Aaron E. Carroll
Almost no one will dispute that when a baby is born, breast milk is the best nutrition a mother can provide. All mammals nurse their young, and breast milk benefits a newborn infant in ways above and beyond nutrition. In fact, until 1 to 2 years of age, the American Academy of Pediatrics, the World Health Organization, the Institute of Medicine and more promote breast-feeding as optimal.
Unfortunately, breast-feeding until that age is often difficult, if not impossible, because mothers have to return to work, and children go off to preschool or day care. So we often replace human milk with the milk of cows or other animals. But at a certain point, we have to acknowledge that we are the only mammals on the planet that continue to consume milk after childhood, often in great amounts.
More and more evidence is surfacing, however, that milk consumption may not only be unhelpful, it might also be detrimental. This is in spite of the fact that the United States Department of Agriculture and other organizations advocate that even adults should drink at least three cups a day.
More than 10,000 years ago, when human beings began to domesticate animals, no adults or older children consumed milk. Many people don’t drink it today because they are lactose intolerant. They do just fine.