The Connection Between Gut Health and Alzheimer’s Disease

Table of Contents

1. What Is the Gut-Brain Connection?
2. How Your Gut Affects Your Mood, Memory, and Mental Health
3. The Connection Between Gut Health and Alzheimer's
4. How to Take Better Care of Your Gut
5. Protect Your Brain by Healing Your Gut
6. FAQs

I have said it before, and I will say it again: The gut is the gateway to health. If your gut is not healthy, neither are you. Your gut does far more than digest your food. It shapes your immune system, your mood, your focus, and even your long-term brain health. More and more research is uncovering the powerful gut and brain connection, including its role in age-related cognitive conditions such as Alzheimer's.

The numbers are striking. An estimated 7.2 million Americans age 65 and older now live with Alzheimer's, and about two-thirds of them are women. (1) Here, I will walk you through the gut-brain connection, how your gut influences your mood and mental health, what the research reveals about its link to Alzheimer's, and the steps you can take to heal your gut and protect your brain.

What Is the Gut-Brain Connection?

The gut-brain connection, often called the gut-brain axis, is the constant two-way communication system that links your nervous system, your immune system, and your gut microbiome. Your gut and brain are always talking to each other, even right now.

This conversation travels along two channels:

• Brain to gut: Your central nervous system (CNS), made up of your brain and spinal cord, carries signals down to your gut. This is why stress and anxiety can so quickly upset your digestion.

• Gut to brain: Your enteric nervous system (ENS), sometimes called your "second brain," carries signals from your gut back up to your brain.

One of the most remarkable parts of this connection is serotonin. Your gut produces roughly 90 to 95% of your body's serotonin, the neurotransmitter that helps regulate mood, sleep, and a balanced nervous system. (2) A healthy, diverse microbiome supports balanced mood, healthy immune function, and a healthy inflammatory response.

How Your Gut Affects Your Mood, Memory, and Mental Health

When your gut microbiome falls out of balance, the effects reach far beyond your digestion. Toxins can leak through a weakened gut wall, activate your immune cells, and drive chronic inflammation that travels to your brain.

In the short term, this can show up as brain fog, low mood, and anxiety, the everyday signs that your gut mind connection is under strain. Left unchecked over months and years, that same ongoing inflammation can contribute to neurodegeneration. This is why caring for your gut matters at every age, not only later in life.

The Connection Between Gut Health and Alzheimer's

A growing body of research links gut health to Alzheimer's through three primary mechanisms.

1. Brain Inflammation and Leaky Brain

Chronic, systemic inflammation can impair your blood-brain barrier, the protective layer of cells that normally shields your brain from harmful substances. When that barrier weakens, you can develop what is known as "leaky brain," which parallels leaky gut and allows toxins to reach brain tissue. This contributes to neuroinflammation and the buildup of amyloid-beta plaques associated with Alzheimer's. (3)

2. Cholesterol and Bile Acid Metabolism

Your gut microbiome helps regulate how your body clears cholesterol and converts bile acids. As your liver breaks down cholesterol, it produces primary bile acids, which your gut bacteria then convert into secondary bile acids. Research has found that people with Alzheimer's tend to have fewer primary bile acids and higher levels of secondary bile acids, a pattern linked to cognitive decline. (4)

3. Age-Related Microbiome Changes

Your microbiome naturally becomes less diverse as you age, and reduced diversity has been linked to accelerated aging and chronic disease. A meta-analysis identified specific bacterial genera, including Collinsella, Veillonella, and Eubacterium, that are associated with a higher risk of Alzheimer's. (5)

The reframe is empowering: keeping your microbiome healthy and diverse is one of the most proactive ways to support your brain as you age.

How to Take Better Care of Your Gut

Supporting your gut is one of the most powerful steps you can take for lifelong cognitive health. Here is where to begin. Start by following the 4R Approach.

4R Approach to Healing Your Gut: Remove, Restore, Reinoculate, and Repair

Step 1: Remove the bad

• Remove inflammatory and toxic foods from your diet and remove intestinal infections such as Candida overgrowth, SIBO, and parasites.

• Determine if you have gut infections → SIBO Quiz or Candida Quiz

Step 2: Restore what’s missing

• Everyone needs to restore optimal digestion of proteins, fats, fiber, and carbohydrates by adding digestive enzymes. At a minimum, I recommend adding a complete digestive enzyme.

• If you are low in stomach acid or have GERD you could likely benefit from adding in HCl 

• If you have had your gallbladder removed or struggle to digest fats, you could benefit from adding in Bile Builder Complete.

• If you are dealing with Histamine Intolerance, consider adding Histazyme in this step, which is formulated with DAO to help break down histamine from foods.

Step 3: Reinoculate and balance with healthy bacteria

• Repopulate the good bacteria in your gut with a high-quality probiotic such as Probiotic 30 Billion for daily maintenance or Probiotic 100 Billion for maximum digestive support. Then balance your immune system in your gut with beneficial immunoglobulins.

• If you have SIBO, choose a soil-based probiotic such as Primal Earth Probiotic to avoid adding fuel to the fire.

Step 4: Repair the gut

Providing necessary nutrients helps the gut repair itself. Herbs such as slippery elm, marshmallow root, and aloe vera found in Leaky Gut Revive® help to produce more mucus which is the protective barrier in your gut.

Protect Your Brain by Healing Your Gut

The gut-brain connection weaves together several of your body's most important systems, and the science continues to confirm what I have always believed: a healthy gut supports a healthy brain. Supporting a diverse, balanced microbiome is one of the most proactive things you can do for your mind at any age. When you remember that "The gut is the gateway to health," protecting your brain becomes one more powerful reason to care for your gut through the Four Pillars of The Myers Way®.

FAQs

• What is the gut-brain connection?
  The gut-brain connection, also called the gut-brain axis, is the constant two-way communication network that links your gut and your brain through your nervous system, immune system, and gut microbiome. Your central nervous system carries signals from brain to gut, while your enteric nervous system, sometimes called your "second brain," sends signals from gut to brain. This is why what happens in your gut can directly influence your mood, focus, and long-term brain health, and why stress and anxiety can so quickly upset your digestion.
• How does gut health affect mental health?
  Your gut produces roughly 90 to 95% of your body's serotonin, the neurotransmitter that helps regulate mood, sleep, and emotional balance. (2) When your microbiome is out of balance, it can drive inflammation and disrupt the production of these mood-regulating chemicals, which may contribute to low mood, anxiety, and brain fog. Supporting a healthy, diverse microbiome is one of the most overlooked ways to support a balanced mind.
• Is there really a link between gut health and Alzheimer's?
  Yes, a growing body of research points to several connections. Chronic gut-driven inflammation can impair the blood-brain barrier and contribute to the neuroinflammation and amyloid-beta plaque buildup associated with Alzheimer's. (3) Studies have also linked altered bile acid metabolism and specific gut bacteria to cognitive decline. (4)(5) While research is ongoing, the evidence consistently shows that a healthy gut supports a healthy brain.
• What is "leaky brain" and how is it related to leaky gut?
  "Leaky brain" refers to a weakened, more permeable blood-brain barrier, the protective layer of cells that normally shields your brain from harmful substances. Just as chronic inflammation can loosen the tight junctions of your gut lining to create leaky gut, it can also compromise the blood-brain barrier, allowing toxins to reach brain tissue. The two are closely connected, because the same systemic inflammation that drives leaky gut can also contribute to leaky brain.
• What is the best way to improve gut health for brain health?
  Start with your diet: remove inflammatory foods like gluten, dairy, and ultra-processed foods, and focus on fiber-rich vegetables, clean proteins, and wild-caught fish. From there, repairing the gut lining with a formula like Leaky Gut Revive® and reinoculating with a high-quality probiotic helps restore a healthy, diverse microbiome. Pair these with stress relief and quality sleep, since both directly influence the gut-brain axis.