Almost 20 percent of the world’s population suffer from sleep problems and spend their nights twisting and turning. And anyone who has stared sleeplessly at the ceiling, counting sheep, knows that this experience can be stressful and extremely frustrating. The next day can also be a real pain, and poor sleep for an extended period of time can cause both illness and affect the memory. Research has also shown that poor sleep affects the gut flora negatively, which can be problematic since this is where most of the immune system is located.

Irregular sleep routines

A study conducted at the Weizmann Institute of Science in Rehovot, Israel, examined what happens to the gut flora when sleep is irregular. The study focused on stool samples from lab mice and then also tested a small group of people who were jet lagged.

One thing that became apparent following the study conducted on mice was that the activity in the gut flora looked different during the day compared with at night. When the mice were awake and active, the bacteria in the gut flora were mainly involved in burning nutrients and repairing DNA. During the period of the day when the mice rested and slept, the intestinal bacteria instead transported away toxins and built up different parts of the gut flora. If, on the other hand, the mice suffered from a disrupted and irregular circadian rhythm, the same fluctuations and activities did not occur in the gut flora, which indicates that the circadian rhythm and sleep quality may have an effect on the composition and function of the gut flora.

“When the study’s test subjects returned to more regular sleeping habits, the concentration of unhealthy bacteria decreased again”

The part of the study that was performed on humans showed that the participants with jet lag had increased concentrations of the type of bacteria more common in individuals suffering from obesity and diabetes. These bacteria are also associated with weight gain, increased levels of blood glucose and a higher percentage of body fat. When the study’s test subjects returned to more regular sleeping habits, the concentrations of unhealthy bacteria dropped again and the balance in the gut flora stabilised.

The largest variety of intestinal bacteria

A study published in the American journal Plos One also showed that there may be a connection between the gut flora and our sleep. In the study, different values in the bodies of test subjects, relating to sleep quality, were monitored while they slept, using advanced measuring tools. The researchers then took samples of the test subjects gut flora, and were able to conclude that those test subjects who got the most qualitative sleep were also the ones who had the greatest variety of bacteria in their guts.

The gut flora and serotonin

You may know that melatonin is the sleep hormone that makes us tired. But in order for melatonin to be created, another hormone is required, namely; serotonin, and 95 percent of the serotonin in our bodies is produced in the gut – which is affected by sleep. Serotonin is often described as a “happiness hormone” and has a powerful effect on our mood and cognitive function and also plays an important role in regulating our sleep cycles. Keeping the intestines in good shape is therefore important for both mood, cognition and ultimately sleep.

Tips for improving sleep quality

So what can one do to ensure a good night’s sleep? Exercising, fresh air, plenty of daylight and regular sleeping hours are some of the things that are said to promote sleep quality. Putting down your mobile phone and avoiding coffee and tea are other examples of measures you can take to attract the Sandman. Lying comfortably on your back in a safe environment and then focusing on your breathing is also said to be helpful. A little bit of mindfulness, in other words. Since intestinal health also seems to have an effect on sleep, an anti-inflammatory and intestinal-friendly diet may be worth trying.

References:

Study by S Eran Elinav, immunologist and microbiome specialist at the Weizmann Institute of Science in Rehovot, Israel: www.sciencemag.org/news/2014/10/are-your-bacteria-jet-lagged

Study published in the medical journal Plos One by American researchers at Nova Southeastern University: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0222394