If your doctor suggests measuring your blood levels of vitamin D at your next physical, ask why, particularly if you’re not at-risk for vitamin D deficiency. New guidelines from the Endocrine Society, released online this week, say the screening is generally necessary only for individuals at risk for deficiency. That echoes our recent advice on vitamin D testing.
The new guidelines from the Endocrine Society suggested specific dietary intakes of vitamin D as well as treatments for specific at-risk groups, including infants, children, obese adults, older adults, and pregnant women. It recommends against using supplementation to prevent cardiovascular disease or death or to enhance quality of life. For the most part, the vitamin D levels suggested in the Endocrine Society’s guidance mirror the amounts recommended by the Institute of Medicine last fall. However, the Society’s guidance provides more detail on how to treat someone with an established vitamin D deficiency.
The average American is not deficient in vitamin D and consumes adequate amounts through supplements or foods, according to the IOM. On the other hand, our medical consultants say those at risk for deficiency could benefit from having their blood levels of vitamin D tested. That includes people with markedly weak bones and those with celiac disease or other ailments that impair the body's ability to absorb the vitamin from food. It’s less clear is whether testing makes sense for people who are at slightly increased risk of low levels because they are overweight, don't get much sun exposure, or eat little vitamin-D rich foods.
Bottom line: Before you get your vitamin D level measured, ask your doctor why you might need to. In terms of how much you vitamin D you should aim for, from food and supplements, stick with the IOM's recommendation: 600 IU for adults up to age 70 and 800 IU for those older than 70. Foods that naturally contain or are fortified with vitamin D include cod-liver oil, button mushrooms, eggs, fortified milk and soy products, mackerel, sardines, and wild Alaskan or sockeye salmon.
If you opt for a supplement, look for a product with the "USP Verified" mark, which means it meets standards of quality, purity, and potency set by the nonprofit U.S. Pharmacopeia. If you get some midday sun exposure during the warmer months and regularly consume vitamin D-rich foods, you probably don't need supplements. People who are middle-aged or otherwise at risk of vitamin D deficiency, including those who are overweight or have darker skin, might need supplements. Even then, the amount in most multivitamins is probably enough.
Read more about vitamin D deficiency and testing.
Evaluation, Treatment, and Prevention of Vitamin D Deficiency: an Endocrine Society Clinical Practice Guideline [The Journal of Clinical Endocrinology & Metabolism]