According to the report:
"Most Americans and Canadians up to age 70 need no more than 600 international units (IUs) of vitamin D per day to maintain health, and those 71 and older may need as much as 800 IUs, says a new report from the Institute of Medicine. The amount of calcium needed ranges, based on age, from 700 to 1,300 milligrams per day, according to the report, which updates the nutritional reference values known as Dietary Reference Intakes (DRIs) for these interrelated nutrients."
The report's recommendations take into account nearly 1,000 published studies as well as testimony from scientists and stakeholders. While the studies focused on the effects of calcium and vitamin D on bone health, the committee also reviewed hundreds of studies and reports on other possible health effects of vitamin D, such as protection against cancer, heart disease, autoimmune diseases, and diabetes.
While these studies point to possibilities that warrant further investigation, they have yielded conflicting and mixed results and do not offer the evidence needed to confirm that vitamin D has these effects. That evidence may come later in form of clinical trials. Then again, it may not - in the past, vitamin E looked very promising for the prevention of heart disease in large population studies, but clinical trials showed that hope to be false.
Confusion about the amount of vitamin D necessary to prevent deficiency has arisen recently, probably due to the blood tests used to measure vitamin D levels. According to the IOM:
"The measurements of sufficiency and deficiency -- the cutpoints -- that clinical laboratories use to report test results have not been based on rigorous scientific studies and are not standardized. This lack of agreement means the same individual could be declared deficient or sufficient depending on which laboratory reads the test. There may be an overestimation of the number of people with vitamin D deficiency because many labs appear to be using cutpoints that are higher than the evidence indicates are appropriate. Based on available data, almost all individuals get sufficient vitamin D when their blood levels are at or above 20 nanograms per milliliter as it is measured in America, or 50 nanomoles per liter as measured in Canada."
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