Breast milk and your baby
There are many reasons why breast milk is typically the best milk for your baby:
Nutrients – Human survival depends more on brain power than on strong muscles, rapid growth (rapid maturity) or body size, so your breast milk is rich in the nutrients that best promote brain growth and nervous system development. The sugar (carbohydrate) and protein in breast milk are also designed to be used easily and more completely by the human baby. Your milk is the perfect first food to help your baby achieve every aspect of ideal growth and development.
Anti-infection properties – Only human milk is alive with many different kinds of disease-fighting factors that help prevent mild to severe infections. Babies who are fully or almost-fully breastfed, or breast milk-fed babies, have significantly fewer gastrointestinal, respiratory, ear and urinary infections. Other anti-infective factors create an environment that is friendly to "good" bacteria – referred to as "normal flora" – and unfriendly to "bad" bacteria, viruses or parasites. Human milk also appears to have properties that help a baby's own immune system work best; if your baby does become ill when breastfeeding and receiving your milk, the infection is likely to be less severe.
Easily digested – Since nature designed human milk for human babies, your milk is the most easily digested food your baby can receive. A nutritious yet easily digested first food is important for a baby's immature digestive tract. Your baby uses less energy yet breaks your milk down more completely into its basic ingredients, so the nutrients, anti-infective factors and all the other ingredients in your milk are more available to fuel your baby's body functions and to promote your baby's growth and development.
Bio-availability – This means how well the body can use the nutrients in a food. The high bio-availability of nutrients in human milk means your baby gets more benefits from the nutrients it contains – even for nutrients that appear in lower levels in breast milk when compared to artificial formulas (because your baby's body can absorb and use them most effectively). It also means your baby saves the energy that would be needed to eliminate any nutrients she/he had difficulty digesting or using.
Suitability – Your milk is best suited to, and so it is more gentle on, your baby's body systems. The suitability of your milk plays a role in your milk's digestibility and it enables your baby's body to function most efficiently while spending a lot less energy on body functions. Suitability is also thought to be one reason that breastfed babies are less likely to develop allergic-related skin conditions and asthma.
The American Academy of Pediatrics recommends that all breastfed babies receive a supplement of 400 IU per day of vitamin D, beginning in the first few days of life. Your baby's doctor can recommend the proper type of vitamin D supplement for your baby.