Many of my clients have been asking me about prebiotics and their role in improving sleep so I thought I would write some more on this subject as insomnia seems to be an increasing problem.

Some of you will have seen the BBC programme where Michael Mosley explored insomnia and gave some ideas of what to do about it.

He used prebiotics in supplement form and and found them helpful as was shown when his sleep cycle was analysed.

Previous research studies have suggested that stress can alter our gut bacteria and these change interfere with the sleep/wake cycle (the circadian rhythm).

Researchers at the University of Colorado found that ‘Diets rich in prebiotics and glycoproteins impact the gut microbiota and may increase gut microbial species that reduce the impact of stress.’

Prebiotics are carbohydrates that are not digested in the stomach but pass through the small intestine and end up in the colon where they act like a ‘fertiliser’ feeding the gut microbiome – our beneficial bacteria through fermentation.

Prebiotics are also known as resistant starches because they ‘resist’ starches in the stomach.

During the research (which was carried out on rats), the scientists noticed that the rats supplemented with prebiotics had higher amounts of beneficial gut bacteria – probiotics – particularly one species Lactabacillus Rhamnosus. This particular species helps to reduce anxiety and depressive behaviour in humans. It also helps to calm the ‘flight or fight’ response in the body that kicks in when we experience stress of one kind or another.

The most common types are inulin and fructooligosaccharides (FOS).

Where do we get prebiotics in our diet?
  • Artichokes (especially Jerusalem)
  • Asparagus
  • Garlic, onions and leeks
  • Bananas
  • Root vegetables
  • Legumes and beans (lentils and dried lima beans are particularly good sources)

Cooked and cooled potatoes, rice and pasta are also sources of resistant starch because the starches ‘gel’ and the increase resistant starch content.

Studies in human beings have found that dietary prebiotics reduce the effects of exposure to stress as well as:

  • Improving the environment of the gut microbiome – increasing variety of species
  • Increased butyrate (a fatty acid that supports the gut), a precursor to GABA ( a neurotransmitter in the brain that helps to regulate relaxtion in the brain which may explain its role in stress reduction)
  • Improved body composition (reduction of body fat)
  • Supports healthy metabolism and may improve insulin sensitivity – the cells response to insulin

Scientists concluded that:

“The results of the current study demonstrate that a (test) diet rich in prebiotics started in early life increases the growth of Lactobacillus rhamnosus and alleviates the stress-induced disruption of REM sleep, diurnal physiology and gut microbial alpha diversity.”

A word of warning – for some individuals dietary prebiotics can be difficult to digest and can cause symptoms such as bloating and flatulence. Introduce these prebiotic-rich foods slowly and start with smaller portions.

Prebiotics are also available in supplement form – often as part of a probiotic supplement – many of which are available over the counter.  They are generally safe to take but you should always consult a healthcare professional if you are taking medications or have a health condition.