According to research that was published in the Journal of Clinical Endocrinology and Metabolism, infants who consume soy-based formula undergo changes in their reproductive system tissues and cells compared their breastfed and cow’s-milk-drinking peers.
The study was carried out by the Nutrition Center at Children’s Hospital of Philadelphia (CHOP). “Soy formula contains high concentrations of plant-based estrogen-like compounds, and because this formula is the sole food source for many babies in the first six months of life, it’s important to understand the effects of exposure to such compounds during a critical period in development,” said the director of the Nutrition Center, Virginia A. Stallings.
The researchers said the differences were not dramatic, but they are very concerning because it is not yet known whether they could be linked to long-term health effects.
Soy protein has high amounts of the estrogen-like compound genistein, which is capable of changing the body’s endocrine system and interfering with typical hormonal development. In lab studies, genistein has been shown to cause abnormal reproductive function and development in rodents.
In the new study, the post-natal development of 410 babies’ estrogen-responsive tissues and their hormone levels were studied and compared across infants who were breastfed, those who drank cow’s milk formula, and those who were given soy formula. The mothers decided how they wished to feed their babies prior to the study, so it was not a randomized trial.