For most of our human existence, mothers have fed their babies breast milk. Breastfeeding is one of the amazing abilities given to women as a natural part of the life cycle. The many benefits of breastfeeding are well known. Mothers who trust their maternal instincts and abilities over industry-driven advice, quickly experience and enjoy their unique capacity to provide superior nutrition along with the emotional attachment that comes with nursing a baby.
Each species of mammal makes milk that is uniquely suited for its young. Cow's milk is perfect for cows. Human milk is biologically specific for human babies.
Breast milk provides all of the nutrients a baby needs for at least the first six months. Beyond that, in recent years, our understanding of the benefits of breast milk has steadily risen above being mere nourishment to something akin to medicine or even a vaccine. Indeed, the U.S. Transportation Security Administration puts breast milk in the same category as "liquid medications”.
There are so many ingredients in breast milk, with so many biological properties for maintaining health and promoting proper growth and development, that it would be impossible to recreate it commercially. Even though the unique enzymes, hormones, antibodies and immunoglobulins that are contained in human milk simply can't be duplicated, formula manufacturers keep trying. They use fancy marketing and billions of dollars to create the illusion that their brand is "most like mother's milk", while agreeing that breast milk is best. It even says so right on the label.
Cow milk (the basis of most commercial infant formulas) is high in protein and minerals because baby calves are in need of rapid muscle and bone growth. If human babies were to be fed only pure cow's milk, however, they would not survive. Human milk, in contrast, is high in factors that promote brain growth; children who were breastfed tend to score higher on intelligence quotient (IQ) tests. Several studies have demonstrated that babies who are exclusively breastfed for the first three months at least, and sometimes for the first 12 months, have better cognitive abilities and general intelligence as they grow. One study showed that longer duration of breastfeeding was associated with improved infant development particularly at 18 months, where babies were more advanced in milestones such as climbing stairs, removing his/her socks, drinking from a cup, writing or drawing, using word-like sounds and putting words together, and walking unassisted.
As a practical matter, breastfeeding is easier than bottle-feeding. It is convenient and free. Breast milk is always ready, always at the perfect temperature, and doesn't need to be measured. There are no bottles to purchase, clean and transport, and no formula to buy, keep cooled and then warmed. Night feedings are easier because all you have to do is tuck the baby in bed with you. Traveling is easier with a nursing baby, as there is much less to carry.
Not breastfeeding has immunological consequences. To protect the infant against illness, breast milk contains antiviral, antibacterial, antifungal, and antiprotozoal factors as well as antibodies to many specific disease organisms.
Breast milk contains natural probiotics, substances which promote the growth of protective bacteria, especially Lactobacillus and Bifidobacteria in their gastrointestinal tracts, while in formula-fed babies, less desirable Streptococcus foecalis and E. coli are at high levels. A result of having beneficial bacteria is that breastfed babies have a lower incidence of many infectious diseases.
In evaluating the benefits of breast milk, the American Academy of Pediatrics conducted a review of the literature for evidence of disease reduction with the use of human milk. In their policy statement on breastfeeding, they found "strong evidence" that breast milk reduces the incidence and/or severity of diseases such as diarrhea, lower respiratory infections, ear infections, bacterial meningitis, and urinary tract infections.
Although the AAP as an organization is cognizant of the many benefits of human milk, many individual pediatricians do not actively encourage the official policy of "breast milk and nothing but" for the first six months.
The most common immunologic consequence of not breastfeeding is the development of allergy to whatever substance is in the artificial feeding (cow milk or soy). The absorption of these foreign (nonhuman) proteins through an immature digestive tract into the bloodstream causes early sensitization and development of atopic dermatitis (eczema) and other manifestations of allergy. Giving a breastfed baby even a single bottle of formula in the nursery can increase the risk of allergy.
Breastfeeding is an important environmental issue. Breast milk production does not pollute anything. Unlike artificial methods of feeding, breastfeeding saves world food resources, and does not use harmful chemicals in production. Breast milk is one of the few foodstuffs which is produced and delivered to the consumer without using up any fuel for transportation over long distances from factory to store to home. There is no wasteful packaging. There is no discarded glass, plastic, silicone or paper using up landfill. As well, breastfed babies are generally healthier, placing less demand on health care services.
Finally, breastfeeding is an important women's issue. Every woman who breastfeeds carries on a tradition of many generations of mothers who have done so successfully and received tremendous satisfaction by seeing their babies grow and thrive in this way.