Sleep & The Gut Microbiome
All of us sleep. In fact, the average person spends one third of their lifetime sleeping. But the amount we get and its quality has a huge impact on our health. Also, research shows that our gut microbiome is deeply connected to sleep. So, why is sleep important? And how is it connected to your gut microbiome?
The importance of sleep
Sleep is vital for both mental and physical recovery. It influences everything from energy levels, mood, hormone production, immune responses, and the digestive system. For instance, a lack of sleep can lead to increased hunger and appetite. This is triggered by changed levels of hormones that regulate appetite: increased levels of ghrelin and decreased levels of leptin.
Short sleep, waking up during the night, or sleep disorders affect sleep quality and quantity. It impacts quality of life and can lead to long term health consequences, such as type 2 diabetes, cardiovascular disease, obesity, and depression.
The circadian rhythm
The circadian rhythm is the 24-hour natural biological clock in the body. It is the phenomenon that governs wake-rest periods. These rhythms modify changes in the body as a response to environmental signals such as light, to prepare the body for expected changes (e.g., sleep or wake up).
Disruption of the circadian rhythm sleep phase, for instance through night-shift work, overnight flights, or jet lag, impact healthy sleeping patterns. Also, blue light exposure from electronic devices at night is shown to suppress melatonin, a hormone that regulates the sleep–wake cycle, and shifts the circadian rhythm.
Long term, this can lead to sleep disorders, chronic health issues, and also disturb the gut microbiome.
How is sleep connected to gut health?
The gut and the brain communicate constantly through a bidirectional axis: the gut-brain-axis. They interact through nerve cells, microbes, microbial metabolites, and short chain fatty acids (SCFAs), among others.
Low quality sleep and a disturbed circadian rhythm affect the microbiome through this gut-brain axis-communication. This is associated with gut dysbiosis (an imbalance between beneficial and non-beneficial bacteria), with lower levels of the beneficial species: Lactobacillaceae and Bifidobacteriaceae, and higher levels of the non-beneficial bacteria: Ruminococcus gnavus.
Does the microbiome in turn affect sleep?
To date, it is not fully clear if the composition of the gut microbiome affects your sleep. But a bidirectional or a cyclic relationship is suggested, which indicates that the sleep we get impacts the microbiome and vice versa.
Evidence shows that the microbiome can lead to alternate sleep patterns through the gut-brain-axis-communication. Overall, an increased microbiome diversity, with a higher number of beneficial bacteria, is positively associated with sleep quality and quantity.
In addition, 90% of the serotonin hormone is produced by gut bacteria. Serotonin is a precursor of melatonin(sleep hormone). A higher concentration of melatonin is linked to an abundance of serotonin-producing bacteria in the gut, which influences sleep and the circadian rhythm positively.
How to improve sleep quality
Sleep is something we can directly control. Therefore, we should strive to get enough sleep and improve its quality, to positively impact our gut microbiome and our overall wellbeing.
- Try to get 7 - 9 hours of sleep every night.
- Try to go to bed around the same time every day, as it helps to set your body’s internal clock and optimize the sleep quality.
- Optimize your sleep environment by ensuring proper lighting, a comfortable temperature, and getting fresh air into the room.
- Avoid exposure to blue light within 1-2 hours of your bedtime.
- Avoid caffeine late in the day and big meals at night.
- Get enough daily exercise and movement.
- Spend time outdoors when it is light to boost your wakefulness.
Takeaway message
- Getting enough good-quality sleep is crucial to maintain optimal health.
- Sleep and the gut microbiome are deeply connected: Disturbed sleep and circadian rhythm impact the gut microbiome negatively. The other way around, a healthy gut microbiome seems to improve sleep quality.
- We should therefore strive to improve our sleep to positively influence our gut microbiome and general health.
Author: Ingeborg Amble Holtmann