BY ELISA SONG, MD

Most parents recognize that quality rest is essential for their child’s mood, learning, and overall development.

What’s less commonly known, however, is that sleep also plays an important role in gut health—with growing evidence linking sleep disturbances to gut dysbiosis.

The question is—which comes first: poor sleep or gut dysbiosis? The answer isn’t so clear-cut.

Which Comes First—Poor Sleep or Gut Dysbiosis?

For a long time, the research and medical community assumed that gut dysbiosis was the major driver for sleep problems. Why? Because our gut microbiome is responsible for producing a significant amount of serotonin and melatonin—neurochemicals that are essential for restorative sleep.

Plus, an increase in the number and variety of good gut microbes is associated with more time asleep, better rest quality, and fewer night wakings. And giving probiotics and prebiotics has been found in studies to improve sleep quality and even protect against the harmful effects of obstructive sleep apnea.

On the other hand, antibiotic use—which can wipe out beneficial gut bacteria and lead to dysbiosis—has been found to disrupt sleep cycles by lowering levels of serotonin and melatonin.

The Sleep–Gut Connection May Be a Two-Way Street

Interestingly, emerging research suggests that sleep may actually play a more influential role in shaping the gut microbiome—and in driving dysbiosis—than previously thought.

One study found that sleep patterns at six months of age predict gut microbiome diversity later in life, and that the sleep–gut connection in infancy can predict later behavioral and developmental outcomes—especially gross motor and social development.

Even short-term shifts in our sleep–wake cycle can affect our gut microbiome. How often does your child or teen go to bed too late at night—whether it’s homework, video games, chatting with friends, or social media? Or maybe they get to bed on time, but they have to wake up far too early for school or sports practice?

Delayed bedtimes, early-morning starts, jet lag, and shift work all disrupt our circadian rhythms and have direct negative effects on our gut microbiome composition, function, and circadian rhythm.

Two Nights Without Rest Can Change the Gut Microbiome

In fact, one study of healthy young men who had no prior sleep problems showed that after just two nights of sleep deprivation, they experienced a significant decrease in beneficial gut bacteria—and an increase in harmful ones. And while it can take only two days for negative changes in the gut microbiome to occur, it may require a whole week of quality sleep to restore it.

Sleep—it does a body (and a gut microbiome) good! What about “fragmented sleep”?

This type of sleep disruption—marked by restlessness and multiple night awakenings—can be caused by true sleep disorders like obstructive sleep apnea.

But it can also stem from normal, occasional night waking that turns into full awakenings—because you decide to check your phone that is right by your bedside and, oh well, now that you’re awake, you might as well check for texts or scroll through your social media feed for anything interesting before trying to fall back asleep.

Persistent and recurrent sleep fragmentation may be the most common modern sleep problem of all.

In one study, mice exposed to sleep fragmentation for four weeks ate more and experienced changes in their gut microbiome that led to increased visceral adipose tissue (read: belly fat), systemic inflammation, and insulin resistance. These mice were headed toward obesity and diabetes—simply from sleep deprivation–induced gut dysbiosis. Fortunately, these changes were reversible once sleep quality was restored.

Hippocrates, the “father of modern medicine,” has been credited with saying, nearly 2,500 years ago, that “all disease begins in the gut.” When we flip this statement around, we can also see that all health begins in the gut.

Supporting gut health isn’t just about improving digestion or immunity—it’s about laying the groundwork for emotional resilience, healthy development, and restorative sleep for years to come. And with up to forty percent of children and teens experiencing a sleep disorder, the need to address this connection has never been more important.

A well-rested child isn’t just more focused or in a better mood—they’re thriving from the inside out.

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Elisa Song, MD is a Stanford-, NYU-, and UCSF-trained integrative pediatrician and author of national bestseller Healthy Kids, Happy Kids. A pioneer in pediatric functional medicine, she blends over 25 years of clinical experience with evidence-based, holistic strategies to help children thrive.

Dr. Song empowers parents with trusted tools for lifelong wellness and has been featured by National Geographic, Forbes, Parents, New York Post, Bloom TV, Healthline, PopSugar, Parents, Motherly, Parade, Verywell Health, and MindBodyGreen, as well as on the Broken Brain and Wellness Mama podcasts.

She is founder of HealthyKidsHappyKids.com, an online resource for trusted holistic pediatric advice.

Well Being Journal adapted the above excerpt from Healthy Kids, Happy Kids by Elisa Song, MD. Copyright © 2024 by Elisa Song, MD, and reprinted with permission from Harvest.