Your gut microbiome is capable of many fascinating things–and while the phrase “gut bacteria” doesn’t conjure up delightful imagery, integrative doctors believe it may hold the key to better understanding neurodegenerative diseases like Alzheimer’s and Parkinson’s.
Come along as we explore the role your gut–and that of your microbiome–plays in influencing brain health for decades to come. Plus, you’ll learn simple ways you can promote a healthy gut beginning today.
Alzheimer’s & Parkinson’s
Alzheimer’s and Parkinson’s disease are the two most common neurodegenerative disorders, causing significant daily impact to individuals suffering, as well as their friends, family, and caregivers (1). In 2016, an estimated 5.3 million Americans were living with Alzheimer’s alone, and more people living longer means more may be affected by neurodegenerative diseases in the coming decades.
Because of this, it’s imperative that integrative medicine continues working to understand how gut bacteria influence the brain, and the interventions we can make now that will impact our brain health later.
Before we continue, let’s take a moment to understand what’s considered a neurodegenerative disease, and some common symptoms.
What Are Neurodegenerative Diseases?
Neurodegenerative diseases are a group of disorders characterized by the progressive worsening (degeneration) of the structure or function of the brain or nervous system (2). This impairs the communication from one neuron–or brain cell–to another.
This progressive degeneration of cellular communication causes symptoms in movement, speech, cognitive function (like learning and memory), or personality.
Dementia is an umbrella term encompassing the collection of conditions caused by the neurodegeneration itself, and include (3):
- Alzheimer’s
- Parkinson’s disease
- Creutzfeldt-Jakob’s disease
- Lewy body dementia
- Vascular dementia
- Posterior cortical atrophy
- Normal pressure hydrocephalus
The change in structure or function of the brain causes various forms of miscommunication between neurons, or cells within the brain, and this can have a wide range of symptoms.
Symptoms of Dementia and Neurodegenerative Disease
Symptoms of dementia or neurodegenerative diseases can appear suddenly, or take several years to progress to a point where they impact daily life. The systems most affected include:
- Behavior: Changes in personality, new irritability or anger, depression, anxiety, or mood swings.
- Speech: Trouble finding words or completing sentences; difficulty holding a conversation.
- Movement: Loss of balance, tremors, weakness.
- Cognition: Memory loss, difficulty remembering names, faces, events, and constantly misplacing items.
If you or someone you love is experiencing symptoms of neurodegeneration or Alzheimer’s, contact CentreSpringMD today to find out how integrative medicine can help you better manage brain health.
Though scientists once believed only the brain acted upon the body, and not the reverse, we now know that what occurs in the rest of the body also impacts the brain. This is referred to as bidirectional communication, and one example of this is the connection between the gut and your brain.
The Gut-Brain Connection
If you’ve ever experienced “butterflies” in your stomach in reaction to something exciting or scary, this is a perfect example of the gut-brain connection.
Hormones, immune cells, neurons, and gastrointestinal cells all interact to provide feedback amongst themselves, and to the brain (4).
Within your digestive tract, there’s an expansive and diverse array of bacteria, fungi, and other microbes that are a part of this communication, known as your microbiome.
Every person’s microbiome is highly adapted to them as an individual and helps carry out metabolic and biological processes that keep our body functioning. Factors such as diet, stress, and exposure to other microbes or antibiotics change the gut microbiome throughout life, creating a microbiome that’s as unique to each individual as their fingerprint.
How Your Gut Microbiome Impacts Brain Health
The body’s microbiome has received remarkable attention in recent years for impacting everything from obesity to cancer. And while researchers are still working to fully understand these mechanisms, they believe gut bacteria play a role in neurodegenerative diseases in the following ways.
Vagus Nerve Stimulation
The vagus nerve extends from the brainstem, all the way down into the abdomen. And while it’s most known for its involvement in hunger, satiety, and stress response, scientists have also shown that gut bacteria can impact its signaling function.
Specific bacterial strains have been demonstrated to utilize vagus nerve signaling to communicate with the brain and to alter behavior. For example, Lactobacillus rhamnosus has been shown to impact depressive symptoms and anxiety via the vagus nerve (4)
Further, vagus nerve stimulation has been shown to impact memory, mood, and the production of a specialized protein known as BDNF, which promotes the survival of neurons, the degradation of which is the primary driver for neurodegenerative diseases.
Immune Activation Creates Neuroinflammation
Prior to recent years, researchers believed the immune system was kept separate from the brain. But we now know that specialized cells called microglia can travel to the brain by crossing a threshold known as the blood-brain barrier.
Poor gut health or an imbalance of bad bacteria can trigger inflammation within the gut, activating an immune response that creates oxidative stress (damage) to neurons in the brain (5).
Neuroinflammation Causes Microglia to Turn on Your Neurons
As your brain’s resident immune cells, your microglia help young neurons establish connections, and “prune” damaged or dysfunctioning neurons to protect your brain from disease. But in the presence of Inflammation, microglia turn into their aggressive form in order to defend the brain.
This results in your microglia “pruning” living and healthy neurons, resulting in the loss of connection with other neurons, which can cause severe issues in brain function (5).
Brain inflammation is common in neurodegenerative diseases, as well as mental health disorders, including depression. Usually, when stress signals stop and anti-inflammatory signals are received, microglia go back to first repairing, then protecting the brain.
Blood-Brain Barrier Integrity
Your brain is separated from the rest of circulation by a selectively-permeable membrane known as the blood-brain barrier. This function allows only certain proteins and signaling molecules to pass while keeping harmful microbes out–protecting your brain.
But in the presence of increased immune activation and inflammation, your body’s blood-brain barrier can become increasingly permeable, allowing inflammatory proteins to cross into the brain, triggering stress and damage to brain cells (5).
Gut Health & Alzheimer’s Disease
Alzheimer’s disease disrupts the communication between neurons, leading to a loss of cell function and eventually cell death. Scientists are still working to fully understand the full scope of the factors that cause the disease, but they have found a link between Alzheimer’s, your microbiome, and gut health overall, as evidenced by (6)(7):
- Your microbiome activating the immune system and increasing inflammation within the brain
- Decreased levels of beneficial bacteria responsible for producing protective short-chain fatty acids (SCFA) within the gut.
- Certain bacteria influence the effects of genetic expression, such as the ApoE gene.
These connections open new and promising pathways to the way integrative medicine approaches the prevention and treatment of Alzheimer’s as well as other neurodegenerative diseases like Parkinson’s.
Improving Your Gut Microbiome
Diet, stress levels, lifestyle, and dozens of other aspects work to shape the type and composition of your microbiome and the health of your gut throughout your lifetime.
For a healthy gut:
- Decrease inflammatory foods such as highly processed foods, refined grains, and sugars.
- Maintain a healthy blood sugar balance and insulin sensitivity.
- Support the production of protective SCFA like butyrate by eating healthy fiber from vegetables, fruits, and minimally processed grains like quinoa or oats.
Restore beneficial bacteria:
- With fermented foods or a high-quality probiotic.
- Add a digestive enzyme for better nutrient absorption and more comfortable breakdown of proteins, fats, and carbohydrates
Repair intestinal permeability (leaky gut):
- With adequate intake of collagen, L-glutamine, and anti-inflammatory nutrients.
- Identify your trigger foods (like allergies or food sensitivities), and avoid them.
How do you uncover hidden food sensitivities? You get tested. Learn more about the integrative approach to gut health.
Integrative Medicine and the Gut-Brain Connection
Researchers are currently working hard to fully understand the connection of your gut and microbiome to neurodegenerative diseases like Alzheimer’s and Parkinson’s, but given the current information, there’s no question that the health of your digestive system impacts brain function.
Integrative medicine can help you find functional solutions to promote whole-body wellness which protects your brain and supports the strength and continued communication of neurons, as well as the healthy function of your nervous system.
Could all neurodegenerative diseases really begin in the gut? What steps, if any, are you taking to protect the health of your gut? Follow the CentreSpringMD Facebook page for more daily integrative wellness info, or visit our Contact page to get started with a provider today.
Resources
- https://www.niehs.nih.gov/research/supported/health/neurodegenerative/index.cfm
- https://www.nature.com/subjects/neurodegenerative-diseases
- https://www.alz.org/alzheimers-dementia/what-is-dementia/types-of-dementia
- https://www.sciencedirect.com/science/article/pii/S0896627319301175
- https://www.nature.com/articles/s41467-019-13812-z
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7084682/
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5739464/
