AbstractIt is the position of the American Dietetic Association (ADA) that broad-based efforts are needed to break the barriers to breastfeeding initiation and duration. Exclusive breastfeeding for 6 months and breastfeeding with complementary foods for at least 12 months is the ideal feeding pattern for infants. Increases in initiation and duration are needed to realize the health, nutritional, immunological, psychological, economical, and environmental benefits of breastfeeding. Breastfeeding initiation rates have increased, but cultural barriers to breastfeeding, especially against breastfeeding for 6 months and longer, still exist. Gaps in rates of breastfeeding based on age, race, and socioeconomic status remain. Children benefit from the biologically unique properties of human milk including protection from illness with resulting economic benefits. Mother's benefits include reduced rates of premenopausal breast and ovarian cancers. Appropriate lactation management is a critical component of successful breastfeeding for healthy women. Lactation support and management is even more important in women and children with special needs caused by physical or developmental disability, disease, or limited resources. Dietetics professionals have a responsibility to support breastfeeding through appropriate education and training, advocacy, and legislative action; through collaboration with other professional groups; and through research to eliminate the barriers to breastfeeding. |
The advantages of extended breastfeeding include nutritional, immunological and psychological benefits to both infant and mother, as well as economic and environmental benefits. Breastfeeding education efforts and clinical management must highlight the importance of breastfeeding for a longer duration to receive the full range of benefits for both mother and infant.
Psychological Benefits
That there are psychological benefits of breastfeeding for both the mother and the infant is generally assumed but has been particularly difficult to characterize and quantify. Studies relating to psychological benefits of breastfeeding have been criticized for methodological flaws such as evaluation tool limitations and a narrow focus on developmental outcomes that exclude the process underlying development (46). Acknowledging the challenges of such investigations, several reports have linked breastfeeding, and especially duration of breastfeeding, with cognitive and emotional psychological benefits. Mothers with early infant contact breastfed (47-48) and showed more attachment behavior than women without early contact (49) and infants who were not breastfed.
The unique composition of human milk, such as the fatty acid composition discussed later, plays an important role in neuropsychological development (50). Premature infants fed breast milk have faster brainstem maturation compared with infants fed human milk substitute (51). Low-Birth-weight infants fed mother's milk scored better on developmental tests at 18 months and intelligence tests at age 7 or 8 years than infants who received human milk substitutes (52). Similarly, significant increases in cognitive development test scores were identified in school-aged children (23,53-54). A meta-analysis of 20 studies about breastfeeding and cognitive development reported that breastfeeding was associated with significantly higher scores for cognitive development than was human milk substitute feeding, and low-Birth-weight infants showed larger differences than did normal-Birth-weight infants (24). More importantly, these cognitive developmental benefits increased with the duration of breastfeeding (23-24).
Nutritional Benefits
Human milk provides optimal nutrition to the infant, with its dynamic composition and the appropriate balance of nutrients provided in easily digestible and bioavailable forms (8,55). The relatively low protein content of breast milk is adequate, but not excessive, so that it presents a relatively modest nitrogen load to the immature kidney. The form of protein in human milk, mainly whey, forms a soft, easily digestible curd. Human milk provides generous amounts of essential fatty acids, saturated fatty acids, medium-chain triglycerides, and cholesterol. Long-chain polyunsaturated fatty acids, especially docosahexaenoic acid, promote optimal development of the central nervous system. Human milk has a relatively low sodium content, allowing the fluid requirements of the exclusively breastfed infant to be met while keeping the renal solute load low. Minerals in breast milk are largely protein bound and balanced to enhance bioavailability. The provision of zinc, iron and calcium in such available forms allows for adequate amounts to be provided to the infant with little waste and reduces the demand for these nutrients from the mother.
Immunological Benefits
Human milk contains many components that contribute to its protective properties (8,55). Cellular components, including specific T- and B-lymphocytes, and nonspecific macrophages and neutrophils, are especially high in colostrum but persist in milk in lower concentrations in activated forms for months. Humoral factors include immunoglobulins, with secretory immunoglobulin A being predominant in minimizing both the exposure to and entry through the gastrointestinal tract of foreign proteins. Infants with a strong family history of allergic disease benefit from this protection, particularly through extended breastfeeding. Other soluble factors include lactoferrin and vitamin B12-binding proteins that bind iron and vitamin B12, respectively, making them unavailable to pathogens that require these nutrients to prosper in the infant's gastrointestinal tract. Such factors are critical to maintaining a striking difference in the intestinal flora of breastfed vs human milk substitute-fed infants. Hormones and hormonelike substances, including insulin and epidermal growth factor, enhance maturation of the infant gastrointestinal tract. These and numerous other factors in human milk directly and indirectly provide critical active and passive protection to the infant, especially neonates, against viral and bacterial pathogens. Because of the delicate balance between nutritional and immunologic factors, maximal protection is offered by exclusive rather than partial breastfeeding.
Infant and Child Morbidity
In studies performed in both developing and industrial countries, infants fed human milk substitutes have fivefold more gastrointestinal illnesses, threefold more respiratory illnesses, and double the episodes of otitis media (6,56-58). Given the challenges of studying effects of feeding method in countries with relatively low morbidity and mixed feeding patterns, it is remarkable that carefully designed and controlled studies have established increased morbidity among infants fed human milk substitutes even in industrial countries (19,56-60).
A dose-response relationship exists where the more breast milk an infant receives in the first six months of life, the less likely the infant is to develop health problems (19-22). Exclusive and sustained breastfeeding realizes the greatest improvements in infant health and extends for periods beyond weaning. For instance, the risk of otitis media is reduced for the duration of breastfeeding and for months after weaning (57) and the protection against atopic disease may extend for years (58,61).
Evidence continues to accumulate confirming the relationship between breastfeeding and other morbidities including reduced risk for childhood asthma (61,62), childhood leukemia (63), childhood obesity (64,65), and malocclusions or malalignment of teeth (66). An association also appears to exist between breastfeeding and Sudden Infant Death Syndrome (SIDS) with the research community currently debating whether breastfeeding has a primary effect in reducing risk or if it is a surrogate for one or more other important variables (67). These studies underscore the impact of early feeding on long-term health.
There is a reemergence of rickets among breastfed infants in the United States (68,69). Risk factors for nutritional rickets include exclusively breastfed infants, especially infants with highly pigmented skin where the melanin (or skin pigmentation) acts as a natural sunscreen and reduces the amount of vitamin D produced when exposed to sunlight. These reports of rickets have generated discussion and debate about universal vitamin D supplementation for breastfed infants. Such a recommendation should address concerns about the potential health risks associated with excessive sun exposure and the uncertain impact of high potency sunscreens on vitamin D conversion. Universal supplementation contrasts with the current recommendation for maternal or infant vitamin D supplementation or adequate infant exposure to sunlight. For white infants, adequate exposure equals 30 minutes per week in only diapers or 2 hours per week clothed (70).
Maternal Health Benefits
Health gains for breastfeeding women include lactation amenorrhea (71), maternal weight or fat loss, protection against premenopausal breast cancer (72) and ovarian cancer (73), bone remineralization to levels exceeding those present before lactation (74), and more optimal blood glucose profiles in women with gestational diabetes (7,75). Although the hormonal milieu of lactation favors fat mobilization from the lower body, the interrelationships of pre-pregnancy nutritional status, maternal dietary intake, physical activity, and duration and exclusivity of breastfeeding can mask the net effect of lactation (76-78).
Extending the duration of breastfeeding also increases maternal benefits of breastfeeding. For example, amenorrhea is increased by exclusive and more frequent nursing (especially at night) (71,76). Duration of breastfeeding is also related to a reduced risk of premenopausal breast cancer (72).