BackgroundParkinson's disease is characterized by a high burden of gastrointestinal comorbidities, especially constipation and reduced colonic transit time, and by gut microbiota alterations. The diverse metabolites produced by the microbiota are broadly relevant to host health. How microbiota composition and metabolism relate to gastrointestinal function in Parkinson's disease is largely unknown. The objectives of the current study were to assesses associations between microbiota composition, stool consistency, constipation, and systemic microbial metabolites in Parkinson's disease to better understand how intestinal microbes contribute to gastrointestinal disturbances commonly observed in patients.MethodsThree hundred participants (197 Parkinson's patients and 103 controls) were recruited for this cross‐sectional cohort study. Participants supplied fecal samples for microbiota sequencing (n = 300) and serum for untargeted metabolomics (n = 125). Data were collected on motor and nonmotor Parkinson's symptoms, medications, diet, and demographics.ResultsSignificant microbiota taxonomic differences were observed in Parkinson's patients, even when controlling for gastrointestinal function. Parkinson's microbiota was characterized by reduced carbohydrate fermentation and butyrate synthesis capacity and increased proteolytic fermentation and production of deleterious amino acid metabolites, including p‐cresol and phenylacetylglutamine. Taxonomic shifts and elevated proteolytic metabolites were strongly associated with stool consistency (a proxy for colonic transit time) and constipation among patients.ConclusionsCompositional and metabolic alterations in the Parkinson's microbiota are highly associated with gut function, suggesting plausible mechanistic links between altered bacterial metabolism and reduced gut health in this disease. The systemic detection of elevated deleterious proteolytic microbial metabolites in Parkinson's serum suggests a mechanism whereby microbiota dysbiosis contributes to disease etiology and pathophysiology. © 2020 International Parkinson and Movement Disorder Society

A BS TRACT: Background: The MIND diet has been linked with prevention of Alzheimer's disease and cognitive decline but has not been fully assessed in the context of Parkinson's disease (PD). The objective of the present study was to determine whether MIND diet adherence is associated with the age of Parkinson's disease onset in a manner superior to that of the Mediterranean diet. Methods: Food Frequency Questionnaires from 167 participants with PD and 119 controls were scored for MIND and 2 versions of Mediterranean diet adherence. Scores were compared between sex and disease subgroups, and PD diet adherence was correlated with age at onset using univariate and multivariate linear models. Results: The female subgroup adhered more closely to the MIND diet than the male subgroup, and diet scores were not modified by disease status. Later age of onset correlated most strongly with MIND diet adherence in the female subgroup, corresponding to differences of up to 17.4 years (P < 0.001) between low and high dietary tertiles. Greek Mediterranean adherence was also significantly associated with later PD onset across all models (P = 0.05-0.03). Conversely, only Greek Mediterranean diet adherence remained correlated with later onset across all models in men, with differences of up to 8.4 years (P = 0.002). Conclusions: This cross-sectional study found a strong correlation between age of onset of PD and dietary habits, suggesting that nutritional strategies may be an effective tool to delay PD onset. Further studies may help to elucidate potential nutrition-related sex-specific pathophysiological mechanisms and differential prevalence rates in PD.

The gut microbiome has been increasingly implicated in Parkinson’s disease (PD); however, most existing studies employ bacterial-specific sequencing, and have not investigated non-bacterial microbiome constituents. Here, we use fungal-specific internal transcribed spacer (ITS)-2 amplicon sequencing in a cross-sectional PD cohort to investigate associations between the fungal gut microbiome and PD. Fungal load among participants was extremely low, and genera identified were almost exclusively of proposed dietary or environmental origin. We observed significantly lower fungal DNA relative to bacterial DNA among PD patients. No fungi differed in abundance between patients and controls, nor were any associated with motor, cognitive, or gastrointestinal features among patients.

I would like to comment on the recently published article titled "Microbiota Composition and Metabolism Are Associated With Gut Function in Parkinson's Disease" in Movement Disorders. Cirstea et al 1 analyzed the correlation between intestinal symptoms, intestinal flora, and serum metabolomics in patients with Parkinson's disease (PD) based on large samples and came up with novel findings. The researchers evaluated 300 participants in detail, including daily dietary intake and intestinal complications. However, I have some concerns. First, it was declared in the Results section that p-cresol (HMDB0001858) and phenylacetylglutamine (HMDB0006344) were both significantly positively correlated with constipation severity among patients (Fig. 3E). Nevertheless, the result of phenylacetylglutamine cannot be found in Figure 3E, and there are 2 plots of different correlations between p-cresol and constipation severity among patients with PD. Second, as shown in the Discussion section, nearly half of controls (43 of 103) were spouses of the PD patients. In other words, within the cohort composed of pairs of couples, the diet-driven heterogeneity in gut microbiota between the patient and the control might be negligible because couples share more of their gut microbiota than individuals from different households. 2 However, an individual's dietary pattern might be a confounding factor for analysis of gut microbiota for the rest of the 147 patients and the other healthy controls. Notably, several studies 2-4 assessing the relationship between gut microbiota and PD included merely couples-based populations to reduce the interfering effect of different dietary patterns. Therefore, we hope that the authors will make a further subgroup analysis to validate their findings in different patient cohorts. To sum up, the present study is interesting and inspiring research in which more detailed information should be analyzed and available to readers so as to be more helpful in a deep understanding of intestinal symptoms, intestinal flora, and serum metabolomics in PD patients.

Background: The MIND diet has been linked with prevention of cognitive decline but has not been fully assessed in the context of Parkinson's disease (PD). Objective: To determine whether MIND diet adherence is associated with the age of Parkinson's disease onset. Methods: Food Frequency Questionnaires from 181 participants with PD were scored for MIND adherence and correlated with age of onset using univariate and multivariate linear models. Results: MIND adherence scores positively correlated with age of onset both independently (p=9.7e-5) and in models including education, sex, disease duration, caloric intake, smoking, and exercise. Differences in age of PD onset in the high vs the low adhering tertiles corresponded to 6 years for men and 10.2 years for women. Effect sizes exceeded those previously reported for the Mediterranean diet. Conclusions: These preliminary data suggest that the MIND diet may be an effective PD-delaying intervention, especially in women.