Your brain and your gut have a unique relationship that makes them inseparable from one another. They are bound to one another, physically, and biochemically – to a degree that science is only just beginning to appreciate. The sum of these connections and interactions is referred to as the gut-brain axis (or GBA) – though the name doesn’t quite fully illustrate just how deeply important the strength of this bond is for us to live healthy, and happy lives.
As a people we seem to have intuitively known this connection existed – even if we weren’t able to fully comprehend its full complexity and importance. Phrases like “gut feeling”, or getting “butterflies” in your stomach when you are nervous exist for a reason. They suggest that our inherent wisdom had long ago established the existence of a link between the brain and the gut. Now the science clearly shows that the link is real. Its infrastructure includes aspects of the nervous system (the gut is now often referred to as the “second brain”), as well as countless bacteria and microorganisms (we need them!), and more. If you are craving a deep dive into the research to learn the intricacies the gut-brain axis, we recommend this article published in the Annals of Gastroenterology, which explores every aspect of the connection between our mind, gut, and health.
Research articles can be dense and redundant at times however. So, we have taken the time here to explain what exactly is the gut-brain axis, and how it pertains to you in relevant, relatable, and actionable chunks. This article will go over what makes up the GBA, how the gut and brain interact, the extent of gut bacteria’s role in the GBA, and we will wrap things up with some actionable steps to protect, or even improve the capability and capacity of this connection to enhance your health and wellness overall.
There is much more required to create lasting balance and health, and you can read our approach to tackling this daunting and perpetual task here. Before we start explaining how to improve it, it is best we begin by detailing just exactly how there is a connection in the first place.
How the Gut and Brain Are Connected
Whether you know it or not, your health and vitality rely upon a delicate, yet strong synergy between your brain, your gut, and the estimated 100 trillion microbes that are living inside your digestive tract at any given moment.
This recently discovered, bidirectional relationship between your enteric nervous system (ENS), and central nervous system (CNS) involves crosstalk between your endocrine system, immune system, and obviously, your nervous system. Explaining every component and their specific roles in the GBA can get very complicated, very quickly. Luckily, there are some major players that you can focus on to get a decent understanding of how it all works, and how you can make steps to improve your own GBA.
The Vagus Nerve
If there were a highway running straight from your brain to your gut, it would be your vagus nerve.
The vagus nerve is the primary nerve leading to and from your digestive tract. It is also the main component of your parasympathetic nervous system – often referred to as the “rest and digest” side of things.
There have been many studies demonstrating the relevance of the vagus nerve for communication between the gut, microbes, and the brain. One study concluded that a more complete understanding of the functioning of the vagus nerve may lead to new nutritional and microbial interventions for mood disorders. This hypothesis is supported by the fact 80% of the nerve fibers that comprise your vagus nerve are headed to your gut from your brain, and the remaining 20% are leading back to your brain from your gut. That means there is a direct line of communication from the 500 million neurons in your enteric nervous system and your brain. An understanding of this fact makes it much easier to comprehend just how two seemingly separate parts of the body (your brain and gut) are able to work in synergy with one another – when everything is going right that is. So if the vagus nerve is the highway that connects your brain and your gut – neurotransmitters can be thought of as the cars that drive on it.
By now everyone has at least heard of neurotransmitters. They are tiny chemical messengers that have an enormous influence on both our psychology and our physiology.
And though we tend to more closely associate neurotransmitters with structures like the brain and spinal cord, there are more than just a few reasons why we may need to rethink that notion just a bit.
There are 5 times as many neurons (these cells use neurotransmitters to communicate) in your enteric nervous system as there are in your central nervous system. That fact alone means we better start thinking of our gut as our “second brain” – as many scientists are already doing. But there is another reason neurotransmitters may be even more of a “gut thing” than a “brain thing”, and that is that the microbes living in your gut make neurotransmitters and other molecules that your body uses everyday.
95% of the serotonin in your body is produced in your cells in your gut, and this process appears to be stimulated and regulated by specific kinds of bacteria according to this study published in the journal Cell. This powerful neurotransmitter is heavily involved in sleep, your circadian rhythm, and many aspects of mental health.
Additionally, the neurotransmitters GABA and dopamine, both of which are needed for overall health and a properly functioning brain, are created as byproducts by certain kinds of gut bacteria. These two facts alone seem to make it a foregone conclusion that the health of your gut, and the microbes within it, can have a much further reach than we ever thought possible.
The conversation about gut microbiome and just how interconnected with the rest of our body it is, has been happening for well over a decade now.
Relative to other health-related topics though, this is very very new – and also very uncertain. The Human Microbiome Project, started back in 2007, is a much needed initiative dedicated to discovering and understanding the diverse array of microbes that live on, and in us.
Researchers have learned a lot thus far about how the gut microbiome in particular may impact your physical and mental health. Most of the research has been done in rodents so far, but the totality of evidence suggests that an imbalance or dysbiosis amongst gut microbes is associated with allergies, autoimmune disorders, metabolic disorders, and many neuropsychiatric conditions. This detrimental effect is either contributed to or compounded by intestinal hyperpermeability, or “leaky gut syndrome” which is becoming increasingly common in modern societies.
The name leaky gut illustrates precisely the malfunction that is occurring within the intestinal tract and the issue can lead to increased levels of systemic inflammation – increasing the likelihood of countless issues you can read about here. When you are experiencing leaky gut syndrome, you are far more likely to experience an inappropriate immune response to your beneficial gut bacteria, as well as the undigested food particles that find their way into your bloodstream.
The impact that the health of your gut, and the microbes in it can have on your mental health is based on two pillars. The sufficient production of neurotransmitters and other signalling molecules that takes place there, and the ability for inflammation in the gut to cause systemic issues including depression, anxiety, and more. Clearly, our mental health is highly dependent on having a healthy, and balanced microbiome within our digestive tract.
Gut Bacteria and Mental Health
We have a tremendous ability (and perhaps responsibility) to influence our health through our diet and lifestyle – and we can influence the health of our gut bacteria in exactly the same way. One of the more popular methods to alter or improve our microbiome is through the use of probiotics – but they may not always be the answer.
Probiotic supplementation has been all abuzz in recent years. But it is likely that most people aren’t even sure what is actually in the capsule they are taking. Probiotics are actual live microorganisms, and supplementing with certain kinds of them has been shown to hold the potential for a ton of beneficial effects. It isn’t an exact science yet, however. And it is difficult to know what bacterial strain to use, how much of it, what combinations work best, etc. Basically there is still a lot left to figure out. Luckily, researchers are hard at work figuring it out for us, and it seems that more and more data comes out every day.
Besides supplementing with probiotics in a capsule, you can just as easily get some beneficial microorganisms from food like:
- Natto (fermented soy)
- Sauerkraut and other fermented veggies
In a study published in the prestigious journal Nutrition, it was found that individuals with major depressive disorder can have observable, positive changes after 8 weeks of supplementing with specific probiotics. They also had notable improvements in markers of inflammation, endogenous antioxidant activity, and more signs that point to enhanced health.
Prebiotics are a little less cool, yet no less beneficial. Prebiotics are compounds that are typically found in the parts of plants we can’t actually digest ourselves – but our gut bacteria love it. Examples of prebiotic foods include:
- Legumes, beans, peas
- Bananas, berries, and other fruits
- Asparagus, leafy greens, and other veggies
- Alliums like garlic, onions, leeks
You’ll notice that none of these foods are processed or in a package. This backs up our own admitted bias towards whole, natural foods – we’ve even posted more than one article about the topic of whole foods and fiber intake. Likely resulting from the downstream effects of it feeding our beneficial microbes, this study determined that prebiotic intake has the ability to both reduce stress, and improve attention placed on positive compared to negative stimuli. Based on these studies, it seems pretty clear that getting both probiotics and prebiotics in your diet or through supplementation can be one of the more important things you do for your gut health and mental health. Your work doesn’t end here though, there is much more that you can however to improve your gut-brain connection.
How to Improve Your Gut-Brain Connection
Many of the diet and lifestyle principles for creating health and improving longevity must owe at least part of their power to the effects they have on your gut and digestive health. These are just some of the many proven strategies to enhance or strengthen your gut-brain axis – but you may have to experiment and do some research of your own to find what works for you. If that is your goal, it is probably best to focus first and foremost on what you are putting on your plate and in your mouth.
As we just explained, a diet based on whole foods will take care of most of the nutritional requirements for a healthy gut-brain axis. This is because you will find nutrients like protein, fiber (both kinds that each have unique benefits for gut health), and micronutrients in whole foods that you simply don’t get from processed and packaged foods.
More specifically, look to incorporate foods that are:
- High in omega 3’s (they have been shown to improve good bacteria and they are crucial for the health of our brains)
- Fermented (the fermentation process creates probiotics)
- High in both soluble fiber, and insoluble fiber (both of which are needed for a healthy gut)
- Rich with polyphenols (anti-inflammation/antioxidant compounds)
- Good sources of the amino acid tryptophan (required for serotonin production)
You are going to need to experiment and find foods that work best for you and your digestion. This is important because individual variances in dietary requirements can vary widely. Also, you may have an intolerance to certain foods, or have an altered need for certain nutrients at certain times. Above all else, it is important to get a wide variety of protein sources, fat sources, fiber sources, and maybe include some fermented foods at least somewhat often to get some good probiotics. Many people in modern society fall short of fulfilling these dietary requirements for a healthy gut strictly from food however.
Vitamins and Supplements
Which supplements to take to help improve the health of your gut-brain axis is going to vary from person to person.
Many of the vitamins, minerals, and other supplements you can take to improve your health are the same ones that you should likely be paying attention to already. For instance, the following minerals are crucial for a healthy gut:
- Vitamin D
All of these are vital for overall health and play various roles in the gut specifically – varying from reducing inflammation to repairing your gut lining. This further enforces the notion that eating a diet based on whole, natural foods is an excellent course of action to begin improving gut health.
Perhaps the most important aspect of maintaining a healthy GBA is the lining of your gut itself. This relatively thin membrane has the paramount role of deciding what comes in and what doesn’t. Hence the increasingly common “leaky gut syndrome”, and its associated disease states, are simply caused by the gut lining letting in stuff that it shouldn’t – for whatever reason. Proven supplements like glutamine, deglycyrrhizinated licorice, and collagen peptides all work to improve the lining of your gut so it can better control what actually makes it through and into our bloodstream – but an extremely interesting peptide called BPC-157 seems to currently reign supreme at the job of restoring a healthy gut lining. BPC-157 (body protection compound 157) is a gastric peptide with an amazingly safe track record, and a growing body of research behind it. One research article exploring existing research on BPC-157 postulated that because it has been so effective at treating certain gastrointestinal issues that it may soon be used strategically to ameliorate some of their associated mental health issues.
Talk To Your Doctor
There really is a ton that you can do on your own to improve the health of your gut, brain, and the microbes that live in it. But in some instances, working with a medical professional will almost certainly be necessary and beneficial. Conditions like Crohn’s disease, irritable bowel syndrome, ulcerative colitis, and more can be more than just a little serious and should be handled by someone with the proper training and experience. That being said, in some ways Western medicine has done quite a bit of harm to our guts.
Your microbiome is a living organism – one that works with you to keep you healthy. But that also means that the antibiotics (the opposite of a probiotic by every definition) can and often do decimate the microbes in your gut. Though they are entirely necessary at times, antibiotics have been shown to consistently and significantly alter the gut microbiome – negatively. Either by reducing the overall number, or eliminating entire species altogether, antibiotics can wreak havoc on our microbes, and the gut-brain axis as well.
Consider Alternative Treatments
Slightly more fringe treatments like fecal transplants or coffee enemas are usually not common dinner table talk. But with gut issues becoming increasingly common,it is important to mention some alternative approaches to creating a strong gut-brain connection. If you are trying to further reduce gut inflammation, improve associated mental health issues, and enhance your overall gut health, take a look at alternative options like:
- Fecal transplants (think of it as a good bacteria transplant)
- Coffee enemas (stimulates bile production in the liver)
- Colonics (these will really clean you out)
None of these treatments are likely to significantly improve the connection between your brain and your gut unless you are doing the most important things for overall health.
- Get enough sleep, every night
- Manage your stress
- Eat a diet full of actual nutrients