Wednesday, March 30, 2011
Getting enough vitamin D?
About one third of Americans are not getting enough vitamin D, a government report says.
One third of Americans are lacking vitamin D
By Mary Brophy Marcus, USA TODAY
The report, out Wednesday from the Centers for Disease Control and Prevention (CDC), parallels what many other studies have suggested in recent years: that a large chunk of the population is at risk for low vitamin D levels.
About two-thirds had sufficient levels, but about a third were in ranges suggesting risk of either inadequate or deficient levels, says report author Anne Looker, a research scientist with the CDC.
Late last year, the Institute of Medicine recommended new daily intakes for calcium and vitamin D when it comes to bone health. They also defined four categories based on results from a common vitamin D blood test, called a serum 25-hydroxyvitamin D, or 25OHD. Looker applied the institutes's four categories (vitamin D sufficiency, risk of deficiency, risk of inadequacy and levels that are possibly too high) to data from the National Health and Nutrition Examination Survey to get the figures.
Sufficient levels are 20 to 50 nanograms per milliliter. Inadequate (unhealthy) levels are 12 to 19 ng/ml. Below 12 ng/ml flags a deficiency; bones are at risk for disease.
The results aren't surprising, says vitamin D researcher Marian Evatt, assistant professor of neurology at the VA Medical Center and Emory University in Atlanta.
Good sources of vitamin D
Few foods are naturally vitamin D-rich; fortified dairy and cereal products often are your best bets. The Institute of Medicine recommends 600 International Units (IUs) a day for adults:
Foods and IUs per serving
• Cod liver oil (1 Tbsp.), 1,360
• Salmon (3.5 oz., cooked), 360
• Mackerel (3.5 oz., cooked), 345
• Sardines (1.75 oz., canned
in oil, drained), 250
• Tuna (3 oz., canned in oil), 200
• Milk (1 cup vitamin D-fortified), 98
• Margarine (1 Tbsp. fortified), 60
• Egg (1 whole), 20
• Liver, beef (3.5 oz. cooked), 15
• Swiss cheese (1 oz.), 12
Source: National Institutes of Health,
Office of Dietary Supplements
"The known risk factors for having low vitamin D levels include getting older, being overweight and having chronic conditions. We're an aging, increasing-girth demographic," she says.
Numerous health problems have been linked to low vitamin D levels, including bone fractures, Parkinson's disease, diabetes and certain cardiovascular outcomes, cancers and autoimmune conditions, Evatt says.
Foods rich in vitamin D include fortified orange juice, cereals and milk, as well as salmon and eggs, says Holly Clegg, author of the Trim & Terrific cookbook series. Also, exposure to sunlight triggers the body's production of vitamin D, Evatt says.
Looker says the report shows the risk of vitamin D deficiency differs by age, sex, race and ethnicity.
"Deficiency was lower in people who were younger, male or non-Hispanic white, and in pregnant or lactating women," she says.
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