Gut Health & Sleep: How Digestion Affects Rest

Turns out your gut might be keeping you up at night. Here’s what the science—and the experts—say can help.

When you can’t sleep at night, you might chalk it up to what’s going on in your head. Maybe you’re tossing and turning over that big presentation at work tomorrow. Or the emails piling up in your inbox. Or a humiliating bit of improv you attempted in the third-grade talent show that really didn’t land. 

But it turns out that it might not just be those pesky thoughts in your brain keeping you up at night…it might also be what’s in your gut. When we eat—and what we eat—has a massive impact on our quality of sleep, and our overall health.

Why Sleep Is an Essential Building Block to Health

A good night of sleep—at least seven hours—is necessary to help your body rest and restore itself. Good sleep helps with brain function, cardiovascular health, and psychological wellness, and chronic sleep deprivation has been linked to hypertension, depression, and diabetes.

Healthy habits like maintaining a routine, getting enough exercise, and managing stress can all contribute to better quality sleep. And studies also show that certain foods and eating habits can really help or hurt our slumber. 

“Usually, people can pinpoint food or beverage triggers that contribute to bad sleep,” says Dr. Marie-Pierre St-Onge, founding director of the Center of Excellence for Sleep and Circadian Research at Columbia University and author of the book Eat Better, Sleep Better. For instance, you might skip the after-dinner coffee if you don’t want to be up all night. But what you might pay less attention to, she says, are the eating habits that affect your sleep in positive ways.

Healthy Digestion Helps You Sleep Better … And Good Sleep Heals Your Gut

There isn’t one magic ingredient or supplement that unlocks good sleep. Instead, Dr. St-Onge emphasizes eating a well-rounded diet rich in fiber and low in saturated fats. Her research suggests that people who consume a Mediterranean diet (rich in fruits and vegetables, complex carbohydrates, and healthy fats) tend to have fewer insomnia symptoms and get worse rest than those who consume diets high in saturated fats and processed sugars.

This could be because these diets are rich in nutrients like vitamin B6, zinc, magnesium, and folate—all of which can help your body produce the sleep hormone melatonin. The antioxidants in a fruit- and vegetable-rich diet can also help reduce inflammation and promote a diverse gut microbiome, which research suggests might help you sleep better, too.

Of course, it’s not just what you eat that can make or break your quality of sleep. It’s also when you eat. “We definitely see people who have odd sleep patterns, like maybe they're eating really close to bed, eating really soon after they wake up, or midnight snacks,” says Emily Martorano, a registered dietitian with a practice in lower Manhattan. “Things like that can definitely change and worsen their gut motility.”

Giving your digestive system a break at night will help your body get to sleep faster and stay asleep longer. For people with irregular eating habits looking to improve their sleep, Martorano often recommends starting with a 12-hour fast at night, “just to give your gut a little bit of time to reset.”

Just as good quality sleep and a healthy diet go hand in hand, Martorano cautions that poor sleep and poor diet can also be a vicious cycle. “When you're not getting enough sleep, your cortisol increases, your inflammation markers increase, and that can impact digestive quality,” she says. 

Lack of sleep can also disrupt the balance of ghrelin and leptin, the hormones that regulate hunger and fullness, making you feel hungrier than usual. “With less sleep, there’s the chance that people are going to have more hunger and overeat,” says Martorano, “which leads to more bloating and stomach issues.” 

Which, in turn, can lead to worse sleep.

Things You Can Do to Improve Your Gut Health and Improve Your Sleep

SUPPORT THE GUT MICROBIOME:

There is growing evidence that suggests a link between a person’s gut microbiome (the ecosystem of microorganisms that live in your digestive tract) and the quality of their sleep. In addition to eating a balanced diet rich in legumes, whole grains, and fiber while reducing sugars and processed foods—all of which support a healthy gut microbiome—a recent study found that taking a multi-strain probiotic before bed can help improve a person’s subjective sleep quality. 

PRACTICE GOOD SLEEP HYGIENE:

Adhering to a schedule—going to sleep and waking up at the same time every day—is key for maintaining consistent circadian rhythms, a major component of quality sleep hygiene. Consider eating at regular times, avoiding eating large meals within three hours of bedtime, and maybe skipping that midnight snack. Avoid caffeine within six hours of sleep.

MANAGING STRESS:

Stress can impact your gut health and your sleep. The physiological effects of stress can impact everything from GI tract motility to inflammation and bloating, in addition to the sleep-wake cycle. The same mindfulness and relaxation therapies you might practice for sleep are often the same interventions that can help treat functional gastrointestinal disorders. 

Words by Emily Kang