The University of Oxford research – backed by prebiotic supplier Clasado Biosciences – also suggested a beneficial effect of the non-digestible galacto-oligosaccharides on brain health and emotions via the immune system and a key serotonin receptor in the brain.
Serotonin is a brain neurotransmitter and about 90% of the body's serotonin is produced in the digestive tract. Conditions like depression and anxiety disorder are often treated with drugs that alter serotonin levels.
Previous research had suggested that altering intestinal microbiota with prebiotics and probiotics could reduce inflammatory response, alter brain chemistry and modulate anxiety behaviour in both rodents and humans.
However, the neuro-immune and behavioural effects of prebiotics on ‘sickness behaviour’ had not yet been explored.
Writing in the journal Brain, Behavior and Immunity, the Oxford researchers said: “Our data suggest a potential role for prebiotics in the treatment of neuropsychiatric disorders where anxiety and neuroinflammation are prominent clinical features.”
The mice were fed the prebiotic for three weeks before being injected with lipopolysaccharide (LPS) to induce acute sickness behaviour and anxiety.
As expected this saw lower locomotor activity compared to the control group within the first six hours and acute inflammation leading to anxiety 24 hours later.
The researchers found that prebiotic-fed mice were significantly less anxious in the light-dark box 24 hours after the LPS injection.
They also observed that elevated levels of the pro-inflammatory cytokine interleukin-1 beta seen in the control mice were not seen in the prebiotic-fed mice and there were further differences in the serotonin receptor 5-HT2A. Cortical interleukin-1 beta has been linked to brain trauma.
Clasado CEO Graham Waters said the paper opened up new knowledge of the mechanisms underlying prebiotics’ potential within emotional and brain health.
“We are hopeful that this research could lead to viable alternatives to existing pharmaceutical treatments targeted towards brain and psychological disorders,” he said in a release.
More than 350 million people worldwide suffer from depression, according to the World Health Organisation (WHO).
Source: Brain, Behavior and Immunity
Published online ahead of print, doi: 10.1016/j.bbi.2015.10.007
“Prebiotic administration normalizes lipopolysaccharide (LPS)-induced anxiety and cortical 5-HT2A receptor and IL1-β levels in male mice”
Authors: H.M. Savignac, Y. Couch, M. Stratford, D.M. Bannerman, G. Tzortzis, D.C. Anthony, P.W. Burnet