Mind & Body

Gut bacteria linked to treating anxiety


In the last few years, the gut microbiome has become big news. We know that the trillions of bacteria that make up the body’s gut microbes can affect everything from digestion to the immune system. And new research supports the fact that it can also impact mental health, specifically anxiety.

Anxiety disorders are the sixth most common causes of disability according to a Global Burden of Disease study in 2010, and they have undoubtedly surged during the pandemic. But the solution may be found in our gut.

A study from Berkeley Lab’s Biosciences Area reveals that nurturing our gut microbiome may alleviate anxiousness. To investigate the connections between genes, gut microbiome composition and anxious behaviour, the team used a genetically heterogeneous lineage of mice known as the Collaborative Cross (CC).

First up, 445 mice were classified with high or low anxiety based on their behaviour in the light/dark box assay. The box has two compartments – one is bright and well-lit while the other is black and in dark – connected by an opening. The mice that overcame their instincts to avoid brightly lit, open spaces to explore a new environment were classified as low anxiety, while the ones that stayed in the comfort zone were considered highly anxious.

The researchers then conducted a genome-wide association study analysis, which is a fancy way of saying they compared high and low anxiety mice and their gut microbiome composition.

Specific genetic variants and families of gut microbes associated with anxiety-like behaviour were identified. This included host genes that influence anxiety indirectly by regulating the amount of specific microorganisms.

The report states: “Our findings have the potential to provide insights on the mechanisms of host-microbe interactions related to anxiety. We further demonstrate that genetic effects on anxiety are partially mediated through modulating the abundance of specific gut microbes, suggesting links between host genetics and anxiety via intestinal health.”

Co-lead author Antoine Snijders, a staff scientist in the Biological Systems and Engineering Division, believes it is an important finding.

“We hope this study will inform future research to evaluate treatments for anxiety that take into account both host genome and microbiome,” he said.