For almost as long as soy infant formula has been available, there have been warnings issued about the dangers of feeding a child formula that is soybean based. While most pediatricians consider soy formula safe for infants, there are a number of health risks that have been highlighted by various organizations. To make a decision about the use of soy formula, parents should understand these concerns and make an informed choice after discussing the issues with their child's pediatrician.
Soy infant formula is used to replace milk-based formulas for those children who are lactose intolerant. Vegetarian and vegan parents often choose soy formula as an alternative to regular formulas for ethical reasons if they find they cannot breastfeed.
Most of the danger of soy formula is linked to studies using lab rats. In some studies, rats fed a soy formula fell behind on expected growth, developed sexual organ deformities and showed levels of decreased fertility. These problems are believed to be linked to the phytoestrogen, or genisteins, found in soybeans, which in turn affects natural estrogen production.
The most purchased brand of soy infant formula is Isomil, followed by Prosobee, Nursoy and Alsoy. Each brand comes in both powder and ready-to-drink forms. All brands list soy as the main ingredient on the label.
Other health problems claimed to be linked to soy infant formula include emotional behavior problems such as ADHD, thyroid disorders, asthma, irritable bowel and immune system deficiencies. These claims are based on anecdotal evidence and have not been confirmed by scientific study.
Based on the many concerns raised by anti-soy activists, many consumer groups in the United States and other countries are requesting that soy-based infant formula be banned. In the United States, the FDA has determined that soy formula is safe although it is considering lowering the limit of manganese since the levels found in soy formula are many times higher than that found in breast milk. Other countries, such as Israel, require doctor's prescription in order to purchase a soy formula.
Some theorists believe that the availability of soy formula in the United States WIC program may be the reason that many young girls from low-income families reach puberty earlier than other children. Others believe that the aggression problems in young men can be traced to being fed soy formulas as babies.