In events of elation such as winning the lottery, eating a delicious chocolate cake, or earning a promotion our brains release chemicals called neurotransmitters that give us feelings of excitement, happiness and energy. Without these neurotransmitters, we wouldn’t feel as good during these moments of elation.
In events of fear and nervousness, like sitting an exam, a job interview or visiting our parents-in-law our brain produces different chemicals making us feel stressed and anxious. The rollercoaster of emotions we feel during our lifetime we believed was the result of these chemicals being released by our brains, but now we know that most of these chemicals actually derive from the gut.
Ok so what does the gut consist of?
It originates from the same clump of tissue as the brain during the embryo stage, so it shares the same nerve endings. There’s 500 million neurons in the gut, all of which can function independently to the brain, but that’s not all! Bacteria, trillions of bacteria! There are 1 billion bacteria per square centimetre on or in the human body!
Your gut is like the amazon rainforest. It’s diverse, and vast with billions of different kinds of species all with specific functions and agendas. Bacteria compete with each other for space in our gut, some feed on others whilst others live in perfect harmony. This diverse universe of life that lives within your gut is integral to your health.
Why is this?
For starters the good bacteria in your gut digests certain foods on our behalf. They produce short chain fatty acids as they ferment fibre. They produce vitamins and minerals, train our immune system and create feel-good neurotransmitters such as serotonin, they even help manage blood cholesterol and blood sugar levels.
A gut devoid of good bacteria is a gut that is less efficient in creating neurotransmitters. It’s a gut that is susceptible to allowing bad bacteria to populate it which can lead to allergies and intolerances, malapsorption of fats and carbs, vitamin and mineral deficiencies as well as increasing the inflammatory response, it can even make us more sensitive to stress.
Bacteria has been around since the world began, it’s evolved and learned how to survive a long time before we came into existence. Humans are mere infants on this world compared to bacteria. In order for me to emphasise the intelligence bacteria has acquired I’ll tell the story of the bacteria t.gondii tachyzoites. It’s a bacteria when ingested by a mouse, makes that mouse sexually attracted to cats. Specifically attracted to cat urine. The bacteria is able to cross the blood brain barrier, and target the amygdala and turn off the mouse’s fear to cats. Not only does it do that, but it plays on the area of the brain that’s associated with sexual activity and makes the mouse actively seek out cat urine. The mouse other than this new found querk for feline attraction, functions normally. It hasn’t dropped in its IQ or ability to do anything else. What you can be certain of though, is the cat won’t reciprocate these feelings and it will eat the mouse, allowing the bacteria to pass to its next host. You may be aware that during pregnancy, it’s advised to stay away from cat faeces, and to avoid cleaning it up if possible. That’s because of this bacteria which can cross the blood brain barrier in the placenta and cause autism, blindness or birth defects. It’s rare, but certainlu worth being aware of.
Another example is rabies in dogs, this bacteria rather than targeting the fear part of the brain, works on the aggressive part of the brain. It makes the dog rabid. When a dog is rabid it is likely to bite. Through this bite the virus is able to continue its life.
Scientists in Ireland made rats depressed when they implemented the bacteria of a depressed human in the rats microbiome. Showing that if you transfer the bacteria, you transfer the behaviour as well.
When a depressed persons microbiome is assessed compared to someone who is healthy, there is a less diverse bacterial environment with depression. We even know which specific strains of bacteria that can produce serotonin, and these strains are included in what is becoming know as “psychobiotics” and psychiatrists in America have begun prescribing psychobiotics in the treatment of mental health issues. I mean it’s not to say that this is the sole cause of depression but it seems to play a significant role in the development and maintenance of depression. The diversity of bacteria is what’s key here. When a mouse is raised in a germ free environment it exhibits symptoms very similar to autism. It isn’t sociable and fails to communicate, it doesn’t play or eat like the other mice. But when the microbiome of a healthy mouse was transferred, its behaviour dramatically changed and it began communicating, and eating like the other mice. Interstingly in humans, Autism is often associated with digestive issues.
What should I do?
Now there’s no need to rush out and buy a probiotic right away, the chances are if you’re symptom free with no digestive issues or mental issues and you’ve a diet with plenty of fibre and colour on your plate you’re alright. But if you suffer from bloating, flatulence, constipation, diarrhoea, bad stomach, bad breath even things like brain fog and fatigue, then it may be worth exploring further. Be mindful that chronic inflammation, stress, antibiotics, a high carbohydrate diet and a high sugar diet change the environment of the gut and have all shown to negatively impact the brain.
Anti-biotic use should be followed by a probiotic regime. It’s a common theme in nutrition clinics where a client has been given a number of courses of anti-biotics throughout a life-time coupled with a diet high in carbohydrates and sugar and low in fibre, resulting in anxiety issues, IBS and re-ocurring UTI’s.
Mental health is multi-faceted. Exercise, good quality sleep and psychological interventions all play a pivitol role. This has only been an introduction to the role the gut plays in mental health. Topics not covered are inflammation and the positive role an anti-inflammatory diet can have on mental health. Adequate protein consumption and avoiding nutritional deficiencies are other pivitool areas in the maintenance of good mental health.