Sleep apnea: bacteria of the gut microbiota implicated
Gut microbiota were suspected of being implicated in sleep apnea. A Mendelian randomization study highlights their potential causal role, pointing at bacteria suspected of increasing respiratory pauses and others capable of protecting us from them.
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About this article
Behind the term sleep apnea lies a pathology characterized by abnormally frequent respiratory pauses during sleep. Even if this disease is often found in children and adults, it is not without risk, in the short term (fatigue) and long term (cognitive impairments, cardiovascular diseases, etc.).
It has multiple causes: tonsillar hypertrophy in children, obesity in adults… The gut microbiota have also been mentioned, but their causal role is yet to be proven. However, a study published in 2023 went a step further in demonstrating their causal role. How? Via a technique called Mendelian randomization, which makes it possible to set aside many confounding factors and biases.
The gut microbiota
Deleterious bacteria, and beneficial ones
The study tracked suspects (bacteria increasing the risk of sleep apnea) but also the superheroes who protect us from these nocturnal respiratory pauses: for example, the Ruminococcaceae bacterial family is thought to promote nights free of respiratory issues.
1 billion people in the world are affected by obstructive sleep apnea?
How can such power over our health be explained? Without a doubt by the ability of these bacteria to produce beneficial molecules, called (sidenote: Short chain fatty acids (SCFA) Short chain fatty acids (SCFA) are a source of energy (fuel) for an individual’s cells. They interact with the immune system and are involved in communication between the intestine and the brain. Silva YP, Bernardi A, Frozza RL. The Role of Short-Chain Fatty Acids From Gut Microbiota in Gut-Brain Communication. Front Endocrinol (Lausanne). 2020;11:25. ) , beneficial for our health in that they reduce inflammation, reinforce our intestinal barrier, and limit the proliferation of pathogenic bacteria; but also because these bacteria are implicated in the metabolism of bile acids, known for their role in sleep and regulating sleep cycles.
Molecules produced by bacteria implicated
The study also tracked various other molecules produced by the bacteria of our digestive tract to identify those with a role in nocturnal respiratory pauses. Bingo: some of them, such as leucine (or others that are more of a mouthful, such as epiandrosterone sulfate) effectively increased the risk of sleep apnea. These molecules often turn out to be unfavorably known: for example, elevated leucine levels were observed in children with sleep apnea; on the other hand, among patients who had been prescribed a mask to reduce sleep apnea, leucine levels fell rapidly.
Therefore, disturbances to our gut microbiota and alterations in the metabolites produced by the bacteria of our digestive tract seem to have beneficial or harmful consequences for sleep apnea based on their profile. Research continues so that one day we can all fall into the arms of Morpheus and sleep soundly.
