Vitamin D: What it is, its benefits and how to get enough

You’ve likely heard a lot of hype about vitamin D in the past few years, but what is it, what is its function and how can we ensure we’re getting enough? Results from many studies concerning vitamin D are mixed, and it’s a complicated topic; the bottom line is, if you’re concerned you’re not getting enough or that you’re getting too much, talk with your health care provider, who can help you create a plan for your unique life and health needs.

Here, learn the basics about vitamin D.

__What it does:__

Vitamin D is a nutrient we eat and a hormone our bodies make that helps the body absorb and retain calcium and phosphorous, contributing to building and maintaining healthy bones. According to the Mayo Clinic, Vitamin D also regulates many other cellular functions in the body, supporting immune health, muscle function and brain cell activity. Insufficient levels of vitamin D result in a softening of the bones, a condition known as osteomalacia; long-term vitamin D deficiency can also cause osteoporosis.

__How much we need:__

The Cleveland Clinic estimates approximately 35% of American adults do not get enough vitamin D. According to the Harvard School of Public Health, the recommended dietary allowance for those ages 19 to 70 is 600 IU, and the recommended dietary allowance for those older than 70 years of age is 800 IU.

According to the Cleveland Clinic, signs your vitamin D levels might be low include fatigue; bone pain; muscle weakness, aches or cramps; or mood changes, such as depression. The Cleveland Clinic also notes it is possible to be asymptomatic, or to have no symptoms of vitamin D deficiency, even if your levels are low.

Carrera Williams, APRN specializing in functional medicine at PC Medical Centers, says there are two reasons why someone may not get enough vitamin D.

“[Many] Americans are going to be low [in vitamin D levels],” Williams says. “We’re not getting enough from our diet. We need to be able to be in the sunlight, as well, to synthesize it. So, it’s kind of a two-part reason why Americans are not getting enough.”

__Groups at a higher risk for low levels:__

Older adults over age 65 are at a higher risk of having low levels of vitamin D, because they are more likely to spend more time indoors; in addition, the skin’s ability to synthesize vitamin D declines with age, according to the National Institutes of Health Office of Dietary Supplements.

According to Medical News Today, people who have dark skin are also at an increased risk of having lower levels of vitamin D, as more melanin in the skin acts as a screen, reducing the body’s ability to absorb ultraviolet B (UVB) rays from the sun.

Those who have a body mass index greater than 30 are also at an increased risk of low vitamin D levels, as high levels of body fat can limit the body’s ability to absorb vitamin D from the skin.

If you suspect your vitamin D levels are low, talk with your physician to receive blood tests that test both active and storage levels of vitamin D, says Crystal Eifert, FWP-BC, functional wellness practitioner at Kingdom Health & Wellness. She says it can also be helpful to test your magnesium levels, as low levels of magnesium can cause low levels of vitamin D.

__How to get it:__

There are three ways the body can get vitamin D: from the sun, from food and from supplements.

Williams and Eifert recommend gettingvitamin D primarily from the sun and food.

“The best source of vitamin D is sunshine. And it is really hard to bottle sunshine,” Eifert says. “Food is naturally low in vitamin D, because we are supposed to get it from the sun.”

According to the National Institutes of Health Office of Dietary Supplements, Vitamin D3 supplements are manufactured by exposing 7-dehydrocholesterol from lanolin obtained from sheep wool to radiation. Because of this, Eifert recommends taking a high-quality cod liver oil rather than supplements and ensuring you are getting enough vitamin K2, magnesium and vitamin A, cofactors needed for the body to utilize vitamin D.

Living in a way that promotes wellness through going outside — using sunscreen with an SPF of 30 or greater if you will be outside for longer than 15 minutes — and following the United States Department of Agriculture’s nutrition guidelines can help ensure you get enough vitamin D.

__Getting too much:__

​​The maximum daily intake of vitamin D unlikely to cause harmful effects on health is 4,000 IU. Consuming more vitamin D than this — often through synthetic supplements — is dangerous and can have negative health ramifications, including nausea, vomiting, muscle weakness, neuropsychiatric disturbances, pain, loss of appetite, dehydration, polyuria, excessive thirst and kidney stones. Extreme side effects include renal failure, calcification of soft tissues throughout the body, including in coronary vessels and heart valves, cardiac arrhythmias and death.

In addition, vitamin D supplements can interact negatively with some medications; because of this, it is important to consult your physician before adding vitamin D supplements into your routine.

Before implementing diet, exercise or supplement changes, be sure to talk with your physician, who can provide you with guidelines for your specific needs and health concerns.

__Foods high in Vitamin D__

-Fatty fish such as salmon, rainbow trout, tuna, mackerel, sardines

-Beef liver

-Mushrooms

-Egg yolks

-Cod liver oil

__Amount of sunshine needed daily__

To get an adequate amount of vitamin D, go outside each day for 10 to 15 minutes between the hours of 10 a.m. and 3 p.m.; if you are outside longer than that, apply sunscreen with an SPF of 30 or greater to all exposed skin, in order to protect your skin from sun damage that could cause cancer. Dermatologists agree tanning beds should never be used as a substitute for the sun.