BBC documentary discusses how gut bacteria may affect our sleep
Did you see the interesting show on the BBC last night about sleep? This programme, titled “The Truth about Sleep”, with Dr Michael Mosley, looked into things like the diet, lifestyle factors, as well as gut bacteria and prebiotic fibres - discussing the way they can affect and possibly increase our sleep quality.
This is a topic I’m quite keen on as sleep is an important aspect of our lives, yet so many of us don’t always get enough of it. One of the things that caught my attention was the importance of your gut microbiome and their influence on sleep!
We are aware that stress could have an effect on our microbiome and lead to dysbiosis (an imbalance of good & bad bacteria) in the gut, which could in turn affect our sleep cycle. Diets rich in prebiotics are thought to help with improving the amount and growth of beneficial bacteria in the gut - which in turn reduces stress linked to sleep deprivation in many people. As the research into prebiotics and sleep is still in its infancy, it was great seeing some new research about this theory and see it tested on Michael Mosley.
A recent murine study by Thompson et al (2017) -from the University of Colorado1- looked into this theory, which is what prompted the experiment done by Dr Mosley in this TV program.
This study found that rats fed with a diet rich in prebiotics, had an increase in the beneficial bacteria in their gut flora after 4 weeks of having a high prebiotic diet. What’s more is, these rats had better quality of sleep compared to the other control rats. This result suggests that the prebiotics caused an increase in the beneficial bacteria in the gut which inadvertently helped with improving sleep 1.
Prebiotic fibres are food sources that feed probiotics (friendly bacteria). So it is not surprising that introducing prebiotics had this same effect on Dr Mosley. His little experiment just goes to show that there is a possible link between prebiotics, probiotics and sleep.
Another interesting point taken from this program is, when we get less sleep, specific gut bacteria become quite active and promote increased absorption of calories and energy uptake from foods 2. The concentration of these strains of bacteria is higher in obese individuals. Sleep deprivation also causes the body to increases the secretion of hormones like ghrelin-also known as a “hunger hormone”. With this hormone promoting the need to eat more and our gut bacteria stimulating increased calorie intake, this could mean there is a possible link between gut flora, sleep deprivation and obesity3.
How might prebiotics help with sleep?
When probiotics feed on and break down prebiotic fibres, the metabolic by-products, which includes molecules like short-chain fatty acids, could affect the brain positively. Also, the increase in beneficial bacteria as a result of increased nourishment in the form of prebiotics could have an effect on the brain and sleep. This demonstrates that both probiotics (friendly bacteria) and prebiotics play an important role in improving our gut health and sleep.
Although the study found promising results and the prebiotics seemed to help Dr Mosley, it's important to take these results with a pinch of salt. Firstly, because the research was carried out on rats and the effects on humans isn't known, we can't be certain that the results can be replicated in a human study. And while it worked great for Dr Mosley, more large-scale human studies would need to be done in order to establish a significant link.
So what now?
Have a look at the following links to find out more about prebiotics and how probiotics can help:
1 R. S. Thompson, R. Roller, A. Mika, B. N. Greenwood, R. Knight, M. Chichlowski, B. M. Berg and M. Fleshner, "Dietary Prebiotics and Bioactive Milk Fractions Improve NREM Sleep, Enhance REM Sleep Rebound and Attenuate the Stress-Induced Decrease in Diurnal Temperature and Gut Microbial Alpha Diversity," Frontiers in Behavioural Neuroscience , vol. 10, pp. 1-16, 2017.
2 The truth about sleep. [TV series]. UK: BBC, 2017.
3 F. Hu, Obesity Epidemiology, Boston: Oxford University press, 2008.