The effects of probiotics supplementation on serum markers of oxidative stress in relapsing-remitting multiple sclerosis: a randomised, double-blind, placebo-controlled clinical trial

Oxidative stress is a significant contributor to neuronal damage in multiple sclerosis (MS), marked by an imbalance in reactive oxygen species and antioxidant defences. Probiotics may modulate oxidative stress and improve antioxidant levels. This double-blind, randomised, placebo-controlled clinical trial aimed to evaluate the effects of probiotics supplementation on serum oxidative stress markers and endogenous antioxidants in patients with relapsing-remitting MS (RRMS). Ninety RRMS patients with expanded disability status scale [EDSS] < 4 were randomised into two groups: a probiotics group (Lactocare®) and a placebo group, and received the interventions twice daily for four months. Serum levels of oxidative stress markers (malondialdehyde [MDA]), endogenous antioxidants (glutathione peroxidase [GPx] activity, superoxide dismutase [SOD], catalase activity [CAT], glutathione [GSH]), and total antioxidant capacity (TAC) were measured at baseline and post-treatment. Fifty-five patients, including 26 patients in the probiotic group and 29 patients in the placebo group, completed the study. Both groups showed significant within-group improvements in GPx activity, SOD, and GSH levels, as well as reductions in MDA levels ( P < 0.05); however, no significant between-group differences were found for any markers ( P > 0.05). TAC and CAT levels remained unchanged in both groups. Findings of this study did not support the evidence for antioxidant effects of probiotics supplementation in RRMS patients, and its effects on oxidative stress markers in RRMS patients are found to be comparable to placebo. Iranian Registry of Clinical Trials: IRCT20220713055465N2, registration date: 2023.5.9.