By Dr. Mercola

You share your body with trillions of microorganisms, the bulk of which reside in your gut, including your stomach and small and large intestines. There, however, they are not restricted to influencing only the goings-on of your digestive process.

Far from it, these microorganisms, collectively known as your microbiome, influence your body's homeostasis daily and are intricately tied to other body systems via a number of complex pathways, including the gut-brain axis and a recently revealed gut-brain-bone marrow axis, the latter of which may influence your blood pressure, mood and more.

One of the most compelling avenues of study relating to your microbiome is how it relates to your sleep. It's already known that sleep influences your gut health, in part because lack of it makes it harder for you to control your impulses and manipulates hormones linked to food intake, causing you to eat more and crave unhealthy foods.

So skimping on sleep is a remarkably good bellwether of a poor diet, the latter of which can quickly take a toll on your gut health. Now researchers are asking whether the opposite also holds true and perhaps your microbiome influences your ability to sleep as well.

Although the science is in its early stages, researchers are looking into whether improving gut health could act as a new form of sleep therapy. Michael Breus, Ph.D., a clinical psychologist and fellow of the American Academy of Sleep Medicine, told The Guardian:1

For instance, writing in the journal Chest, researchers pointed out that changes in gut microbiota have long been linked to lifestyle behaviors such as diet, travel, exercise and disturbances to circadian rhythm.2 Meanwhile, diseases once primarily attributed to lifestyle, such as obesity, heart disease and depression, are turning out to have increasing links to microbiota. In this case, they believe that "microbial-immune cross-talk" may be playing a role in obstructivesleep apnea (OSA), particularly in fatal cases.

"[W]e posit that altered patterns of sleep and oxygenation, as seen in OSA, will promote specific alterations in gut microbiota which in turn will elicit the immunological alterations that lead to OSA-induced end-organ morbidities," they stated. Likewise, in the Journal of Clinical Gastroenterology, researchers evaluated the interplay between sleep dysfunction, gastrointestinal health and disease, with particular focus on how the effects of sleep and circadian rhythm disruption could affect the microbiota.3

Yet another study pointed out that partial sleep deprivation is known to alter gut microbiome, and its composition is linked to cognitive flexibility. Their study found that there could be a link between sleep quality, composition of gut microbiome and cognitive flexibility in older adults, such that "improving microbiome health may buffer against sleep-related cognitive decline in older adults."4

Prebiotics, which act as food for the beneficial bacteria, orprobiotics, in your gut, have already been found to influence sleep in animal studies. When young rats were fed a diet containing prebiotic fiber or a control diet for four weeks, the prebiotic group spent more time in restful and restorative non-rapid eye movement (NREM) sleep cycles.5

In addition, rats eating prebiotics had an increase in beneficial gut bacteria as compared to the control group and spent more time in REM sleep after being stressed, which is important for promoting recovery. The researchers noted:6

Dr. Michael Mosley, a doctor-journalist with BBC News, conducted a similar trial on himself, taking prebiotics for five days, and noticed a remarkable improvement in his sleep. Prior to the prebiotics, he spent 21 percent of his time in bed awake but this dropped to 8 percent after the prebiotics.7

This isn't definitive proof that prebiotics improve sleep, but considering the many other benefits they add to your health, there's little harm, and potentially great gain, in adding them to your diet. If you're interested in adding more prebiotic fiber to your diet to improve the health of your microbiome, and possibly your sleep, the following foods are good sources:8

Apples

Asparagus

Banana

Beetroot

Breast milk

Burdock root

Cashews

Chicory root

Couscous

Fennel bulb

Garlic

Grapefruit

Green peas

Jerusalem artichokes

Jicama

Konjac root

Leeks

Nectarines

Onion

Persimmon

Pistachios

Pomegranate

Savoy cabbage

Seaweed

Shallots

Snow peas

Tamarillo

The many ties between your microbiota, your sleep and your overall health only continue to grow. For instance, melatonin, the sleep hormone, is made from serotonin, and is normally found in abundance in your gut — even more so than in your brain. Gut bacteria affect both serotonin and melatonin production.

Further, the composition and functions of your gut microbiome is affected by circadian rhythm disruptions, including jet lag. Researchers believe circadian rhythms play a key role in regulating the gut microbiome as well as its responses to gastrointestinal pathogens.9

If you skimp on sleep, you also prompt changes in your body's microbial community. When men slept for just four hours a night for two nights in a row, the balance of bacteria in their gut shifted.10 Specifically, they had increased firmicutes to bacteroidetes ratio, higher abundances of the families Coriobacteriaceae and Erysipelotrichaceae and lower abundance of Tenericutes, changes that have previously been linked to metabolic disturbances. The researchers concluded:11

Your gut microbiome plays an intricate role in your mood, and sleep plays a role in depression, raising intriguing questions about how all three — microbiome, sleep and depression — are related. Tim Spector, professor of genetic epidemiology at King's College London, told The Guardian:12

Also intriguing, a small study involving adults diagnosed with irritable bowel syndrome (IBS) and depression found the probiotic Bifidobacterium longum provided depression relief. At six weeks, 64 percent of the treatment group had reduced depression scores compared to 32 percent of the control group that received a placebo.13

Those receiving the probiotic also reported fewer symptoms of IBS and improved overall quality of life. At the end of 10 weeks, approximately twice as many in the treatment group were still reporting lower levels of depression.

Interestingly, functional MRI scans revealed a link between reductions in depression score and actual changes in brain activity, specifically in areas involved in mood regulation, such as the amygdala. As noted by Dr. Roger McIntyre, professor of psychiatry and pharmacology at the University of Toronto, who was not involved in the study:14

Another common thread affecting both your sleep and your gut is your diet. One study evaluating the diets and sleep patterns of more than 4,500 people found distinct patterns:15

Further, Spector told The Guardian, "[I]f we eat badly, we sleep badly … If you wanted to improve sleep, you could try a gut-friendly regime by eating a broad and inclusive diet with real food, not processed."16 Indeed, it's likely that eating a varied, whole food diet is one key to normal, healthy sleep and gut health alike. If you need some help in this area, check out my nutrition plan for a step-by-step guide to optimizing your eating habits.

As for how to support a healthy microbiota, which could do more to improve your sleep than is currently appreciated, it isn't very complicated, but you do need to take proactive steps to encourage its health while avoiding factors known to cause harm. This includes:

Sources and References

1, 7, 12, 16 The Guardian March 19, 2018

2 Chest. 2018 Mar 13.

3 J Clin Gastroenterol. 2018 Mar;52(3):204-209.

4 Sleep Med. 2017 Oct;38:104-107.

5, 6 Frontiers of Behavioral Neuroscience January 10, 2017

8 Monash University, FAQs for the High Fiber, High Prebiotic Diet

9 Curr Opin Gastroenterol. 2016 Jan;32(1):7-11.

10, 11 Mol Metab. 2016 Oct 24;5(12):1175-1186.

13 Gastroenterology August 2017, Volume 153, Issue 2, Pages 448-459.e8

14 Time June 2, 2017

15 Appetite January 20, 2013

16 The Guardian March 19, 2018

17 Scientific American March 17, 2015

18 ISME Journal 2012 Aug;6(8):1469-79