Brief Report: Benefit of Probiotic Supplements in Parkinson’s

“Taking probiotics is a habit that can really benefit the digestive system, which is intricately connected to our overall health.”  Dr. Michael F. Roizen

“Compelling new studies are showing how probiotics can help keep healthy people healthy. One study showed a decreased incidence of common infectious diseases among kids in day care.”  Dr. Mary Ellen Sanders

Overview: Dr. Tamtaji and colleagues are from the Kashan University of Medical Sciences in Iran: Tamtaji OR, Taghizadeh M, Daneshvar Kakhaki R, Kouchaki E, Bahmani F, Borzabadi S, Oryan S, Mafi A, Asemi Z. Clinical and metabolic response to probiotic administration in people with Parkinson’s disease: A randomized, double-blind, placebo-controlled trial. Clinical Nutrition. 2018. doi: https://doi.org/10.1016/j.clnu.2018.05.018. {NOTE:  It is not clear to me if when fully published, whether or not this article will be given ‘Open Access’ status.)

To begin, what is a double-blind placebo-controlled clinical trial?  A double-blind, placebo-controlled clinical trial is (i) a medical investigation using human subjects, (ii) neither side knows who’s getting what treatment, and (iii) a placebo is given to a control group. Thus, neither patient nor physician was aware of which patient was receiving the probiotic supplement or the placebo capsule.

Current understanding of Parkinson’s:  Several pathological (or disease-promoting) processes cause the death of dopamine-producing neurons that can lead to Parkinson’s.  One of these significant events is neuroinflammation.  The ‘hottest and newest’ pathological route found in the development of Parkinson’s is the “gut-brain axis”.  More precisely, the role of the microbiota, which is defined as the microbial population in a specific ecosystem (such as that found in the gut).  The gut-brain axis is a communication hub (or bi-directional signaling site) between the gastrointestinal tract and the brain, and the gut microbiota can trigger the interaction (click here to see recent research in this area).  Our gut microbiota produce many substances (including neurotransmitters). And it can communicate with the gut-brain axis using various communication links (or pathways): vagus nerve;  neuroendocrine (gut hormone) signaling; interference with Tryptophan metabolism;  immune system; altered intestinal permeability; and production of microbial metabolites.  [Click here for an overview of the role of gut microbiota in the gut-brain axis in neuropsychiatric disorders, especially look over the schematic figure.]  The implication for Parkinson’s is that the gut microbiota/gut-brain axis is somehow different/altered and generates either pathological signals or toxic substances that promote neuroinflammation, which eventually leads to the loss of dopamine-producing neurons in the mid-brain substantia nigra region.

Goals and Methodology: The question asked (goal) of the study was quite simple; do probiotic supplements have any impact on people-with-Parkinson’s (PwP)?  Using a randomized, double-blind, placebo-controlled designed study, 30 PwP were given a probiotic supplement compared to 30 PwP receiving placebo for 12 weeks.  The probiotic capsules contained Lactobacillus acidophilus, Bifidobacterium bifidum, and Lactobacillus reuteri (each at 2 × 10⁹ CFU/g).  The Movement Disorders Society-Unified Parkinson’s Disease Rating Scale (MDS-UPDRS) and several inflammatory/physiological markers were determined at the beginning and the end of the clinical trial.

Translating/Explaining the Results: This is apparently the first report on the use of probiotic supplements in PwP.  There were some important health benefits described for the probiotic treatment group when compared to the placebo group (please note that only the most relevant metabolites to the Parkinson’s story will be presented here). General characteristics (age, BMI, dietary intake, etc.) of the participants were not statistically different in the probiotic treatment group compared to the placebo group. Compliance of taking the capsules was excellent; and there were no reported side-effects from ingesting the probiotic capsules.

Table 1 shows that PwP taking the probiotic supplement for 12 weeks, when compared to the placebo, significantly reduced both the MDS-UPDRS rating score and the inflammation marker C-reactive protein (CRP). while blood plasma levels of glutathione (GSH) were increased. Table 2 shows additional metabolic parameters related to inflammation, oxidative stress, insulin metabolism, and lipid profile (please refer to the paper itself if you are interested in the complete list of substances measured).

Conclusions (importance/relevance to Parkinson’s today and our future): There is substantial evidence that probiotic supplements have both antioxidant and anti-inflammatory properties. Thus, the authors were hopeful that probiotic therapy would be useful for treating Parkinson’s. The only study aspect directly related to Parkinson’s was the dramatic improvement in the MDS-UPDRS score, which is a clinical measurement for assessing one’s status with Parkinson’s. Besides the MDS-UPDRS changes, probiotic therapy in PwP also showed changes related to inflammation and oxidative stress. Probiotic supplementation is known to modulate gut microbiota, which implies the newly introduced microorganisms reduce oxidative stress, and through the gut-brain axis positively influence the brain. How this occurs in a PwP  remains an open question.

This work had some limitations.  It would have been bolstered by merely reporting what type of Parkinson’s medication the 60 participants were using. While some of the results were statistically significant, repeating this study with a larger group of PwP, a longer time-period, and possibly a more complex mixture of probiotic supplement (many commonly available supplements have up to 10 different strains of microorganisms) would be valuable. Furthermore, there are many tests for Parkinson’s related to “quality of life”, movement and cognitive function that could be performed to better understand how and if probiotics work when given to a PwP. As noted by the authors, fecal bacterial changes and differences in gene expression would augment our understanding of how probiotics positively influence life with Parkinson’s.

In summary, the publication from Tamtaji OR, et al.: https://doi.org/10.1016/j.clnu.2018.05.018 implies that probiotic therapy is beneficial for PwP. Exactly how probiotics function in this disorder remains to be determined. One could speculate that the bacteria in the probiotic supplement creates an anti-oxidative/anti-inflammatory ‘gut-message’ (signal), that through the gut-brain axis, helps to reduce the existing neuroinflammation in the PwP.  Probiotic therapy is becoming more widely used and accepted for treating many other disorders. There is growing evidence of gut-brain axis, and gut microbiota contributes to some aspect of the development/progression of Parkinson’s. The results of this paper may provide a framework for future studies showing the benefit of probiotic supplements for those of us living with Parkinson’s.

“Friendly bacteria are vital to proper development of the immune system, to protection against microorganisms that could cause disease, and to the digestion and absorption of food and nutrients.” National Center for Complementary and Alternative Medicine

 Cover photo credit: https://hdfreefoto.wordpress.com/2014/09/15/sunrise-over-beach-in-cancun/