We have long understood the unique and intimate connection between the gut and the brain and the influence they have over one another. The thought, sight or smell of food can trigger the digestive juices of the gut long before you start to eat. Our gut is sensitive to our emotions, like anger, sadness, grief, anxiety and joy. We even have metaphors to describe these emotional experiences, like “butterflies” in your stomach when feeling anxious or nervous, or having your stomach “sink” when we get bad news. This signalling can go both ways, where the emotion can trigger the gut, or where gastrointestinal distress can have an impact on the brain, contributing to anxiety, depression or mental fogginess and fatigue. For example a person with chronic diarrhea may be constantly worried about accessibility to a bathroom causing anxiety and stress.
Stress in turn can influence the nervous system and reduce the ability of the gut to digest and process food, leading to indigestion, bloating, constipation, diarrhea, and can even increase inflammation and leave you more susceptible to infection.
The brain and gut communicate through several different pathways. The central nervous system, comprising the spinal cord and the brain, connects to the rest of the body, including the digestive system, through nerves, neurons (nerve cells) and neurotransmitters (chemical messengers). The vagus nerve is a large communication highway between the gut and the brain, sending information in both directions. The digestive system also has its own nervous system, called the enteric nervous system that runs along the entire length of the digestive tract. This system communicates the same way as the central nervous system and is often referred to as the second brain. When the “fight or flight” response is triggered by fear or danger the central nervous system is activated. The enteric nervous system responds to this by slowing down or stopping digestion. This action diverts the body’s energy so you can react to the situation. Neurotransmitters like serotonin, our happy hormone, are made in the gut in a greater amount then the brain makes and has action on the rest of the body. Gut bacteria also produce gamma-aminobutyric acid (GABA), which has a calming effect on the brain and can reduce anxiety.
The gut and the brain also communicate through hormones, like ghrelin, which is the hunger hormone. It is mainly released by the stomach and small intestines to let the brain know it is time to refuel with food.
The digestive system and bacteria play a large role in the immune system by controlling what is absorbed into the body and what is passed out. There is also a large portion of lymphoid and immune tissue residing in the gut and is thought to be the largest immune organ in the body. Inflammation is also regulated by the gut and gut microbes. High levels of inflammation can influence many psychiatric disorders, like depression.
If you find that your gut is highly sensitive, or you have anxiety and depression, it might be time to consider the role your brain could be having in your condition, or how your gut could be influencing your mood. Consider talking to a functional MD or a naturopathic doctor about probiotics and how they can influence your gut micro biome and overall health.
Next time you are feeling anxious or nervous and start to notice your stomach doing somersaults, you could also try the following simple breathing exercise and see if you can calm both your mind and your gut down.
4-6 Count Breathing
Inhale through your nose for a count of four, and exhale through your nose for a count of 6. On your inhale try to breath deep and low, allowing your abdomen to rise, and then fall as you exhale. Repeat this several times until you start to feel more relaxed.
Dr. Lindsey Hanson, ND
Better Medical Clinic
#518-922 5th Ave SW | Calgary, AB | T2P 5R4