The Magic of the Gut-Brain Connection: A Look at the Science

The Magic of the Gut-Brain Connection: A Look at the Science

If you didn't already know, the gut and the brain are best friends. They gab and chat all day, every day. In fact, they are so interconnected that the gut has been coined our "second brain." While our gut may not speak English in words that we understand verbally, it is certainly communicating every second of every day directly to our subconscious brain. And our brain, in turn, responds in a great many ways. 

The gut and the brain work synergistically together through a bidirectional link that is known as the gut-brain axis. The gut-brain axis links our Central Nervous System (CNS) (which rules our cognition) and our Enteric Nervous System (ENS) (which encompasses the microbiota found in our gut), and they talk to each other via efferent and afferent signals. This basically means that when one isn't functioning properly, the other one will react by exhibiting unfavorable symptoms that might seem - to the untrained eye - to be unrelated to the other. In fact, a lot of what we used to know about the connection between the gut and the brain has been flipped on its head in more recent, comprehensive research.  

Take, for instance, the big emotional shifts - like anxiety or depression - that commonly coincide with gut-related issues such as irritable bowel syndrome (IBS). A high percentage of patients who experience IBS also report symptoms of depression and anxiety. Practitioners used to think that people with anxiety or confounding emotional issues were simply more prone to experiencing IBS, or that these emotional shifts could exacerbate the IBS symptoms. Recent studies out of John Hopkins Center for Neurogastroenterology, however, have found that it's not quite that one-sided! These mental and emotional shifts related to IBS are outcries from our gut signaling to our brain that something is out of whack with our digestive system. Almost like its crying out for help! 

Oppositely, the state of our brain can impact the function of our gut. Most of us have had experience with extreme nervousness (maybe from public speaking or playing in a big sporting event) that prompted us to have to urgently use the restroom. Or perhaps a heart-wrenching break-up caused us lose our appetite altogether. A disturbing piece of news can make you sick to your stomach. These are all common ways our brain and gut interact with each other.  

To put this as simply as possible, if the brain and gut cannot communicate properly to one another because they aren't functioning well, then your physical, emotional and mental health could all suffer as a result. It may consequently be short-sided to treat the brain and the gut as isolated systems. Research is strongly suggesting the benefit of treating them instead as a cohesive unit.

Let’s look at the science:

There are six main pathways in which the microbiota in our gut directly influence the function and health of our brain.

1.     Through the Vagus Nerve. Our intestine will sends signals to the brain which then stimulates the part in our brain called the hypothalamus that is responsible for the regulation of our emotions. All of this happens through our Vagus Nerve.

2.     Neuroendocrine singling, otherwise known as gut signaling. Our microbiome can help stimulate neuropeptides which can help to stimulate other processes to occur inside our body. For example, there is a neuropeptide called cholecystokinin that is created in our gut. When cholecystokinin is released into our blood, it will then tell our gallbladder to produce bile. We need bile to breakdown the fats that we eat. 

3.     The production of serotonin. Over 95% of the serotonin that our body produces is actually produced in the gut. Serotonin is the "feel good hormone" that we typically associated with our brain. This actually begins in our gut. Our gut is responsible for breaking down the amino acid called tryptophan (a nutrient you'll probably remember in food products like turkey). And tryptophan is the precursor to serotonin production. So if we aren’t feeling happy mentally, it could be a problem that is stemming from our gut.

4.     Immune function. The lymphoid tissue that lives in our gut comprises 70% of our immunes system. As talked about in much more detail in my last blog, our gut is the largest “immune "organ” in our body. When we keep our gut healthy, we are keeping our entire body healthy.

5.     Altered intestinal permeability. When we are stressed either from conscious, mental stress, or from internal stress (which can be from foods or our external environment), we create low-grade inflammation. Chronic, low-grade inflammation can influence the permeability to our gut, which them makes it harder for our brain to function optimally. This dysbiosis in our gut could actually be a precursor to neuropsychiatric disorders like schizophrenia, autism and depression.

6.     Production of Microbial Metabolites. Certain bacteria found in our gut like the strains from Lactobacillus or Bifidobacterium produce GABA, which is the main neurotransmitter in the brain. Others help to produce serotonin (as mentioned before), and even a different strain called Bacillus can help produce dopamine, another “feel good hormone” that our brain needs. Also certain short-chain fatty acids like Butyric acid is produced in our gut and that helps to influence our ability to learn new things and store memory.

How can we keep our gut healthy in order to keep our brain working at it’s best?

Consider the following diet and lifestyle additions:

·       Eating seasonal vegetables. The more colorful your fresh produce, the better. Eating seasonal produce will also give you the most nutrients because these foods are more likely to be ripe when you buy them!

·       Incorporate fermented veggies. There are important, healthy living organisms found in fermented vegetables that will help populate your gut. Try foods like sauerkraut, kimchi or kombucha as sources of fermented foods in your diet. These days, you can buy nearly any vegetable in a fermented form!  

·       Reduce added sugar. Refined sugar is hidden in so much of our food, especially processed or packaged foods. Sugar is well-known to add to our chronic, internal inflammation. So removing added sugars is one huge tip for a healthy gut and a healthy brain.  

·       Get outside and move. Studies have shown that people who spend time outdoors have a more robust microbiome. Exercise is also a big component to a healthy gut. Kill two birds with one stone and get outside when you exercise!

·       Think long and hard about taking antibiotics. Western societies have glorified antibiotics and doctors are dolling our antibiotics like ibuprofen. If you do not have an acute health condition and can potentially remedy your health situation without antibiotics, strongly consider that option. Antibiotics kill off the bad AND good bacteria in your gut. It can wreck havoc on your microbiome and can take months to repopulate. Antibiotics are great for a great many number of things, but it’s realistic to not take them, consider that option.

·      Reducing stress. Many of my other blogs talk about reducing your stress. Stress is a major driver of illness because it can break down our gut. And you know now that your gut is 70% of your immune system. If it’s not working, your far more apt to getting sick. Find the things that you love to do and do them everyday! Find your joy. It will help to reduce your stress.