Zinc Helps Children Think

Peanuts, popcorn, whole-wheat crackers and other foods high in zinc could help some children learn and reason better. In a study led by scientists with USDA’s Agricultural Research Service, daily zinc supplements helped Chinese schoolchildren with very low body zinc levels to score better in perception, memory, reasoning and psychomotor skills such as eye-hand coordination.

An ARS psychologist spearheaded the study with Chinese scientists because of earlier conflicting reports. Changes in zinc intake had affected measures of cognition in three studies of adults, but failed to do so in two studies of adolescent boys and girls.

Findings of the new study with 372 Chinese schoolchildren--conducted in three poor, urban areas of China--support the adult studies and have important implications for countries where low zinc intakes are common. They could also apply to the 10 percent of U.S. grade-school-age girls and 6 percent of boys who get less than half the Recommended Dietary Allowance of zinc through their diets. The RDA for this age group is 10 milligrams daily.

The Chinese children, age 6 to 9 years, were divided into three groups. One group took a 20-milligram zinc supplement daily for 10 weeks. A second group took the zinc supplement plus a micronutrient supplement containing all essential vitamins and minerals, except for zinc and four other minerals known to interfere with its absorption. A control group got only the micronutrients to alleviate any other deficiency that could affect performance on the psychological tests.

Before and after the supplement period, each child took a series of computer-administered tasks developed by the ARS psychologist. The tasks measured attention, perception, memory, reasoning and motor and spatial skills necessary for successful school performance.

The children who got the zinc supplement or zinc plus the micronutrients had the most improved performance, especially in perception, memory and reasoning skills.

In addition to peanuts, popcorn and whole wheat products, the most common source of zinc is red meat. Oysters are the richest source.

Scientific contact: James A. Penland, ARS, Grand Forks Human Nutrition Research Center, Grand Forks, N.D., phone (701) 795-8471, fax (701) 795-8395, jpenland@gfhnrc.ars.usda.gov.