Scienists have already figured out that there’s a link between gut health and mental health
Previous research has shown that probiotics can reduce stress and improve mental health, and it’s been found that sugary diets can cause anxiety and depression in men.
Scientists often use tests involving mice to show the link between the two, and the latest research shows that mice bred in a germ-free environment (and therefore free of gut microbiota) have shown that the absence of gut microbiota has an impact on brain development and behaviour – specifically anxiety.
Microbiota, or flora, include things like bacteria, fungi and viruses, which it is thought that we pick up along the germ cell, and these things are usually beneficial to our bodies.
The research, published in the journal Microbiome, showed that bacteria in the gut may have an influence on microRNA (molecules, basically, and called miRNAs for short) in the prefrontal cortex and amygdala – two areas of the brain which are associated with anxiety and depression.
The findings show that a healthy gut is necessary to keep these particular sections of the brain working properly, and this is the first research to look into both these regions.
Researchers at the APC Microbiome Institute at University College Cork did tests using regular mice and mice free of gut flora.
They found out which miRNAs were already present in the prefrontal cortex and amygdala of 10-12 control mice, germ-free mice and mice who were once germ-free but have had gut flora introduced.
They also used adult rats who had had their gut flora depleted by giving them antibiotics.
Scientists found that mice free of gut flora exhibited abnormal anxiety, increased depressive-like behaviour and deficits in sociability and cognition.
They found that giving the rats antibiotics affected some miRNAs in the brain, in a similar way to the germ-free mice.
This goes to show that even if there’s a healthy level of microbiota from a young age, any changes made in later life can still affect the brain, and therefore your anxiety levels.However, the study authors say that while these findings are exciting, there is still a lot more research to be done before the results can be confidently applied to humans, as they haven’t yet figured out the exact way the bacteria affects the brain’s miRNA’s.