Probiotics for improving motor and nonmotor symptoms of Parkinson’s disease Original paper

In this meta-analysis, supplementation with probiotics in adults with Parkinson’s disease improved motor symptoms, constipation-related parameters, and anxiety and depression symptoms.

The effect of supplementation with probiotics on motor and nonmotor symptoms of Parkinson’s disease (PD).

A total of 663 men and women (average ages of 66–71) with PD.

A meta-analysis of 9 randomized controlled trials was performed. The trials were conducted in China (5 trials), Malaysia (2 trials), Italy (1 trial), and Iran (1 trial). Three trials administered single-species probiotics, and 6 trials administered multispecies probiotics. In most trials, the comparator was a placebo. The intervention duration ranged from 2 to 12 weeks.

The outcomes were motor symptoms measured with the Movement Disorder Society Unified Parkinson's Disease Rating Scale part 2 (activities of daily living) and part 3 (motor examination) (MDS-UPDRS II and III) scores; constipation-related parameters measured with the Patient Assessment of Constipation Quality of Life (PAC-QOL) score, Bristol scores, bowel movements scores, complete spontaneous bowel movements (CSBM) score, and laxative use; cognitive function measured with the Mini-Mental State Examination (MMSE) score; anxiety measured with the Hamilton Anxiety Rating Scale (HAM-A); depression measured with the Hamilton Depression Scale-17 (HADM-17); nonmotor symptoms measured with the Non-Motor Symptoms Scale (NMSS); disease-specific quality of life measured with the 39-item Parkinson's Disease Questionnaire (PDQ-39), and Activities of Daily Living (ADL) scores; and glutathione concentrations (low levels of which have been associated with higher PD severity).

Supplementation with probiotics improved MDS-UPDRS III scores (small effect size), PAQ-QOL scores (large effect size), Bristol scores (medium effect size), bowel movement scores (large effect size), CSBM scores (medium effect size), HAM-A scores (small effect size), and HADM-17 scores (small effect size). It also decreased the use of laxatives (small effect size) and increased glutathione concentrations (medium effect size).

The risk of bias was low in 6 trials and unclear in 3 trials.