Vitamin D can help with everything from bone growth to reducing inflammation. It's naturally present in some foods, added to others and produced when skin is exposed to sunlight, but there can be confusion about how much vitamin D is necessary and when levels might be too low.
This is what doctors say about the best sources of vitamin D and how to maintain healthy vitamin D levels.
How much vitamin D is necessary?
The amount of vitamin D recommended daily varies based on age, health conditions, location and other factors, according to the National Institute of Health.
For children under the age of one year, the recommended daily value of vitamin D is 400 IU, or International Units, per day. For children older than one year, teenagers, adults between the ages of 19 and 70, and pregnant or breastfeeding women, the recommended daily amount is 600 IU. Adults over 71 years of age should take 800 IU daily.
For most people, eating a regular, balanced diet and getting enough sunlight will keep them within the optimal range of vitamin D levels, according to Dr. Andrew Jagim, the director of sports medicine research at the Mayo Health Clinic System, who researches vitamin D. However, those living in a "sheltered area" with limited sunlight may find it more difficult.
Where can vitamin D be found?
Most people meet at least some of their vitamin D needs through exposure to sunlight. Other natural sources of vitamin D include cod liver oil, fish like salmon and tuna, eggs with yolks and some cheeses, according to the NIH. Jagim added that several whole foods also have vitamin D.
Many staples, like milk, breakfast cereals and orange juice are fortified with added vitamin D, which Jagim said is not the same as taking separate supplements.
"Fortified foods provide most of the vitamin D in the American diet," the NIH said. But, there are many cases where doctors recommend extra supplements.
When should people consider supplements?
While there is some controversy about whether vitamin D supplements are necessary, Jagim said there are some populations who may need an extra source of the vitamin, such as those living in areas with less sunlight, such as northern areas.
"A lot of people will actually fall below the lower range, to the point where they could be classified as vitamin D deficient, mostly because we're not getting the sun exposure that we do during other points of the year," Jagim told TODAY. "Vitamin D deficiency in this part of the country can be as high as 40 to 60 percent at certain times of the year."
Low levels of vitamin D can lead to problems like rickets, hair loss, and osteoporsis. However, Jagim said there is some skepticism about using supplements to bump up vitamin D.
"Some people are really just against dietary supplements in all situations and they think it's best to always opt for whole foods first, which is a good strategy and I certainly agree with that," he said. "But there's the exception with certain nutrients like this, where it's going to be really challenging to get levels in the right range because we just are limited in terms of being able to get that vitamin from natural sources like the sun."
What supplements are the best?
Jagin said when choosing a supplement, make sure it's a high-quality brand that has been independently approved by a third party and has been tested.
"I usually recommend looking for supplements that have a label like NSF, one of those third parties, and having that stamp of approval on there," he said. "There's a lot of brands that fit that description of what a good-quality supplement is."
"If you follow recommendations, supplementation with at least vitamin D is going to be safe and will really help a lot of people and put them in the right range, because it'll be difficult for them to get there without supplementing," he said.