Gut health: how the intestines influence body and psyche

The gut: more than just a digestive organ

When we receive troubling news, we first have to digest it. Injustice is difficult to stomach. An unkind remark leaves a bad taste in our mouth. If we are particularly tense and stressed, we get diarrhoea: the way that the digestive tract has entered into our language, and also how it reacts to our state of mind, is telling. Proof enough that the gut should not be reduced to its digestive function.

Gut: the Inside Story

With German doctor and author Giulia Ender’s book, Gut: the Inside Story of Our Body’s Most Underrated Organ, published in 2014, the topic finally achieved social acceptance, and now even the most elevated circles may be heard discussing the marvels of the gut. And rightly so – because the intestine is the largest immune organ in our body, includes as many nerve cells as the spinal cord, and digests around 30'000kg of solid food over the course of a lifetime.

Intestinal flora and related bacteria

The intestinal flora – consisting of trillions of bacteria – has a fundamental influence on our state of health. This is because approximately 100 trillion intestinal bacteria train our immune system and protect the body from unwanted germs, assist in the formation of vitamins and neutralise toxins. No less than 80 percent of our entire immune system is in the intestine, and using its millions of nerve cells the gut continuously collects information about our general condition.

You are what you eat – from calories to obesity

Even obesity cannot be viewed in isolation from the intestinal flora: certain bacteria in the intestines can cause people to gain weight, even though they don't consume more calories than slim people. This is because overweight people’s intestines often contain more bacterial genes for breaking down carbohydrates. However, we don’t have to be victim to our bacteria and their effect on our body. What we eat and how we live influence our intestinal flora. Bacterial researchers believe, for example, that different bacteria survive in the intestine of people dealing with constant stress, than in those with a relaxed lifestyle. Although these bacteria cope with the stress, they dampen the person’s mood.

Gut and psyche: a close connection

The link between gut and psyche is often referred to as the “gut-brain axis”. This connection is a key factor in our general health. Studies show that a healthy gut flora not only influences digestion, but also plays a significant role in our mental health. Imbalances in the microbiome can lead to mood swings, anxiety and even depression. Conversely, mental stress and emotional strain can affect our gut health. It's therefore important that we take care of both our physical and mental health to keep gut and psyche well balanced.

The gut and brain are linked too

It’s now beyond any doubt that our gut influences our well-being. The truth is that the intestine – via a nervous system and its vast surface area – is closely linked to the brain. This is illustrated by the fact that humans know exactly what the needs of their digestive tract are, i.e. when they should go to the toilet. Conversely, heightened anxiety, for example, affects activity in the large intestine: it no longer has enough time to absorb fluid, and the result is diarrhoea. This type of diarrhoea is the intestine’s strategy of coping with the increased energy required by the brain due to stress – it wants to get rid of the food early.

Influence of hormones on gut health

Hormones influence our intestinal activity and therefore the way in which the gut and brain function together. This makes the human being a complex ecosystem. Hormones released in the intestine directly influence our feelings and mood, while hormones produced in the brain affect intestinal activity. In positive cases, a person has butterflies in their stomach, in negative cases, they have a runny tummy. “Our self is created in our head and belly,” is how Giulia Enders put it in her book Gut: the Inside Story of Our Body’s Most Underrated Organ. For people with irritable bowel syndrome, the connection between the intestine and the brain can lead to serious problems – these people suffer above-average anxiety or depression. The same applies to people with chronic abdominal inflammation.

Well-being not only has to do with the mind, but with the gut too

Pleasure, uncertainty, fears and bad moods don’t come from the head alone. Reason enough to pay more attention to your gut – and not only when it no longer functions as it should.