Connection Between Gut Microbes and Parkinson’s Disease

Researchers have long suspected that there’s a link between our digestive system and the brain, particularly regarding the onset of Parkinson’s disease. A new study has pinpointed specific gut microbes that may play a role, suggesting that lower levels of riboflavin (vitamin B2) and biotin (vitamin B7) could be involved. This leads to the intriguing possibility of a simple treatment: vitamin B supplementation.

“Supplementation therapy targeting riboflavin and biotin holds promise as a potential therapeutic avenue for alleviating PD symptoms and slowing disease progression,” said Hiroshi Nishiwaki, a medical researcher from Nagoya University, when the study was released in May 2024.

The neurodegenerative condition affects nearly 10 million people worldwide, whose best hope currently lies in therapies that only manage symptoms.

Symptoms generally start subtly, often with constipation or sleep issues, and can appear as much as 20 years before more severe problems arise, such as dementia and significant loss of muscle control.

Earlier research indicated that alterations in gut bacteria can be detected in individuals with Parkinson’s long before other symptoms manifest.

The study analyzed fecal samples from 94 patients with Parkinson’s and 73 healthy individuals in Japan, comparing these findings with data from various countries like China, Taiwan, Germany, and the US.

Although the specific bacterial groups varied by country, all appeared to affect the synthesis pathways of B vitamins. The research found that changes in gut bacteria were connected to lower levels of riboflavin and biotin in those with the disease.

Nishiwaki and his team also noted that the reduction of B vitamins correlates with diminished levels of short-chain fatty acids (SCFAs) and polyamines, which are essential for maintaining a healthy mucus layer in the intestines. “Deficiencies in polyamines and SCFAs could lead to thinning of the intestinal mucus layer, increasing intestinal permeability, both of which have been observed in Parkinson’s disease,” explained Nishiwaki.

This deterioration may expose the intestinal nervous system to various toxins we’re increasingly encountered. These include common substances like cleaning agents, pesticides, and herbicides.

Such toxins can lead to the overproduction of α-synuclein fibrils, molecules that accumulate in dopamine-producing cells in the brain’s substantia nigra, resulting in inflammation and the more debilitating symptoms associated with Parkinson’s.

A past study showed that high doses of riboflavin might help some patients regain motor function, especially when combined with dietary changes like eliminating red meat. It’s feasible that higher levels of vitamin B might help mitigate some damage, according to Nishiwaki and his colleagues.

The findings hint that maintaining a healthy gut microbiome could be protective, and reducing environmental toxins might aid as well.

Naturally, given the complex interplay in Parkinson’s disease, not every patient will have the same triggers or causes. Thus, a personalized approach will be crucial.

“We could perform gut microbiota analysis on patients or conduct fecal metabolite analysis,” Nishiwaki suggested, explaining that this could lead to tailored treatments. “Using these findings, we could identify individuals with specific deficiencies and administer oral riboflavin and biotin supplements to those with decreased levels, potentially creating an effective treatment.”

This research appeared in the journal npj Parkinson’s Disease.