Be Wary of Vitamin D Deficiency

By Stephanie Watson @WatsonWriter
January 04, 2016

How to get enough of this important vitamin without risking your skin in the process.

A fear of skin cancer and premature aging has driven many of us indoors, and made us smear on a thick layer of sunscreen whenever we are exposed to the sun. This high-level protection is good for our skin, but it might not be so good for our bones and overall health. Our bodies rely on sunlight as the most abundant source of vitamin D. Without this “sunshine vitamin,” particularly during winter, we could become more susceptible to diseases like osteoporosis, cancer, diabetes, arthritis, and dementia.

It’s hard to know exactly how many Americans are lacking in vitamin D, because the estimates vary so widely. African Americans are at greatest risk for a deficiency, because their skin pigment acts like a built-in sunscreen, blocking vitamin D production from the sun. Between 31 percent and 82 percent of African Americans are vitamin D deficient, depending on which statistics you follow. People who live in northern cities like Boston, Mass., or Edmonton, Canada, can also become deficient during the winter months, when the sun is low in the sky.

Are you deficient?

The Institute of Medicine recommends that adults get 600 international units (IU) of vitamin D daily, and those over age 70 get 800 IU. If you don’t get enough sun exposure and you’re not making up the difference with diet or a supplement, you could have a vitamin D deficiency. 

It can be hard to tell whether you’re deficient by looking for symptoms alone because irritability, sweating, and a depressed mood can herald many different conditions. Even symptoms of a more serious deficiency, like bone pain and muscle weakness, can be hard to pinpoint as a lack of vitamin D.

Not sure of your vitamin D status? Get a blood test from your doctor to find out whether you need more. Testing is a good idea for people at risk for a deficiency because they get very little sun and eat few vitamin D-rich foods, or they have GI, kidney, or liver disorders.

How to get more D

How can you balance your need for vitamin D with concerns over skin cancer? Expose your skin to the sun, but get the timing right. “We need about 10 to 15 minutes of daily sun exposure for proper vitamin D levels,” says Ida Orengo, MD, professor of dermatology and director of the Mohs/Dermatologic Surgery Unit at Baylor College of Medicine. After your 15 minutes are up, go inside or apply a broad-spectrum sunscreen.

Can you get your daily D from a tanning bed? “A tanning bed will never provide you with the vitamin D that you need, nor is it safer than tanning outdoors,” says Deborah Sarnoff, MD, a clinical professor of dermatology at NYU School of Medicine. Inside a tanning bed you’re mainly exposed to ultraviolet A (UVA) light, not to the ultraviolet B (UVB) light that helps your skin produce vitamin D. “So you are increasing your risk of skin cancer without receiving any benefit!”

Don’t forget diet as an important source of vitamin D. Up your intake of foods rich in this nutrient, such as fatty fish (tuna, sardines, swordfish, salmon), fortified milk and orange juice, yogurt, egg yolks, cheese, and beef liver. If you still aren’t getting enough vitamin D, consider taking a supplement.

Don’t overdo it 

When taking vitamin D supplements, aim for the RDA and don’t go overboard. There’s no evidence mega-doses will give you greater protection against disease. “Healthy people have been popping these pills, but they should not continue taking vitamin D supplements unchecked,” says Muhammad Amer, MD, MHS, an assistant professor in the Division of General Internal Medicine at the Johns Hopkins University School of Medicine. “At a certain point, more vitamin D no longer confers any survival benefit, so taking these expensive supplements is at best a waste of money.” 

Overdoing it on vitamin D could even be risky. Too much of this vitamin can cause calcium to build up in your blood, leading to side effects ranging from constipation to kidney stones. Before you buy a supplement, check with your doctor to make sure the amount meets your dietary needs without exceeding them.


January 04, 2016

Reviewed By:

Janet O’Dell, RN

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