Gut Health & Sleep on BBC

Naomi Osun Registered nutritionist, ANutr

Did you see the interesting show on the BBC about sleep? The programme, titled “The Truth about Sleep”, with Dr Michael Mosley, looked into factors such as diet and lifestyle, as well as gut bacteria and prebiotic fibres - discussing the way they can affect and possibly increase our sleep quality.

woman distressed listening to alarm clock

Prebiotics could improve sleep quality

This is a topic I’m very 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 can have an effect on our microbiome and lead to dysbiosis (an imbalance of good & bad bacteria) in the gut. However, what we didn't know until recently was that this 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 firstly hearing about some new research into the topic, and then seeing it put to the test on Dr. Michael Mosley himself.

The study

A recent murine study by Thompson et al. (2017) - from the University of Colorado- looked into this theory, and examined the effect that taking prebiotics had on sleep quality. It was this research that prompted Dr Mosley to try it on himself in his TV program.

woman waking up refreshed

There is a possible link between prebiotics, probiotics and sleep

The study found that rats fed with a diet rich in prebiotics, had an increase in beneficial bacteria in their gut flora after just 4 weeks. What’s more, these rats had better quality of sleep compared to the other control rats. This result suggests that the prebiotics caused an increase in beneficial bacteria in the gut which consequently improved sleep1.

Prebiotic fibres are food sources that feed probiotics (friendly bacteria). So it is not surprising that introducing prebiotics had the same effect on Dr Mosley when he tried it himself. 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 that when we get less sleep, specific gut bacteria become more active. The strains in question are known to promote increased absorption of calories and energy uptake from foods2. Whilst this may be helpful in dealing with the energy deficit caused by poor sleep, it can also cause weight gain. Interestingly, the concentration of these strains of bacteria is higher in obese individuals.

Sleep deprivation also causes the body to increase the secretion of hormones like ghrelin (the “hunger hormone”). With this hormone promoting the urge to eat more and our gut bacteria already stimulating increased calorie intake from our food, the link between gut flora, sleep deprivation and obesitylooks even more likely.

grains in bags

Foods like lentils, chickpea, green peas and artichokes are great natural sources of prebiotics

How might prebiotics help with sleep?

When probiotics feed on and break down prebiotic fibres, they produce metabolic by-products. These by-products include molecules such as short-chain fatty acids, which have a positive affect on brain chemistry.

Also, the increased numbers of beneficial bacteria resulting from the nourishment provided by the prebiotics could have a direct effect on the brain and sleep. Beneficial bacteria are known, for instance, to help in the synthesis of neurotransmitters and hormones such as serotonin and melatonin, which are important for our sleep:wake cycles. This demonstrates that both probiotics (friendly bacteria) and prebiotics play an important role in improving our gut health and sleep.

Although the study detailed on the TV show found promising results, and the prebiotic 'experiment' also 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 haven't yet been replicated in a large-scale clinical trial. Whilst the prebiotics worked well for Dr Mosley, more large-scale human studies would need to be done in order to establish a significant link.

So what now?

Even without further evidence from large-scale human clinical trials, I’m sure the next question on our minds will still be 'How can I use prebiotics to improve my overall health and sleep?'. Unfortunately, there is no one-size fits all approach to choosing a product, or finding the best way to introduce more friendly bacteria to our guts, as we all have unique gut microbiomes. Finding a well-researched product that is clinically proven to reach the gut alive is always a good starting point. Additionally, choosing a probiotic and prebiotic in combination could provide extra benefits. You can read more about synbiotics here.

Supporting gut health means finding the most suitable type of friendly bacteria for every individual. Our FAQ, 'Are all types (strains) of friendly bacteria the same?' goes into further detail about the importance of getting the right bacteria depending on need.

Have a look at the following links to find out more about prebiotics and how probiotics can help:

What are Prebiotics? (and where to find them)

Does a lack of sleep affect our gut bacteria?


  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.