Over-the-counter anti-oxidant therapies for use in multiple sclerosis: A systematic review

Background: Anti-oxidant compounds that are found in over-the-counter (OTC) supplements and foods are gaining interest as treatments for multiple sclerosis (MS). They are widely used by patients, sometimes without a clear evidence base. Objective: We conducted a systematic review of animal and clinical research to determine the evidence for the benefits of OTC anti-oxidants in MS. Methods: Using predefined criteria, we searched key databases. Two authors scrutinized all studies against inclusion/exclusion criteria, assessed study risk-of-bias and extracted results. Results: Of the 3507 titles, 145 met criteria and included compounds, (alpha)-lipoic acid (ALA), anti-oxidant vitamins, Ginkgo biloba, quercetin, resveratrol and epigallocatechin-3-gallate (ECGC). The strongest evidence to support OTC anti-oxidants was for compounds EGCG and ALA in animal models; both consistently showed anti-inflammatory/anti-oxidant effects and reduced neurological impairment. Only vitamin E, Ginkgo biloba and ALA were examined for efficacy in pilot clinical trials with either conflicting evidence or evidence of no benefit. Conclusion: OTC anti-oxidants EGCG and ALA show the most consistent benefit, however only in preclinical studies. There is no evidence that they alter MS relapses or progression. Future work should focus on testing more of these therapies for clinical efficacy before recommending them to MS patients.