conduction velocities), etc.
Among the clinical manifestations, pain, perhaps the most disabling symptom of DPN, was significantly reduced with ALA (-0.78 overall standard mean difference (SMD), as was paresthesia (-0.99 SMD), TSS burning pain (-0.68 SMD), and TSS numbness (-0.25 to -0.34 SMD at 600 vs. 1200 mg). Glycated hemoglobin and fasting glucose levels were not significantly reduced. Most quality-of-life scales and physical function improved with ALA, particularly at the 600 mg dose. Of course, larger, longer-term studies would help further elucidate the benefits of ALA for DPN.