ABSTRACT
Abstract .................................................................................................................. 164 Introduction ............................................................................................................ 164 Linear Growth Retardation (Stunting) ................................................................... 165
Stunting and Cognitive Development ............................................................... 165 Longitudinal Studies of Stunting and Cognitive Development .................... 165
Stunting and Social-Emotional Outcomes........................................................ 165 Impact of Supplementation on Development .................................................... 167
Supplementation Trials with Undernourished Children ............................... 167 Supplementation Trials to Prevent Undernutrition in High-Risk Populations ................................................................................................... 168
Insufficient Breastfeeding ...................................................................................... 169 Iodine ..................................................................................................................... 170
Iodine Supplementation Studies ........................................................................ 171 Peru ............................................................................................................... 171 Ecuador ......................................................................................................... 171 Zaire.............................................................................................................. 171 Papua New Guinea ....................................................................................... 171 China ............................................................................................................ 171
Iron Deficiency Anemia ......................................................................................... 172 Follow-Up Studies of IDA ................................................................................ 172 Studies of the Impact of Treatment on Development ........................................ 172 Studies of the Benefits of Preventive Supplementation .................................... 173
This chapter presents the evidence linking inadequate nutrition in children with poor developmental outcomes. Children are most likely to experience undernutrition in the early years, coinciding with the period of greatest brain development. Chronic undernutrition can result in linear growth retardation or “stunting,” which affects about one third of children under 5 years in developing countries. There are other markers of poor nutrition, including deficiencies of micronutrients and insufficient breastfeeding, that may also affect children’s development. There is very strong evidence that iodine deficiency causes cognitive deficits, leading to cretinism as well as less-devastating deficits in development. There is also strong evidence that chronic undernutrition leading to linear growth retardation and iron deficiency anemia have long-lasting effects on children’s cognitive development and behavior. There is an urgent need for strategies to reduce the numbers of children who become undernourished and the negative impact on children’s development as well as to strengthen efforts to prevent iodine deficiency in mothers and children. It also appears important that efforts are made to reduce iron deficiency anemia among women and children. Most studies suggest that breastfeeding is associated with a small benefit in IQ, but problems with the study designs and interpretation have not been fully addressed. Several other nutrients, such as zinc, vitamin A, and vitamin B12, may affect children’s development, but the evidence is inconsistent, and further research is needed.
