Zinc supplementation may be particularly beneficial for children in their early development because zinc is an important trace element for several organic processes. Specifically, zinc plays a critical role in cell division and maturation and in the growth and function of many organ systems, including the neurological system. Furthermore, children who are small for their gestational age have a higher risk of developmental complications, such as a zinc deficiency.
Zinc supplementation trials have shown beneficial effects on mortality, growth, and overall health. For example, zinc supplementation helps treat conditions like diarrhea and pneumonia. In addition, zinc supplementation has been proven to improve infant behavior. Nutritional deficiency may render babies less active and thus less likely to seek stimulation from their environment.
Nutritionally deficient babies may also develop difficult temperaments that hinder interaction. Consequently, mothers may not respond as much to their children, limiting opportunities for enrichment. However, investigations on the impact of zinc supplementation on the development and behavior of babies have yielded inconsistent results.
In one study, a group of American researchers designed an investigation in order to find out if zinc deficiency is a factor in the association between birth weight and early cognitive and motor development. The researchers also examined whether the caregiver’s response capacity varied according to the mother’s perceptions of the child’s temperament. They believed that mothers would be more receptive to babies perceived as easy than babies who were perceived as irritable.
More About the Study
For this study, entitled “Cognitive and Motor Development among Small-for Gestational-Age Infants: Impact of Zinc Supplementation, Birth Weight, and Caregiving Practices,” researchers recruited infants who were small for their gestational age from a low-income community in India where rates of fetal malnutrition are high and most community members are vegetarian or consume few sources of bioavailable zinc.
This community had no paved streets, no electricity, no running water or sewage systems, and very few health services. Historically, infant mortality was 83 per 1000. About 14 percent of births were premature, and 42 percent of birth weights were less than 2500 grams. More than two-thirds of the women were illiterate. Most babies were born at home (72 percent) and were exclusively breastfed during the first months of life.
Pregnant women were identified as part of a household survey. After delivery, a team consisting of a doctor, a nutritionist, and a field assistant visited the home and recorded the weight, length, and circumference of the baby’s head and performed an examination to determine gestational age.
The eligible newborns were permanent residents of the community. They were randomly allocated to one out of four supplement groups: 1) a micronutrient mixture including riboflavin, calcium, phosphorus, folate, and iron with 5 mg of zinc sulfate; 2) the same micronutrient mix without zinc; 3) riboflavin; and 4) riboflavin with 5 mg of zinc sulfate.
Babies’ growth was measured at six and nine months of age when the administration of supplements was finished. Infants were weighed and measured using systematic procedures and examined by a pediatrician. A development clinic was established in the community, guided by child development specialists. At six and ten months, mental, motor, and behavioral development was assessed using special scales.
A four-item questionnaire used a four-point scale to ask caregivers how much their baby cried and how easy or difficult it was to calm them down, put them to sleep, and give them daily attention. This scale was administered to the caregivers in the development clinic and in the home.
What Did They Find?
Zinc supplementation did not affect childhood development or behavior at six or ten months. These findings are generally consistent with previous studies that reported that zinc supplementation had no effect on cognitive or motor function among infants and young children with zinc deficiency.
Although zinc supplementation has been shown to improve growth, no such effects were evident in this sample. It has also been shown that zinc improves cooperation and activity in babies, but in this sample, zinc had no effect on infant behavior during the test. Why? Perhaps these babies were not zinc-deficient or the dose administered was insufficient. A third possibility is that the scales used were not able to capture the specific processing abilities influenced by zinc.
Do the results of this study mean that babies do not need zinc? No. Zinc is still essential for children. A pediatrician can explain the benefits of zinc supplementation and make dietary recommendations to obtain an adequate supply of zinc.
References
Black, Maureen M., Sunil Sazawal, Robert E. Black, Sonu Khosla, Jitendra Kumar, and Venugopal Menon. “Cognitive and Motor Development among Small-for-Gestational-Age Infants.” Pediatrics 113, no. 5 (2004): 1297–1305. Retrieved from https://jhu.pure.elsevier.com
