Causes of Stunting and Preventive Dietary Interventions in Pregnancy and Early Childhood.

Stunting of linear growth, a highly prevalent problem in children of low- and middle-income countries, is the result of the exposure of the fetus and/or young child to nutritional deficiencies and infectious diseases. Maternal undernutrition results in fetal growth restriction, and infectious diseases in pregnancy can result in preterm delivery. Both of these conditions are important contributors to stunting in early childhood, albeit their relative contribution varies by world region. After birth, growth faltering may begin at 3-5 months of life and becomes more prominent from 6 to 18 months. During this time, the young child is exposed to many infectious diseases, such as diarrhea, that have an adverse effect on growth. There is also increasing evidence that frequent ingestion of microorganisms results in damage to the small intestine. The resulting condition, referred to as environmental enteric dysfunction, even without clinical symptoms, may cause growth faltering. The complementary foods that the child receives in addition to breast milk are often inadequate in nutrients and energy, negatively affecting growth. Harmful exposure during pregnancy and the first 2 years of life, a critical period for growth and development, has led to a programmatic focus on this "1,000 days" in the life cycle. Dietary interventions, including nutrition education and for undernourished women provision of food supplements during pregnancy, result in improvements in fetal growth that position the newborn for healthier growth. Interventions in the first 2 years of life include promotion of exclusive breastfeeding for the first 6 months of life and continued breastfeeding for at least the first 2 years, nutritional counseling to assure adequate complementary feeding, and, if necessary in food insecure areas, the provision of supplemental food to be given to the child. Evidence shows that each of the interventions has a beneficial effect on the growth of the young child, yet that the effect is modest in relation to the degree of stunting observed in these underprivileged populations. Nevertheless, in recent years, reductions in the prevalence of stunting in some low-income countries show that substantial improvements are possible as a result of socioeconomic changes along with specific infection control and dietary interventions.