Medically reviewed by
Dacelin St Martin, MD
Triple board-certified in Sleep Medicine,
Internal Medicine, and Pediatrics.
The number of factors that influence how one sleeps is virtually immeasurable, and the benefits from obtaining healthy sleep are equally as numerous.
However, the ability to consistently maintain quality rest is not equal across the population as millions of people struggle to fall asleep and stay asleep throughout the night.
Those who struggle with sleep issues may seek to improve upon one of the many variables proven to influence sleep. They may try to get more sleep, exercise more, or add a relaxing bedtime routine; however, these actions may not be enough for some people.
Those who try everything to improve their sleep and still struggle could find that their issue lies within their gut. Through the last decade, science has increasingly recognized the relationship between gut health and overall health, including obtaining quality sleep.
In the center of gut health is the gut microbiome, which consists of bacteria living in one’s body that influence various bodily functions. Of these bodily functions, many can affect sleep either directly or indirectly.
Lacking quality sleep for any reason can lead to adverse side effects, including daytime sleepiness, reduction in cognition, and difficulty regulating mood.
While the direct association between the gut and the brain doesn’t automatically seem intuitive, science supports it.
The gut-brain axis (GBA) combines connection pathways that the brain shares directly with the gut.
The methods of communication that occur between the brain and gut are quite involved and include the following biological processes.
1) The Nervous System
Spread throughout the body, there’s a complex network of nerves, and a connection between the brain and the gut is no different.
The vagus nerve plays an integral role in the brain as a communicator of bodily functions and is directly connected to the digestive system as a communicator for gastrointestinal activity.
Networking between the brain and the gut can occur in both directions. Meaning, if the gut microbiome is in a non-ideal state, then a disruption in mood can occur, followed by a feeling of anxiety.
Anxiety is known as a significant cause of sleeplessness and low-quality sleep.
2) Hormonal Connection
Recent research has also shown that the gut plays a significant role in how the body regulates and secretes hormones. Surprisingly, the gut creates 95 percent of the serotonin in the body.
Serotonin is key to regulating mood, and difficulty in mood regulation can be a strong contributing factor, leading to sleeplessness. A lower level of serotonin is attributed to higher rates of depression, which comes with sleep-related issues.
Additionally, serotonin works as the building block for many other hormones. Melatonin is most notably one of the body’s main sleep-wake hormones.  Meaning, if the microbiome levels inside the gut are off, the effect could cause a direct change in the sleep cycle.
When the sleep cycle is compromised, slow-wave restorative sleep could be reduced. A reduction in restorative sleep could result in daytime sleepiness, concentration issues, and an agitated mood.
3) Illness Immunity
Studies show that the gut acts almost exclusively as a second brain. It also plays a significant role in the health of the body by housing and creating a large part of the immune system.
The gut houses about 70 percent of immune-related tissue responsible for the creation and memory of viral or bacterial antigens.
This system plays a vital role in the pursuit of healthy sleep because illness can cause significant difficulty in initiating or maintaining quality sleep.
There’s increasing evidence that obstructive sleep apnea (OSA) induces a gut bacteria imbalance, known as dysbiosis, which predisposes to low immunity. In some cases, if immunity is reduced by a lack of a quality gut microbiome, the body becomes more susceptible to infections.
OSA causes a reduction in oxygen during sleep, resulting in snoring, gasping, and abrupt wakings during the night. This breathing-related sleep disorder has been associated with significant sleep-related deficits. 
It’s not uncommon for the development of OSA and hypertension to co-occur in individuals. Studies show that one of the mechanisms by which patients develop hypertension is low oxygen and the alteration of gut bacteria.
The gut microbiome plays an integral role in how the body functions and profoundly impacts how well it can obtain restful sleep. That is why it is vitally important to keep the gut healthy.
Microbiota in the gut is nothing more than healthy forms of bacteria. There are several ways to improve the number and health of the gut biome and a few ways it can be harmed.
Eating a broad range of foods has been shown to increase the health and number of gut bacteria. Some foods positively influence gut health include:
- High Fiber Vegetables
- Fermented Foods (Sauerkraut, Yogurt, Kimchi)
Additionally, probiotic or prebiotic supplements can improve the number of gut bacteria and provide nourishment for present bacteria.
Just as there are ways that healthy gut bacteria can be increased, there are also many ways that the gut microbiome can be destroyed. Things to avoid when protecting gut health include:
- Unnecessary use of Antibiotics 
The gut microbiome is a delicate ecosystem inside the body that has vast importance in the body’s functions. Many of the gut microbiome processes can negatively impact the quality of sleep if the gut bacteria reach non-ideal levels.
However, with proper care of the gut, the ecosystem that participates in one’s immunity, mood, and sleep can be kept healthy. Eating the right foods and avoiding unnecessary fats, sugars, and antibiotics will allow the gut microbiome to flourish.
If one experiences trouble with sleep and has seemingly tried everything, a change in diet and lifestyle may be the necessary change to improve gut health, and ultimately sleep quality.
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