Читать книгу Infants and Children in Context - Tara L. Kuther - Страница 162

Nutrition plays a role in prenatal development both before and after conception. The quality of men’s and women’s diets influences the health of the sperm and egg (Sinclair & Watkins, 2013). Most women need to consume 2,200 to 2,900 calories per day to sustain a pregnancy (Kaiser, Allen, & American Dietetic Association, 2008). Yet about 41 million people in the United States (about 12% of households) reported food insecurity in 2016 (U.S. Department of Agriculture, 2017). That is, at least sometimes they lacked access to enough food for an active healthy lifestyle for all members of the household. About 795 million people of the 7.3 billion people in the world, or one in nine, suffer from chronic undernourishment, almost all of whom live in developing countries (World Hunger Education Service, 2017). Fetal malnutrition is associated with increased susceptibility to complex diseases in postnatal life (Chmurzynska, 2010). Dietary supplements can reduce many of the problems caused by maternal malnourishment, and infants who are malnourished can overcome some of the negative effects if they are raised in enriched environments. However, most children who are malnourished before birth remain malnourished; few have the opportunity to be raised in enriched environments after birth.

Some deficits resulting from an inadequate diet cannot be remedied. For example, inadequate consumption of folic acid (a B vitamin) very early in pregnancy can result in the formation of neural tube defects stemming from the failure of the neural tube to close. Spina bifida occurs when the lower part of the neural tube fails to close and spinal nerves begin to grow outside of the vertebrae, often resulting in paralysis. Surgery must be performed before or shortly after birth, but lost capacities cannot be restored (Adzick, 2013). Spina bifida is often accompanied by malformations in brain development and impaired cognitive development (Donnan et al., 2017). Another neural tube defect, anencephaly, occurs when the top part of the neural tube fails to close and all or part of the brain fails to develop, resulting in death shortly after birth. As researchers have learned and disseminated the knowledge that folic acid helps prevent these defects, the frequency of neural tube defects has declined to about 1 in 1,000 births (Viswanathan et al., 2017; Williams et al., 2015). However, in a national study of U.S. mothers, only 24% consumed the recommended dose of folic acid during pregnancy (Tinker, Cogswell, Devine, & Berry, 2010).