Our gut is home to hundreds of trillions of bacteria. It breaks down food into smaller elements which are then absorbed for use in the body. Our gastrointestinal (GI) tract is one of the largest systems in the body. The gut is one long continuous tube that is constantly in contact with the outside world, which is part of how we build our immune systems. 

The gut is the first line of defense against viruses and harmful bacteria. 70-90% of our immune system is in the gut. Studies have shown that restricting food intake changes the bacteria composition in the gut, which can contribute to anxiety, depression and impulsivity. 

The gut is known to have a mind of its own. This is called the enteric nervous system (ENS). Every time we experience an emotion, our guts feel it too. Our emotional signals move from the brain to the gut and from the gut to the brain. They are in constant communication. When we feel emotions such as fear, sadness, happiness, and more, our gut feels it too. When we feel sad, our gut knows it, and will slow down digestion. When we feel afraid, our gut knows it, and our digestion will increase motility causing diarrhea or sometimes vomiting. And sometimes when we eat something that upsets the stomach, it may put us in a bad mood. 

The ENS commands digestive functions independent of the brain. Neurotransmitters that are found in the brain and also found in the gut. 90-95% of the body’s serotonin is found in the gut. So it would make sense that stress, anger, anxiety, depression and other emotions have an impact on our gut health.

When we are under stress or experiencing anxiety, specific neurotransmitters are released (epinephrine, norepinephrine, cortisol). This is otherwise known as our “fight or flight” response. Epinephrine (adrenaline) narrows blood vessels and opens airways which increases heart rate, blood pressure, and breathing ability. Norepinephrine increases heart rate and blood pressure, releases glucose from energy stores, increases blood flow to muscle and the GI system, inhibits bladder and GI function. Cortisol increases glucose in the bloodstream and enhances your brain’s use of it. Cortisol also increases the repair of tissues and decreases non-essential functions during a stress response. These neurotransmitters put our body in crisis/response mode and diverts attention to lifesaving functions by inhibiting biological functions that are not immediately necessary (like growth and digestion). 

During stressful times, our GI system is actually frozen. Our body stops digestion from continuing or sometimes will force food out of the system via vomiting, diarrhea, or increased bowel movement frequency. The problem with this, is that our bodies don’t understand the difference between “real” stress (like a bear chasing you) and “perceived” stress (like an exam). Take a moment to think about how often you feel anxious or stressed, and imagine that your body feels attacked every time you experience this. Mindful techniques can be helpful for the body to feel less stressed and can aid in digestion.

So, what’s the best way to feed our gut? 

1. Don’t restrict foods, unless medically necessary. When we restrict certain nutrients or food groups we are selecting for certain bacteria populations and killing off other ones. This is why we want to prioritize eating a whole foods balanced diet. Eating a balanced diet representative of all food groups helps with our mood stabilization, energy, and overall relationship with ourselves and food.
2. Eat more fiber! In order to fuel your gut bacteria, you have to boost your diet with fiber. Fiber is our gut bacterias primary food source. You can find fiber in plant foods – such as beans, nuts, seeds, whole grains, fruits and vegetables. 
3. Choose probiotics. Probiotics, which are live good bacteria found in foods, have been shown to promote a healthy gut. You can naturally find probiotics in foods like yogurt, fermented foods (like pickles, kimchi, kombucha and sauerkraut).  
4. Eat foods rich in prebiotics. Certain fibers act as prebiotics to provide nourishment for our gut. Prebiotics feed probiotics. You can find prebiotics in apples, bananas, asparagus, garlic, onions, jicama root, artichokes, and more. 
5. Stay active and practice mindfulness. Beyond eating, lifestyle factors play a major role on gut microbiota health. Physical activity and stress both impact our gut. Physical activity (that you enjoy!) has been shown to have a positive impact on a healthy microbiome. Stress can negatively affect our gut microbiome by reducing something called secretory IGA, which helps the body to clear bad bacteria and promotes a healthy intestinal barrier. Finding ways to reduce or manage stress can be an essential part of supporting our gut health.