All major national and international organizations focused on nutrition and infant and child health support breastfeeding to provide optimal nutrition for healthy full-term infants. The recommended period of exclusive breastfeeding during which the infant receives “no other food or drink, not even water, except breast milk (including milk expressed or from a wet nurse)”—although the infant can receive oral rehydration solution, drops, and syrups (vitamins, minerals, and medicines)—has been the subject of much discussion and varies from 3 to 4 months to 6 months. The American Academy of Pediatrics (AAP) recommends that children be exclusively breastfed for approximately the first 6 months of life, followed by continued breastfeeding as complementary foods are introduced for 1 year or longer as mutually desired by the mother and infant. The World Health Organization’s (WHO) growth standards reflect the growth of breastfed infants and are now commonly used to plot the growth of infants and young children.
Benefits of breastfeeding are numerous. In addition to providing nutrition to the infant and supporting early development, breastfeeding may impart additional health benefits to both child and mother. Cost analyses suggest significant economic benefits of breastfeeding.
Breast milk is a complex biologic fluid with nutrients that support the growth and development of infants as well as the health of the mother. It contains all the nutrients necessary for infant survival during the first 4 to 6 months of life, including fat, protein, carbohydrates, vitamins (with the exception of vitamin K in the postpartum period and then vitamin D), minerals, and water. The level of nutrients in human milk varies within a single lactation, during the period of lactation and also between mothers, with maternal diet playing a role in the levels of selected nutrients. Generally, about one half of the energy content of breast milk comes from fats, including long-chain polyunsaturated fatty acids (LCPUFA) that are not found in other milks/infant formulas, although the formulas are now routinely fortified with selected LCPUFA. The protein in breast milk is well suited to infant development in both quantity and quality, relative to other animal milks. With the exception of vitamin D, breast milk of a healthy mother contains all the vitamins and minerals that an infant needs in sufficient quantities, although the concentrations of zinc and iron decline substantially beginning at 4 months of age. Breast milk also contains a number of non-nutrient, biologically active substances, including hormones, immunoglobulins, growth factors (both human and microbial), digestive enzymes, cytokines, pheromones, and its own microbiota (Table 16-1 and Table 16-2).
TABLE 16-1NUTRIENT COMPOSITION OF BREAST MILK ||Download (.pdf) TABLE 16-1NUTRIENT COMPOSITION OF BREAST MILK
| ||Preterm ||Postpartum |
| ||Early ||Late ||Colostrum ||Transitional ||Mature |
|Fat (%) ||— ||2 ||2 ||2.9 ||3.6 |
|Fat (g) ||— ||— ||2.9 ||3.6 ||3.8 |
|Lipid (g/dL) ||1.15 ||1.28 ||3.16 ||3.49 ||4.14 |
|Phospholipid (mg/dL) ||37 ||40...|