Probiotic Supplementation May Improve Motor, Non-Motor Symptoms and Depression in Adults with Parkinson’s Disease

by | May 9, 2023 | 2023, Brain Health, Parkinson's, Probiotics

Written by Taylor Woosley, Staff Writer. Results of the meta-analysis including 11 randomized controlled studies shows improved motor scores (SMD, -0.65; 95% CI -1.11 to -0.19), non-motor scores (SMD, -0.81; 95% CI -1.12 to -0.51), and mental health scores (SMD, -0.72; 95% CI -1.10 to -0.35) in subjects in the probiotic groups compared to the control group. 

Parkinson's diseaseParkinson’s disease (PD) is the second most common neurodegenerative disease with a global prevalence of more than 6 million individuals, which corresponds to a 2.5-fold increase in prevalence over the past generation1. Pathologically, PD is defined by loss of dopaminergic neurons in the substantia nigra pars compacta located in the midbrain and associated with Lewy bodies, which are cytoplasmic inclusions that include insoluble alpha-synuclein aggregates2. Previously, PD was largely considered a movement disorder but is now understood to be a multi-system disorder with notable neuroinflammation and immune dysfunction that has been implicated in the development of various non-motor symptoms such as sleep and gastrointestinal dysfunction3.

Recently, GI tract, enteric nervous system (ENS), gut microbiota, and a cross talk of gut-brain have become a spotlight as a potential mechanism underlying development of PD4. Probiotics, microbial strains beneficial to health, can enhance mucosal barrier function, modulate the innate and adaptive immune systems, and regulate the enteric and central nervous systems5. Previous research on probiotics show that they can be beneficial in the treatment for PD, given their propensity to reduce inflammatory responses and oxidative stress, and elevate brain-derived neurotrophic factors6.

Park et al. conducted a meta-analysis to analyze the quantitative effects of probiotics on gastrointestinal symptoms, inflammation, metabolic disease risk, and PD symptoms in subjects with PD. Study inclusion consisted of following the Population, Intervention, Comparison, Outcomes and Study design (PICOS) framework, with a target population including adult subjects with idiopathic Parkinson’s disease who were 18 years or older and diagnosed according to certain criteria. The “intervention” groups were comprised of participants who were administered probiotics such as pills or fermented milk over a period. The control group contained subjects who were not administered probiotic or in whom a placebo was administered.

Included outcomes consisted of gastrointestinal symptoms, inflammation with data relating to inflammatory markers, and antioxidant markers, risk of metabolic syndrome determined by fasting glucose, serum insulin, and serum cholesterol levels, and scores of Parkinson’s disease-related scales: The Parkinson’s Disease Questionnaire (PDQ-39), Non-Motor Symptoms Questionnaire (NMSO), and Unified Parkinson’s Disease Rating Scale (UPDRS). The study design included only randomized controlled trials with reported baseline and post-intervention data or changes in baseline data.

Heterogeneity between studies was analyzed using I2 and P-values using the Cochrane Q test. The Egger bias test and visual inspection of funnel plots was utilized to assess publication bias. A total of 11 randomized controlled studies were used in the final analysis. The number of participants ranged from 40 to 133, with the average age being between 66.5 and 75.6 years. Probiotics administration duration ranged from 4 to 12 weeks and were administered in the form of fermented milk, capsules, or powder in sachets. Significant findings of the meta-analysis are as follows:

  • 6 studies reported weekly gastrointestinal motility and the meta-analysis showed significant improvement in the probiotic groups (SMD, 0.83; 95% CI 0.63 to 1.04). Furthermore, 3 studies that followed up after 4 weeks showed significant improvement in the probiotic groups (SMD, 0.78; 95% CI 0.35 to 1.12).
  • 3 studies assessed serum inflammatory markers and the meta-analysis revealed a significant reduction in the serum levels of inflammatory markers in the probiotic groups (SMD, -5.98; 95% CI -9.20 to -2.75).
  • Regarding PD scale scores, 2 studies included UPDRS Part III motor scores, and there were significant improvements in the probiotic groups (SMD, -0.65; 95% CI -1.11 to -0.19). 2 studies reported Non-Motor Symptoms Questionnaire (NMSQ) scores and the meta-analysis revealed a significant reduction in NMSQ scores in the probiotic groups (SMD, -0.81; 95% CI -1.12 to -0.51).
  • Regarding mental health, 2 studies used the Hamilton Anxiety Rating Scale (HAMA), and one study used the Hospital Anxiety and Depression Scale (HADS) Anxiety subscale. Meta-analysis results show significant improvements in the probiotic groups (SMD, -0.72; 95% CI -1.10 to -0.35).

Results of the study show that probiotic supplementation significantly improved motor, non-motor PD symptoms, and depression in subjects. Furthermore, probiotic supplementation increased gastrointestinal motility and quality of life, while also reducing anxiety. Study limitations include the small number of study and participants included, the high heterogeneity among studies, and the short and insufficient study durations.

Source: Park, Jong Mi, Sang Chul Lee, Chorom Ham, and Yong Wook Kim. “Effect of probiotic supplementation on gastrointestinal motility, inflammation, motor, non-motor symptoms and mental health in Parkinson’s disease: a meta-analysis of randomized controlled trials.” Gut Pathogens 15, no. 1 (2023): 1-17.

© The Author(s) 2023. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which
permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the
original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or
other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line
to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory
regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this
licence, visit http://creativecommons.org/licenses/by/4.0/. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data.

Click here to read the full text study.

Posted May 8, 2023.

Taylor Woosley studied biology at Purdue University before becoming a 2016 graduate of Columbia College Chicago with a major in Writing. She currently resides in Glen Ellyn, IL.

References:

  1. Tolosa E, Garrido A, Scholz SW, Poewe W. Challenges in the diagnosis of Parkinson’s disease. The Lancet Neurology. May 2021;20(5):385-397. doi:10.1016/s1474-4422(21)00030-2
  2. Simon DK, Tanner CM, Brundin P. Parkinson Disease Epidemiology, Pathology, Genetics, and Pathophysiology. Clin Geriatr Med. Feb 2020;36(1):1-12. doi:10.1016/j.cger.2019.08.002
  3. Tansey MG, Wallings RL, Houser MC, Herrick MK, Keating CE, Joers V. Inflammation and immune dysfunction in Parkinson disease. Nat Rev Immunol. Nov 2022;22(11):657-673. doi:10.1038/s41577-022-00684-6
  4. Gazerani P. Probiotics for Parkinson’s Disease. Int J Mol Sci. Aug 23 2019;20(17)doi:10.3390/ijms20174121
  5. Liu Y, Tran DQ, Rhoads JM. Probiotics in Disease Prevention and Treatment. J Clin Pharmacol. Oct 2018;58 Suppl 10(Suppl 10):S164-s179. doi:10.1002/jcph.1121
  6. Mirzaei H, Sedighi S, Kouchaki E, et al. Probiotics and the Treatment of Parkinson’s Disease: An Update. Cell Mol Neurobiol. Nov 2022;42(8):2449-2457. doi:10.1007/s10571-021-01128-w