Reference Number: 200
Year: 2015
Link: Link to original paper
Health: Stress
Summary
Rationale
There is now compelling evidence for a link between enteric microbiota and brain function. The ingestion of probiotics modulates the processing of information that is strongly linked to anxiety and depression, and influences the neuroendocrine stress response. We have recently demonstrated that prebiotics (soluble fibres that augment the growth of indigenous microbiota) have significant neurobiological effects in rats, but their action in humans has not been reported.
Objectives
The present study explored the effects of two prebiotics on the secretion of the stress hormone, cortisol and emotional processing in healthy volunteers.
Methods
Forty-five healthy volunteers received one of two prebiotics (fructooligosaccharides, FOS, or Bimuno®-galactooligosaccharides, B-GOS) or a placebo (maltodextrin) daily for 3 weeks. The salivary cortisol awakening response was sampled before and after prebiotic/placebo administration. On the final day of treatment, participants completed a computerised task battery assessing the processing of emotionally salient information.
Results
The salivary cortisol awakening response was significantly lower after B-GOS intake compared with placebo. Participants also showed decreased attentional vigilance to negative versus positive information in a dot-probe task after B-GOS compared to placebo intake. No effects were found after the administration of FOS.
Conclusion
The suppression of the neuroendocrine stress response and the increase in the processing of positive versus negative attentional vigilance in subjects supplemented with B-GOS are consistent with previous findings of endocrine and anxiolytic effects of microbiota proliferation. Further studies are therefore needed to test the utility of B-GOS supplementation in the treatment of stress-related disorders.
SIGNIFICANCE OF THIS STUDY
This is an encouraging study that shows that the intake of prebiotics had a marked effect on salivary cortisol levels, a marker of stress response. The reduction in the levels is significant and so part of the core of what we teach is to include foods in you baking or the accompanying foods you eat with your sourdough contains galacto-oligosaccharides – these foods include lentils, chickpeas, apples, pistachio, cashew nuts, Freeka, blueberries and pears.
