One in five teenager girls is iron deficient, and up to 35% of teen athletes are.
The problem can start young, affecting 7% of toddlers.
If left untreated, it can cause irregular or rapid heartbeat, and growth problems.
As a mother, one of Liz Joys' biggest concerns is her kid’s appetite.
Tyler was tired all the time and doctors found out he did not have enough iron.
"We know that if kids do not get enough iron they can have problems in school. They can have behavior problems. Their brain development just isn't maximized," says Julie Metros, R.D. of University of Utah.
Meat is loaded with iron, but vitamin "C" can also boost iron levels.
Strawberries, kiwi, or orange juice can double absorption from iron fortified foods like cereal.
Another tip is to use cast iron cookware.
Iron supplements can help, but too much iron can be toxic, so never give it to your child unless your doctor tells you to.
A blood test can reveal whether or not you child is getting enough iron.