There’s evidence that incidences of true cow’s milk protein allergies, while rare, are more common in babies who have received formula, says Ferry. Breast milk from moms who ingest cow’s milk products contain some of these proteins, though in smaller amounts and often in a denatured way that’s less likely to lead to an inflammatory response or trigger an allergy. Formula can make baby gassy if bubbles form while you shake up the bottle. Talk to baby’s pediatrician about their symptoms for recommendations on the best formula for baby.