Gut health and sleep: 5 ways your gut microbes may be affecting your sleep

Emerging research shows that the gut may play a bigger role in regulating sleep than previously thought affecting sleep quality mood and overall health.(Image: pexels)

For decades, sleep has been linked to brain chemistry; neurons, signals, and synapses, all shifting from alertness to rest. But a recent research from Washington State University reveals something new. Scientists have discovered bacterial molecules in the brain that rise and fall with sleep cycles, suggesting that slumber isn't just brain-driven—it's a team effort between body and microbe.

A crucial part of the discovery is a molecule called peptidoglycan, abbreviated as PG. Found in the cell walls of bacteria, PG has long been known to influence sleep when introduced externally in lab animals. But the recent study led by PhD candidate Erika English found something no one expected: PG is naturally present in the brain.

Even more compelling is that its levels fluctuate depending on the time of day and whether the body is sleep-deprived. In short, this tiny molecule—once assumed to remain locked in the gut—is now a serious player in the science of sleep.

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The findings support a theory called the “holobiont condition”—a concept that views sleep as a collaboration between two deeply intertwined systems: the brain and the gut microbiome. Rather than thinking of sleep as being solely switched on by the brain, this model proposes that it’s a whole-body process involving microbial signals, too. “It’s not one or the other,” said English. “They have to work together.”

In fact, these microbial signals may help kick-start local sleep in tiny cellular networks throughout the body, gradually taking us from wakefulness into full slumber.

5 ways your gut microbes may be affecting your sleep:

• Sleep may be driven by microbial molecules: Peptidoglycan from gut bacteria appears in the brain and rises and falls with sleep cycles, suggesting microbes may play a role in regulating sleep, not just neurons.

• Local sleep starts in the body, not the brain: Cells throughout the body enter sleep-like states on their own. As more follow suit, the whole body eventually “shuts down.” Microbial signals may influence when this happens.

• Sleep is communication: Sleep could be the result of a coordinated communication between the nervous system and the gut microbes, a process refined over billions of years of evolution.

• Sleep disorders may have microbial roots: The new model could open doors to treatments that target the microbiome, offering hope for people with insomnia or other sleep-related issues.

• Your gut bacteria may shape how you think: Beyond sleep, gut microbes have been linked to appetite, mood, sex drive, and even decision-making. Sleep might be just one part of a much bigger picture.

Co-author James Krueger, a veteran in sleep science, believes that ancient bacteria may have developed sleep-like cycles billions of years ago. The same molecules driving their activity may still be influencing our brains today. “Sleep likely began with bacteria,” Krueger told Moneycontrol. “And their molecules still guide how we rest, think, and behave.”

This research doesn’t just deepen our understanding of sleep, it turns the spotlight on the quiet, invisible universe within us. As scientists continue to explore how our microbial partners help shape not just health, but consciousness itself, one thing’s clear: we’re never truly alone, not even in our dreams.

FAQs about gut

1. What is the main discovery regarding sleep from Washington State University?

Scientists found that bacterial molecules in the brain, such as peptidoglycan, rise and fall with sleep cycles, suggesting a collaborative effort between the brain and microbes.

2. What is peptidoglycan (PG), and why is it significant?

Peptidoglycan is a molecule found in bacterial cell walls, previously known to influence sleep when introduced in lab animals. The new discovery shows it is naturally present in the brain and fluctuates with sleep cycles.

3. How do the findings support the “holobiont condition” theory?

The findings suggest sleep is a collaboration between the brain and gut microbiome, indicating sleep involves microbial signals in addition to brain activity.

4. How might gut microbes affect sleep disorders?

Understanding the role of gut microbes in sleep regulation could lead to new treatments targeting the microbiome for sleep-related issues like insomnia.

5. What other aspects of human behaviour might gut bacteria influence?

Beyond sleep, gut bacteria are linked to appetite, mood, sex drive, and decision-making, indicating they play a role in multiple aspects of human behaviour.

Disclaimer: This article, including health and fitness advice, only provides generic information. Don’t treat it as a substitute for qualified medical opinion. Always consult a specialist for a specific health diagnosis.