Vitamin D Deficiency: How Common Is It?

Vitamin D Deficiency: How Common Is It?

By Karen Schwartz

These dark and dreary winter months have many Chicagoans longing for warmer climates. But hot rays and relaxing days are not all that Chicagoans may miss by living in a colder and less sunny locale. Living in Chicago may predispose numerous Chicago residents to having a vitamin D deficiency.

In fact, about 50 percent of Americans are deficient in vitamin D, says Dr. Lisa Holmes, a family care physician at Hinsdale Primary Care. And this deficiency, which is diagnosed by a simple blood test, is very common in the northern latitudes, she notes.

We absorb vitamin D through many of the foods we eat, but most effectively through our skin, which is why the winter months have many of us feeling so lackluster.

“Vitamin D helps boost immune function, reduce inflammation; it aids in neuromuscular function and helps protect against some forms of cancer,” Holmes says. Additionally, vitamin D helps us feel clearer of mind and supports strong teeth and bones. Together with calcium and magnesium, vitamin D prevents osteoporosis in older adults. “A lot of times, patients [with a deficiency] don’t have any specific symptoms, but may feel fatigued, have trouble losing weight, have general achiness and get sick frequently,” Holmes says.

Dr. Kimbra Bell, an internist at Northwestern Memorial Hospital, routinely orders a vitamin D screening when her patients come in for their annual physicals, and finds that about 70 percent are deficient in that vitamin. The optimum level of vitamin D can vary based upon an individual’s age, health, weight and even where he or she lives. A person who lives in the northern part of the United States, for example, will most likely require a higher level of vitamin D due to the lack of sun exposure a greater number of months during the year.

“The percentage would be a lot different—I might be saying 20 percent—if my patients came from California or Florida, where the climate is warmer,” Bell says, “But living in Chicago, where we’re covered up nine months out of the year… without exposure to the sun, we miss out.”

That doesn’t mean we need to lie in the sun for hours, baking ourselves to get the right amount of vitamin D. Just having casual exposure will do the trick. Even when it’s cold, but the sun is out, getting outside and spending 20 minutes in the sun allows your body to make 20,000 International Units (IUs) of vitamin D, Bell says.

Still, even with a healthy, balanced diet and plenty of skin-in-the-sun time, some of us may still be coming up short.

“Our skin is the receptor,” says Bell. “The melanin in the darker-skinned people interferes with the synthesis of the vitamin D that starts at the level of the skin when the sun comes into contact [with it]. Therefore, darker-skinned people tend to be more deficient.”

So, when the sun hides for weeks at a time, as is sometimes the case in Chicago, or you happen to have a darker complexion, what can you do to maintain a proper level of vitamin D?

Dietary supplements, or multivitamins, provide one way of getting the amount you need. Vitamin D3 is what you should be looking for—it’s the most active form of the vitamin. And it’s the type most commonly found in multivitamins. But multivitamins may only have 400 IUs of the vitamin, and that may not be enough, which means you’ll have to purchase additional supplements to meet your recommended daily allowances (RDA) of vitamin D3.

The dosage of vitamin D3 that’s suggested to patients depends on the degree of deficiency. Bell prescribes 800–1,000 IUs a day for mildly deficient patients and 2,000–5,000 IUs daily if a patient is moderately deficient. For her patients that are severe cases, she prescribes 50,000 IUs once a week for eight weeks and then transitions them to 2,000 IUs daily.

While vitamin D3 overdoses are not common, you don’t want to overdo it. The idea, Holmes and Bell both agree, is to do your best to keep your vitamin D3 levels at the appropriate RDA. Maintain a balanced diet and make sure to steal some time with the winter sun when it peeks through the clouds. [email_link]