Parkinson’s disease (PD) is a relatively common neurodegenerative disorder among the elderly population. According to some data, about 8.5 million people currently suffer from this ailment, and as the population “ages,” this number will increase. The exact factor causing Parkinson’s disease is still unclear; however, its development is due to a combination of genetic and environmental factors. Considering that less than 10% of cases are genetic, it is important to identify environmental risk factors for the development of Parkinson’s disease.
As a gastroenterologist-nutritionist, I cannot overlook the importance of the gastrointestinal tract and its inhabitants in the functioning of our entire body. Various microorganisms inhabiting the gastrointestinal tract can have a profound impact on the nervous system through neurological, endocrine, and immune pathways involved in the microbiota-gut-brain axis
And My Beloved Gut serves as a gateway to the very environment, the gastrointestinal tract as a kind of interface for interaction with it Although the gut has immune and physical barrier functions that can protect us from environmental exposure, these functions deteriorate with age, leading to increased opportunities for the body to be exposed to potentially harmful environmental elements .
Within each of us is a whole separate coexisting world—the microbiota. Approximately 2-3 kilograms. Intestinal microbes help regulate gastrointestinal and immune functions. They also affect the digestion and metabolism of a number of foods, nutrients, metabolites, and drugs. The balance of gut microbes and its impact on human health is receiving a lot of attention. Imbalance of gut microbiota is associated with many human diseases, including gastrointestinal, neurological, metabolic, respiratory, and cardiovascular diseases. Intestinal microbes are a key link in the gut-brain connection and have been called the body’s second brain. The term “microbiota-gut-brain” was introduced to characterize this complex mechanism.
Patients with Parkinson’s disease often come to the appointment, requiring medication and nutritional assistance.
It is well known that Parkinson’s disease affects not only the central nervous system but also the digestive system and the enteric nervous system. Pathological changes in the peripheral nervous system occur in the early stages of Parkinson’s disease, even before pathological changes in the central nervous system.
For example, constipation occurs several years before the actual onset of Parkinson’s disease, as noted in many sources. During consultations, we work on stool correction through diet and medications. I often talk about the gut-brain axis and how it is involved in their disease.
Now a little about the complex, I will try to reveal the topic. The main pathological changes in Parkinson’s disease are the damage to dopaminergic neurons in the substantia nigra of the central nervous system and the formation of Lewy bodies. These pathological changes also occur in the gastrointestinal tract and are closely related to changes in the intestinal flora.
During clinical studies, it was found that patients with Parkinson’s disease experience significant changes in the β-diversity of gut flora: Lactobacillusaceae и Verrucomicrobiaceae significantly increase, and Lachnospiraceae и Prevotellaceae significantly decrease (https://pubmed.ncbi.nlm.nih.gov/33763383/) Moreover, a longer course of treatment for Parkinson’s disease was associated with fewer bacteria and probiotics producing short-chain fatty acids, but with a greater number of pathogenic bacteria. Movement symptoms in patients with Parkinson’s disease may be associated with enterobacteria and bacteria.
Other dysbiosis conditions are also associated with Parkinson’s disease, including elevated levels Helicobacter pylori (H. pylori) and small intestinal bacterial overgrowth ( SIBO), both of which were associated with greater severity of motor symptoms in patients with Parkinson’s disease Infection Helicobacter pylori and excessive bacterial growth in the small intestine can contribute to disease progression and affect the effectiveness of therapies, such as L-dopa (https://dx.doi.org/10.3390/biom15010026). During a consultation at our clinic, we have the ability to identify both conditions and therefore treat them.
There is another problem for these patients: almost half of patients with Parkinson’s disease suffer from involuntary weight loss. About 42.29% of cases of weight deficiency in this disease are due to changes in the gut microbiota. An increase in pro-inflammatory bacteria and a decrease in bacteria producing short-chain fatty acids have been identified. These changes in the microbiota, in turn, affect the inflammatory state, metabolism, and appetite regulation in patients with Parkinson’s disease (https://dx.doi.org/10.1038/s41531-023-00587-w)
And thus, gut-related dysbiosis and changes in microbial components are risk factors and important determinants of Parkinson’s disease.
In turn, alpha-synuclein, which is detected in patients is also located in the intestines with Parkinson’s disease
There are even many discussions where the onset of Parkinson’s Disease is debated, questioning whether it begins in the gut?
This led to the hypothesis of the “ascending anatomical theory”. This theory postulates that disruption of the gut microbiome can cause misfolding and aggregation of alpha-synuclein in the enteric nervous system and spread to the brain through cell-to-cell transfer (https://dx.doi.org/10.1007/s12602-024-10433-x)
Thus, changes in the quality of the microbial composition in the gut clearly affect the onset, progression, and treatment effectiveness of Parkinson’s Disease.
Despite advances in research on gut microbes and Parkinson’s disease, existing studies are not sufficiently consistent, most likely because gut microbes are influenced by numerous factors such as fecal collection methods, DNA extraction procedures, sequencing methods, deep heterogeneity, and statistical methods, as well as various individual patient-related factors (e.g., geography, age, ethnicity, host genetics, diet, medications, lifestyle habits, disease severity, and other comorbid factors). All of this can affect the results. At the same time, the influence of accompanying factors, such as comorbidities and medications, should be considered.
What I have described highlights the role of the microbiome in the pathophysiology of Parkinson’s disease and provides opportunities where working with the human microbiome can play a role in patient care. Although it will not cure the disease, it may play a role in preventing disease progression and improving the quality of life for these patients.
Scientists have discovered that microbes in our gut can affect how well the drug Levodopa works, which is used to treat Parkinson’s disease. Levodopa helps increase dopamine levels in the brain, but not all of the drug reaches the brain because some of it is broken down by bacteria in the gut before it can get there.
Researchers studied how exactly gut microbes affect Levodopa. They found that one of the bacteria Enterococcus faecalis, absorbs Levodopa and helps it convert into dopamine, which is then used by the bacteria itself. For people not taking Levodopa, this bacteria is harmless, but when it encounters Levodopa, it begins to actively break it down.
Different samples of microbes in people showed different results: in some cases, bacteria did not absorb Levodopa at all, while in others, up to 98% of the drug was absorbed. Scientists noticed that the more in the sample there was Enterococcus faecalis, the more Levodopa he “s’ye-dal “.
Now researchers are looking for ways to use this information to improve the treatment of people with Parkinson’s disease. They have found a small substance that can block the influence Enterococcus faecalis on Levodopa, without harming healthy microbes in the gut. This discovery may help better predict how people with Parkinson’s disease will respond to treatment and improve its outcomes (Vayu Maini, 2019)
Treatment goals specific to the intestines may include:
Thus, I hope I was able to draw your attention to the role of the gut not only in patients with Parkinson’s disease but in general. The potential for microbiota correction using probiotics, prebiotics, synbiotics, fecal transplantation, and antibiotics represents a promising direction for new treatment methods. Meanwhile, we continue to monitor research, new methods, and implement them in our practice.
Do you know that tremor and stiffness in Parkinson’s disease can be alleviated with ultrasound? You can read about it here
Impact of Nutrition on the Gut Microbiota: Implications for Parkinson’s Disease.Sobral, Joana, Empadinhas, Nuno,Esteves, Ana Raquel,Cardoso, Sandra MoraisNutr Rev. 2025 Jan 15
Probiotic: A Gut Microbiota-Based Therapeutic Approaches for the Treatment of Parkinson’s Disease.Rout, Monalisa,Prusty, Shakti Ketan, Kar, Durga MadhabCurr Rev Clin Exp Pharmacol. 2024 Dec 23
Unravelling the mechanisms of underweight in Parkinson’s disease by investigating into the role of gut microbiome. Shih, Ling-Chieh. Lin, Ru-Jen. Chen, Yan-Lin. Fu, Shih-ChenNPJ Parkinson’s dis.. 10(1):28, 2024 Jan 24.
The Role of the Gastrointestinal Microbiota in Parkinson’s Disease. Gabrielli, Maurizio. Zileri Dal Verme, Lorenzo. Zocco, Maria Assunta. Nista, Enrico Celestino. Ojetti, Veronica. Gasbarrini, AntonioBiomolecules. 15(1), 2024 Dec 28.
https://pubmed.ncbi.nlm.nih.gov/33763383
https://translationalneurodegeneration.biomedcentral.com
https://www.naturalmedicinejournal.com/journal/parkinson-disease-and-the-microbiome
Doctor - Obstetrician-Gynecologist, Ultrasound Diagnostics Doctor