Understanding the Gut-Brain-Immune Connection
Have you ever felt butterflies in your tummy when you are nervous or suffered from digestive problems during periods of stress and anxiety? This is a sign of the link between the gut and the brain.
According to research, your brain and your gut are interconnected and can influence each other. The gut is actually being called “the second brain” by a lot of experts for this reason. There’s another dimension to this too, with both the gut and the brain being linked to the immune system. This can extend to autoimmune diseases, and there is growing evidence that autoimmune conditions may start in the gut.
What is autoimmune disease?
Before we dive into the link to the gut-brain and gut-immune connections, let’s talk briefly about the immune system and autoimmune disease.
Under normal circumstances, your immune system is designed to protect your body against viruses and bacteria that can be harmful. It also produces antibodies that offer protection against viruses that you have been exposed to in the past.
For some people, the immune system acts on healthy cells rather than invaders and produces autoantibodies in response to this. This is known as autoimmunity and causes a lot of the symptoms that we associate with autoimmune disease.
The gut-brain link
Your brain has an abundance of neurons, which tell your nervous system what to do. There is a less known part of the central nervous system in the gut called the enteric nervous system, which lies in the lymphatic tissues below the lining of the intestines. It uses the same type of neurons and neurotransmitters as the central nervous system, hence the term of “second brain”.
The brain and gut are also linked by neurotransmitters, which are produced in the brain. One of the most well-known neurotransmitters is serotonin, which controls your mood. A lot of neurotransmitters are also present in your gut too. In fact, the majority of serotonin is actually produced there, rather than in your brain. This means that it is very important to help your gut to produce the right levels of serotonin and be in the best shape to harness it.
The gut-immune link
Your gut does a lot more than just digest and absorb nutrients from your food and excreting waste products. It’s also involved in helping your body to fight off bacteria and germs that could make you sick. There is a large concentration of immune cells in your gut.
When “bad” bacteria start to outnumber the “good” bacteria in your gut, it sets the scene for a lot of health problems and this includes poor immunity and development of autoimmune diseases.
Inflammation in the gut can play a role in autoimmune diseases, including autoimmune encephalomyelitis and multiple sclerosis. Its role in Inflammatory Bowel Disease (IBD) probably won’t be a great surprise, but an unhealthy gut can be involved in autoimmune diseases that are nothing to do with the gut itself.
Studies on mice have shown that bacteria in the gut can travel to other parts of the body and trigger an autoimmune response, according to a study from Yale. The research focused on a bacterium called Enterococcus Gallinari, which has the ability to relocate itself to the lymph nodes, liver and spleen. They found that tissues outside of the gut kick started production of markers of autoimmune response.
Researchers believe that dopamine signalling also controls the inflammatory response to prevent it going haywire. With autoimmune conditions, the immune system attacks healthy cells. Animal studies have suggested that controlling dopamine could help to stop this from happening.
Research is also finding links between Leaky Gut Syndrome and autoimmune conditions such as lupus, Hashimoto's Disease, Graves’ Disease, Rheumatoid Arthritis, Celiac Disease and Type 1 Diabetes. If food that has not been digested properly is able to leak through the lining of the intestines, it tells the immune system that it needs to produce antibodies and leads to the range of symptoms that characterize Leaky Gut Syndrome. The immune response can go far beyond the gut and it’s been suggested that it can be a big culprit in autoimmune disease in general.
It’s looking more and more likely that an unhealthy gut can be a major factor in autoimmune disease and that doing what you can to help your gut to heal could be highly beneficial for autoimmune disease.