Gut Health and Sleep

Gut Health and Sleep

Summary

1. The gut microbiome consists of trillions of microbes, and plays a key role in health, including digestion, immune function, and even sleep quality.
2. The gut-brain axis (GBA) allows communication between the brain and gut, linking gut health to emotional and sleep regulation. In fact this relationship is so profound, the gut is often referred to as the "second brain".
3. Studies suggest a diverse gut microbiome supports better sleep quality, while imbalances can lead to issues like insomnia, fragmented sleep, and disrupted circadian rhythms. 
4. During the development of Nightly Greens, our team discovered specific probiotics that can enhance sleep.
5. Conversely, sleep also influences gut health. Poor sleep increases stress hormones like cortisol, contributing to "leaky gut" and unhealthy food choices that negatively affect the microbiome.
6. We suggest 7 easy ways to improve your gut health. Taking a probiotic supplement like Nightly Greens, is one of them. 

Most people may not realize this, but we have a host of bacteria, fungi, and viruses that live in and on our bodies. Otherwise known as a microbiome, trillions of microorganisms (microbes, for short) call our bodies home. 

And those microbes are everywhere — some live in our noses, others live in our throats, and there are even microbes in our mouths and on our skin. Most of the microbes in our bodies, however, reside in our digestive system or, more specifically, in our large intestine. (1) The number of microbes living in your digestive tract numbers somewhere to the tune of 200 different species, and altogether, they are commonly referred to as the gut microbiome. 

Did you know? While there are roughly 38 trillion bacterial cells in the human body, there are only 30 trillion human cells. This spooky fact means you are quantifiably more bacteria than human. (2)

Perhaps one of the most interesting things about the bacteria in the human gut microbiome is that while some bacteria may be harmful, others are quite beneficial to our overall health and wellness. (3)

While studies have shown that healthy gut bacteria may help reduce the risk of chronic conditions like diabetes and inflammatory bowel disease (IBD) (3), mounting evidence suggests that not only can your gut health affect your sleep, but it would seem that sleep can affect your gut health as well. 

The Gut-Brain Connection 

Most people only ever associate their gut health with digestive issues. But what you may not know is that your brain (part of your central nervous system) communicates with your gut (or enteric nervous system) via the gut-brain axis (GBA). (4) 

The communication between your brain and gut goes both ways. And apparently, these two have a lot to talk about, as they regularly communicate about everything from the physical to the emotional courtesy of a network of nerves. Ultimately, the gut-brain axis allows the brain to regulate the activity in our gastrointestinal tracts and our gut to regulate emotional activity in our brain. (4) The two are so deeply linked that your gut is commonly referred to as your second brain. 

A good example of the gut-brain connection (and your second brain at work) is “butterflies in your stomach,” — where the nervousness or excitement being assessed and processed in your brain triggers an uneasy feeling in your gut.

Your Gut Health Can Affect Your Sleep… 

Your second brain (or gut) does some pretty heavy lifting to keep your body in good working order. While a healthy gut biome can help with digestion, immune health, and staving off disease, study after study has shown that our gut microbiome may be linked to how much, how well, and even when we sleep. Essentially, a healthy gut microbiome may improve sleep, and a disturbed microbiome may hamper it. 

For example, one study from 2019 demonstrated that the composition of your gut microbiome, specifically increased microbiome diversity, was linked with longer sleep times and better sleep efficiency (how much time you spend actually sleeping versus your total time in bed. (5) 

In 2023, another study out of China examined the relationship between sleep habits and the assortment of gut bacteria most of us have. Ultimately, the researchers found that some types of gut bacteria may impact sleep duration, chronotype (early bird or night owl), and the probability of developing specific sleep issues like snoring or insomnia. (6) 

Other potential sleep issues associated with microbiome imbalances in your gut are fragmented sleep and disrupted circadian rhythms. (7) One interesting animal study examining the relationship between gut bacteria, sleep, and serotonin levels, found that lowered serotonin levels in mice (possibly created by antibiotic use) were linked with disrupted sleep cycles. 

Did You Know? Serotonin is a neurotransmitter that plays a crucial role in myriad biological functions, not the least of which is sleep. Serotonin regulates some aspects of REM sleep, promotes wakefulness, and is a precursor for the production of melatonin (the hormone that makes us sleepy). (8) And while it's tempting to think that serotonin is produced in the brain like many other neurotransmitters, it's not — 95% of your body's supply of serotonin is produced in your gut. (8)

During the research and development phase here at Nightly Greens, our team stumbled upon specific bacteria that support sleep. These good bacteria are typically known as probiotics. 

More specifically, one study from 2019 found that a probiotic mixture containing probiotic strains known as Lactobacillus fermentum LF16 and Bifidobacterium longum BL04 (among others) was linked to improved sleep quality. Meanwhile, another study from 2024 found the same improvements in sleep quality, this time from a probiotic strain known as Bifidobacterium longum 1714. (9,10)

Needless to say, we did our homework, and after some intense fine-tuning, we believe we have the formula that works. In each serving of Nightly Greens, you’ll find 2+ Billion CFUs of probiotics, including the Lactobacillus & Bifidobacterium genera. We’re pretty sure you’ll also find a better night’s sleep.  

…and Your Sleep Can Affect Your Gut Health

Just as your gut health can impact your sleep, so too can sleep impact your gut health — the two share a bidirectional relationship. Case in point, while we’ve already seen that the proliferation of certain bacteria can lead to fragmented sleep and disrupted circadian rhythms, other studies have shown that fragmented sleep and short sleep can disturb the delicate balance of your gut microbiome. (7, 11)

Additionally, a lack of sleep can upset your gut health by increasing stress and upending your diet. 

The playbook for stress looks something like this: Insufficient sleep boosts cortisol levels (aka the stress hormone). (12) An increase in stress, in turn, has been associated with a condition known as leaky gut — where food and toxins pass freely through the intestine and into your bloodstream. (13) A leaky gut then causes a host of health issues like inflammation, bloating, stomach pain, food sensitivities, and, you guessed it, changes to your gut microbiome.

Regarding your diet, a lack of sleep wreaks havoc on your gut by disrupting the delicate balance of hormones that regulate your appetite — leptin and ghrelin. More often than not, the scales tip in favor of ghrelin, the hormone that makes you feel hungry. The problem here is that most people aren’t reaching for veggies or some other healthy snack — they’re more likely to snack on high-carb, high-sugar foods, which can torpedo gut health. (14)

How to Improve Your Gut Health

Now that you know your gut health may be what's keeping you up at night, you might consider some dietary changes to help you catch your forty winks. 

To improve your gut microbiome:

• Switch to a plant-based diet
• Add a probiotic supplement (like Nighty Greens) that supports both sleep and gut health 
• Eat more fermented foods (i.e., kefir, kimchi, kombucha, sauerkraut)
• Eat more prebiotic foods
• Take a probiotic supplement
• Eat whole grains
• Use antibiotics only when necessary

We'll add here that keeping your gut microbiome in balance requires a multi-pronged approach. In addition to the suggestions outlined above, remember to manage your stress and get plenty of sleep. 

Sources

1. Hills, R. D., Jr, Pontefract, B. A., Mishcon, H. R., Black, C. A., Sutton, S. C., & Theberge, C. R. (2019). Gut Microbiome: Profound Implications for Diet and Disease. Nutrients, 11(7), 1613. https://doi.org/10.3390/nu11071613
2. Sender, R., Fuchs, S., & Milo, R. (2016). Revised Estimates for the Number of Human and Bacteria Cells in the Body. PLoS biology, 14(8), e1002533. https://doi.org/10.1371/journal.pbio.1002533
3. Integrative HMP (iHMP) Research Network Consortium (2014). The Integrative Human Microbiome Project: dynamic analysis of microbiome-host omics profiles during periods of human health and disease. Cell host & microbe, 16(3), 276–289. https://doi.org/10.1016/j.chom.2014.08.014
4. Carabotti, M., Scirocco, A., Maselli, M. A., & Severi, C. (2015). The gut-brain axis: interactions between enteric microbiota, central and enteric nervous systems. Annals of gastroenterology, 28(2), 203–209.
5. Smith, R. P., Easson, C., Lyle, S. M., Kapoor, R., Donnelly, C. P., Davidson, E. J., Parikh, E., Lopez, J. V., & Tartar, J. L. (2019). Gut microbiome diversity is associated with sleep physiology in humans. PloS one, 14(10), e0222394. https://doi.org/10.1371/journal.pone.0222394
6. Yue, M., Jin, C., Jiang, X., Xue, X., Wu, N., Li, Z., & Zhang, L. (2023). Causal Effects of Gut Microbiota on Sleep-Related Phenotypes: A Two-Sample Mendelian Randomization Study. Clocks & sleep, 5(3), 566–580. https://doi.org/10.3390/clockssleep5030037
7. Li, Y., Hao, Y., Fan, F., & Zhang, B. (2018). The Role of Microbiome in Insomnia, Circadian Disturbance and Depression. Frontiers in psychiatry, 9, 669. https://doi.org/10.3389/fpsyt.2018.00669
8. Terry, N., & Margolis, K. G. (2017). Serotonergic Mechanisms Regulating the GI Tract: Experimental Evidence and Therapeutic Relevance. Handbook of experimental pharmacology, 239, 319–342. https://doi.org/10.1007/164_2016_103
9. Marotta, A., Sarno, E., Del Casale, A., Pane, M., Mogna, L., Amoruso, A., Felis, G. E., & Fiorio, M. (2019). Effects of Probiotics on Cognitive Reactivity, Mood, and Sleep Quality. Frontiers in psychiatry, 10, 164. https://doi.org/10.3389/fpsyt.2019.00164
10. Patterson, E., Tan, H. T., Groeger, D., Andrews, M., Buckley, M., Murphy, E. F., & Groeger, J. A. (2024). Bifidobacterium longum 1714 improves sleep quality and aspects of well-being in healthy adults: A randomized, double-blind, placebo-controlled clinical trial. Scientific Reports, 14(1), 1-15. https://doi.org/10.1038/s41598-024-53810-w
11. Matenchuk, B. A., Mandhane, P. J., & Kozyrskyj, A. L. (2020). Sleep, circadian rhythm, and gut microbiota. Sleep Medicine Reviews, 53, 101340. https://doi.org/10.1016/j.smrv.2020.101340
12. Hirotsu, C., Tufik, S., & Andersen, M. L. (2015). Interactions between sleep, stress, and metabolism: From physiological to pathological conditions. Sleep science (Sao Paulo, Brazil), 8(3), 143–152. https://doi.org/10.1016/j.slsci.2015.09.002
13. Madison, A., & Kiecolt-Glaser, J. K. (2019). Stress, depression, diet, and the gut microbiota: human-bacteria interactions at the core of psychoneuroimmunology and nutrition. Current opinion in behavioral sciences, 28, 105–110. https://doi.org/10.1016/j.cobeha.2019.01.011
14. Potosky, E., Taylor, C., Wexler, R., & Pratt, K. (2021). Differences in Snacking Intakes by Meeting Sleep Recommendations. Journal of the Academy of Nutrition and Dietetics, 121(9), A52. https://doi.org/10.1016/j.jand.2021.06.145

Byline:

Sharon Brandwein is a Certified Sleep Science Coach and a freelance writer. She specializes in parenting, health, and, of course, all things sleep. Sharon’s work has also appeared on ABC News, USAToday, and Forbes. When she’s not busy writing, you’ll probably find her lecturing her friends and family about sleep and adding more books to her ever-growing TBR pile.