They're indoors all day. And when they do go out, they go slathered in SPF 1 Gazillion skin cream because their parents are afraid the little rugrats will get cancer if they live to be the age of, say, John McCain.
Anyway, the latest study from Childrens Hospital in Boston claims to be representative, and states one kid in five is courting rickets, heart disease, and various forms of cancer because they're not getting Vitamin D pills with their morning milk.
But how much? There's the rub. A study from 2008 conducted in Beirut indicated up to 2000 International Units of a version of the vitamin called D3 was safe. (That's a representative bottle up there, from Amazon.com. But this is not a commercial endorsement.)
The proper dosage will differ depending on how much Vitamin D your kid is getting from milk, vegetables, and going outside. Doctors recommend anywhere from 50-100 nanomoles per liter (nmol/L) be in the blood. The latest study considered 50 nmol/L a healthy dose, and found 20% of kids fall below that.
But if you really need 75 nmol/L then two-thirds of kids are at risk, including nearly all Hispanic and African-American children. Melanin-heavy skin also resists the Sun's vitamin D. This is one day it's good to be Irish. Oh, and you probably need more supplements in the winter than the summer.
We go to doctors and medicine looking for answers, but this is one of those days when the answer is terribly unclear. Supplements seem like a good idea, 2,000 IUs seem to be well-tolerated, but keep an eye out for the next study that might show a different result.