Clinical and metabolic response to probiotic administration in people with Parkinson's disease: A randomized, double-blind, placebo-controlled trial

Background & aims: The investigation was done to assess the impacts of probiotic supplementation on movement and metabolic parameters in individuals with Parkinson's disease (PD).

Methods: The study is randomized, double-blind, placebo-controlled clinical trial, which was done in sixty people with PD. Individuals were randomly divided into two groups in order to take either 8 × 10⁹ CFU/day probiotic or placebo (n = 30 each group) that lasted 12 weeks. The Movement Disorders Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS) was recorded at pre- and post-intervention.

Results: Compared with the placebo, consuming probiotic decreased MDS-UPDRS (-4.8 ± 12.5 vs. +3.8 ± 13.0, P = 0.01). Probiotic supplementation also reduced high-sensitivity C-reactive protein (-1.6 ± 2.5 vs. +0.1 ± 0.3 mg/L, P < 0.001) and malondialdehyde (-0.2 ± 0.3 vs. +0.1 ± 0.3 μmol/L, P = 0.006), and enhanced glutathione levels (+40.1 ± 81.5 vs. -12.1 ± 41.7 μmol/L, P = 0.03) in comparison with the placebo. Additionally, probiotic consumption resulted in a statistically significant reduction in insulin levels (-2.1 ± 3.4 vs. +1.5 ± 5.1 μIU/mL, P = 0.002) and insulin resistance (-0.5 ± 0.9 vs. +0.4 ± 1.2, P = 0.002), and a statistically significant rise in insulin sensitivity (+0.01 ± 0.02 vs. -0.006 ± 0.02, P = 0.01) in comparison with the placebo. Probiotic intake had no any significant impact on other metabolic profiles.

Conclusions: Our study evidenced that 12 weeks of probiotic consumption by individuals with PD had useful impacts on MDS-UPDRS and few metabolic profiles. Registered under ClinicalTrials.gov Identifier no. http://www.irct.ir: IRCT2017082434497N4.