Harvard Health Letter

Do you need a vitamin D screening?

Vitamin D levels are a hot topic right now, with low levels being linked to all kinds of conditions, such as cognitive decline, fractures, and heart disease. But that doesn't mean you need to get your vitamin D levels checked on a regular basis. The U.S. Preventive Services Task Force says there's just no evidence that the testing helps seemingly healthy people. The group released its first-ever guidelines on the issue in the Nov. 24, 2014, Annals of Internal Medicine, noting that there's disagreement when it comes to an official low vitamin D level. Some labs define it as 20 nanograms per milliliter (ng/ml); others set it at below 50 ng/ml. In addition, tests for vitamin D aren't standardized or reliable. But some people should check their vitamin D levels, including people who have osteoporosis, people who have conditions that affect fat absorption, and people who take medications that might interfere with vitamin D activity, such as anticonvulsants and glucocorticoids. To make sure that you're getting enough vitamin D, aim for the recommended daily intake for your age from food, modest sun exposure, and a supplement if it's needed. The Institute of Medicine advises that adults ages 31 to 70 take 600 international units (IU) per day, and adults ages 71 and older take 800 IU per day. Many nutrition specialists recommend that people take even higher daily doses, up to 1,000 to 2,000 IU per day.

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