Gut bacteria linked to anxiety-like behaviours in children

The study - a collaboration between Deakin University, Barwon Health and the Murdoch Children's Research Institute (MCRI) - is the first to show that children with a lower amount of Prevotella at age one are more likely to have anxiety-like behaviours at two.

Researchers examined data from 201 children in the Barwon Infant Study (BIS), analysing poo samples at one, six and 12 months of age, then measuring behavioural outcomes at two years.

They found children with a lower abundance of the bacteria Prevotella in their poo at 12 months of age had a higher prevalence of anxiety-like behaviours, including shyness, sadness and an internal focus, an indicator they may be at higher risk of going on to develop childhood anxiety.

Study leader Professor Peter Vuillermin, from Deakin, Barwon Health and MCRI, said the bacteria Prevotella was much more common in the guts of people living in non-westernised environments. He said the study found less Prevotella in children who had recently taken antibiotics.

"Growing evidence supports the idea that antibiotics, poor diet and other factors in the modern world are leading to the loss of our traditional gut bacteria, and in turn, health problems," Professor Vuillermin said.

"There is intense interest in the relationship between gut bacteria and brain development, but most of the evidence has come from experiments in mice. This is one of the first human studies to compare the composition of baby's gut bacteria to subsequent behavioural outcomes."

The paper's first author, Dr Amy Loughman, from the Food and Mood Centre in Deakin's Institute for Mental and Physical Health and Clinical Treatment, said the study also added to the growing evidence supporting the role of the infant gut microbiota for neurodevelopment and mental health in later life. In previous cross-sectional studies Prevotella abundance has been associated with both autism and Parkinson's disease.

"The actions of the gut microbiome play a role in the structural and functional development of the brain. This can occur through several different mechanisms, including via interactions the microbiome has with our immune, endocrine and metabolic systems," Dr Loughman said.

"The composition of gut microbiota develops rapidly over the course of infancy, prompted in particular by changes to feeding and the introduction of solid foods. This study and previous research suggests that the early life gut microbiota may be important for health outcomes in later life."

The research team now hope to build further evidence to consider Prevotella as a gut bacteria key to both identifying health risk, and potentially, as an intervention to improve health outcomes.

"One day we could get to the point where we can look at a child's poo at 12 months, and if they are showing levels of bacteria that put them into a high-risk category for anxiety we can offer an early intervention," Dr Loughman said.

"This might be a supplement of Prevotella or other bacteria, or it could be in the form of behavioural and family support to bolster their psychosocial environment. But we need to get more research behind us before we can reach that point."

In the meantime, Dr Loughman encourages parents to follow Australian dietary guidelines and feed children a diet high in fibre, including plenty of fresh fruits and vegetables, and to work with their doctor to minimise the use of antibiotics.

"This is the most evidence-based guidance we can offer to support children's physical, mental and gut health," she said.

'Gut microbiota composition during infancy and subsequent behavioural outcomes' was published today in the journal EBioMedicine.