Gut health impacts more than the gut

March 1, 2023
/ Digestion, Food Science, Health, Nutrition, Research

February is gut health month, and some Australians have been taking it very seriously. In honour of this most vital bodily system, and to launch a program of healthy eating, intrepid residents temporarily changed the name of their Victorian town (Poowong) to Pooright.

Pooing right is not just a tribute to healthy intestines but reflects the myriad of vital roles that the gut and the trillions of microbes, or “friends with benefits”, that reside there have in our health, including digestion, metabolism and immune function.

These microscopic organisms, which include bacteria and fungi, can also impact personality and behaviour, and research has linked gut bacteria to a host of mental health conditions ranging from anxiety, depression and stress to schizophrenia, dementia and motivation.

Gut-brain axis

In the early 1800s an unfortunate gunshot wound led to a permanent hole in the poor victim’s stomach. The surgeon saw this as a window of opportunity to investigate the workings of the survivor’s gut, finding among other things that its functions were impacted by emotions such as anger.

The surgeon’s discoveries heralded the notion that the gut and the brain are connected, which might explain why people with psychiatric illness commonly have gastrointestinal problems. This two-way connection came to be known as the gut-brain axis and research over the past couple of decades has started to reveal that microorganisms play a key.

Much of the research so far has been in animals and is not an exact science, having only touched the tip of the iceberg. But it has identified some bacteria that appear to promote wellbeing, such as bacteroidetes, lactobacillus and those that produce the short-chain fatty acid butyrate, which has been linked to better quality of life outcomes.

Clinical trials have found that giving people prebiotics (which bacteria feed on) or probiotics (live bacteria) may improve mental health outcomes, such as mood in people with depression and cognition and problem-solving ability in people with psychosis. One study even found that the gut microbiome of mice had more impact on their motivation to exercise than genetic, metabolic or behavioural traits.

Of course, there has been a flurry of excitement about how these findings could be translated into therapies to improve brain function, producing the term “psychobiotics”. What’s really exciting is that while we can’t (necessarily) change our genes, we can have a good deal of influence over the microbial communities in our gut.

Improving gut health

Ultimately, growing insights about the vital importance of a healthy gut lends further weight to the undeniable and irreplaceable benefits of a healthy lifestyle, including a focus on diet, physical activity and mindfulness.

Conversely, eating highly processed food, a sedentary lifestyle and stress are likely to produce an unhealthy microbial community – or a state of dysbiosis – which could have a great deal to do with the impact of these lifestyle habits on poor physical and mental health.

This should boost our motivation to adopt, and enjoy, a Mediterranean-style diet that includes plenty of fibre from plant foods (fruit, vegetables, legumes, nuts, seeds and whole grains), getting regular exercise and plenty of sleep, and taking time out to destress, whether that be enjoying yoga, meditation or simply relaxing in nature.