Nearly 40 percent of all children in developing countries have stunted growth due to poor nutrition, researchers said Friday.

In some areas, such as Southeast Asia, more than half the children are much shorter than they should be, nutritionist Edward Frongillo and colleagues at Cornell University said."These figures are just the tip of the iceberg," Frongillo said in a statement. "They indicate that the whole population in certain regions is not growing as well as it should be."