(Web Desk) - When it comes to treating stress, depression and anxiety, you might not think what you eat has anything to do with it.
But new research suggests that the key to better mental health could be in your gut - and your favourite breakfast food.
University of Virginia School of Medicine researchers found that Lactobacillus - a bacterium found in yogurt, as well as fermented foods - could help the body manage stress and may help prevent depression and anxiety.
Led by UVA researcher Alban Gaultier, the team said the findings pave the way for treating mental health conditions.
The study was published in the journal Brain, Behaviour and Immunity and was conducted using mice.
Our bodies are populated by thousands of microorganisms - collectively referred to as microbiota - that are critical to our health and well being, and our guts are no different.
The UVA team said that "disruptions" to the microbiota - whether from illness, poor diet, or other causes - contribute to many diseases and even help cancer spread.
This means that scientists are now increasingly looking to the gut as a tool to battle diseases and improve health.
And there is also interest in how microorganisms in the gut can influence mental health.
Dr Gaultier and his team sought to separate Lactobacillus from other microorganisms in the gut to determine its role - with previous research suggesting that the bacteria could reverse depression in lab mice.
Dr Gaultier said: “We were aware from our prior research that Lactobacillus was beneficial in improving mood disorders and was lost following psychological stress, but the underlying reasons remained unclear, primarily due to the technical challenges associated with studying the microbiome."
The team used a collection of bacteria, known as Altered Schaedler Flora, which includes two strains of Lactobacillus and six other bacterial strains.
The team used mice who either did or did not have Lactobacillus in their gut.
By conducting behavioural tests and exposing them to a range of stressors - like moist bedding or a tilted cage - they found that mice who didn't have the bacteria displayed more signs of anxiety and depression.
And they observed that transferring the microbiota from stressed mice to germ-free mice was enough to induce depressive and anxiety-like behaviours.
Scientists were able to identify that Lactobacilli can maintain the levels of an immune mediator, called interferon gamma, that regulates the body’s response to stress and helps stave off depression.
Dr Gualtier explained: “Our discovery illuminates how gut-resident Lactobacillus influences mood disorders, by tuning the immune system.
“Our research could pave the way towards discovering much-needed therapeutics for anxiety and depression.”
Researcher Andrea R. Merchak added: "With these results in hand, we have new tools to optimise the development of probiotics, which should speed up discoveries for novel therapies.
"Most importantly, we can now explore how maintaining a healthy level of Lactobacillus and/or interferon gamma could be investigated to prevent and treat anxiety and depression."