Vitamin D is a powerhouse nutrient that strengthens your bones, supports your immune system, and promotes a strong, healthy heart. But its influence doesn’t end there. Vitamin D could also be the ticket to better sleep, as research suggests a deficiency in the nutrient may be linked to sleep disorders.
About 30 percent of adults are deficient in vitamin D, while up to 46 percent don’t get enough—and studies suggest that boosting your vitamin D intake may improve the quality of your shut-eye. We tapped experts to understand why this nutrient is vital for sleeping well at night, as well as how you can optimize your vitamin D levels for better slumber.
- ABOUT OUR EXPERTS: Cintara Bradley, N.D., is a naturopathic doctor and resident physician at Sonoran University of Health Sciences. Samantha Peterson, M.S., R.D., is a registered dietitian and co-founder of Simply Wellness.
The Vitamin D Breakdown
“Vitamin D is nicknamed the ‘sunshine vitamin’ because your body makes it naturally when your skin gets direct sunlight,” says Samantha Peterson, M.S., R.D., a registered dietitian and co-founder of Simply Wellness. “It’s also a fat-soluble vitamin, which means your body stores it in fat tissue and the liver.”
While our main natural source of vitamin D is sunlight, it’s also found in foods like salmon, mackerel, sardines, egg yolks, and certain mushrooms, says Cintara Bradley, N.D., a naturopathic doctor and resident physician at Sonoran University of Health Sciences. You can also find it added to certain milks and cereals through fortification, as well as in supplements.
Read More: 5 Possible Reasons Why You’re Not Absorbing Enough Vitamin D
What makes vitamin D especially unique is that it behaves more like a hormone than a typical vitamin, says Peterson. “That means it helps send signals throughout your body, influencing bone strength, immune function, muscle health, and even your mood and energy,” she explains. “Vitamin D is a true multitasker, so I like to think of it as a key that unlocks several important doors in your body.”
Vitamin D’s Impact On Sleep
On top of keeping your body strong and resilient, vitamin D is connected to sleep in more ways than one. “Vitamin D interacts with areas of the brain that help set your circadian rhythm, or your body’s internal clock that tells you when it’s time to be alert and when it’s time to wind down,” Peterson says. “If that clock is off, falling asleep and waking up at consistent times becomes harder.”
This is because vitamin D plays a role in the production of serotonin, a “feel-good” brain chemical that helps regulate mood and stress levels during the day. “At night, serotonin is also converted into melatonin, the hormone that signals your body it’s time to rest—and if your vitamin D levels are low, you may not produce enough serotonin or melatonin at the right times,” Peterson says. The result? Trouble falling asleep, staying asleep, or waking feeling refreshed.
Furthermore, vitamin D also helps the body maintain a balanced inflammatory response and may support easier sleep if inflammation-related discomfort keeps you awake, Peterson says. (Interestingly, vitamin D deficiency typically presents with muscle aches, sore joints, and/or bone pain.)
How To Optimize Your Vitamin D Levels For Better Sleep
Reaping vitamin D’s many benefits—including better slumber—is as simple as making a few upgrades to your daily routine.
1. Get Morning Sunlight
“Aim for 10 to 20 minutes of sunlight on your skin first thing in the morning,” says Peterson. This naturally helps your body make vitamin D and sets up your circadian rhythm for better nighttime rest. Exposure to sunlight helps your body produce the right hormones, including serotonin and melatonin, which support restful sleep.
Read More: 4 Ways To Boost—And Balance The ‘Feel-Good’ Hormone Serotonin
Taking a quick walk around the block or sipping your morning coffee on the porch usually does the trick. However, those with darker skin tones may need to spend a few extra minutes in the sun, since dark skin contains more melanin, a compound that may slightly inhibit vitamin D production, Peterson says.
2. Snack On Vitamin D-Rich Foods
Another easy way to support your vitamin D levels is to eat a variety of foods high in the nutrient, such as fatty fish (think mackerel, sardines, salmon), egg yolks, and fortified milk and yogurt, Bradley says. (A serving of sockeye salmon, for example, offers 570 IU of vitamin D, while one egg offers around 44 IU.) For optimal absorption, pair these foods with healthy fats like avocado, nuts, seeds, and olive oil.
3. Take Breaks Outside
Whether or not you get outside in those earlier morning hours, short bursts of sunlight throughout the day work wonders for sleep later on. “Step outside for five to 10 minutes on a work break, eat lunch near a sunny window, or take an afternoon walk,” Peterson suggests. “Consistent daylight exposure helps your body produce vitamin D and reinforces your circadian rhythm, which can lead to better sleep at night.”
4. Consider A Supplement
If you live in a cold, cloudy climate, don’t get much sun, or have darker skin, consider adding a vitamin D supplement to your routine. Peterson recommends opting for vitamin D3, since it’s the form your body absorbs and uses most efficiently.
The recommended daily allowance for most adults is about 600 to 800 IU, but Peterson says supplementing with 1,000 to 2,000 IU daily often better supports optimal levels for quality sleep. That said, too much vitamin D from a supplement may lead to gastrointestinal upset (especially if you live in a sunny environment or eat plenty of vitamin D-rich foods), so Bradley always recommends checking in with a healthcare provider for personalized dosing needs.