By Molly Knudsen, MS, RDN

What keeps you up at night? Is it the lure of scrolling through social media? The temptation of clicking “next episode” on the show you’re watching? Or is it the stress of an important meeting or test the following day?

There are more reasons than sheep to count for things getting in the way of a good night’s sleep, and many adults in the United States are not getting the sleep they need. According to the Centers for Disease Control and Prevention, adults need seven or more hours of sleep each night to support overall health.1 An estimated 35.2% of adults get less than seven hours of sleep per night, which is also known as short sleep duration.1 Lack of sleep has the potential to negatively impact both mental and physical health.1

Exposure to light, electronic media usage, and caffeine consumption late at night are all habits that have been shown to contribute to poor sleep quality.2 But one surprising culprit that may be stealing some ZZZs from you is your gut health.

What is the gut-brain axis?

There is no doubt that sleep plays a crucial role in brain health and function, and as it turns out, the gut and the brain are basically in constant communication through the gut-brain axis.3 More specifically, the gut in gut-brain axis refers to the microbiome, or the collection of all microorganisms like bacteria, yeasts, and fungi that live in the intestines. The gut-brain axis is a two-way communication, so not only can those little critters in the gut influence heath, but mental and emotional state of a person can impact the microbiome.4

What is known about sleep and gut health?

The science of gut health and sleep is still emerging, but one recent study was able to dig a little deeper into the relationship between the microbiome and sleep quality.4 In this study, 40 healthy men wore an Actiwatch®, which is basically a fancy smart watch, for 30 days. This watch collected information on the men’s sleep patterns, such as exactly when they went to bed and woke up in the morning, how efficiently they slept, and the number of times they woke up throughout the night. Stool samples were also collected to measure microbiome richness and diversity (i.e. the number of different species of bacteria and the number of individual bacteria from each species).

Results of the study showed that microbiome diversity and richness were associated with better sleep efficiency and longer sleep times at night. Having more diversity and richness in the microbiome was also associated with fewer arousals or less interrupted sleep throughout the night.

What’s the takeaway from this study?

This study provides insight to how microbiome diversity may influence sleep patterns in people, as many previous studies were done in animals. Other human studies have shown that short-term sleep deprivation may change the make-up of the microbiome, further emphasizing the two-way communication between the gut and brain.5 So not only does gut health have the potential to impact sleep and the brain, but poor sleep may negatively impact the microbiome.5 Still, more research is needed to better understand this relationship.

How can you promote microbiome diversity and richness?

1. Eat a varied diet: The more diverse the diet, the more diverse the microbiome!6 Load up on a variety of different-colored fruits and vegetables, whole grains, and lean protein sources like fish and legumes.
2. Eat a diet rich in fibrous foods: Guess what? If you eat a varied diet high in plant-based foods as mentioned in step one, you will also be eating a fiber-rich diet. A diet high in fiber is considered beneficial for gut health.7
3. Eat fermented foods: Fermented foods like yogurt, kefir, kimchi, and kombucha often contain live beneficial microorganisms, which may contribute to intestinal health.8

 References:

1. Sleep and sleep disorders. CDC.gov. https://www.cdc.gov/sleep/data_statistics.html. Accessed January 2020.
2. Shochat T. Impact of lifestyle and technology developments on sleep. Nat Sci Sleep. 2012;4:19–31.
3. Carabotti M et al. The gut-brain axis: interactions between enteric microbiota, central and enteric nervous systems. Ann Gastroenterol. 2015:28(2):203-209.
4. Smith RP et al. Gut microbiome diversity is associated with sleep physiology in humans. PLoS ONE. 2019; 14(10): e0222394. 
5. Thaiss CA et al. Transkingdom control of microbiota diurnal oscillations promotes metabolic homeostasis. Cell. 2014;159(3):514-529.
6. Heiman ML et al. A healthy gastrointestinal microbiome is dependent on dietary diversity. Mol Metab. 2016:5(5):317-320.
7. Makki K et al. The impact of dietary fiber on gut microbiota in host health and disease: Cell Host Microbe. 2018;23(6):705-715.
8. Bell V et al. One health, fermented foods, and gut microbiota. Foods. 2018;7(12):195.

(Article c/o Metagenics Blog)