Like me, I’m sure you’ve all been told that you should “listen to your gut” when making important decisions. You may feel that this is a little too woo woo for you, but hear me out. The gastrointestinal tract (GI) – which houses your gut microbiome – is the largest sensory organ in your entire body. It not only digests all of our food, but it also provides each of us with invaluable information about what is going on both inside and outside of our bodies. It is the only organ that has its own independent nervous system, with a sophisticated network of 100 million neurons living in the gut wall. The gut microbiome is often referred to as your “second brain” and is in fact larger than the average human brain, weighing nearly 5 pounds. There are 10x more microbial cells in the human gut than in the rest of the human body, housing over 5,000 different types of species of bacteria.

Every individual has a unique microbial composition – like a fingerprint – that is connected to and impacts every single system in the body. Gut bacteria plays a crucial role in hormone regulation, protects us from harmful microbes, disease, and outside pathogens, helps regulate blood sugar, and plays a large role in immunity. Gut bacteria also makes vitamins and extracts nutrients from the foods that you eat and regulates digestion, metabolism, and weight. Not surprisingly, diet seems to be the most important influence over the composition of an individuals gut bacteria. Processed foods containing emulsifiers – which are very common in almost all shelf-stabilized foods in the US – may damage the intestinal lining and lead to inflammation and issues such as “leaky gut.” The good news is that by changing your diet, you can also change your gut.

The result of positive dietary and lifestyle changes can have a ripple effect and improve our physical and psychological health. That’s right – your gut is also connected to your mental health. In fact, the gut microbiome can influence our neural development, brain chemistry, emotional behavior, and our perception of pain. Many neuro-chemicals like serotonin are produced in the gut. Most people have heard of serotonin, the hormone that helps regulate memory, learning, mood, and even sexual desire, but what you probably don’t know is that approximately 90-95% of serotonin is produced in the gut, and only 5-10% is produced in your brain. Serotonin and other neurotransmitters travel from the gut to the brain and vice-versa via the vagus nerve, which is the largest nerve in your entire body. It is a two-way system.

Just as gut bacteria can influence brain health, activity in the brain can also impact the gut, which is why a state of perceived stress can actually cause inflammation in our bodies. Research behind the gut-brain connection is still relatively new, but this means that people with gut issues may be at a higher risk of mood imbalances, anxiety, and depression. There is so much more to cover on this topic, and I will dive more in depth on the gut-brain axis in a later blog post.

So, what does this all actually mean? With an intricate and large neural network made up of trillions of bacteria, your gut sends powerful messages to your brain and the rest of your body. That “gut feeling” you get may actually be your brain and gut talking to each other. Perhaps, then, there is some wisdom to the saying “listen to your gut.” I’ll let you come to your own conclusion.

Stay tuned for way more posts related to the gut microbiome, and let me know if you have any questions!