Sleep Apnea Causes Gut Microbiome Imbalance, Study Says

Human study suggests hypoxia may be driving bacterial changes that lead to related disease

A man with sleep apnea disorder getting treatment in a hospital. Shutterstock

A new study examining the link between obstructive sleep apnea (OSA) and the gut microbiome links an imbalance in microbiota, known as dysbiosis, with mild, moderate, or severe apnea.

Our body depends on its microbiota—the bacteria, fungi, and viruses that live symbiotically in and on the body—for several functions, including an effective immune response.

Earlier research shows shifting bacteria levels can ease or exacerbate systemic inflammation and create symptoms that go hand-in-hand with sleep apnea.

Similar shifts in bacteria levels can also lead to inflammation. Research from 2018 found that this happens when an overgrowth of some gut bacteria begins to damage the intestinal mucosal barrier, allowing the translocation of microbiota in the body. This inflammatory response can drive symptoms such as high insulin, hypertension, fatigue, and inattention.

The new study, published in Scientific Reports in January, was conducted with 48 Chinese subjects at a sleep lab using blood and stool tests. It validates earlier animal studies and strengthens the pathology hypotheses that linked OSA to intestinal dysbiosis. In doing so, it shows that while the bacterial imbalance may be slightly different based on where you live, disease progression and dysbiosis are predictable.

“It’s not surprising. The concepts have been around for a long time. It confirms other studies that have hinted at it,” Dr. Steven Park told The Epoch Times.

Author of the Amazon bestseller “Sleep, Interrupted,” he said this study offers a plausible explanation for the vicious cycle between sleep apnea and disease.

The Danger of Sleep Apnea

Nearly 1 billion people worldwide are estimated to have sleep apnea—China, the United States, and Brazil are the top three affected countries—with many being undiagnosed.

The word “apnea” means to stop breathing, usually the result of the upper airway collapsing, interfering with the sleep cycle and forcing mouth breathing. This dysfunctional process leads to intermittent hypoxia, which is when too little oxygen is being delivered to tissues, thereby affecting circulation, cognition, and organ function.

Sleep apnea has long been associated with cardiovascular and respiratory diseases such as heart disease and asthma, obesity, Type 2 diabetes, and cancer. These illnesses also are linked to intestinal dysbiosis, which occurs when problematic microbes proliferate.

The relationship between sleep apnea, damage to the intestinal barrier, and an imbalance of microbiota was shown in this and other studies. But it’s repeated hypoxia that has a direct effect on dysbiosis, according to the new study.

“Increased tissue oxygenation can directly affect microorganisms, such as reducing anaerobes. Therefore, the gut may provide a unique environment conducive to living aerobic and facultative anaerobic organisms,” the authors wrote.

Oxygen concentrations in the intestine have been shown to affect the distribution and metabolism of microbes, as most intestinal bacteria are obligate anaerobes and fail to grow at oxygen concentrations greater than minus 0.5 percent. Shifts in the balance can impact the integrity of the intestinal mucosal barrier.

Previous research has found that repeated hypoxia can manifest in all blood-perfused organs. The new study hypothesizes that multi-organ damage could result from suspected microbiome changes in different mucous membranes associated with sleep apnea, such as the nasal, oral, and lung microbiomes.

Observations from the study include:

• Hypoxia induces systemic inflammation, and inflamed tissues worsen hypoxia in a frustrating feedback loop. Protein markers in the blood associated with early arterial disease rapidly rise after episodes of hypoxia.
• The microbiome in those with severe sleep apnea correlated with blood glucose and body mass index (BMI). “Therefore, alterations of these microbiota could cause low-grade chronic inflammation, immune and metabolic abnormalities,” the study reads.
• Specific imbalances discovered are also already linked to cardiovascular disease, colorectal cancer, oral and lung infections, chronic kidney disease, infections, and diabetes.
• Those with severe sleep apnea also had intestinal barrier dysfunction biomarkers.

A Vicious Cycle

Park said that while he agrees with the study’s assumption that sleep apnea is what’s causing dysbiosis, it’s possible that in some cases it could be the other way around, too.

“It’s nice to have some explanation or answers as to why these things happen,” he said. “The problem is the gut microbiome is so sensitive to things in our environment, our stress levels, our diet, environmental toxins, sleep deprivation. It’s a vicious cycle. It’s hard to prove what causes what.”

A mice study published in Experimental Neurology in 2020 shows that when healthy mice received a fecal transplant from mice with sleep apnea, they began to have sleep disturbances. This raises the possibility of fecal transplants—transfer of stool usually by way of colonoscopy into the large intestine—working as a treatment for sleep apnea. Currently, the Food and Drug Administration has only approved fecal transplants for Clostridium difficile (C. diff) overgrowth, which is associated with life-threatening diarrhea.

If such a “quick fix” was readily available for sleep apnea, Park warned that there’s no guarantee it would be long-lasting without addressing root causes. More research is needed on long-term microbiome health after fecal transplants, he said.

Previously considered the standard of care for sleep apnea, continuous positive airway pressure (CPAP) machines are scrutinized in a 2016 article in the Journal of Otolaryngology–Head & Neck Surgery. Twenty years of data suggest that only 34 percent of patients are adhering to the proper use of the device. This review of studies on CPAP concluded that the many techniques for improving compliance have had no effect.

Unless they have a severe gut issue, most people aren’t even aware that they have dysbiosis, nor understand what it means or what causes it. Sleep apnea can also be a quiet agitator. Snoring is a telltale sign, but you can have the disorder without being a snorer. And while it often coincides with obesity, thin people and even children can suffer from sleep apnea.

Because specific bacteria—Fusobacterium, Megamonas, and Lachnospiraceae—are associated with sleep apnea, the authors of this latest study suggest tests could be used as a tool to identify those at risk of related gut microbiome disorders.

Protecting the Microbiome

In the meantime, evidence isn’t necessary for those who know or suspect they’re at risk and want to end the cycle, Park said. There’s enough evidence that we’re losing important gut bacteria that taking basic steps for better health is essential to human health. Root causes for dysbiosis include taking antibiotics, poor diet, and toxins. Chronic sleep deprivation, whether associated with sleep apnea or not, also taxes the body.

Often we prioritize family and work over essential hours of sleep, Park said. Because it has broad implications for overall health and affects those relationships, good sleep habits are vital for everyone.

He offered these simple suggestions:

1. Don’t use screens within two to three hours before bedtime. Blue light lowers melatonin, the sleep hormone that regulates circadian rhythm, and consuming content that’s disturbing or overstimulating can also affect sleep.
2. Go to bed and wake up at the same time every day—even on weekends.
3. Get as much early morning light as possible. “That’s why people who walk dogs early in the morning are healthier and happier,” he said. “You need to reset your circadian clock.”
4. Maximize light during the day and minimize light at night.
5. Don’t eat within three to four hours before going to sleep. This causes the body to prioritize digesting over important detoxification tasks that happen during sleep. “If you’re already eating late at night and stop eating, your sleep quality will improve and you’ll lose weight, too,” Park said.

The new research may open up new treatments for sleep apnea. Using gut microbial composition could conceivably be part of an individualized treatment protocol for sleep apnea, according to the study. Precision medicine will drive more individualized treatment plans, and such components will undoubtedly become an important part of future efforts to reduce disease.