Parents might give their infants soy-based formula because of a lactose intolerance, milk allergies, or other feeding problems, but a new study shows this could be a case of trading one problem for another.
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.
The babies studied were part of the Infant Feeding and Early Development study and had been born in one of eight Philadelphia hospitals between 2010 and 2013. Half of the babies involved were girls, and 70 percent of participants were African American.
The researchers evaluated and measured the babies several times up until they reached 36 weeks of age in the girls and 28 weeks in the boys. They looked at a maturational index that is based on the epithelial cells in their urogenital tissue, ultrasound measurements taken of their testicular, ovarian, or uterine volume and breast buds, and their blood hormone concentrations.
The major differences they uncovered were mostly between the girls studied. The baby girls who were given soy formula had developmental trajectories that were consistent with estrogen exposure responses, with higher vaginal cell maturity and a slower decrease in uterine volume.
The researchers would like to see replication studies carried out by other scientists as well as follow-ups with the same children later in childhood and adolescence. The study was funded by the National Institutes of Health’s National Institute of Environmental Health Sciences.
According to the American Academy of Pediatrics, babies who have a hereditary disorder that prevents them from digesting milk properly, such as galactosemia or lactase deficiency, are sometimes advised to use soy formula; it is not recommended for pre-term infants.
Soy is a bad idea regardless of your age or gender
Research has shown that diets rich in soy products are linked to problems like allergies, reproductive disorders, thyroid problems, weight gain, premature puberty, and cancer. Experts have long warned pregnant women and children to avoid it because of its estrogen-imitating chemicals. It’s also important not to forget that most soybeans are genetically modified and loaded with pesticides and herbicides.
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