Optimizing Your Microbiome and Liver Health for Better Brain and Hormonal Health: Part I

The Many Wonders of the Microbiome

Throughout almost every topic I have written about, especially hormones and brain health, I have weaved in the influence that the tiny bugs that inhabit our bodies, specifically the ones taking residence in the digestive tract, have on our health outcomes. This is because, if you want to balance your emotions and/or endocrine system, you can’t ignore the importance of our gut microbiota.

In fact, the more researchers dig into the role that our gut microbiome (the collection of all microbes, such as bacteria, fungi, and viruses, and their genes) has on both our physical and psychological states, the more we are awed. Their discoveries have led both conventional and integrative medicine doctors to call a truce and conclude what naturopaths have said throughout time: we need a healthy digestive tract to maintain health, resiliency, a positive mood, and to age gracefully.

These microbes in our gastrointestinal system have broad and impressive functions which has earned them the respect that they are receiving. These include:

·        synthesizing, assimilating, and absorbing nutrients

·        metabolizing and excreting toxins and wastes

·        housing over 70% of our immune cells

·        producing 90% of our serotonin and other vital neurochemicals

·        regulating hormone excretion

·        communicating with our brain to help supervise many bodily processes through the gut-brain axis

·        skin health (yes, there’s even a gut-skin axis)

The Power of Our Hormones

Our hormones control and coordinate many interactions in the body as well, including:

• metabolism (e.g., maintaining homeostatic balance of blood pressure, blood sugar, temperature, cellular energy, and more)
• reproduction, fertility, and sex drive
• growth and development
• responses to injury, stress, infections, and/or environmental factors
• mood
• digestive function

The Microbiome-Hormone-Liver Health Link

If you take into account the powerful impact that both our microbes and hormones have on our health, and add to this how vital the liver is in influencing almost all bodily processes, including hormones as it interacts with the gut…

You can understand why one can’t gain much ground in living a wellness lifestyle without an optimized digestive system.

I’ve highlighted before the importance of the connection between the gut and brain, thyroid and gut, and liver and hormones.

Now, it’s time to discuss how a healthy interchange between the liver and the gut, the liver-gut axis, is vital for achieving mind-body harmony.

We’ll begin with a review of the many wonders of the liver. Next, we’ll discuss the liver-gut connection. Finally, I’ll highlight what “leaky gut”, aka intestinal permeability, is and how it relates to a healthy interchange between the liver and gut.

For those who missed out on my previous posts, I’ll provide the full links for more details, but I will also summarize along the way to connect all the cognitive dots. (Welcome new subscribers and clients!)

Let’s get started…

*Note: This post is based on one of my publications within the 10 article series that I wrote for Rupa Health. As usual, it contains some additional information and my clinical experience.

A Review of the Liver Functions… Again

Your liver is a superstar multitasker. It is responsible for managing over 500 different functions while interacting with virtually every organ in your body. Along with its most well-known roles in detoxification and digestion, our liver does the following:

– regulates most chemicals in the body

– processes all the blood leaving the stomach and intestines

– breaks down, balances, stores, and creates nutrients

– expels bile to carry away wastes

– produces proteins that regulate metabolism, signaling compounds, hormones, nutrient status, and various other metabolic functions

– metabolizes drugs and harmful compounds (from the environment and internally) into non-toxic byproducts to be excreted

– regulates, metabolizes, activates, inactivates, and coverts hormones

– interacts with our gut microbiome to assist with estrogen recycling and toxin and waste metabolization and excretion

Based on the effects the liver and our microbiome have on our health, any breakdown in either can lead to inflammation, liver disease, hormonal deregulation, and many other bodily symptoms and diseases.

This means that knowledge about the liver-gut axis, including how it becomes dysfunctional and how it gets rejuvenated, is critical to enhance and empower our lives.

What is the Liver-Gut Axis?

Just as there is a two-way communication axis between the gut-brain and the gut-thyroid, there is a bidirectional relationship between the gut-liver. These critical interactions not only affect the function of one another, but also play vital roles on other organs.

Genetics, nutrients, microbial byproducts, lifestyle factors, and liver bile acids all influence and help to regulate the metabolism, immunity, and health of the gut microbiome and liver.

The portal vein (a blood vessel that carries blood from the gastrointestinal tract, gallbladder, pancreas, and spleen to the liver) serves as the bi-directional connecting link between the gut and the liver. This feedback loop between the gut and liver is called enterohepatic circulation, and it determines the amount of bile acids produced, which is necessary for effective detoxification and digestion of fats.

Bile Production and Gut Microbes

The portal vein is responsible for the delivery of metabolites made in the intestines to the liver. These serve to stimulate the liver to produce bile as well as antibodies. Bile and these immune substances are then cycled back into the digestive tract where they can be further metabolized by its microbes. In fact, it is within the gut lining that bile acids are transformed into secondary bile acids.

Whereas primary bile acids effect cholesterol metabolism, lipid digestion, and host-microbe interactions, secondary bile acids influence inflammation and can lead to diseases of the colon. Thankfully, certain gut microbes can produce metabolites, such as short chain fatty acids, to balance out this inflammation and promote a healthy gut.

Therefore, if there is any disturbance in this process, including an unhealthy microbe population, it can compromise the gut lining and the gut vascular barrier (GVB). The GVB is what regulates the metabolites produced by the gut microbiome to enter the portal vein.

The Importance of Intestinal Barrier Integrity

What is Leaky Gut?

In a healthy gut, the inner lining of the intestinal wall is an intact barrier which selectively filters through helpful molecules and prevents access of potentially dangerous compounds. It allows water and nutrients to cross it, while it inhibits undigested food, toxins, bacteria, and viruses to enter the bloodstream.

Our intestinal barrier is one of the major players in our immune response. It helps to maintain gut and immune tolerance by separating gut microbiota and human immune cells. This fulfills two seemingly opposing functions:

(1) to allow for a peaceful co-existence between intestinal microbes and what our body needs for nourishment, without causing chronic inflammation, and

(2) to allow for an inflammatory and defensive response if there is a threat from pathogens

A healthy digestive tract has multiple layers of defense to do this job. They include:

1. The external mucus layer. It is composed of microbiota on the outside and an inner layer of sparse bacteria and peptides (components of proteins) with antibacterial functions.
2. The middle intercellular junctions. A thin layer of intestinal cells with three sets of intercellular junctions: tight junction [zonula occludens (ZO)], adherens junction (zonula adherens), and desmosome comprise the apical junctional complex. This supports the brush border of the intestinal barrier and regulates its function and transport between cells.
3. The outer gut vascular barrier (GVB). The final defensive shield is the GVB which regulates the release of microbial metabolites into the portal circulation.

A breakdown in the intestinal barrier can occur in any one of these places: the mucus layer, tight junctions, or the GVB.

Causes of Leaky Gut

Various triggers can cause the inner lining of the intestinal wall to “leak,” aka the term “leaky gut.” Specifically, intestinal permeability can be fueled by:

• certain medications
• stress
• excessive exercise
• lifestyle
• toxic exposures
• inflammatory dietary components (which are related to individual responses)
• alcohol
• infections
• food sensitivities (related to the lack of specific enzymes or due to digestive disorders)

“Leaky gut” is a symptom, not a diagnosis.

The Consequences of Leaky Gut on the Liver and Overall Health

With a breakdown in the gut barrier, it can no longer prevent larger, unfiltered particles from crossing into the bloodstream. This allows for detrimental substances to enter systemic circulation. When the GVB is affected, inflammatory metabolites or microbes can spread throughout the body and recycle back into the liver. This can lead to liver inflammation, liver pathologies, and numerous other health conditions.

Intestinal permeability (leaky gut) is currently gaining more attention in research and in clinical applications. This is related to a rise in awareness of how gut health impacts all diseases. For example, there have been associations with leaky gut to chronic inflammatory health conditions such as Celiac disease, Crohn’s disease, autoimmune disorders, neurological disorders, and mood disorders.

Summary of the Gut-Liver Axis

The gut and liver are connected through the portal vein. They influence each other through the metabolites they produce through this interaction. Pathological alterations in the gut flora and enhanced intestinal permeability from various lifestyle, genetic, and environmental factors can lead to inflammatory changes in the liver and microbiome. This can result in systematic liver, gut, and chronic diseases.

Thankfully, naturopathic doctors have been schooled in treating “leaky gut” long before it become popular. One can use a combination of naturopathic and functional medicine modalities to assess and address the underlying triggers and mediators that lead to intestinal wall damage, microbiome changes, and resultant gut-liver axis dysfunction.

In the follow up post, I’ll discuss more about how harm to our microbiome and intestinal barrier can fuel liver disease. Then, I will highlight in more detail specific conventional and functional testing that can be done to assess liver-gut health. Finally, I will complete this circular axis with some complementary information on how to keep your microbiome and liver healthy throughout the lifespan, using naturopathic and functional medicine strategies.

In the meantime, take this knowledge and start applying some liver healthy tips I highlighted at the end of this article here.

Stay tuned.

Naturopathic Medicine and Holistic Resources for Hormonal, Mood, and Digestive Support

• Free resources and more education on essential oils and mind-body wellness are available to you here.
• An Integrative Mental Health and Stress Resource Guide.
• Tools for coping with isolation and separation.

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References

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5017946/

https://pubmed.ncbi.nlm.nih.gov/33670115/

https://pubmed.ncbi.nlm.nih.gov/31622696/

https://www.mdpi.com/1422-0067/23/1/426

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8085382/

https://pubmed.ncbi.nlm.nih.gov/36208625/

https://www.journal-of-hepatology.eu/article/S0168-8278(19)30604-X/fulltext

https://pubmed.ncbi.nlm.nih.gov/30862015/

https://www.rupahealth.com/post/what-is-leaky-gut

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4253991/

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6790068/

https://pubmed.ncbi.nlm.nih.gov/31076401/

https://www.medicalnewstoday.com/articles/326117#causes-and-risk-factors

https://my.clevelandclinic.org/health/diseases/21688-food-intolerance

https://www.health.harvard.edu/blog/leaky-gut-what-is-it-and-what-does-it-mean-for-you-2017092212451

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8427160/

See the full article and additional references in the Rupa article here.