Breastfeeding doesn't produce the long-term benefits it's purported to, a new Ohio State University study has concluded, calling into question loads of previous research. Most older studies suffer from selection bias, lead author Cynthia Colen argues, because wealthier, better educated moms are more likely to breastfeed. Colen's research avoided that by focusing on sibling pairs in which one child was breastfed and another wasn't. The result? Breastfeeding had no effect on 10 out of 11 long-term health and well-being outcomes, and for the 11th—asthma—it actually increased risk.
"I'm not saying breast-feeding is not beneficial," Colen says. But if it doesn't improve long-term outcomes, "we really need to focus on other things" that do, like maternity leave policies and subsidized day care. Colen's study doesn't examine, or attempt to contradict, previous work showing short-term immunity boosts against chest and gut infections for infants, the New Scientist explains. One breastfeeding advocate argued that the study is flawed, complaining for instance that babies fed with a mix of breast milk and formula were counted as breastfed.