The second brain

The gut is often called the ‘second brain’ and if you’ve ever felt those butterflies in your stomach before a big event, or perhaps have been unable to eat following an argument or emotional time you’ll appreciate that the gut is not just an isolated organ dealing with digestion.

This idea of the gut being inherently linked to the mind goes back to many ancient practices of medicine – from Traditional Chinese Medicine to the Indian system of Ayurveda. Yet it’s only recently become more accepted in western medicine that the gut may be more than just an organ for dealing with food, and it may not only influence the mind, but also be influenced by the mind.

It was first discovered around 100 years ago that the gut contains its own nervous system called the “enteric nervous system”, which is located in the lining the food pipe, stomach, small intestine and colon. Just like the larger brain in the head, researchers now believe that this system sends and receives impulses, records experiences and respond to emotions. And just as the gut can upset the brain, the brain can also upset the gut.

Stress and digestive health

Stress leads to numerous physiological changes in the body – many of them in the gut. When anxiety or stress hits, the body goes into what’s known as the ‘fight or flight’  response – adrenaline increases, blood diverts from the mid section of the body to the arms, legs and head (to run and prepare for action!) and as well as less blood flow to the digestive system, the enzymes released by the digestive system also decrease. It’s not surprising then that conditions like Irritable Bowel Syndrome (IBS), stomach ulcers and Gastroesophageal reflux disease (GERD) are all triggered by increased mental, and physical stress.

Interestingly, it also works in reverse – imbalances in the gut, particularly in certain bacteria found in the gut are now known to be linked to conditions such as depression and anxiety. In fact, it’s even been shown that babies whose mothers have experienced stress during pregnancy have an altered gut bacteria make up that may affect the way they respond to stress.

Looking after your second brain

As well as the obvious recommendations to eat a well balanced diet and consume foods that promote good bacteria in the gut such as natural yogurts, fermented foods and leeks, onions and garlic, there are other ways to ensure that this complex nervous system is working at its optimum.

1. When you’re eating, eliminate the fight or flight response – this means, not eating while rushing around, multitasking or in a state of excitement. Find a calm environment in which you can focus solely on your food, savouring each mouthful with no distractions.

2. Take time after eating to just sit and let your body digest properly – again, we want to avoid taking the body back into the sympathetic nervous system, and stay in the parasympathetic nervous system (which deals with digestion) for as long as possible.

3. Practice activities like meditation, yoga, deep breathing, and laughter to help the body relax.

4. Sleep in complete darkness – this is necessary for proper production of the hormone melatonin. Studies have suggested that melatonin is an important mediator of the brain/gut relationship. 


Written by Ruth Tongue
(MSc Nutrition)