Here's the evidence why breast is best

It’s a mantra repeated by health providers Australia-wide: breast is best. And while we’ve always known that there is something about mother’s breast milk that causes a baby to thrive, it has taken until 2015 to discover why that is.
Dangerous bacteria in babies can be held at bay by a unique chemical reaction that occurs between breast milk and baby saliva, a University of Queensland breakthrough study has shown. The reaction allows good bacteria through, and prevents dangerous bacteria from being passed onto the infant.
UQ researchers, including neonatal care specialist Associate Professor Helen Liley, found that bacteria established in the mouth and intestines of babies have lifelong effects on health and development.
“This research discovered a previously unknown interaction – between milk and saliva, that  appears to provide a unique mechanism in mammals that boosts early immunity.” Dr Liley said.
In another positive for breastfeeding, the team led by Professor Nick Shaw from the School of Pharmacy also found it simultaneously stimulates the development of a baby’s digestive system.
“This has critical implications for preterm, small and sick newborns,” Professor Shaw said.
“Babies who are fed by intubation (gastric tube to the stomach) bypass the milk-saliva interaction, so there should be consideration of this factor."
“There’s an also an important aspect for breast milk banking."
“Increasingly in hospitals, donated breast milk is given to preterm babies rather than using formula milk, but pasteurising the breast milk removes the beneficial mechanism.”
The demonstrated milk-saliva mixing is short-lived, for about six weeks after birth, with an apparent function of encouraging healthy bacteria. For babies on a mixed feeding schedule of breast milk and formula, this indicates good news as the benefits are still carried through via the combination of mother’s breast milk and baby’s saliva. However the authors were quick to note that the study was only carried out on babies who were fully breastfed or fully formula fed.
The interaction of the two substances with enzymes in breast milk (xanthine and hypoxanthine) inhibited the growth of harmful bacteria Staphylococcus and Salmonella, while baby saliva promoted non-harmful Lactobacillus.
The research, published in PLOS ONE, was a collaboration with the Mater Mothers’ Hospital Neonatology Unit and the Queensland University of Technology Department of Microbiology.
It also involved research from UQ’s School of Veterinary Science, showing that saliva from cows, sheep, goats, horses, dogs, cats and even a camel shared the anti-bacterial function.
UQ  researchers included Dr Saad Al-Shehri, Dr Amith Hewavitharana, Associate Professor Bruce Charles, Dr John Duley and veterinarian Dr John Wright.