A new microbiome study has found that specific gut bacteria are linked to some sleep conditions, and that fibre could be linked to getting a better night's sleep

What we eat can significantly impact the quality of our sleep. Healthy habits, like eating enough fruit and wholegrains, promote better rest. Unhelpful habits, like meals high in sugar, saturated fats, or caffeine too close to bedtime, can disrupt sleep, leaving us sleeping lighter, waking up more often, and feeling less refreshed. When we don’t get enough of the right nutrients – particularly calcium, magnesium, and vitamin D – we often don’t get enough sleep. 

Your gut microbiome is made up of a mixture of beneficial ‘good’ bacteria, potentially harmful bacteria, and pathogenic ‘bad’ bacteria. Everyone’s gut microbiome is unique and is impacted by what you eat, the environment you are in, medications, your lifestyle (stress levels, exercise, and sleep), as well as early life, genetics, your age, and health conditions.

Your microbiome helps produce vitamins, aids with digestion, trains your immune system, and even influences your mental health. Imbalances have been linked with autoimmune issues, skin problems, and obesity. A growing body of research suggests that our gut microbiomes have a greater impact on us – and our health – than we may realise.

Thanks to a new systematic review of studies, the link between our fibre intake, gut microbiomes, and how well we sleep is becoming clearer. Previous studies have found links between several sleep conditions and the gut microbiome; however, the specific microbial species that affect sleep health haven’t previously been pinpointed. Additional challenges have also impacted research, such as how lifestyle factors, including poor diets and irregular sleeping patterns, can also affect the composition of participants' gut microbiomes. 

A new systematic review of earlier studies conducted by Zhe Wang at Shandong First Medical University in China seeks to help pinpoint the microbial species (and identify the foods they thrive on) that impact our sleep quality. This new systematic review included looking at the findings of 53 observational studies that compared gut microbiota of those with sleep disturbances and those who didn’t experience disturbed sleep, with a combined 7,497 individuals with sleep conditions, and 9,165 without. 

Researchers found that the alpha diversity (the overall number of different bacterial species) was lower in people with sleep conditions. Those with insomnia, obstructive sleep apnea, or REM sleep behaviour disorder also had a consistent reduction in anti-inflammatory producing bacteria, and an increase in pro-inflammatory bacteria.

Researchers say this suggests that dietary fibre is important, as it is through the fermentation of these foods that Faecalibacterium (one of the anti-inflammatory, butyrate-producing bacteria) produces butyrate (a crucial short-chain fatty acid that acts as a main energy source for colon cells and supports gut health, immune function, and metabolic regulation). Butyrate is important in helping strengthen the gut barrier and reducing inflammation.

While this new meta-analysis supports the idea that Faecalibacterium and insomnia are linked, it’s important to note that, as these studies were observational, the causality cannot be determined. To establish if there is a causal relationship, further studies may be needed. However, these results add to the growing body of research that highlights the importance and impact of the gut microbiome on our sleep health.

While it might still be a little too early to say that fibre will help improve your sleep for sure, there are many ways you can still use your diet to help promote better sleep.

Diet and sleep: Optimising your diet for better sleep

Research suggests that a lack of healthy fats, carbohydrates, and protein can all be linked to less or worse quality sleep. Not getting enough protein can leave you feeling fatigued and weak, while both complex carbs and fibre have been linked to shorter sleep. Low levels of healthy fats can lead to poorer quality sleep, while processed carbs can cause disrupted sleep, thanks to blood sugar spikes and crashes. But what can we do to help optimise our fiets to get a better, more restful night’s sleep?

  • Focus on having a balanced diet filled with fruit, veg, and enough macronutrients (protein, fat, and carbs). This can help you to sleep more deeply while supporting your gut microbiome.
  • Keep the time in mind. Having a lighter, balanced meal at least three hours before bed can help to keep your circadian rhythm on track, as well as to avoid some of the food and drink that can lead to indigestion, discomfort, and feeling more awake. Large, sugary meals, alcohol, caffeine, and even spicy foods can all contribute to a poorer night’s sleep. 
  • Go caffeine-free (before bedtime). Studies have suggested that drinking tea, coffee, energy or fizzy drinks that contain caffeine up to eight hours before bed can disrupt your sleep.
  • Get your vitamin levels checked. Studies have suggested that a lack of vitamin D can be associated with a higher risk of sleep disorders. Find out more about supplements and focusing on food first to give your body what it needs. 
  • Opt for foods rich in melatonin, like nuts, milk, tart cherries, and kiwi. Melatonin helps regulate your sleep-wake cycle, meaning it helps you feel sleepy at night and awake in the day. Tryptophan helps your body to produce melatonin, so foods like fatty fish, eggs, seeds and nuts can also help, while magnesium and potassium-rich foods promote muscle relaxation, calming your nervous system, regulating sleep hormones, and supporting the neurotransmitters that induce rest. Including more leafy greens, sweet potatoes, bananas, and avocados can help you increase your magnesium and potassium intake. 

Although food isn’t a quick fix for a good night’s sleep, what, how, and when we eat can all have a significant impact when it comes to getting a more restful night. So while researchers continue to look for better ways we can improve our sleep, taking small, everyday steps with our diet is something we can start right now. Adding a little more fibre, variety, and balance to your plate won’t magically knock you out at bedtime, but it could help set the stage for better rest over time. Think of it as giving both your gut and your sleep a gentle nudge in the right direction – one satisfying, fibre-filled meal at a time.