Behind Closed Doors: The secret worlds within us…

By Rahi Patel, Year 12.

Have you ever wondered where the common phrase ‘gut feeling’ stems from or how this meandering smooth tissue could be related to such complexities as emotions?

For centuries Aryuvedic medicine (An ancient Indian branch of medicine) has regarded the gut as the centre of our wellbeing; however, in modern medical practice this once revered organ has been pushed to the side in order to make way for the big players: the brain and the heart. However, recent developments in the medical field are beginning to reveal evidence to prove this ancient theory: showing us that our ‘gut feelings’ truly are the most significant.

In order to understand this rather counter-intuitive principle we must first establish the functions of our brain; it is the centre of conception and movement, the organ that led us to the discovery of electricity, and the organ helps us to coordinate the complexities of standing for Mrs Lunnon in a Monday morning assembly. Although we have created a strong link between the term ‘self’ and our brains we can see through the exploration of this underrated organ, the gut, that there may be more to ‘ourselves’ than what lies behind the eyes.

Our guts possess a multitude of nerves found uniquely in this part of the body. This immediately poses the question of why such an elaborate and complicated system would be needed if the sole purpose of the gut were to create a pleasant journey for food to move from the mouth through to the colon, accompanied by the occasional release of gaseous sounds?

So the scientists amongst us must all be wondering where the evidence is to support these new claims. Well, several experiments have been conducted around the world highlighting the importance of our gut with regard to mental well-being.

The ‘forced swimming test’ is a commonly used experiment to assess the effectiveness of antidepressants. A mouse is placed in a basin of water too deep for it to stand in, so it is forced to swim; mice with depressive tendencies give up swiftly, however, the ones with greater motivation persevere. Most antidepressants tend to increase the time that a mouse swims for, before giving up. One scientist, John Cryan decided to feed half the mice with Lactobacillus Rhamnosus: a bacterium widely known to be beneficial for gut health. Impressively, the mice with enhanced gut health not only swum for longer, but their blood also contained significantly less stress hormones.

Cooperation between the gut and the brain, via the vagus nerve, is thus proving to be a promising field for the curing of mental disorders and diseases. The gut is our largest sensory organ, so it would only make sense for the brain to form a close relationship with it, to create a detailed image of the state of our bodies, given ‘knowledge is power’. This understanding is helping to shed a light on complex neurological diseases, such as depression, as scientists are now aware that there is more to the ‘self’ than the brain, questioning the philosophical proposition of ‘I think therefore I am’…maybe we should adapt this to ‘I eat, then I think, therefore I am’.

Lining the labyrinth of organs known as the gut are approximately 100 trillion bacteria (weighing 2kg) eagerly waiting to help us break down and assimilate the billions of particles that enter our bodies each day. They also help to produce new vitamins, for example sauerkraut is significantly higher in vitamins than plain cabbage.

Not only do our bacteria increase nutrient values in our food they also advise us on the foods that we should be eating – a perplexing idea I know! But what we eat is a matter of life and death for our friendly cohabitants, so it only makes sense for them to influence our choices. In order to trigger a craving the brain must be accessed, which is a tough feat considering the armour-like meninges and the blood – brain barrier. Bacteria can synthesise molecules small enough to access our brains, such as the amino acids, tyrosine and tryptophan, which are converted into dopamine and serotonin within the brain. Of course this is not the only way in which cravings materialise, but it is far easier to control our brain with bacteria than with genes, which may help to pave the future of treatments for diseases such as hypertension and diabetes.

So next time you wonder why you’re craving a tortilla or your favourite brie, just eat it, since 95% of serotonin (the happiness hormone)  is produced by the gut and we all now know the significance of ‘gut feelings’ on our well-being!

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