The IOM expert report on Vitamin D and Calcium suggests two changes: increasing your vitamin D intake from 200IU (under age 50) to 600IU daily, or 800IU if you are 71 or older; and not supplementing with calcium.
The new safe daily upper limit of vitamin D is 4000IU; for calcium it’s 2000mg, which increases kidney stone risk.
The IOM believes this much of each is best for bone health. Much of the public and many physicians believe that vitamin D is needed for more than that. People love supplements– and almost half of U.S. adults take them.
Especially in Winter, especially for dark-skinned Americans, vitamin D helps the body’s own immune system fight flu virus and improve multiple sclerosis.
I recommend few supplements, because high quality meals can contain everything you need. But pregnant and nursing women, newborns and the elderly on restricted diets need specific supplements.
Few foods, except wild salmon, mackerel, herring and caviar(!) have much vitamin D; the dairy adds vitamin D to milk, just enough to prevent rickets.
The smartest and safest approach is to have your 25-hydroxyvitamin D level measured. Your doctor can order it, or you can with ZRT lab. The test uses radioimmunoassay, the most accurate testing available.
The IOM thinks your level should be 20ng/ml; many vitamin D experts think it should be 30ng/ml; an independent group of vitamin D researchers (not vitamin sellers) thinks 40ng/ml. Ask your MD.
And check out a new national federally funded Vitamin D/Omega-3 study testing 2000IU daily, for optimal health.