Who needs more vitamin D?

A question from Allison: “I just read that 40% of children are thought to be vitamin D deficient. How can we figure out if our child falls into that 40%? Should we give vitamin D supplements just in case? What should we do to make sure they stay vitamin D healthy?”

The honest, insider answer to these excellent questions is: we don’t know. We don’t know how much vitamin D a child ought to ingest every day, and we don’t even know what the “normal” blood levels of vitamin D should be!