Couldn't resist posting this: http://www.dailycandy.com/san-francisco/article/100111/Milkmaid-Breast-Milk-Frozen-Yogurt-Parlor, but seriously, early on in my breastfeeding journey, I was astounded to learn about the suite of antibodies (aka natural antibiotics) that breastmilk contains. Surely THIS is the foundation of the claim that breast is best! But don't accept my two-second  comment about this...

Here is the bottom line on health benefits of breastmilk from the Institute of Medicine - the non-profit arm of the National Academy of Sciences, that "works outside of government to provide unbiased and authoritative advice to decision makers and the public": http://books.nap.edu/openbook.php?isbn=0309043913&page=134#pagetop

If your eyes are glazing over because you are not a biologist, the takeaway is that breastmilk contains an abundance of antibodies throughout the phases of breastfeeding...including after the first year.