Recently, scientists have been exploring the prospects of the human gut microbiome—a colony of different microorganisms, predominantly bacteria—in understanding health conditions and age-related diseases. Parkinson’s disease (PD) is a neurological degenerative disease suspected to be caused by Lewy bodies which are made up of aggregated alpha-synuclein (αSyn), a protein that is abundantly found in the brain. The symptoms of PD include debilitating movement disorders, sleep disorders, cognitive impairment, gastrointestinal and autonomic dysfunction. A study published in Cell details how scientists studied mice with excess aggregated alpha-synuclein (laboratory mouse model for PD) and presented that the gut microbiota was required for the promotion of motor deficiency, neurological dysfunction, and αSyn activity—the symptoms common in the PD patients. They also proposed that alterations to the gut microbiota could be a risk to Parkinson’s disease. Furthermore, a meta-analysis study on the gut microbiome of Parkinson’s disease patients, published in Nature revealed that despite an enrichment of the genera Lactobacillus, Akkermansia, and Bifidobacterium, there is a decrease in the concentration of bacteria that produce short-chain fatty acids, namely bacteria in Lachnospiraceae family and the Faecalibacterium genus. These short-chain fatty acids (SCFAs) play many important roles in the body and have been associated with gut barrier function, glucose balance, homeostasis in the immune system, appetite regulation, and obesity. Sodium butyrate, a short-chain fatty acid (SCFA), has been found to increase dopamine levels in PD mouse models
Diet and Butyrate Production
In a study published in Nature, scientists investigated the role of dietary fiber in butyrate production in both Parkinson’s disease patients and healthy controls. Different dietary fiber substrates—including inulins, gums, vegetables and quinoa, starch, pectins, and polydextrose—were included in the diet of their study participants a day before their fecal samples were collected. These fecal samples were fermented and assessed for butyrate concentration. The scientists discovered that although the butyrate concentration was increased in both PD patients and the healthy controls after the dietary fiber intake, it was still lower in the former compared to the latter—among the dietary fibers, inulin had the largest effect, while Xanthan gum had the lowest production. The scientists suggest that more research should be done to investigate the effects of dietary fiber intake on both short-chain fatty acid concentration in blood plasma and motor disabilities of PD patients.
Despite the decrease in SCFA producing bacteria, it is clear that dietary fiber intake can increase butyrate concentration in the body and appears to be a promising approach in PD treatment.