How quick should you be to change your baby's formula?

When parents choose to bottle feed, they often interpret "difficult" behavior as a sign that cow's milk formula doesn't suit their baby. In one study, 30 percent of babies had their feed switched because of feeding difficulties, or because their parents suspected an allergy to cow's milk.

However, a new study suggests that you might not gain much by switching. The study, published free online by Nutrition Journal, looked at 333 healthy babies. Physician-diagnosed intolerance was similar for both ordinary cow's milk formula and partially hydrolyzed whey protein formula (a type of modified formula that removes some of the proteins found in cows' milk). The study lasted 60 days, and roughly 1 in 10 babies were diagnosed as intolerant, with the figure hardly varying between the different formulas.

Parents often interpret vomiting, crying, or fussiness as signs of intolerance to formula milk, and switch to a different kind, but these behaviors are common regardless of how a baby is fed. Studies show that about half of babies vomit at least once a day, and about one third have moderate or severe episodes of crying, colic, spit-ups, or feeding difficulties. So, the types of behavior that parents interpret as a reaction to formula milk are actually quite common in healthy babies.

Although the new study is interesting, it was fairly small, and about a quarter of the babies were withdrawn by their parents before the study finished. The study was funded by Mead Johnson Nutrition, the maker of the cow's milk formula used in the study. It's probably best to check with a doctor if you suspect your child has a food allergy (where he or she gets a bad reaction to a particular food) or an intolerance (where a food is difficult to digest). However, the nutritional value of hydrolyzed infant formula is the same as other infant formulas, so if you do decide to switch, it's unlikely to do your baby any harm.

What you need to know. Breastfeeding is recommended as being the healthiest choice for both mothers and babies. However, if you choose not to, formula milk is an adequate source of nutrition. We need more research to be sure, but for healthy babies, there's probably not much difference between ordinary cow's milk formula and partially hydrolyzed kinds.

—Philip Wilson, patient editor, BMJ Group

ConsumerReportsHealth.org has partnered with The BMJ Group to monitor the latest medical research and assess the evidence to help you decide which news you should use.

Find out how to reduce your baby's exposure to BPA. And take a look at colic symptoms and treatment (subscribers only), and why you should watch what you eat if you're breastfeeding (subscribers only).