Children taking zinc supplements five days a week displayed better mental performance after three months than did their classmates, said researchers in a presentation at last month's Experimental Biology meeting in San Diego. Those who took an extra 20 mg of zinc responded more quickly and accurately when performing memory tasks, and had more sustained attention.
These beneficial effects were seen regardless of the children's zinc status prior to supplementation, said Dr. James Penland, who led a team of researchers from the U.S. Agricultural Research Service's Grand Forks Human Nutrition Research Center in North Dakota.
In the study, 111 girls and 98 boys, age 11, consumed 4 oz. of fruit juice containing either 0, 10, or 20 mg of zinc gluconate each school day for up to 12 weeks. Neither the students nor their parents and teachers knew who was receiving supplemental zinc; all took a battery of tests designed to measure mental and motor skills at the beginning and end of the study.
Compared to those who received no supplemental zinc, students who consumed an additional 20 mg daily decreased reaction time on a visual memory task by 12 percent vs. 6 percent; increased correct answers on a word recognition task by 9 percent vs. 3 percent; and increased scores on a task requiring sustained attention and vigilance by 6 percent vs. 1 percent. Those who received only the U.S. Recommended Dietary Allowances for this age group --10 mg -- did not show significantly improved performance.
Source: Vitamin Retailer Magazine, May 2005