The Gut-Brain-Immune Connection

Ever felt butterflies in your tummy when you’re nervous or suffered from digestive problems during periods of stress and anxiety?

This is a sign of your gut-brain-immune connection, which we’re only just starting to learn more about.

According to research, your brain and your gut are interlinked and can have big effects on each other. The gut is actually 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 experts are increasingly realizing that autoimmune conditions begin in the gut.

what is autoimmune disease?

Before we dive into the gut-brain-immune connection, 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, bacteria and other “nasties” 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 (this is usually the result of improper nutrition, toxic exposures, high levels of emotional stress, drugs/medications, infections and lifestyle choices) rather than invaders and will produce auto-antibodies in response to this. This is known as autoimmunity and causes a lot of the symptoms that we associate with autoimmune disease. Read here for a deeper understanding on your immune system and how it regulates.

the gut-brain link

Your brain has plenty of neurons, which tell your nervous system what to do. There is a less well-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 “second brain”.

Your gut-brain-immune connection is 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, a huge proportion of serotonin is actually produced there, rather than in your brain. This means it’s super important for your gut to produce the right levels of serotonin and be in the best shape to harness it.

One study revealed that people with depression are missing certain types of gut bacteria, and another study showed that regulating gut microbiota could help to minimize symptoms of anxiety. Chronic stress can also influence both your mood and your gut health. The gut microbiota affects so many aspects of our overall wellbeing!

The vagus nerve is one of 12 cranial nerves. It’s also one of the largest nerves that connect your gut and the brain, sending signals in both directions. One study revealed that people with reduced vagal tone are more likely to experience various gastrointestinal issues.

the gut-immune link

Your gut does a lot more than just digest and absorb nutrients from your food and excrete waste products. It’s also involved in helping your body to fight off bacteria and germs that could make you sick. There are a huge amount of immune cells in your gut.

When “bad” bacteria gets the opportunity 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 be a big factor 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 have 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 this study from Yale. The research focused on a bacterium called Enterococcus gallinarum, which has the ability to relocate itself to the lymph nodes, liver and spleen. They found that tissues outside of the gut will kick start production of markers of an autoimmune response. This was reduced in mice by using therapeutics and antibiotics that targeted E. gallinarum, which stopped it growing in the tissues and meant it had less effect on the immune system.

Researchers believe that dopamine signaling also controls the inflammatory response to prevent it going haywire. Autoimmune conditions arise from an abnormal immune response to a functioning body system. Animal studies have suggested that regulating dopamine could help to stop this from occurring, although a lot more research needs to be done to confirm this possibility.

Research is also finding links between Leaky Gut Syndrome and autoimmune conditions such as lupus, Hashimoto’s, Graves’ disease, rheumatoid arthritis, celiac disease and type 1 diabetes. If food that hasn’t 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 this 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.

The Gut-Nutrition Link

A very important aspect of gut health is nutrition and the critical roles it plays in supporting our digestive system and mental health.

Food + nutrients that have been shown to support gut health include the following:

Probiotic-rich foods-sauerkraut, yogurt, kimchi, kefir, brine cured olives, apple cider vinegar + pickles
Healthy fats–salmon, sardines, olive oil, avocados, coconut oil, sesame seeds + sprouted nuts
Tryptophan-rich foods-(tryptophan is converted into serotonin-the “happy hormone”) turkey, pastured eggs + raw cheese
Mushrooms-high in B6 (improves mood and reduces stress)
Polyphenol-rich foods-dark chocolate (yum!), green tea + coffee

Eliminate out of the diet for optimal digestive and brain health:

Refined sugar
Alcohol
Processed foods
Gluten
Pasteurized, homogenized dairy

The Gut-Lifestyle Link

Beyond our diet there are other factors to consider when making changes towards a stronger gut-brain connection:

Exercise-research indicates how exercise affects our gut
Sleep-keeping your bedroom cooler helps you sleep better and improve your overall immune health
Get outdoors-getting outside in natural sunlight increases our Vit D level which regulates the integrity of the intestinal barrier
Mindfulness practice-can help decrease stress levels and improve gut health

It’s looking more and more likely the gut and the brain are inextricably connected and an unhealthy gut-brain-immune connection could be a major factor in autoimmune disease. Taking your gut health seriously is highly beneficial for preventing autoimmune disease, mood disorders and cognitive difficulties. Along with gut health, striving to make healthier lifestyle changes, consume foods that are appropriate for you and manage stress that works to support your WholeHealth. Consider working with a functional medicine practitioner to partner with you to support you and guide you on your own personal health journey.

Grab a complimentary copy of my Immune Boosting Foods guide here.