Randomized controlled trial of probiotics and vitamin B₃ on gut microbiome and quality of life in people with Parkinson's disease

Abstract

Evidence suggests that administration of probiotics and vitamin B₃ may improve multiple symptoms and outcomes of Parkinson’s Disease through alterations in gut microbiome. Therefore, the purpose of this dissertation is to determine whether a 12-week placebo-controlled randomized clinical trial is able to observe changes in constipation, drug efficacy, neuroendocrine levels, and indicators of quality of life in people with Parkinson’s disease. Methodology: A total of 54 people enrolled for this study, six were either excluded and/or did not meet inclusion criteria. Forty-eight participants were randomly assigned into three groups to receive: 1) probiotics + vitamin B₃; 2) probiotics + vitamin B₃ placebo; or, 3) the placebos for the probiotic and vitamin B₃ for 12 weeks. Constipation, depression, anxiety, quality of life, mood, diet, and nutrition were assessed at the baseline, middle, and end of the supplementation period. Blood and stool samples were collected for blood chemistry and microbiome analyses, respectively. Next-generation sequencing of 16S rRNA genes (Illumina MiSeq) was used for gut microbiota analysis. Within-group and between-group differences were statistically analyzed, with significance set at p<0.05. Results: The results showed improvements in constipation problems, quality-of-life scores, Movement Disorder Society- the Unified Parkinson's Disease Rating Scale (MDS-UPDRS), Parkinson’s Disease Questionnaire-39 (PDQ-39), decreased issues with communication via the PDQ-39 in probiotics and vitamin B₃ groups compared to the placebo group. Blood chemistry were within normal reference ranges. Supplementation did not change assessments of anxiety, depression, or mood. Gut microbiome analyses indicated significant differences in alpha and beta diversity, salient gut microbiome composition relating to different interventions, disease status, anxiety, and depression. Conclusion: Probiotics and vitamin B₃ supplementation was beneficial for constipation symptoms, gut microbiome, and quality of life in these patients. Vitamin B₃ appeared to have a more stabilizing effect on the gut microbiome. Several differences were greater after 12 weeks compared with 6 weeks of the intervention. This appears to support that the duration of supplementation is greater than 6 weeks for most of the assessed outcome measures. For quality of life and mood measures, an increased duration of study and/or larger sample size may be necessary to detect differences.