A randomized trial in JAMA Pediatrics found that newborns who received cow’s milk formula (CMF) in the first three days of life had a higher risk of food allergies at age two than newborns not given CMF. Three hundred and thirty newborns in Japan whose parents or sibling had a history of allergies were randomized at birth to receive breastfeeding supplemented with either CMF or amino acid-based elemental formula for the first three days of life. At 24 months, 13.2 percent of the CMF group had food allergies, compared to 2.6 percent of the non-CMF group.
This study contradicts an earlier one in which exposure to cow’s milk protein within 14 days of birth reduced risk for allergy. In the United States, exclusive breastfeeding is recommended for all newborns whenever possible.