On Food and Cooking

cow’s milk seemed a good substitute for
mother’s milk: more than half of all six-
month-olds in the United States drank it. Now
that figure is down to less than 10%.
Physicians now recommend that plain cow’s
milk not be fed to children younger than one
year. One reason is that it provides too much
protein, and not enough iron and highly
unsaturated fats, for the human infant’s needs.
(Carefully prepared formula milks are better
approximations of breast milk.) Another
disadvantage to the early use of cow’s milk is
that it can trigger an allergy. The infant’s
digestive system is not fully formed, and can
allow some food protein and protein
fragments to pass directly into the blood.
These foreign molecules then provoke a
defensive response from the immune system,
and that response is strengthened each time
the infant eats. Somewhere between 1% and
10% of American infants suffer from an
allergy to the abundant protein in cow’s milk,