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Little is as frustrating as spending hours awake in bed, unable to do anything other than stare at the ceiling. Whether you’re suffering from insomnia or can’t stay soundly asleep once you’ve snoozed for a few hours, sleep woes can leave you feeling just plain terrible the next morning. While there are plenty of sleep-stealing culprits that could be at play, your gut might be responsible if you’re having trouble getting to or staying asleep.
Your gut – specifically, your gut microbiome – is linked to your overall health. It shapes everything from your brain health to your immunity, your mental health to your ability to lose weight. With such a far-reaching impact, it’s no surprise that your gut and its microorganisms can affect how you’re sleeping.
And research confirms that the gut microbiome plays a central role in your ability to drift off to sleep each night. Increasingly more scientific evidence suggests that your microbiome affects your sleep in multiple ways.
Your gut follows your circadian rhythms
Circadian rhythms are central to a consistent sleep schedule. As the CDC explains, your circadian rhythms are internally driven cycles that time your “internal clock” throughout the day. It’s these rhythms that help you fall asleep and wake up at the appropriate times, following the light and dark cycle of the sun.
Yet according to a 2018 research review published in Frontiers in Psychiatry, your gut microbiome can affect just how your circadian rhythm functions. According to that review, the microorganisms present in your gut microbiome actually exhibit circadian rhythms. The most prevalent microorganisms – bacteria like Lactobaillales and Bacteroidales – fluctuate based on the time of day and change in abundance from day to night.
As your gut bacteria follow your circadian rhythms, they process nutrients differently. When you wake, when you eat and when you sleep all affect your gut’s very own internal clock. As a 2019 research review highlighted, changes to your circadian rhythm also directly affect your gut. A shift in schedule, like changing when you’re eating and your sleeping patterns, can disturb your gut bacteria, leading to sleep loss, insomnia, and other issues like metabolic syndrome.
So, when you aren’t sleeping well, your gut is directly affected. And that can lead to even worse sleep, compounding a problem you’re already facing.
Your gut bacteria shape your sleeping patterns for better or worse
In addition to being sensitive to your circadian rhythms, your gut microbiome also exerts influence over your normal sleep patterns. A 2020 research study discovered that gut bacteria play a role in the creation of key brain chemical messengers that affect your sleep-wake cycle.
Researchers divided 25 identical male mice into two groups. One group was fed water with broad spectrum antibiotics, which depleted the mice’s gut bacteria. The other group drank regular, antibiotic-free water. After one month, the group that sipped antibiotic water had depleted gut microbiota and far fewer intestinal metabolites – which, in turn, meant that these mice were unable to properly produce the brain chemical messengers they needed.
As a result of the missing metabolites, the antibiotic-fed mice struggled to produce neurotransmitters. They had higher levels of tryptophan yet almost no serotonin. It appeared that the mice’s bodies were unable to process the tryptophan found in food and properly produce serotonin from it. In EEGs, the researchers also discovered that the antibiotic-fed mice had trouble sleeping. The mice experienced more sleep disturbances, struggling to sleep soundly and consistently.
What does this mean for your own sleep schedule? Well, research shows that serotonin is a must-have brain chemical messenger. When the brain releases serotonin, it increases “sleep pressure”, or feelings of sleepiness. Higher serotonin levels encourage you to fall asleep, while lower levels leave you feeling more awake and alert.
Without a diverse gut microbiome (and those key intestinal metabolites), you may not get the amount of serotonin that you need. This can mess with your usual sleep patterns and altering when you’re ready to fall asleep.
If your gut microbiome is struggling to digest tryptophan and turn it into serotonin, you’re likely going to find it much more difficult to feel sleepy when it’s time to head to bed. You may also be more prone to experiencing restless sleep, or find that you’re waking up more often.
Indicators of sleep disorders may also appear in your gut
Your gut might also impact your odds of developing sleep disorders or conditions that prevent a restful night of shut-eye. The close connection between your brain and your gut microbiome can be exactly what causes issues like insomnia.
According to a 2019 study, individuals who suffer from insomnia actually have significantly different gut microbiota than those who don’t. Researchers found that those with insomnia have a different composition of bacteria, diversity in the types of bacteria present and bacteria with different metabolic function.
While the study’s researchers weren’t able to determine whether these differences in the gut microbiome directly caused insomnia or resulted from insomnia, it was clear that altered gut bacteria played a role in some way. The study’s authors hypothesized in the results that, based on their findings, insomnia disorder can significantly change the bacteria population in the gut microbiome.
If you’re living with insomnia, achieving a balanced microbiome might potentially help promote or encourage sleep. More research is needed to determine how, exactly, you might be able to fine-tune your microbiome to help insomnia or its impact on your sleep schedule. But current research does show that your bacterial makeup plays a role.
Better gut bacteria diversity can lead to sounder, more restful sleep
Ultimately, whether you’re struggling to fall asleep or find that you aren’t well-rested in the morning, your sleep woes could potentially be rooted in your gut.
Turning to prebiotics may be a potential sleep aid. A 2020 research study conducted by the University of Colorado at Boulder found that a prebiotic diet helped animals sleep better, and it even offered a bit of a buffer against the physiological effects of stress. Fiber-rich foods in particular were great for the gut and for sleep. Eating the right amount of fiber nourished gut bacteria and helped positively influence those all-important metabolites that affect your brain’s serotonin production.
And that isn’t the only research study that’s found that improving your gut microbiome’s diversity can have a positive effect on your sleep. A 2019 study discovered that increased diversity – specifically, more variety in the kinds of bacteria present in your gut – was linked to better sleep quality and reduced sleepiness. An older study from 2017 also found that when stressed rats were given probiotics, their healthy gut bacteria grew and the rats slept more soundly than those that didn’t consume probiotics.
Together, all of this information shows that feeding your gut with probiotics and working towards a healthy, diverse microbiome may help you sleep better. If you’ve been frustrated by poor sleep quality or found yourself struggling to stick to a sleep schedule, fermented foods and other gut health habits may offer help. Learn how to heal your gut and feed it well: