Nutraceutical Approach to Peripheral Neuropathies: Evidence from Clinical Trials

Peripheral neuropathies are damages to or disorders of the peripheral nervous system including radiculopathies, plexopathies, mono-, multi- and polyneuropathies. The etiopathogenetic mechanisms include genetic, traumatic, toxic, metabolic, infectious, nutritional, inflammatory and paraneoplastic causes. The treatment of peripheral neuropathies should primarily address their contributing causes. However, symptomatic therapy is also key in these conditions, particularly in pain relief. Several nutraceuticals have been used in the treatment of peripheral neuropathies and seem promising, due to assumed neurotrophic action, low toxicity and favorable metabolic profile. We performed a review of the literature to evaluate safety and effectiveness of nutraceutical compounds in peripheral neuropathies, focusing on the single agents for which randomized controlled trials versus placebo were performed. Vitamin B complex, alpha lipoic acid, L-acetylcarnitine,vitamin E and Coenzyme Q proved effective to different extents in neuropathic pain in polyneuropathies. They all proved less consistently effective on other neuropathic symptoms, neuropathic signs and neurophysiological parameters. All the considered compounds were tolerable even for long periods, however alpha lipoic acid at doses equal or larger than 1200 mg/die was associated with nausea and vomiting in a large number of patients.