Better understanding the gut microbiome

By Charlene Grosse, Advanced Accredited Practising Dietitian, Subiaco

The role of the gut microbiome (also called ‘microbiota’) in health and disease is an area of intensive research, which has shown that it plays a critical role in many aspects of physical and mental health, including mood, cognition and behaviour.

The gut and brain are intimately connected forming what is known as the gut-brain axis. This axis allows for bidirectional communication between the two organs via the vagus nerve with signals being transmitted from the gut to the brain and vice versa.

Individuals with depression and anxiety have alterations in their gut microbiome, including changes in the abundance and diversity of certain bacterial species. Alterations in the gut microbiome can lead to increased inflammation throughout the body.

Lack of exercise, stress, poor sleep, smoking and an unhealthy diet can all contribute to chronic inflammation. While counselling and medications have been key treatments in managing mental health problems, we are now discovering what we eat can also have an important role.

Diet has a big influence on our gut microbiota composition through influencing the effect on inflammation. Some researchers suggest today’s typically low-fibre, Western-style diet as a reason for a loss of diversity in the gut microbiome. Our gut microbial profile will be different if we eat, for example, a diet based on plant foods or one rich in animal foods, due to corresponding changes in the bacteria involved in metabolising the nutrients in these foods (whether that be carbohydrates or protein).

In 2020, the Australian and New Zealand College of Psychiatrists updated their clinical practice guidelines for mood disorders with a specific recommendation around diet and other positive lifestyle habits such as exercise. While there

Key messages

The role of the gut microbiome is subject to intensive research

Alterations in the gut microbiome are associated with a number of medical conditions is no single diet that is considered the best way to eat for mental health, a Mediterranean-style diet is has been associated with a reduced risk of depression. There are two key principles for the Mediterranean diet.

Exercise and a healthy diet can make a difference.

1. Eat plenty of vegetables, fruits, wholegrains, fish and seafood.

2. Eat less red meat and less highly processed foods and added sugars.

Healthy eating means a well-fed and more diverse population of microbes in the gut. Aim for a healthy, balanced and varied diet, based around whole foods, and rich in fibre. Resistant starch is also important for gut health, and consider probiotic and prebiotic foods, which are considered safe to eat.

Exercise has also been shown to be beneficial for gut health through increasing the diversity and abundance of beneficial gut bacteria, while reducing the abundance of harmful bacteria. Additionally exercise can have a positive effect on mood and cognitive function through its effects on the gut-brain axis.

While the gut microbiome is complex, improving gut health through diet and exercise may be an effective way to promote better mental health and wellbeing.

Autor competing interests – nil