This June 2022 review cited twenty 2022 papers for relationships between Parkinson’s disease and gut microbiota:
“Clinical diagnosis of PD is based on typical motor symptoms, and novel diagnostic biomarkers have been developed such as imaging markers, and α-synuclein fluid and tissue markers. Multimorbidity of non-motor disorders heighten the risk of adverse outcomes for patients with PD, which usually appear 20 years before onset of motor symptoms.
The gut microbiota is intimately connected to occurrence, development, and progression of PD, especially in early stages. A better understanding of the microbiota–gut–brain axis in PD can provide an opportunity to monitor an individual’s health by manipulating gut microbiota composition.
Several approaches like administration of probiotics, psychobiotics, prebiotics, synbiotics, postbiotics, FMT, and dietary modifications have been tried to mitigate dysbiosis-induced ill effects and alleviate PD progression.
Epidemiological studies have reported that diet affects (positively or negatively) onset of neurodegenerative disorders. Evidence suggests that diet composition’s effects on brain health is not due to diet-induced inflammatory response, but because of its effects on the gut microbiome.
Dysbiotic gut microbiota (including altered microbial metabolites) may play crucial roles in PD via various mechanisms, such as:
- Increased intestinal permeability;
- Aggravated intestinal inflammation and neuroinflammation;
- Abnormal aggregation of α-synuclein fibrils;
- Imbalanced oxidative stress; and
- Decreased neurotransmitters production.
Future studies are essential to further elucidate cause-effect relationships between gut microbiota and PD, improved PD therapeutic and diagnostic options, disease progression tracking, and patient stratification capabilities to deliver personalized treatment and optimize clinical trial designs.”
https://www.frontiersin.org/articles/10.3389/fimmu.2022.937555/full “Gut Microbiota: A Novel Therapeutic Target for Parkinson’s Disease”