Article Image

How Gut Health Affects Sleep

Hayley Dawes
13 July 2022

Anyone who has ever been kept up at night due to an afternoon cup of coffee has experienced first-hand how what’s happening in your gut can affect your beauty sleep. The gut-brain connection is real – and that means that what’s going on in your microbiome (aka the makeup of the bacteria in your gut) directly affects your sleep cycle. But the relationship extends beyond your coffee habits or what you ate for dinner.

Getting the right amount of good quality sleep is important because it doesn’t just affect whether you feel tired – lack of sleep and poor-quality sleep are both associated with increased risk of certain diseases and cardiovascular issues. Research suggests that your gut health can affect your sleep, and vice versa. This is in part due to the connection between your brain and what’s known as your gut microbiome – the trillions of bacteria and other microscopic organisms that live in your gut. 

The range of “good” and “bad” microbes in your gut has been linked to how well you sleep, and some researchers believe that changing your microbiome can improve your sleep.

Meanwhile, lack of sleep can impact your digestive health by increasing the risk of obesity, type 2 diabetes, and gastrointestinal diseases, as well as by influencing the foods you choose to eat.

Changes to your diet can help improve your gut health, which may also lead to better sleep.

How are the gut and the brain linked?

The gut doesn’t just turn food into energy and waste matter, it’s a smart organ that is in constant communication with your brain. Our gastrointestinal tract (our gut) is often referred to as the second brain, which is not a surprise considering all the things it affects. It’s also home to the enteric nervous system that’s in contact with our brain and central nervous system, helping to regulate vital processes. 

Your gut and your brain are connected, and they can communicate with each other in a number of ways. These different mechanisms all involve your gut bacteria and can influence things like your mood, appetite, sleep, and stress levels.

The gut-brain connection works in both directions. Your gut can send signals to your brain, and your brain can in turn influence the makeup of your gut microbiome. There are three main ways that your microbiome and your brain can affect each other:

  1. Through interacting with the immune system.
  2. By regulating the production of essential neurotransmitters, like serotonin, which signal your brain cells to take certain actions.
  3. Through the vagus nerve, which connects your gut directly to your brain. Through this route, substances produced by your gut microbiome can affect brain functions including sleep.

How gut health can affect sleep

As microbes in the gut produce sleep-regulating hormones, gut health has a direct effect on circadian rhythm. Research surrounding how what we eat affects serotonin, dopamine, and GABA levels is an emerging field of study for using food to boost mood and lower depression. Because these same hormones are linked to the sleep cycle, this means eating with them in mind could potentially help you sleep better, too.

There’s an increasing amount of evidence that the makeup of your gut microbiome is linked to how well you sleep. Research has looked at the relationship between gut bacteria, sleep, and levels of the neurotransmitter serotonin. Serotonin is involved in regulating our sleep cycle, and our gut microbiome is a part of the process that controls the amount of serotonin in our body. 

How lack of sleep can affect gut health 

Studies suggest there is a link between disturbed sleep and increased risk of gastrointestinal diseases. Lack of sleep can increase stress, which affects the gut. This can lead to a host of issues including bloating, inflammation, stomach pains, food sensitivities, and changes to the gut microbiome.

Sleep specialist Dr. Michael Breus told The Guardian that “the microbial ecosystem may affect sleep and sleep-related physiological functions in a number of different ways: shifting circadian rhythms, altering the body’s sleep-wake cycle, affecting the hormones that regulate sleep and wakefulness.” However, the connection also goes the other way. How you sleep, and particularly how much sleep you get, affects the variety and diversity of microbes flourishing in your gut – and that has knock-on effects for your health more widely.

How to improve sleep through gut health

What’s happening in your gut is very likely related to how well you sleep at night. Since there’s a strong connection between good bacteria and good sleep (and bad bacteria and poor sleep), diets heavy on sugars, fatty, and highly processed foods can alter the make-up of your gut microbiome, reducing the abundance of beneficial microorganisms. Limiting these foods, and replacing them with whole, unprocessed nutrient-rich foods like vegetables, fruits, and wholegrains, can help restore and protect the beneficial bacteria in your gut.

People who go to sleep earlier have better blood sugar control after eating the next morning, while those who go to bed later have worse control. Blood sugar dips can increase appetite and may lead you to eat more processed foods.

A diet rich in whole fruits and vegetables is the foundation of healthy living. Good foods for gut health include:

  • Fruits and vegetables
  • Nuts and seeds
  • Prebiotic foods
  • Legumes
  • Wholegrains
  • Probiotic fermented foods
  • Coffee
  • Unprocessed or minimally processed foods

Probiotic foods

These foods are fermented foods that contain live microbes, such as unsweetened natural yogurt, kefir, kimchi, sauerkraut, and certain cheeses, like parmesan, aged cheddar, and Swiss cheeses. When you eat probiotic foods, these bacteria may take up residence in your gut, increasing the diversity of your microbiome. 

Prebiotic foods

These foods contain fiber that feeds the bacteria in your gut and encourages a diverse microbiome, rich in beneficial microbes. Foods that contain prebiotics include asparagus, onions, leeks, garlic, bananas, Jerusalem artichokes, beans like chickpeas and lentils, and certain whole grains, including barley, oats, and rye. 

Our diet and the environment where we live have an important influence on the composition of our gut microbiome. Sugary and processed foods, lack of fibers, exercise, hydration, antibiotics, physical or emotional stress can all have a negative impact on the microbiota. In order to live a normal and healthy life, we need a well-balanced gut microbiota.