Parkinson’s Disease and the Gut: Symptoms, Nutrition, and Microbiota

Abstract

Parkinson’s disease (PD) is the second most common neurodegenerative disease worldwide, characterized by symptoms of bradykinesia, rigidity, postural instability, and tremor. Recently, there has been a growing focus on the relationship between the gut and the development of PD. Emerging to the forefront, an interesting concept has developed suggesting that the initial pathophysiological changes occur in the gastrointestinal tract before changes are seen within the brain. This review is aimed at highlighting the relationship between PD and the gastrointestinal tract, along with the supporting evidence for this. Firstly, we will focus on the gastrointestinal conditions and symptoms which commonly affects patients, including both upper and lower gastrointestinal issues. Secondly, the impact of nutrition and diet on neurological health and PD physiology, with particular emphasis on commonly consumed items including macronutrients and micronutrients. Finally, variability of the gut microbiome will also be discussed and its link with both the symptoms and signs of PD. The evidence presented in this review highly suggests that the initial pathogenesis in the gut may proceed the development of prodromal PD subtypes, and therefore building on this further could be imperative and lead to earlier diagnosis with new and improved therapeutics.

Inflammatory microbes and genes as potential biomarkers of Parkinson’s disease

“…Increased Akkermansia (Figs. 3 and 5 ) which has been reported 47 may lead to intestinal permeability, as this genus requires mucus for energy, leading to biofilm disruption. Defects in the gut barrier increase the risk of systemic exposure to inflammatory microbial products such as lipopolysaccharide 18 .…”

“…These microorganisms and their metabolites can cross the blood-brain barrier through the humoral system, resulting in microglia and astrocytes activation and brain neuroinflammation 9 . Pathologic α-synuclein may be transmitted to the brain through the vagus nerve or other pathways 14 , 15 , 47 . These inflammatory factors, pathological α-synuclein, and microbial metabolites lead to the dysfunction and even death of dopaminergic neurons, eventually causing PD.…”

Diagnostic Performance for Differential Diagnosis of Atypical Parkinsonian Syndromes from Parkinson’s Disease Using Quantitative Indices of 18F-FP-CIT PET/CT

“…Atypical parkinsonian syndromes (APS), such as multiple system atrophy (MSA), progressive supranuclear palsy (PSP), corticobasal degeneration (CBD), and dementia with Lewy bodies (DLB), are other causes of Parkinsonism. Although the clinical progression and pathology can differ between Parkinsonism, there are evident difficulties for achieving confirmed diagnosis based solely on clinical features, particularly in the elderly and in patients at an early stage of disease [ 1 , 2 ]. To date, the therapeutic strategies for these chronic neurodegenerative disorders are based on symptomatic treatments.…”

The Endocannabinoid System: A Bridge between Alzheimer’s Disease and Gut Microbiota

“…An increasing number of studies have explored a possible bidirectional connection between gut microbiota and the brain, for which the term gutbrain axis has been coined [3,4]. Moreover, the link between the gut microbiota and human diseases is more and more evident as alterations in gut microbial community composition have been reported in several pathological conditions including neurological and autoimmune disorders, obesity and cancer [5][6][7][8][9][10]. The microbiome studies on a transgenic AD model and patients highlighted alterations in gut microbiota providing new understanding of AD and additional features for its pathological characterization [11,12].…”