Parkinson’s disease (PD) is a complex neurodegenerative disorder that affects movement and non-motor systems such as digestion, cognition, mood and even weight management. Emerging research reveals a fascinating connection between PD and the gut microbiome - the vast community of microorganisms that live in our digestive system. Understanding this relationship offers a promising way to help manage symptoms and improve quality of life for those affected by PD.

How Does the Gut Microbiome Impact Parkinson’s Disease?

1. An Imbalanced Microbiome (Gut Dysbiosis)

In PD, studies show a clear pattern: the gut microbiome becomes disrupted. There’s often a drop in beneficial bacteria and an increase in less friendly ones (pathobionts). This imbalance- called dysbiosis - can lead to digestive troubles, poor nutrient absorption, and even inflammation that spreads from the gut to the brain via the gut-brain-axis. Certain microbial byproducts, like lipopolysaccharides (LPS), can trigger this inflammatory response, which is thought to contribute to PD progression.

2. Weight Loss and Nutritional Gaps

Weight loss is common in people with PD, partly due to changes in gut health. A reduction in short-chain fatty acids (SCFAs) - produced by specific gut bacteria - can weaken the gut barrier and impair nutrient absorption. Key players like Faecalibacterium and Roseburia, known for producing SCFAs like butyrate, are often found in lower levels in people with PD.

3. Gut Permeability and Parkinson’s Disease

Emerging evidence shows that increased intestinal permeability, or "leaky gut," plays a significant role in PD. In PD, the gut barrier - maintained by tight junction proteins - becomes compromised, allowing harmful microbial products like lipopolysaccharides (LPS) to enter the bloodstream. This contributes to systemic inflammation and neuroinflammation, both of which may exacerbate PD progression (Forsyth et al., 2011).

Gut dysbiosis, or an imbalance of gut bacteria, is a major contributor to this dysfunction. A reduction in beneficial bacteria, such as SCFA producers, weakens the gut barrier by impairing tight junction integrity. Dysbiosis also increases the presence of pro-inflammatory toxins and oxidative stress, further damaging the gut lining (Caputi & Giron, 2018).

Other factors, such as chronic stress, processed diets, certain medications (e.g., NSAIDs), and gastrointestinal infections, can exacerbate gut permeability by disrupting the mucosal layer or altering the gut microbiome (Schwiertz et al., 2018). Animal studies support these findings, showing that gut barrier dysfunction can precede and accelerate PD-related alpha-synuclein accumulation in the colon (Kelly et al., 2014).

Addressing leaky gut through high-fibre diets, stress reduction, and gut-targeted therapies may help protect the gut barrier, reduce systemic inflammation, and potentially slow disease progression in PD.

4. The Gut-Brain Axis and Neuroinflammation

The microbiota-gut-brain axis is a two-way communication network between the gut and brain. Dysbiosis can upset this balance, increasing inflammation in both the gut and brain. This contributes to worsening motor and non-motor symptoms in PD, highlighting the critical role of gut health in managing the disease.

Supporting Gut Health Through Diet

Adopting a gut-friendly diet is one of the simplest and most effective ways to nurture your microbiome. A Mediterranean-style diet is particularly beneficial, focusing on:

Fibre: Found in whole grains, legumes, fruits, vegetables, and nuts.
Healthy fats: Extra virgin olive oil and omega-3s from fatty fish.
Polyphenols: Compounds in green tea, berries, and dark chocolate that encourage beneficial bacteria like Bifidobacterium.
Fermented foods: Yoghurt, kefir, and sauerkraut, which provide probiotics and prebiotics to support microbial diversity.

This type of diet helps increase beneficial bacteria and SCFA production, reducing inflammation and improving nutrient absorption.

Enhancing Gut Health with Prebiotics and Gentle Herbal Support

Fuelling Friendly Bacteria with Prebiotics

Prebiotics are specific fibres that nourish healthy gut bacteria. For those with PD, prebiotics like inulin, fructo-oligosaccharides (FOS), and resistant starch (found in foods like cooked then cooled potatoes and green bananas) can be particularly helpful. They support bacteria like Faecalibacterium and Roseburia, which produce SCFAs vital for gut and brain health.

Supporting Bifidobacteria in Parkinson’s Disease

Bifidobacteria, including Bifidobacterium bifidum, play a vital role in maintaining gut health by producing short-chain fatty acids (SCFAs), supporting gut barrier integrity, and reducing inflammation. These functions are particularly relevant for Parkinson’s disease (PD), where gut dysbiosis and neuroinflammation are common features.

To support Bifidobacteria in PD, it is best to nourish the existing microbial colony through prebiotics like inulin, resistant starch, and fructo-oligosaccharides (FOS). These fibres feed indigenous Bifidobacteria, helping to restore microbial balance and improve gut function (O’Callaghan & van Sinderen, 2016).

If microbiome testing reveals a significant absence of Bifidobacteria, introducing a specific probiotic strain may help temporarily re-establish populations. However, sustaining these benefits requires prioritising dietary prebiotics to ensure long-term microbial diversity and health.

Supporting the Gut Barrier Function

Maintaining a healthy gut barrier is essential in managing Parkinson’s disease (PD). Key strategies to support the gut barrier include:

Enhancing Butyrate Production:

Butyrate, a short-chain fatty acid (SCFA), is a vital energy source for colon cells and helps maintain tight junction proteins. Consuming prebiotics like resistant starch, inulin, and fructo-oligosaccharides (FOS) can promote butyrate production by supporting beneficial bacteria such as Faecalibacterium prausnitzii and Roseburia (Singh et al., 2023).

Encouraging Beneficial Microbes:

Akkermansia muciniphila and Faecalibacterium prausnitzii are key bacteria for gut health. Akkermansia strengthens the mucosal lining, while Faecalibacterium produces anti-inflammatory SCFAs. A diet rich in fibre and polyphenols (e.g., berries, pomegranate, green tea) supports their growth (Ottman et al., 2017).

L-Glutamine:

This amino acid is a critical fuel source for intestinal cells and can aid in repairing damage to the gut lining. Supplementation may help restore mucosal integrity in cases of increased permeability.

Zinc:

Zinc is essential for tight junction maintenance and immune function. Foods like pumpkin seeds, lentils, and chickpeas or a targeted supplement can help strengthen the gut barrier.

Incorporating these dietary and supplemental strategies into a personalised care plan can significantly improve gut barrier function, reducing inflammation and supporting overall health in PD. Always consult a healthcare provider before starting supplements or dietary interventions.

Herbal Strategies for Gut and Brain Health in Parkinson’s Disease

For managing gut dysbiosis and neuroinflammation in Parkinson’s disease (PD), natural antimicrobials, anti-inflammatory herbs, and nootropics offer a gentler approach compared to conventional antimicrobial treatments. However, any use of herbal remedies should be undertaken with caution, particularly for patients taking medication, as herb-drug interactions are a potential risk.

Certain herbs can gently reduce harmful bacteria without disrupting the overall microbial balance:

Pomegranate Husk: A Gentle and Effective Antimicrobial

Pomegranate husk is rich in polyphenols, particularly ellagitannins, which provide dual benefits:

Antimicrobial Effects: Targets pathogenic bacteria like Clostridium difficile while sparing beneficial species such as Bifidobacterium and Lactobacillus (Bialonska et al., 2009).
Prebiotic Support: Promotes the growth of beneficial gut microbes by providing substrates that are metabolised into anti-inflammatory compounds, such as urolithins (Espín et al., 2013).

Oregano Tincture:

Why Tincture, Not Oil? Oregano tincture offers antimicrobial benefits without the overwhelming strength of oregano oil, which can disrupt the microbiome if misused.
Effectiveness: Contains carvacrol and thymol, which target pathogens while preserving microbial balance when used appropriately.

Garlic Extract:

Antimicrobial Action: Garlic’s allicin is a broad-spectrum antimicrobial, effective against certain pathogens.
Use with Caution: While effective, garlic may impact beneficial microbes if used excessively, so it should be employed for short-term interventions under supervision.

Green Tea: Anti-Inflammatory and Antimicrobial

Green tea, rich in catechins like epigallocatechin gallate (EGCG), offers multiple benefits:

Mild Antimicrobial Action: Effective against harmful gut bacteria without disrupting beneficial microbes.
Neuroprotective and Anti-inflammatory Properties: Green tea reduces oxidative stress and inflammation in the brain, supporting overall neurological health (Mandel et al., 2011).

It’s essential to use these herbs with professional guidance to ensure they fit safely into your care plan.

Evidence-Based Probiotics for Parkinson’s Disease

Probiotics can play a critical role in supporting gut health and reducing systemic inflammation in Parkinson’s disease (PD). Clinical trials and studies have highlighted several strains with specific benefits:

Lactobacillus plantarum PS128:

Benefits: Associated with improvements in motor symptoms and reductions in anxiety in PD patients.
Clinical Evidence: A study demonstrated that supplementation with L. plantarum PS128 positively affected mood and motor function, likely by modulating the gut-brain axis (Lin et al., 2020).

Bifidobacterium bifidum:

Benefits: Enhances short-chain fatty acid (SCFA) production, improves gut barrier integrity, and may reduce neuroinflammation.
Reference: While specific PD studies are limited, evidence supports the role of B. bifidum in promoting gut health and mitigating inflammatory responses (O’Callaghan & van Sinderen, 2016).

Lactobacillus rhamnosus GG:

Benefits: Shown to reduce lipopolysaccharide (LPS) levels, which can decrease systemic inflammation and protect the gut barrier.
Clinical Evidence: L. rhamnosus GG has been demonstrated to lower LPS and systemic inflammation in various populations, including those with gut-related conditions (Forsyth et al., 2009).

These probiotics should always be chosen in consultation with a healthcare provider to ensure they align with individual needs and medical history.

Key Takeaways for Patients and Clinicians

Caring for gut health offers a practical, evidence-based way to support people living with Parkinson’s disease. Here’s a quick summary:

Adopt a Mediterranean diet with plenty of fibre, healthy fats, and fermented foods.
Add prebiotics like inulin and resistant starch to encourage beneficial bacteria.
Heal your gut barrier by balancing your microbiome and supporting barrier function with diet and supplements.
Use herbal antimicrobials carefully, under professional guidance.
Incorporate targeted probiotics to address specific gut imbalances.

Taking small, thoughtful steps toward better gut health can make a meaningful difference in managing PD symptoms and improving quality of life.

If you’re living with Parkinson’s or caring for someone who is, consider speaking to a healthcare provider or microbiome specialist about the best strategies for you.

If you’re ready to take the next step in supporting your gut and brain health, feel free to reach out - I’m here to help guide you on your journey.

Nurturing Gut Health in Parkinson’s Disease: Practical Insights for Patients