Good sleep can be seen from the gut. Or, rather, from the gut microbiota. What may sound like an advertising slogan actually has a strong scientific basis, as shown by a review of studies on the subject conducted by Peking University and recently in Brain Medicine.
For decades, scientists and physicians have looked for the keys to understanding and treating sleep disorders by looking almost exclusively at the brain. But a new research frontier is revealing that the quality of our rest depends significantly on a constant, two-way dialogue between the central nervous system and the digestive system, known as the microbiota-gut-brain axis.
What can cause sleep disorders?
Sleep is a fundamental physiological process for physical and mental health. The study highlights how the gut microbiota — that is, the immense community of microorganisms that populates our gastrointestinal tract — can influence sleep patterns both directly and indirectly. This communication system uses several pathways: metabolic signals, neurological pathways and immune responses.
What is the link between the microbiota and insomnia?
Alterations in the composition of these bacteria, a condition called dysbiosis, are in fact closely linked to various sleep disorders. For example, people who suffer from chronic insomnia often show low microbial diversity and altered levels of bile acids and bacterial metabolites such as butyrate. Similarly, in patients with obstructive sleep apnea (OSA), nighttime drops in oxygen modify the intestinal flora, triggering systemic inflammation that further worsens the clinical picture.
“As a psychologist and neuroscientist specializing in sleep disorders, I believe this review of studies on the microbiota-gut-brain axis is revolutionary — comments Ginevra Pignata, part of the SoLongevity Clinic team in Milan — It confirms that sleep is intimately connected to the digestive system, going beyond a purely brain-centered view. In my practice, while using effective protocols such as CBT-I (Cognitive Behavioral Therapy for Insomnia), which remains the gold standard for treating and resolving chronic insomnia, I adopt a holistic view that includes awareness of the fundamental role of nutrition. For this reason I collaborate with nutritionists. At the SoLongevity Clinic, we offer an integrated assessment and treatment service, where the patient is followed in a 360-degree way, combining psychology, neuroscience and nutrition for a deep well-being that begins, surprisingly, right in the gut”.
Ginevra Pignata
The chemical messengers of the night
But how exactly does the gut “talk” to the brain while we sleep? The review identifies several protagonists:
- Neurotransmitters: Over 90% of the body’s serotonin, a precursor of melatonin (the sleep hormone), is synthesized in the gut. GABA too, a chemical messenger that promotes relaxation, can be produced by specific strains of gut bacteria such as Lactobacillus and Bifidobacterium.
- Short-chain fatty acids (SCFAs): Produced by the fermentation of fiber, such as butyrate, they have been shown to improve sleep quality and protect the brain from damage caused by sleep deprivation.
- The vagus nerve: It acts as a true information highway, transmitting signals from gut microbes to the brain regions that regulate the sleep stages.
The “sleep bacteria”
The review also identified several groups of gut bacteria that play a crucial role in regulating sleep and wakefulness. Although the specific composition may vary, some alterations common to several sleep disorders emerged, such as:
- Increase in Actinobacteria and Collinsella
- Decrease in Bacteroides, Bifidobacterium and Faecalibacterium
- Increase in the Firmicutes-to-Bacteroidetes ratio
How to restore the microbiome?
The discovery of this link opens the door to innovative and less invasive therapies. Interventions targeting the microbiota include:
- ProbioticsFoods containing specific bacterial strains from the intestinal environment. and PrebioticsSubstances not digestible by the human body, often plant fibers, which are nourishment for bacteria.: Taking specific “good bacteria” (such as Lactobacillus plantarum) has shown promising results in improving deep sleep and reducing stress in insomnia patients.
- Fecal microbiota transplantation (FMT): This technique, which consists of transferring microbiota from healthy donors to patients, is emerging as a strategy to address complex disorders, showing insomnia remission rates significantly higher than conventional treatments in some clinical studies.
An integrated and holistic view
According to the researchers, in the future the diagnosis of a sleep disorder could therefore also involve a detailed analysis of our internal “ecosystem”. “Today we have confirmation that sleep, a pillar of our physical and mental health, is intimately connected to our digestive system — Dr. Pignata continues — And the evidence that microbiota dysmetabolism can contribute to the pathogenesis of sleep disorders is a catalyst for the adoption of a model of care that considers the whole system. Since nutrition is the main modifiable factor that shapes our microbiota, the link becomes inescapable: integrating nutritional interventions targeting the microbiota can considerably enhance the results obtained with standard insomnia therapy. This — Pignata concludes — pushes us to move beyond a fragmented view of health and embrace an integrated model, where sleep well-being begins, surprisingly and profoundly, right in the gut”.
