Vitamin D is good for more than just your bones
There are some vitamins that you’re probably pretty well-versed in, like vitamin C. But you might be a little vague on others, like vitamin D. Plenty of people joke about getting some when they go out in the sun, but is that legit? And what are the benefits of vitamin D, anyway?
Vitamin D is a fat-soluble vitamin that’s naturally found in some foods, added to certain products (think: cereal and milk), and available as a dietary supplement, according to the National Institutes of Health (NIH). And yep, you can get it through something called vitamin D synthesis when your skin is exposed to UV rays from sunlight. And there are two main types of vitamin D: vitamin D2 or ergocalciferol, and vitamin D3 or cholecalciferol.
This vitamin plays a role in different bodily functions, the main one being helping your body absorb calcium and phosphorus. “Both nutrients are crucial for bone health,” says Keri Gans, RD, the author of The Small Change Diet. More on the others in a sec.
While you may think it's super easy to get your fill by simply spending time outside, research estimates that about 18 percent of Americans are at risk of vitamin D deficiency. Needless to say, it’s tough to ballpark how much vitamin D you’re actually absorbing from sunlight.
So what’s the deal with vitamin D and how can you tell if you’re getting enough? Here’s everything you need to know.
What are the benefits of vitamin D?
Vitamin D offer several important health benefits.
It supports strong bones. Again, vitamin D helps your body absorb calcium and phosphate, which helps build up and strengthen your bones. “Vitamin D is really important to support strong bones,” says Jessica Cording, R.D., author of The Little Book of Game-Changers.
It can lower your risk of osteoporosis. Speaking of bone health, not having enough vitamin D can lead to your bones becoming thin and brittle, says Arashdeep K. Litt, MD, an internal medicine physician. “Together with calcium, vitamin D helps protect older adults from osteoporosis,” she adds.
It may help with your mood. “Vitamin D has been linked with preserving a stable mood,” says Cording. A 2020 meta-analysis of more than 7,500 people with depression found that those who took a vitamin D supplement reported being in a better mood than those who didn’t. (Worth noting: The researchers cautioned that being deficient in vitamin D may play a role in this.)
It fights bodily inflammation. “Vitamin D lowers inflammation, and inflammation is the common thread between most chronic diseases,” says Sonya Angelone, RD, a spokeswoman for the U.S. Academy of Nutrition and Dietetics. Vitamin D may even lower your risk of cardiovascular disease this way. (But study results on this have been mixed.)
Got it. Then what are the best foods to eat to get more vitamin D?
While most people get their vitamin D from sunlight exposure, it’s possible to get it from some foods. Here’s a breakdown of the biggies, according to the NIH.
Cod liver oil: One tablespoon has 34 micrograms (mcg)
Trout: Three ounces has 16 mcg
Sockeye salmon: Three ounces has 14.2 mcg
Mushrooms: Half a cup has 9.2 mcg
Fortified two percent milk: One cup has 2.9 mcg
Fortified cereal: One serving has 2 mcg
How much vitamin D do you need every day, anyway?
Vitamin D needs vary by gender and age, but most adult women need 14 to 70 micrograms or 600 IU of vitamin D a day, according to Johns Hopkins Medicine. (That number stays the same when you’re pregnant and breastfeeding too.)
Okay, so what about that vitamin D you get from the sun? That’s tricky to calculate. “If you are fair-skinned and go into the sun for 10 minutes without sunscreen in simply shorts and a tank top, your body will make 10,000 IU of vitamin D,” Gans says. “The less skin exposure, the less amount your body will produce within the same time.” What about sunscreen? Gans points out that studies have shown that using it doesn’t really affect your body’s synthesis of vitamin D, so make sure you slather up before heading out.
But your best bet is to aim to get 10 to 15 minutes of sunlight per day and eat a diet full of vitamin D-rich foods like fatty fish and moderate amounts of fortified, low-fat dairy, per Johns Hopkins Medicine.
How do you know if you have a vitamin D deficiency?
A vitamin D deficiency can lead to rickets, which is a disease w where the bones don’t properly mineralize, then become soft and cause skeletal deformities, according to the NIH. It can also lead to osteomalacia, which is a condition that can lead to weak bones.
The only way to know where your vitamin D levels stand is to get a blood test. And, in general, doctors only order these for high-risk patients, including those who may suffer from malnourishment due to a gastrointestinal disease, women who have been through menopause, and women who don’t have ovaries, Dr. Litt says.
“You are what you eat, digest, absorb, transport, and metabolize,” Angelone says. “Same with vitamin D. Your levels depend on the ability of your body to adequately make vitamin D from the sun, transport vitamin D to the liver, kidneys, and cells through the body then get absorbed into the cells.”
If anything is off with any of those steps, you could have insufficient vitamin D levels, she says. If you’re concerned about your vitamin D levels, talk to your doctor. They should be able to order a blood test for you.