Demand grows for Vitamin D tests as deficiency increases

Monday, November 7, 2011 | 7:39 a.m. CST; updated 9:50 a.m. CST, Monday, November 7, 2011
Vitamin D is a fat-soluble vitamin that can be produced by our bodies. A few foods also contain vitamin D, such as salmon and beef liver.

COLUMBIA — You do the right thing: You apply sunscreen faithfully every morning. You try not to spend too much time soaking up rays.

Say goodbye to vitamin D, which is a casualty of the heightened awareness of the dangers of sun exposure, and hello to vitamin D deficiency.

Sources of vitamin D

Eggs — 41 IU/large egg

Milk — 100 IU/cup

Orange juice — 100 IU/cup

Fatty fish, including tuna, mackerel and salmon — 100-500 IU/serving

Supplements — Available in 200-5,000 IU/pill

Cod liver oil — 1,360 IU/tablespoon

 UVB from sun — 0-10,000 IU

Artificial UVB — 2,000-4,000 IU/10-minute tanning session

The Food and Nutrition Board recommends that a person between the ages of one and 70 get 600 international units of vitamin D per day. Infants younger than one year old should get 400 IU/day, and people older than 70 should get 800 IU/day.

 More information about vitamin D can be found at the National Institute of Health.

Columbia's medical community is seeing a growing demand for vitamin D level testing as more physicians order tests for their patients — and as patients ask  for the test. Here's what you should know:

Q: Why is there a growing demand for vitamin D tests?

A: The prevalence of reporting about vitamin D has brought the importance of it to the forefront of people's minds, and patients are beginning to ask their doctors about testing, Brenda Dolan, director of laboratory management at Boone Hospital Center, said.

"More people have read about vitamin D and are interested if their pain can be related to it," Sarah Swofford, family and community medicine physician at MU Health Care, said. "They are reading about it in a magazine, bringing it up and requesting it."

Q: What causes vitamin D deficiency?

A: Catherine Peterson, associate professor and director of undergraduate studies in the nutrition and exercise physiology department, said that many people lack vitamin D because they have been taught to stay out of the sun because of skin cancer concerns.

"We've been told to cover up, use sunscreen," Peterson said. "Which is probably good for reducing our susceptibility to skin cancer, but the downside of that is that now we're losing our greatest source of vitamin D."

People are also working indoors more, and women are less likely to drink milk now than they did in the past, Peterson said.

Peterson stressed that every action has a reaction and that people need to make sure they are getting the correct amount of vitamin D daily, especially as the winter months approach. We only make vitamin D on our own from March through October, she said.

Q: Why is vitamin D important for my health?

A: Vitamin D deficiency has been widely known as the cause of bone diseases: rickets in children and osteomalacia in adults. But health experts have found that the vitamin actually plays a larger role in overall health.

An adequate level of vitamin D can prevent bone diseases; it can also regulate the body, prevent other diseases and treat depression, Peterson said.

Vitamin D regulates cell growth, which helps prevent cancer; blood pressure; insulin production, which helps prevent diabetes; and immune cells, which help prevent autoimmune diseases.

"Nearly every tissue in the body has a vitamin D receptor," Peterson said, explaining that a receptor means a cell can receive and respond to that chemical. "So, it probably has a role in human health beyond bone."

Q: How much vitamin D should I be getting?

A: The Food and Nutrition Board recommends that a person between the ages 1 and 70 get 600 international units per day.

Peterson said that recommendation is probably too low for most people. Research suggests that people could benefit from taking between 1,000 and 2,000 IU per day to maintain sufficiency and more than that if a person is deficient in vitamin D, she said. This should be done under doctor supervision, she said.

People who are obese or have dark skin need even more vitamin D, Peterson said. A person who is obese does not receive vitamin D well, because it is stored in the fat, reducing its availability to other tissues that need it, she said. Dark skin does not generate vitamin D well because it doesn't receive UVB rays as well as light skin. The melanin in dark skin acts as a natural sunscreen.

Q: What if I'm not getting enough vitamin D?

A: Research has shown that 25 to 30 percent of adults are vitamin D deficient or insufficient, Peterson said.

If a person is deficient in vitamin D, physicians work with the patient to replace it. 

Vitamin D is replaced by receiving a 50,000 IU oral capsule from a doctor once a week for eight weeks, Swofford said. After that, the patient will take 1,000 IU, once a day. Some patients continue this for three months, or longer.

Q: How can I get vitamin D naturally?

A: To achieve and maintain vitamin D sufficiency, there are many options. Eating fatty fish such as salmon, drinking milk and orange juice, taking supplements and being exposed to solar UVB rays and artificial UVB rays are all ways to receive vitamin D.

A natural way for a person to get vitamin D is to have arms and legs exposed to the sun for 15 to 20 minutes three times per week in the summer, Swofford said.

Q: How can I get my vitamin D levels checked?

A: Boone Hospital Center started offering vitamin D tests in May. The hospital does the tests, which measure levels by a blood draw, three days a week: Monday, Wednesday and Friday. The test takes about four hours to complete.

Dolan could not say how much a vitamin D test costs a patient but said most insurance companies cover what the hospital charges.

MU Health Care hospitals and clinics can do vitamin D tests, but they send their tests away, said Matt Splett, media coordinator for MU Health Care.

Some websites are offering "home test kits" that include a blood spot test. These tests come with alcohol swabs, lancets, a blood sample bag and other materials. A person then mails their sample out to a lab for analysis, which is then mailed back to the person.

Dolan doesn't recommend that people use home tests on their own.

"You need to get your doctor involved to make the determination if it's even necessary for you to have the test done," she said. "The only time home testing works is when you're doing it in coordination with your physician."

More information about vitamin D can be found at the National Institute of Health.

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