Bimuno, patented and available commercially from Clasado, was found to decrease waking cortisol levels and attentional vigilance towards negative versus positive information. The trial compared B-GOS with fructooligosaccharide (FOS) and a placebo.
Bimuno has previously been hailed as a 'second generation' prebiotic, since it not only boosts probiotic bacteria at a group level, but also offers additional functionality by inhibiting the adhesion of 'bad' bacteria to the gut wall.
The new findings, published in Psychopharmacology, add to the expanding body of knowledge on microbiome-behavior and microbiome-endocrine interactions, said Dr Phil Burnet, Head Researcher at the Department of Psychiatry, University of Oxford.
“The study makes an important contribution to the existing clinical evidence linking the gut and its microbiota to brain function,” he added.
‘A valuable addition to our knowledge of brain-gut interactions’
The gut-brain axis
Previous studies have reported potential mood and behavioral benefits from probiotics, but the new study is the first to extend such links to behavioral effects of prebiotics in humans, said the researchers.
According to the Mental Health Foundation, 25% of people in the western world will experience a mental health problem at some point during a 12 month period and anxiety is the most common mental illness, affecting approximately one in six people in the US and UK.
“Mental health problems affect a significant proportion of people in the western world. Indeed, depression and anxiety account for 40% of reported disabilities worldwide,” said Graham Waters, CEO of Clasado.
“This latest study by Clasado and the Department of Psychiatry, University of Oxford is a valuable addition to our knowledge of brain gut interactions and may pave the way for alternatives to existing drug therapies with their associated side effects.
“This trial is part of a wider program of clinical research in which we are currently engaged, investigating the central role of the gut in improved health and wellness.”
The researchers recruited 45 subjects and randomly assigned them to receive either fructooligosaccharides (FOS) or Bimuno-galactooligosaccharides (B-GOS) or a placebo for 3 weeks.
Results suggested that B-GOS may have an anxiolytic effect and reduce stress reactivity in healthy subjects. In addition, the salivary cortisol awakening response (CAR) – used to assess HPA (hypothalamic-pituitary-adrenal) axis reactivity and processing – was found to be significantly lower after B-GOS, compared with placebo. (The HPA axis is often dysregulated in individuals suffering from depression and anxiety impacting affective and memory processing as well as having strong directional links with the gut microbiome.)
The researchers also found that B-GOS was associated with decreases in attentional vigilance to negative versus positive information, compared to placebo and FOS treatment. Increased processing of negative material is seen as a core functional marker of anxiety and depression and can be modulated by antidepressant/anxiolytic medication. No effects were found after administration of a FOS prebiotic, they said.
“Although we were unable to test the mechanisms of action directly through characterisation of gut microbiota, a previous characterisation of B-GOS and FOS prebiotics showed pronounced increases in bifidobacteria in faecal pellets of rats treated with B-GOS administration compared to placebo, with more moderate effects following the FOS intervention,” wrote the researchers. “The specificity of galactooligosaccharides affecting behavioural and endocrine changes is thus in line with previous findings of galactooligosaccharides as particularly effective in stimulating enteric microbial growth.
“Of course, the possibility of an additional, direct effect of B-GOS on the gut mucosa cannot be ruled out.”
The study was funded by the UK’s Biotechnology and Biological Sciences Research Council (BBSRC), Clasado Ltd., Wellcome Trust Vacation Scholarship, and the Medical Research Council (MRC).
Bimuno is a trans-galactooligosaccharide (GOS) second generation prebiotic, and has US GRAS certification (GRN 000484), through scientific procedures, for use as an ingredient in a variety of food and beverage categories at levels ranging from 0.8 to 3.0 grams per serving (g/serving).
Published online ahead of print, doi: 10.1007/s00213-014-3810-0
“Prebiotic intake reduces the waking cortisol response and alters emotional bias in healthy volunteers”
Authors: K. Schmidt, P.J. Cowen, C.J. Harmer, G. Tzortzis, S. Errington, P.W.J. Burnet