"No one is ever going to be able to put breast milk in a can," said Dr. Russell Merritt, medical director and chief scientific officer for Abbot Nutrition, one of the companies that makes soy formulas. "Soy has a long history of use and is well integrated in pediatric practice. A lot of babies have benefited from it."
Lactose intolerance — an inability to digest milk sugars — is the major medical reason to use soy formula for an infant, according to the report, because soy milk has different sugars. Even so, lactose intolerance is rare in infants. Too rare, some think, to support the amount of soy formula consumed by the infant population.
The American Academy of Pediatrics estimates as much as 25 percent of the formulas on the market today are soy protein-based. Out of the 4 million children born in the United States each year, about a quarter of them are fed soy.
"The sale of soy infant formula is out of proportion for its perceived indications," Bhatia said. "You wouldn't do that with other things to babies — why would you do that to milk?"
Formulas, whether cow milk or soy, are still not without risk.
"In general, formula use is associated with increased illnesses, both infectious and chronic, like diabetes and cancers, and yet there is no warning on the label," said Dr. Miriam Labbok, director of the Center for Infant and Young Child Feeding and Care at the University of North Carolina at Chapel Hill. "We must begin to view formula as a risky choice for infant feeding, and do more to support women to succeed in breast-feeding."
The report from the American Academy of Pediatrics also referred to theories that some of the hormones in soy protein formulas can interfere with an infant's reproductive development because of their similarity to the human sex hormone estrogen. But no studies have supported these ideas.
Choosing cow milk formula, soy formula or breast-feeding ultimately comes down to personal preference, or, in a few cases, to medical necessity. But without any demonstrated benefit to soy formula for the average healthy infant, choosy pediatricians still choose cow milk.