Like Bonny and Clyde, Bert and Ernie, Ross and Rachel…your brain and your gut are deeply connected to each other. Til death do they part. This article is going to explain how they are linked, and why you should care.
Many of us already have an inkling of how amazing our brains are. After all, the brain controls our entire body, right? Well, that’s not quite the whole story. While the brain does send signals to the gut to help it digest and do its thing, most of us don’t realize just how much talking back our gut does. That’s right, “you don’t own me!” could be your gut’s theme song to your brain.
But let’s first take a look at the very under-glorified gut to see all that it contributes besides the fuel tank we treat it as. I’m going to refer to it as the GI tract from now on, because gut kind of gives it a bad connotation it really doesn’t deserve.
Of course the GI tract’s main job is to take food from the outside, stuff that isn’t “us” and break it down and convert into stuff we can use, get that good stuff inside to become “us” and sift through the waste and toxins to excrete that out the other end. This job is big enough in itself. But the GI tract also happens to make up 70-80% of our immune system. That’s right, most of our immune system is contained in the single-celled lining of our GI tract.
To do its huge job, the GI tract has more nerve endings than the spine. And get this – it produces more neurotransmitters than the brain! All the neurotransmitters that are made in the brain, are also produced in the GI tract. This includes 95% of our serotonin, the happy neurotransmitter.
The GI tract also produces hormones like the brain, and it contains a huge network of organisms called the microbiome. The microbiome actually runs our metabolism, supports the immune system, and produces nutrients.
Part of how the GI tract can do all that it does is from it’s incredible size. I don’t just mean the size if you took out all your gut and lined it up, which would still be very sizable around 30 feet long. But I am talking about the enormous surface area that is made by a network of small finger-like protrusions called villi. The many villi have even smaller protrusions on them called microvilli, and then there are tiny hairs called cilia on top of them. All this, if you were to flatten it out, would be the size of a double tennis court!
All this vast surface area is what allows us to absorb all the nutrients we need. If any of this surface area gets damaged, we don’t absorb nutrients as well.
So now that you know our GI tract on its own is pretty impressive, I hope you see how it’s not just blindly taking orders from our brain, but actively sending messages back to the brain depending on what’s going on down there.
I have talked a bit about the way the brain communicates with the GI tract via the stress response. So you know that feeling stressed or anxious can lead to changes in your digestion. It does this by altering the gut bacteria and causing mild inflammation, which we feel as either diarrhea, cramping, heartburn, etc. So the brain and our emotions can certainly impact our GI tract.
The reverse can also happen. The brain and gut are in an equal relationship, so both are allowed to express themselves. For example, I mentioned that the GI tract makes most of our serotonin, which can affect mood, sex drive, sleep, appetite, social behavior and memory.
Serotonin, and all neurotransmitters, are made from amino acids, which come from digested proteins. So what happens if your GI tract has trouble digesting protein? You won’t have as many amino acids to make neurotransmitters like serotonin. And since up to 95% of serotonin is made in the GI tract, good luck getting by with the 5% in your brain!
There are many different things that can lead to a dysfunctional GI tract. I won’t go into all of them here, but one that affects 10-20% of the U.S. population is likely familiar to you. Irritable Bowel Syndrome, or IBS. It’s one of those diagnoses that means, I have no idea what’s wrong with you, but it’s somewhere in your gut.
It can be incredibly frustrating because there may not be an obvious trigger, but it can be quite daunting and time consuming touring every bathroom in a one mile radius if you’re out shopping, or cause you to avoid social situations for fear of rumbling and gas.
Often an IBS diagnosis makes you feel like nothing “real” is wrong with you, only a nuisance you have to put up with. But there is a growing connection between IBS and things like generalized anxiety, depression, autism, and schizophrenia.
In fact, 70-90% of people with IBS have anxiety or mood disorders, and people with fibromyalgia, migraines or depression have 40-80% increased risk of having IBS. What’s more, any kind of tension or stress release can reduce IBS symptoms.
I mentioned that many things can contribute to imbalances in the GI tract, but a major one is the microbiome, or the trillions of bacteria living there. And it’s no wonder they play a huge role, we have 4.5-5 pounds of them! We have more bacterial DNA from these guys than our own human DNA! Talk about a massive part of the GI system. These guys can either be our best friends or if the wrong type takes over, our worst enemies.
A healthy microbiome keeps our metabolism running smooth, keeps our cravings in check, boosts our immune system, keeps things regular, manufactures vitamins and other healthy substances for our bodies, and puts us in a good mood. An imbalanced microbiome causes inflammation, lowers immunity, causes irregularity and discomfort, and may even cause depression.
So what can you do to ensure your gut-brain communication is sending the right signals, the ones for health, comfort and happiness? These are 4 lifestyle factors you can start doing right away for gut health and happiness!
- Diet – eat plenty of foods rich in both probiotics and prebiotics, which is food for the good bacteria. You can find a food list here. Limit sugar, caffeine, processed foods, and artificial sweeteners. Drink plenty of water.
- Limit alcohol – I hate this one, but the research is showing that any amount of alcohol can negatively impact our gut bacteria. I am learning this the hard way, with my own IBS symptoms in close relation with my indulgence in my love of wine. But I am taking a breather from all alcohol so my gut has a chance to heal.
- Stress Reduction – any kind of stress reduction can help IBS symptoms and improve digestion. Yoga, meditation, deep breathing, being in nature, doing a hobby, aromatherapy, listening to relaxing music, taking a bath, etc.
- Exercise – enough, but not too much. Regular exercise has been shown to increase the healthy population of gut bacteria, and improve regularity, reduce inflammation, and prevent colon cancer, diverticulosis and inflammatory bowel disease. However, very intense exercise, like in military training or endurance athletes, may worsen the gut bacteria and lead to more inflammation. But most people don’t have to worry about getting too much. Low to moderate intensity for 30-60 minutes most days a week is usually a good goal.
If you found this interesting or helpful, please comment and share!
Desbonne L. et al, J Psych Res. 2008 Dec.
Lipski, E. Digestive Wellness. 2011 – McGraw-Hill – New York, NY.
Moderate alcohol consumption is associated with small intestinal bacterial overgrowth. American College of Gastroenterol. 2011, Nov.
Monda, V. et al, Exercise modifies the gut microbiota with positive health effects. Oxidat Medicine & Cellul Longev. 2017.