Breastfeeding: Unraveling the Mysteries of Mother's Milk.
Most of the major progress in understanding the unique and complex features of human breast milk has emerged in just the past 2 decades. Since the late 1970s, key research has examined such aspects as the composition of breast milk, effects of maternal and environmental factors on human milk, and the effect of human milk on the infant, including the protection against disease that breast milk can confer on the newborn. The composition of human breast milk includes growth factors, hormones, enzymes, and other substances that are immune-protective and foster proper growth and nutrition in the newborn. Research suggests that lactation is robust and that a mother's breast milk is adequate in essential nutrients, even when her own nutrition is inadequate. Mature breast milk usually has constant levels of about 7g/dL carbohydrate and about 0.9g/dL proteins. But the composition of fats essential for neonatal growth, brain development, and retinal function varies according to a woman's intake, the length of gestation, and the period of lactation. Vitamins and minerals also vary according to maternal intake. But even when these nutrients are lower in breast milk than in formulas, their higher bioactivity and bioavailability more nearly meet the complete needs of neonates than do even the best infant formulas. Also, in many instances human milk components compensate for immature function, such as a neonate's inability to produce certain digestive enzymes, immunoglobulin A (IgA), taurine, nucleotides, and long-chain polyunsaturated fatty acids.
Hamosh
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Division of Developmental Biology and Nutrition, Department of Pediatrics, at Georgetown University Medical Center in Washington, D.C.