Antibodies in cow's milk.

Human milk contains most of the intestinal antibodies needed by newborn infants, providing them a natural protection against many common infections. But a study at Johns Hookins Medical School in Baltimore shows that cow's milk, like human milk but unlike commercial infant formulas, contains antibodies that protect infants from a common diarrhea virus called rotavirus.

The scientists, who reported their study in the March 7 NEW ENGLAND JOURNAL OF MEDICINE, detected antibodies to rotavirus in both raw and pasteurized cow's milk. Although most infant formulas are made with cow's milk, antibodies are absent, they say, probably because of the high-temperature processing of cow's milk before it is added to formula preparations. Lower temperatures used in simple pasteurization allow many of the antibodies to be retained in pasteurize milk. If rotavirus antibodies could be preserved in infant formula, the researchers say this food also might protect infants from rotavirus-related diarrhea.

Antibodies to rotavirus in cow's milk probably appear because of naturally occurring rotavirus infection in cow herds or vaccination with rotavirus preparations, according to the researchers.