Gut Microbiota Aids Sleep and Improves Health (Part One)
The "2021 White Paper on Exercise and Sleep" released by the Chinese Sleep Research Society indicates that over 300 million people in China currently experience sleep disorders. The past three years of the pandemic have led to a delay of 2 to 3 hours in the overall sleep onset time for people, with a 43% increase in sleep-related searches, highlighting the growing concern over sleep issues. Sleep disorders generally refer to conditions such as frequent dreaming, easy awakening, early awakening, or the inability to fall back asleep after waking. Sleep disorders are associated with the onset and progression of various diseases, including obesity, type II diabetes, cardiovascular diseases, depression, and cancer. Insufficient sleep also affects judgment and intelligence.
Normal physiological sleep consists of five stages: Stage 1 sleep (the transition between wakefulness and sleep); Stage 2 sleep (body temperature decreases, heart rate slows); Stage 3 sleep (transition from light to deep sleep); Stage 4 sleep (slow brain waves); and Stage 5 sleep (rapid eye movement sleep, or REM sleep).
Sleep begins in a normal sequence but then cycles in an irregular order. While modern medicine recommends that people ensure more than 8 hours of sleep, the actual duration of sleep is less important than completing 4 to 5 sleep cycles.
Insomnia is the most common sleep disorder. The criteria for diagnosing insomnia are:
- Sleep onset latency [Sleep onset exceeding 30 minutes]
- Difficulty maintaining sleep [Waking up and taking more than 30 minutes to fall back asleep]
- Early awakening [Waking up more than 30 minutes earlier than usual]
- Conditions 1-3 occurring more than three days a week
- Impaired social function and physical discomfort the next day
Factors affecting sleep quality and duration are as follows, with various internal and external factors interfering with them.
The Gut Microbiota is Closely Linked to Sleep
The gut-brain axis can communicate bidirectionally through immune regulatory pathways, neuroendocrine pathways, and the vagus nerve pathway. When the gut microbiota is imbalanced and harmful bacteria proliferate, various neurotoxic metabolites enter the brain via the vagus nerve, thereby affecting brain function, stress response, and sleep.
A study published in "Frontiers in Psychiatry" shows that the gut microbiota not only affects the host's digestion, metabolism, and immune function but also regulates the host's sleep and mental state through the microbiota-gut-brain axis.
The gut microbiota can produce metabolites of GABA, a natural aminohexanoic acid, which is also the safest sedative for the human brain, possessing natural sleep-inducing, anti-anxiety, and anti-depressant effects.
The Probiotics strains likeBifidobacterium animalis subsp. lactis F1-7 and Lactiplantibacillus plantarum YZX21 in gut microbiota can promote the production of serotonin (5-hydroxytryptamine) and dopamine, which are sleep-regulating neurotransmitters, thereby improving sleep disorders.
In addition, most of the gut microbiota produces short-chain fatty acids, especially butyrate, which ultimately forms butyrate salts in the body to promote sleep.
The Microbial Clock Affects the Body's Biological Clock
Every organ and cell in the body has its own biological clock, and the microbial community in the gut is also under circadian rhythm control.
Staying up late and sleep disorders affect the composition and health of the gut microbiota. Every time one stays up late, the trillions of gut bacteria in the body are forced to operate, disrupting their original rhythm, which may lead to the proliferation of harmful bacteria and damage to the intestinal mucosa.