En español | A report from the Institute of Medicine setting new guidelines for vitamin D and calcium increases the recommended level of D but actually maintains the same or decreases the recommended levels for calcium.
Most Americans and Canadians, the report states, are getting enough vitamin D and calcium, although older men and women may fall short.
The long-awaited 2010 recommendations update those set in 1997. (See box at right.)
The report also notes that taking more than 4,000 IU of vitamin D daily (up from 2,000 IU) or 2,000 mg of calcium daily (down from 2,500 mg) increases the risk for harm.
In the years since the first report was published, studies have linked these two nutrients, both individually and combined, to a surprisingly wide range of health benefits, including lower blood pressure, reduced risk of bone fracture and decreased risk of breast cancer, as well as protection against heart disease, Parkinson's disease and type 2 diabetes.
As a result, scientists have called for high levels of vitamin D from supplements, anywhere from 1,000 to 2,000 IU a day, in addition to sun exposure, fortified foods and mutivitamins.
Although the report confirms the role of calcium and vitamin D for bone health, it points out that studies of vitamin D for other health problems have yielded conflicting and mixed results.
Very high levels of vitamin D (above 10,000 IU a day) may cause kidney and tissue damage. Evidence of possible risks at lower levels is limited, but some studies offer tentative signals about adverse health effects. The report also notes that standards for vitamin D blood test results have not been based on rigorous studies and could lead to doctors diagnosing vitamin D deficiency when people have enough.
"In light of the new evidence about the benefits of vitamin D, the increased recommendation for older men and women is a good one," says Bess Dawson-Hughes, M.D., director of the Bone Metabolism Laboratory at the Human Nutrition Research Center on Aging at Tufts University.
But Dawson-Hughes expressed surprise that the recommended blood levels for vitamin D weren’t higher. She says the National Osteoporosis Foundation recommends taking more vitamin D than the new Institute of Medicine report.
Her bottom line advice: In general, older people can achieve healthy levels of vitamin D by taking the recommended 800 IU of vitamin D a day and don’t need to be tested.
“But if you fall into a high-risk group, you need more than that,” says Dawson-Hughes, who was not involved in the report. People who spend little time in the sun, use sunscreen whenever they go outside, have dark skin or are overweight are among those considered high-risk. "These men and women should be tested,” she adds.
If the new recommendations leave you confused, you're not alone. Keep in mind that these numbers are important for developing national nutritional guidelines for food programs. When it comes to your own health, you might want to have a heart-to-heart talk with your doctor.
Nissa Simon, a health writer, lives in New Haven, Conn.
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