Research appearing in the International Journal of Preventative Medicine (2014 Mar; 5(3):280-6) looked at children in two areas of Iran where moderate levels of malnutrition exist to find if zinc supplementation contributed to growth. The subjects of the study were 838 children under the age of two. They were randomly selected to receive either a placebo or five milligrams of elemental zinc each day for three months. All of the subjects (393 in the zinc group and 445 in the control group) also were given iron and a multiple vitamin or a supplement containing vitamins A and D.

Measurements were performed at the start of the study and each month during the study. Overall, the children who were given the zinc supplement grew a half centimeter longer, on average, when compared to the control group. The supplementation did not affect weight. The authors concluded, “Oral zinc supplementation was found to be both practical and effective in increasing linear growth rate of children less than 2 years of age through primary health care.”