Both neurological and gut health issues can have a serious impact on quality of life with Parkinson’s disease (PD). Probiotics have been used to help support the management of symptoms related to PD – some for the gut, others for the brain.
Gut-health probiotics can benefit people with PD by addressing common GI complaints like constipation. But gut-brain probiotics may also benefit people with PD when used as dietary management alongside regular treatment. We’ll look at how these probiotics for Parkinson's patients work, and how they both help people with PD live their best lives.
Why probiotics?
Probiotics are clinically-studied living microorganisms that confer a health benefit to their host when taken in adequate amounts.
These health benefits can vary.
One type of probiotic may improve gut issues, like constipation. Still others may influence brain function and mental health, and may or may not influence gut health at all. These are known as psychobiotics. We will learn more about these soon, especially the relevance of the psychobiotic PS128 in the dietary management of Parkinson’s disease.
But, let’s begin by taking a look at the possible gut health benefits of probiotics for GI issues in PD.
Can probiotics help with digestion in Parkinson’s disease?
Gastrointestinal (GI) issues are common in Parkinson’s disease and are directly related to the disease's effects on gut health. Constipation in particular occurs often and can precede motor symptoms of PD by several years. This has prompted scientists to hypothesize that PD may start in the gut and spread to the brain (we will discuss this interesting finding later in the article).
Besides constipation, many people with Parkinson’s will also experience trouble with swallowing, delayed emptying of the stomach, and bloating. These uncomfortable gastrointestinal symptoms can be distressing for people with PD and can contribute to feelings of loss of dignity and loss of independence.
Studies show that probiotics may help improve these GI issues. For example, in one double-blind, placebo-controlled study, PD patients with constipation randomly received either a multi-strain probiotic (Lactobacillus sp and Bifidobacterium sp) or a placebo (fermented milk). After 8 weeks, it was found that those who took the probiotic experienced a significant improvement in bowel movements, along with improved gut motility and bowel opening frequency.
Probiotics may also influence overall gut health. Studies suggest that gut dysbiosis (a disruption in the gut microbiota) may lead to a chain reaction of undesirable effects. These effects include a weakened intestinal barrier and reduced short-chain fatty acids, which have been demonstrated in cases of PD.
Balancing the gut microbiome with beneficial bacteria from a probiotic may help improve these issues. Beyond gut health, probiotics may provide dietary management of Parkinson's in ways you would never have imagined. In the next section, we will discuss these benefits, with a spotlight on PS128.
Can probiotics help the brain in Parkinson’s disease?
Scientists have long been intrigued by how signals from the gut influence the brain in neurodegenerative conditions like Parkinson’s. In their investigations, they have found that through the bidirectional communication system known as the gut-brain axis, the gut microbiota can influence brain functions, such as learning, memory, and cognition. This influence led scientists into researching the possibility that probiotics may help improve neurological symptoms in PD. Their results are promising.
Certain probiotics have been shown to help improve GI issues like constipation in people managing PD. However, some probiotic strains are clinically found to confer a mental health benefit apart from the gut. These are known as psychobiotics - a special class of probiotics that exert their benefits via the microbiota-gut-brain axis.
Psychobiotics have been the subject of several studies that explore their possible mode of action in improving health for people managing neurological disorders. PS128 may be the only psychobiotic that has been investigated for its impact on PD.
Psychobiotic PS128 in Parkinson’s disease
Studies in mice suggested that PS128 might be helpful for Parkinson’s patients, suggesting an effect on dopamine in the brain, neuroprotection, and impacts on movement. PS128 appears to work via the gut-brain axis. A clinical study in humans suggests dietary management of Parkinson’s by PS128 may be beneficial for some. Let’s explore these studies in detail.
Preclinical Studies: Neuroprotective effects of PS128 in Parkinson's disease
Parkinson’s disease is characterized by the loss of dopamine-producing neurons in the substantia nigra - a part of the brain involved in movement. This leads to a decrease in dopamine levels in the brain followed by the hallmark motor symptoms (i.e., tremors, muscle rigidity, instability, etc.).
Dopamine deficiency, however, does not only impact movement. Dopamine plays a pivotal role in several brain functions. These include the regulation of mood, memory, sleep patterns, and gastrointestinal function.
Previous animal studies with PS128 showed that mice that took PS128 had higher amounts of dopamine in their brains compared with those that did not take PS128. Other studies suggested that PS128 appears to help with oxidative stress and inflammation in both humans and rodents.
For example, in mice treated with oxidizing substances within the brain, PD-like motor symptoms developed.
These symptoms were significantly decreased if the mice were also given PS128, and more intact dopaminergic neurons were seen in the substantia nigra of these animals. Thus, studies suggest PS128 may play a role in dopamine production and metabolism, partially compensating for lost neurons.
PS128 may also reduce inflammation in the brain that kills dopamine-producing neurons, potentially slowing disease progression in Parkinson’s disease. In this study, a Parkinson’s disease-like model, scientists assessed the neuroprotective properties of PS128 using mice. In the study, the researchers examined concentration of short-chain fatty acids (SCFAs) and microbiota compositions.
The researchers observed the following after administration of PS128:
- Increased levels of dopamine
- Reduced loss of dopaminergic (dopamine-related) neurons
- Reduced activation of microglia - the immune cells of the central nervous system
- Reduced levels of inflammatory factors
- Enhanced expression of neurotrophic factor (crucial for brain health and function)
Lastly, the researchers noted significant improvement in the motor deficits of the PD-like mice.
Clinical Pilot Study: Add-on effect of PS128 in Parkinson's disease
A recent clinical pilot study suggests that PS128 may influence brain-signaling and associated neurological activity relevant to Parkinson’s patients. For 12 weeks, 25 individuals with PD took two capsules of PS128 (a total of 60 billion CFUs) in addition to their usual medications, including levodopa. All the participants had been diagnosed with Parkinson’s disease for an average of 10 years.
At the end of the study, there was a significant improvement in akinesia, or difficulty moving. This was measured by the participants’ ability to perform finger, hand, and leg movements with agility. The improvements in akinesia were seen both in the ON state when a levodopa dose was maximally effective, and in the OFF state in the low point between doses. Many (68%) of the participants reported that they felt PS128 had helped them, with some (20%) saying they felt much or very much improved.
Overall, the majority of participants said they received a noticeable improvement in their quality of life from PS128.
The findings from these studies support the use of psychobiotics like PS128 as dietary management to help improve quality of life for those living with Parkinson’s disease. While the mechanisms that underlie these observed improvements are yet to be clearly defined, scientists hypothesize that a possible link between the gut and Parkinson’s disease may play a role.
Is there a link between gut health and Parkinson’s disease?
Scientists have known for some time that Parkinson’s disease is not confined to the brain, but impacts the gut as well. More often than not, digestive issues like bloating and constipation are reported by individuals who are later diagnosed with Parkinson’s. While not considered an early indicator of Parkinson’s, some studies suggest that the disease may start in the gut and move to the brain.
The pathogenesis (origination and development) of Parkinson’s disease is complex and not fully understood. Nonetheless, the current understanding is that there are two possible pathways that lead to the neurodegeneration prevalent in Parkinson’s disease. One is called the “gut-first” (or body-first), and the other “brain-first”.
Several studies have suggested that PD may start in the gut and spread to the brain. In these gut-first patients, alpha-synuclein, a protein linked to Parkinson’s disease, is found to aggregate in the gut before spreading to the brain because it is misfolded. Specifically, these proteins originate in the enteric nervous system (ENS) of the gut and invade the brain via the vagus nerve. Scientists have observed this alpha-synuclein pathology all along the GI tract of someone with Parkinson’s.
However, not all patients have this “gut-first” accumulation of misfolded alpha-synuclein. Other cases of Parkinson’s disease present with an accumulation of alpha-synuclein in the brain, specifically the olfactory bulb. From here, these aggregates (also called Lewy bodies) spread quickly via the olfactory nerve to the amygdala and the adjacent substantia nigra.
This distinction is why separate subtypes of gut-first and brain-first PD exist.
Gut-first pathway and altered microbiome in PD
Long before motor symptoms of Parkinson’s disease appear, problems in the gut and/or brain may begin setting the stage.
While non-motor symptoms of Parkinson’s, (i.e., dysphagia, delayed stomach emptying, and constipation) have not been directly linked to pathogenesis of the disease, some researchers hypothesize that they may be related. PD is also associated with altered gut microbiome composition and function.
In some people, the microbial imbalance of the digestive system causes symptoms before neurological decline is noted. In other cases, the dying off of neurons in the substantia nigra of the brain happens first. In either of these pathways, the communication of the gut-brain axis is altered, exacerbating both the motor and non-motor symptoms of the disease.
Several studies have looked for evidence of changes in the composition of the microbiome itself. The research revealed that the gut microbiome in Parkinson’s disease might be different from the microbiome in people who do not have PD.
One recent study with a large pool of participants (490 individuals with Parkinson’s disease and 234 healthy controls) found that people with Parkinson’s disease experience widespread changes in their gut bacteria.
Geneticists in the study discovered that clusters of microbes tended to grow together or be depleted together in the participants with PD. In these clusters, high levels of opportunistic pathogens (i.e., E. coli and Klebsiella) were found to be present. These microbes do not usually cause harm individually, but can do so when the microbiota as a whole is out of balance. The scientists also found that species that digest dietary fibers and produce short-chain fatty acids (beneficial compounds) were severely depleted.
Despite these findings, there currently is not enough evidence to definitively state that alterations in the gut microbiome are a driver in the development of PD.
No matter the origin, Parkinson’s is known to interfere with normal gut function and this can lead to symptoms both in and out of the bathroom. If you or a loved one is living with PD, you may be looking for ways to manage these uncomfortable symptoms or overall gut health. Next, we will talk about some strategies you can use to do just that.
Can you improve gut health issues in Parkinson’s?
Talk to your healthcare provider before starting any new change, including diet, exercise, and supplementation, to make sure it is safe for you.
Gastrointestinal issues are some of the most common and troublesome non-motor symptoms in Parkinson’s disease. However, making a few lifestyle changes may make a difference. Proactively changing your diet and adding a regular exercise routine into your daily practice can potentially help improve these uncomfortable symptoms.
A recent study suggests that GI issues are more prevalent in PD patients who have low-quality diets. For example, it was found that low dietary fiber and higher added sugar intake was associated with chronic constipation.
Diet can also impact the microbiome in Parkinson’s. For example, researchers in the same study observed a higher abundance of pro-inflammatory bacteria in patients with a low-fiber and/or high-sugar diet. On the other hand, a healthy diet (rich in dietary fibers, fruits, whole grains, and low in sugar) was associated with a higher abundance of anti-inflammatory bacteria.
Specifically, the Mediterranean diet and higher consumption of flavonoids – chemical compounds found in many colorful fruits and vegetables – appear to delay the onset of PD in some individuals.
Another strategy to improve your diet is by eating prebiotic-rich foods. Prebiotics are fibers and other compounds (i.e., polyphenols) that promote the growth of beneficial bacteria in your gut. When you eat a diet rich in prebiotics, the beneficial bacteria in your gut thrive. Foods that contain prebiotics include greens, garlic, bananas, oats, and apples.
Exercise is helpful overall. Regular exercise provides broad benefits, including improving motor function and GI issues like constipation. It may also provide neuroprotection. According to the Yale School of Medicine, exercise (especially high-intensity exercise) may have brain-protective effects in Parkinson’s disease.
For example, one study involving 10 patients revealed that high-intensity interval training (HIIT) preserved dopamine-producing neurons in Parkinson’s disease. This is especially relevant when considering that the destruction of these neurons is a critical factor in the progression of the disease.
Exercise programs should be moderate to vigorously intense, last from 45-60 minutes, and done at least twice weekly. Be sure to check with your healthcare provider before starting any new exercise regimen to make sure it is safe for you.
Staying hydrated is also important. Swallowing problems and a reduced ability to detect thirst (which also can happen as we age) can keep people from drinking enough water. Further, dehydration can worsen GI issues like constipation and slow digestion, while also increasing fatigue and brain fog. Proper hydration promotes regular bowel movements, helps your body process medications, and is good for your overall well-being.
Beyond gut health: probiotics, the brain, and Parkinson’s
PD is a gut-brain disease, not just a brain disease. Depending on the person, the aggregation of toxic proteins that lead to motor symptoms may begin in the gut or the brain. Many people also experience both brain and gut symptoms.
The good news is that regardless of where PD starts, the microbes in your gut can positively impact your quality of life.
Care for your natural microbiome and your digestive system by following a healthy diet that is high in fiber and low in added sugars.
Care for your brain by considering dietary management with a gut-brain psychobiotic that may influence brain dopamine, as suggested by preclinical studies.
The psychobiotic PS128 has shown promising brain health benefits in Parkinson’s disease-like models and pilot studies. Unlike probiotics that primarily support digestion, PS128 may impact neurological function by influencing dopamine levels - a key factor in PD symptoms.
If you or a loved one is managing Parkinson’s disease, you may find a benefit from the gut-brain probiotic L. plantarum PS128, the main ingredient in Neuralli MP. The psychobiotic PS128 may support longer “on” times and quality of life as a nutritional add-on.**
**Neuralli MP is a probiotic medical food that provides dietary management of autism and Parkinson’s disease. PS128 was used in a single-arm pilot study alongside levodopa.
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