As mentioned, clinical or severe zinc deficiency is rare in the U.S., but may be prevalent in developing countries. The problem was first noted more than three decades ago in poor people of the Middle East. "Zinc deficiency is similar to iron deficiency, in that, when the first clinical (serious) symptoms.. appear, the depletion has already had a significant effect."

"Unlike iron deficiency, however, there are no relatively simple, objective tests to determine the degree of zinc deficiency. The condition can only be confirmed by the reversal of symptoms when adequate zinc is added to the diet. Due to the normally low body stores of (zinc), response to zinc repletion is usually very rapid."

This article said pediatricians should stress the importance of providing a variety of zinc-containing foods in infants' and toddlers' diets. Foods considered a naturally good source of zinc include: Meats, liver, eggs, seafood, and some whole-grain cereals.

The article states that "zinc deficiency is rare in individuals whose diets are low in phytate, but common in those whose diets are high in phytate." Foods high in phytate include things like starch-based foods, cereals, grains and legume-based foods. The authors think it is important to balance these foods with those providing a good source of zinc.