The intimate connection between your gut and brain health

There’s a close, bidirectional connection between your gut and your brain. It’s called the gut-brain axis.

If your brain isn’t functioning well, it can lead to ongoing digestive symptoms.

Conversely, if your gut is compromised, it can affect your brain function.

Your gut is your second brain

Like your brain, your gastrointestinal tract has a nervous system that includes neurons, neurotransmitters, and electrical signals. Called the enteric nervous system or ENS (as opposed to our central nervous system), it is sometimes referred to as the ‘second brain’.

The ENS is made up of two thin layers with more than 100 million nerve cells in them, including in the spinal cord. These cells also line the gastrointestinal tract, controlling blood flow and secretions to help us digest food. This is what helps us feel what’s happening in our gut.

While your second brain doesn’t get involved in thought processes, it does control behaviour on its own, making digestion more efficient in your body through this on-site brain that handles things closer to the source.

In addition, it appears that your gastrointestinal tract contains chemical messengers – peptides and hormones – that profoundly impact the brain’s immune system and its neurotransmitter pathways (neurotransmitters are brain chemicals that relay information between neurons and affect brain function, mood, personality and more).

Your vagus nerve

The communication between your gut and brain happens through your vagus nerve, a large, wandering nerve that starts in the brain stem and connects with all or your organs and gut.

This nerve makes it possible for the brain to play its critical role in gut function.

Your brain releases stomach acid and digestive enzymes to break down food, controls the movement of food through your intestines (motility, or muscle contractions), and regulates the flow of blood carrying key nutrients to support gut health.

Poor brain function can affect YOUR vagus nerve

When your brain ages, degenerates or becomes impaired, brainstem activation may be compromised. Because the brain stem sits at the rear base of the brain and leads to the vagus nerve, compromised brain function can lead to in sufficient output (like a muscle not getting exercised), which in turn can hinder the vagus nerve.

The consequence of this can be low stomach acid leading to poor digestion of proteins and fats, poor gut movement and constipation, and intestinal bacterial and yeast overgrowths.

Poor brain function can cause leaky gut

Poor brain health, brain trauma or brain degeneration decreases vagus nerve activation. This inhibits blood flow to the intestines, which prevents the intestinal wall from functioning and regenerating normally.

This can lead to the development of intestinal permeability known as ‘leaky gut’, where your gut wall becomes too porous.

This leakiness allows large, improperly digested proteins, bacteria, fungi, parasites and other pathogens to cross the intestinal wall directly into your bloodstream where they alert the immune system to attack and destroy not only the pathogens, but eventually body tissue. This is called autoimmunity.

With leaky gut, this immune activation is constant, leading to inflammation across your entire body causing pain, food sensitivities, rashes, brain health issues, mood problems and other symptoms. In fact, most disease is linked to inflammation.

The irritation can also lead to a build-up of mucous on the intestinal wall that results in mal- absorption of key nutrients. In addition, damage to the intestinal mucosa can make the gastrointestinal tract unable to produce enzymes to digest food.

In a vicious cycle, this leads to malnutrition, further intestinal inflammation, further permeability, and the development of food sensitivities, bacterial and yeast overgrowths, and poor intestinal immune health. Our gut is where 70-80% of our immune system lives.

Gut flora and your brain

Our gut flora, the kilo of bacterial organisms that we carry in our intestines, affects our brain chemistry. To put the importance of our microbiome into perspective, most of our DNA is not human, but that of our microbiome meaning we are co-dependent.

Healthy gut flora serves many critical roles. But poor diet, stress, excess sugar and refined carbohydrates, the overuse of antibiotics and over the counter medicines, and other factors tip the balance of gut flora so that harmful bacteria and other pathogens outweigh the beneficial.

Studies implicate such imbalances in our gut flora in mood disorders like depression and various psychiatric disorders.

It may be more accurate to describe our gut-brain axis as our microbiota-gut-vagus-brain axis.

Leaky gut can cause depression

Leaky gut also plays a role in severe depression by allowing harmful bacteria into the bloodstream. These bacteria carry lipopolysaccharides (LPS) in their membranes, large molecules that trigger inflammation. LPS inflame the gut wall and cause inflammation throughout the body once they’ve entered your blood stream.

These inflammatory cell signalling molecules (cytokines) also activate the brain’s immune system, creating brain inflammation and degeneration, altering how well neurons function and communicate. This can ultimately change brain function and cause severe depression.

This inflammatory mechanism is called the ‘cytokine model of depression’ and it relates to inflammation in the brain rather than a lack of neurotransmitters.

What you can do to improve your gut-brain axis health

Eat a whole foods diet
Reduce starchy foods – sugars and refined carbohydrates like flours
Drink plenty of clean water
Do vagus nerve exercises regularly – gargle, sing loudly, gag, do yoga and pranayama (breathing) and meditation, have coffee enemas
Reduce stress
Reduce alcohol an over-the-counter drugs
Move regularly
Restore your gut microbiome through a natural 5Rs protocol
1. Remove pathogens
2. Replace deficient natural digestive juices like stomach acid and digestive enzymes
3. Reinoculate your gut with healthy beneficial bacteria
4. Repair the gut lining
5. Rebalance your gut and lifestyle