A recently published report looked at the health effects of breastfeeding on both infants and mothers in developed countries. The report was based on a massive review of scientific studies; after screening over 9,000 studies, researchers identified publications representing more than 500 individual studies for inclusion in their review. The review was conducted by the Agency for Healthcare Research and Quality (AHRQ), a branch of the federal government.
For infants, there were numerous health effects found to be associated with breastfeeding. These included a reduced risk of ear infections (otitis media), stomach viruses, and severe lower respiratory tract infections. There was also a lower risk of asthma, atopic dermatitis (eczema), obesity, type 1 and type 2 diabetes, leukemia, and sudden infant death syndrome (SIDS). These findings were consistent across numerous studies. There was no apparent relationship found between breastfeeding and cognitive performance, and the relationship between breastfeeding and cardiovascular diseases was unclear. Some of these effects were quite dramatic. Breastfeeding for more than 3 or 6 months reduced the risk of otitis media by 50 percent, atopic dermatitis by 42 percent, stomach viruses by as much as 64 percent, and lower respiratory tract diseases by 72 percent.
There were also numerous health effects found for mothers, including a reduced risk of type 2 diabetes and breast and ovarian cancers. Not breastfeeding or stopping breastfeeding early was associated with a higher risk of postpartum depression. There was no association found with osteoporosis, and the effects of breastfeeding on postpartum weight loss were unclear.
Breastmilk provides the optimal nutrition for human infants. It includes the right nutrients in the right proportions and chemical structures for optimal human nutrition, growth and development. The unique chemistry of the nutrients in breastmilk has yet to be duplicated by artificial formulas. However, not only does breastmilk contain the proper nutrients; it contains numerous other organic compounds including immunoglobulins, lactoferrin, and even undiscovered components. These not only provide some immunity and protection from infection to infants, but they also affect the developing immune system, providing long-lasting health benefits. For mothers, breastfeeding alters the hormonal balance as well as having other metabolic effects.
Most of these studies can only show that breastfeeding is associated with these health effects; they were not designed to prove a cause-and-effect mechanism. Still, the evidence is overwhelming. These effects were already well-known; it is helpful, however, to review all findings at once and see if patterns really are true. While the effects of breastfeeding in developing countries are dramatic, the effects in developed countries like the United States are equally compelling but are not as evident. Even in developed countries with good nutrition, access to infant formula, clean water, and excellent health care, breastmilk still offers tremendous health benefits for both the infant and the mother.