Is mental health affected by gut health? Have you ever gotten a ‘gut feeling,’ about someone, that later on turned out to be spot on? Or experienced butterflies in your stomach when that person you had been crushing on smiled at you?
These phenomena happen because our entire digestive system is lined with a mesh-like body of neurons which is referred to as the ‘Enteric Nervous System.’ Our brains are connected to the rest of our bodies through something called the ‘vagus’ nerve. This nerve allows the brain to communicate with other major organs such as our eyes, vocal cords, heart, lungs, and of course, our digestive systems.
The vagus nerve is responsible for the human ‘fight or flight’ response to external stimuli, which is why when you’re under a great deal of stress, your heart might race, or you may feel short of breath or get that ‘gut feeling’ we mentioned at the beginning of this article.
However, while this amazing network is constantly working to send messages from the brain the rest of your body (even when you’re sleeping!) scientists have discovered that 80%-90% of the nerve fibres from the enteric nervous system are actually driving against traffic, and going from the gut to the brain!
In fact, our entire enteric system, (which runs all the way from your gums to your bum) doesn’t actually require the brain to function at all! If the vagus nerve were to take a vacation from running the brains messages all over your body, your digestive system would literally be the only part of your body that would continue to do its job without the brain’s instruction. Next time you’re in a job interview and you’re asked if you can work autonomously, tell them that you’re more autonomous than an enteric nervous system, and you’ll for sure get the job!
The brain-gut connection evolved in the early stages of human development when we were spending most of our time trying to find out what we should eat to keep us alive. Because foods high in fat were a great source of energy in a time where people had to hunt or forage for every meal, our guts learned to send signals to our brains, telling it to release ‘dopamine’ the feel-good hormone. This in turn ensured that early humans enjoyed eating the high-fat foods they needed to stay alive, and they would seek out more foods of similar ilk. This is why today, when you take a break from your diet and indulge in a juicy cheeseburger, you immediately feel happy…at least until the guilt kicks in!
Now…this doesn’t mean that when you’re feeling down you should go and eat an entire pint of ice cream! There’s much more that your gut does to manage your mental health than simply telling your brain to feel happy when you’ve eaten a fatty, sweet treat.
Your gut is filled with TRILLIONS of microbes that make up each person’s microbiome. These little friendly bacteria are working overtime each and every day to produce about 50% of the dopamine found in your body and up to 90% of the neurotransmitter serotonin. These two neurochemicals are responsible for your mood, your happiness levels, pleasure and joy.
These little guys can also influence your appetite to make sure you eat things that make them healthier. Your diet essentially dictates which microbes live and die, and as a result, the bacteria that survive can send signals to your brain telling you to eat the food that they like most. This is why after going on a health kick for a few days, eating healthy foods becomes easier over time, whereas the opposite is true if you’ve been off the wagon for a while.
By taking probiotics regularly and eating dietary prebiotics, it is theorized that you can help the good microbes get rid of the bad microbes that trigger cravings for high fat and high sugar foods which helps combat over-eating.
This is why research is showing that people who take care of their microbiomes have an easier time dealing with mental and emotional health, as people with a rich and diverse microbiome have more good microbes working away to build your serotonin and dopamine levels.
In a 30 day study, subjects showed a decrease in anxiety and depression after consistently eating dairy products packed full of probiotics, as these probiotics were able to help cultivate their microbiomes and produced higher levels of serotonin. The other half of subjects that consumed dairy products with no probiotics saw no change in their moods.
As these happy-chemicals are produced, they must travel up the vagus nerve to the brain from the gut. The vagus nerve itself is a very active and busy highway for neurotransmitters, so if there’s a bit of a traffic jam in there, it makes it more difficult for your happy-chemicals to make their way from your ENS (enteric nervous system) to your brain.
In these cases, it’s a best practice for people who suffer from anxiety and depression to take steps to stimulate their vagus nerve to get things moving again. Things like yoga and Thai-chi are great ways to unblock that nuro traffic-jam, so Namaste your way to better mental health!