Many U.S. children are eating potentially harmful amounts of vitamins and minerals in fortified foods, according to a report by the Environmental Working Group. The EWG found that nearly half of kids 8 or younger may be getting too much vitamin A, zinc and niacin.

The report focused on 1,550 cereals and 1,000 snack bars and found that 114 had 30 percent or more of the adult daily value for some vitamins and minerals, which can cause liver damage, skeletal abnormalities, hair loss and more in kids.

They include General Mills Total Raisin Bran, General Mills Wheaties Fuel, Kellogg's Cocoa Krispies and Kellogg's Krave, among others. EWG also found that 27 common brands of snack bars, such as Balance Bars, Kind bars and Marathon bars, were fortified with 50 percent or more of the adult Daily Value of at least one of these nutrients.

"Heavily fortified foods may sound like a good thing, but it when it comes to children and pregnant women, excessive exposure to high nutrient levels could actually cause short or long-term health problems," said Renee Sharp, EWG's research director and coauthor of the report. "Manufacturers use vitamin and mineral fortification to sell their products, adding amounts in excess of what people need and more than might be prudent for young children to consume."

Read more from Environmental Working Group.