The gut-brain connection

Originally written for Lawtalk Magazine, published 3 August 2018

When you get to that mid-afternoon lull and you just want sugar, or you find you’re feeling anxious and a little bit ‘off’, or something happens in your work day that has a bigger impact on your mood than you expect, consider how your food, or more specifically your gut, might be behind how you feel.

We all know how your food choices can impact your physical health, particularly your weight, but these choices could also be influencing your mental and emotional state. Hippocrates brought this to our attention when he said all disease begins in the gut. And while he may have cast the net a bit wide, there is evidence that many chronic metabolic diseases and your level of brain health are influenced by the health of your gastrointestinal tract.

The gut is more than just the thing that absorbs and digests your food. Research is showing it has a much wider role, to the extent that it has been called the ‘second brain’. Its not so much a brain that gets involved in thought processes like logical reasoning and theoretical debates like the one in your head, but it does influence mood and is capable of controlling behaviour on its own.

More technically known as the enteric nervous system and separate from the central nervous system (that is, your brain and spinal cord), your gut lining is populated with around 100million neurons.  There’s more neurons in the gut than there is in the spinal cord. These cells not only control blood flow and secretions to help digest food, they also help us feel what’s happening in the gut – included in that are the feelings brought on by your stress response like that pit in your stomach feeling or those butterflies you get when you’re nervous.

Up to 90% of these cells carry information to the brain rather than receiving information from it – your feelings and moods are just as likely to be ruled by your gut as they are by your head.

Within the gut, you’ll also find your microbiome. This refers to all the genes contained in the unique collection of bacteria and other microbes that live in your gastrointestinal tract. There’s trillions of microbes in there – around 1-2kg – you’ll actually find more bacterial cells in your body than human cells, and they help with almost all body functions.

Its reported that that there’s up to 1000 species of human gut bacteria, all with different roles in the body.

Just like the brain in your head, the enteric nervous system uses around 30 neurotransmitters. Of interest is that around 90% of your serotonin, your happy mood neurotransmitter, is made in your gut along with about 50% of your dopamine, the feel-good neurotransmitter that communicates with your brain’s reward and pleasure centre. GABA (gamma-aminobutyric acid) which helps control feelings of fear and anxiety is also found throughout the gastrointestinal tract.

What we eat provides the building blocks for these neurotransmitters so when we eat the wrong foods it causes the gut to get out of balance and it affects the production of these chemicals, ultimately impacting on our moods.

With 70% of your immune system in your gut as well, the effect of poor gut health can be felt throughout the rest of your body very quickly.

The health of our microbiome is determined by many things like what we eat, our sleep, the bacteria we’re exposed to each day as well as our ongoing stress levels.

When you get dysbiosis, or an imbalance in your gut flora, it starts to impact not just on gut function like leaky gut or irritable bowel, it also influences issues like autoimmune diseases, inflammatory conditions like arthritis, neurological disorders like dementia, skin disorders like eczema and heart disease as well as contributing to feelings of anxiety, depression or that just ‘blah’ feeling.

So if we can keep our gut healthy through good food and lifestyle choices, we keep many health issues at bay and keep our brain function sharp.

Improve gut health with these steps:

Reduce processed food, artificial sweetener and sugar intake. These encourage unhealthy bacteria in the gut leading to symptoms like fatigue, mental fog, mood swings, headaches, inability to concentrate, insomnia, anxiety and depression.

Eat a variety of wholefoods. The more diverse your diet, the more diverse your microbiome which makes it healthier. The typical Western diet is usually quite limited and its estimated around 75% of the world’s food is made from 12 plant and 5 animal species. Focus on high fibre plant foods, whole fruit, healthy fats and moderate protein.

Eat fermented foods. Fermented foods like yoghurt, sauerkraut, kimchi, kombucha and kefir contain probiotics and healthy bacteria that promote nutrient absorption, support your immune system and control the amount of disease-causing species in the gut.

Eat prebiotic foods. Prebiotics promote a healthy gut ecosystem.  They are mostly fibre or complex carbs that your gut bacteria breaks down for fuel which in turn promotes the growth of more beneficial bacteria.  Many fruits, vegetables and wholegrains contain prebiotics and some particularly prebiotic rich foods include artichokes, bananas, asparagus, oats and apples.

Eat healthy fats. Healthy fats are necessary for brain development and things like olive oil, avocado and fish oil contain antioxidants to protect against cell damage, improve memory and brain function and are anti-inflammatory.

Eat polyphenol rich foods. Found in red wine, green tea, dark chocolate, olive oil and wholegrains, polyphenols are a type of antioxidant that your microbiome breaks down to instigate increased healthy bacteria growth.

Eat nuts.  Nuts like almonds, cashews, walnuts and Brazil nuts can help boost serotonin thereby boosting your mood.

Consider a probiotic supplement.  Probiotics can help restore gut health after dysbiosis but may not make a substantial difference in an already healthy microbiome. It may be just as beneficial to increase your fermented and whole food intake.

Decrese stress.  Chronic ongoing stress slows gut function so look for ways to reduce your stress load. Gentle exercise like Vinyasa yoga, walking in nature, meditation, breathing exercises or mindfulness techniques can all help.

Get good sleep.  Without enough sleep, immunity is lowered, inflammation increases, and gut function slows down.  Turn off your devices and aim for eight hours of uninterrupted sleep.

While the gut-brain connection is complex, the science is still emerging. Replacing your coke with kombucha may not totally get rid of your anxiety or depressive symptoms but consistent efforts to improve gut health may lift your mood, improve brain health and make you more pleasant to be around.