Zinc supplements can help children learn certain tasks, a new federal study suggests. Because nearly all the children already had diets supplying the recommended amount of the mineral, the findings suggest that “the recommended intake may need an adjustment,” says study leader James G. Penland of the Agriculture Department’s Human Nutrition Research Center in Grand Forks, N.D.
Penland recruited 209 boys and girls to drink a 4-ounce glass of juice at the start of school every day for 10 to 12 weeks. He randomly assigned the children to groups that would receive either plain juice or juice fortified with 10 milligrams or 20 mg of zinc. The lower quantity constitutes the recommended zinc intake for these children.
At the beginning and end of the trial, Penland asked the children to perform a battery of tests on a computer. Children who drank plain juice improved 6 percent on tests of their memory of abstract images. However, those getting 20 mg of zinc in their juice improved twice as much, and those getting 10 mg fell somewhere in between. Zinc fortification also raised scores on remembering lists of words and on hand-eye coordination, Penland reported at the Experimental Biology meeting in San Diego earlier this month.