The mind-gut connection: microbes and emotions.

We know there is a connection between our mind and our gut because we feel it. That sinking feeling when we hear bad news, the ‘butterflies’ when we get excited, the loss of appetite when we feel stressed. These are some of the ways our mind and body communicate. It’s not always immediate or obvious that our mental states are having an effect on our body, but it’s now known that gut bacteria change in response to different emotions. In the last decade revolutionary research has discovered the complex interactions between the brain, gut and emotions, and how the microbiome in our intestines affect our mental health, mood and thoughts.

In Emeran Mayer’s book The Mind-Gut Connection he refers to the digestive system as a supercomputer – complex and powerful, influencing our emotions, sensitivity and even our decision making. The enteric nervous system(ENS) within the gut is often called the ‘second brain’ because it is made up of millions of nerve cells. Thick bands of nerves communicate information back and forth, signalling a variety of triggers, responses and feelings. This bidirectional(two-way) pathway, known as the brain-gut axis processes information that produces ‘gut reactions’. These gut reactions ultimately affect every aspect of lives, from the food we eat to the people we spend time with, basically every decision we make.

In 2007 the Human Microbiome Project made some major discoveries about the influence of the human microbiome on health and disease. The diversity of our microflora has a profound impact on our health – helping to digest food, modulate the immune system, regulate metabolism and detoxify harmful substances. Conversely, diminished microbial diversity is associated with a variety of digestive problems, allergies, immune disfunction and even neurodegenerative brain disorders.

The relationship between mood disorders and digestive function is generating a lot of interesting research. Some microorganisms in the gut have been shown to have a a direct effect on depression and anxiety by influencing the neurotransmitter, serotonin, which is produced by specialised cells in the intestinal wall. Mayer says, “your gut microbes are in a prime position to influence your emotions, by generating and modulating signals the gut sends back to the brain”. There is now a large body of research showing that some of the most serious brain and emotional disorders are related to changes in the gut microbiome, and the way these microbes communication with the brain.

This chart found on https://www.sciencemag.org/news/2020/05/meet-psychobiome-gut-bacteria-may-alter-how-you-think-feel-and-act clearly explains the various pathways gut bacteria can use to hijack your behaviour.

We know the gut plays a major role in wellbeing, both physical and mental, so in order to address any underlying health problems or to simply optimise your overall wellbeing, gut health is where to start.

• Avoid processed foods and increase fresh, whole foods. Get in the habit of shopping at your local farmer’s market rather than a supermarket. You’ll cut back on the plastic and packaging as well as the additives. Eating seasonally is a great idea as you’ll get a diverse range of foods and nutrition, exactly when nature wants you to eat them.
• Choose animal products carefully. Know where your animal products come from and how they are grown. Farmed fish are only sustainable with the use of antibiotics and other chemicals. Chickens are also given regular antibiotics. Beef is allowed a certain amount of growth hormone in Australia. To avoid all this I’d recommend finding organic, local, small batch producers.
• Eat smaller portions. Numerous studies have shown life extension in rats that consume fewer calories.
• Fasting has positive effects on the function and composition of the gut microbiome, says Dr Mayer. When the stomach is empty it activates the peristaltic(muscular) action of the digestive tract, releasing secretions of enzymes from the pancreas and bile from the gallbladder. This is akin to an intestinal wash, flushing bad bacteria out of the small intestine. Fasting also resets appetite control mechanisms.
• Do not eat when you’re stressed or angry. Emotions have a profound effect on the gut, as we’ve all felt. Negative emotions can trigger stress hormones and immune responses that can make the gut leakier and restrict blood flow to the intestines, making proper digestion impossible.