At least one out of five U.S. children are deficient in vitamin D, according to a new national study of children ages 1 to 11 years of age. And that could cause a variety of health problems, including weak bones.
It's even more serious for black and Hispanic children. Dr. Johnathan Mansbach of the Harvard Medical School says 90% of black children and 80% of Hispanic kids could be vitamin deficient.
The new analysis is published online by the journal Pediatrics.
The American Academy of Pediatrics recommends 400 daily units of vitamin D for children. They can get it by drinking four cups of fortified milk, or through supplements.
The body also makes vitamin D when sunlight hits the skin, but many children don't spend enough time outdoors.
That's one reason lower levels are found in children who live in colder climates, and those with darker skin, which absorbs less sunlight.
