New parents get a lot of mixed messages about what they should be feeding their newborns, says Kathy Parry of the Carolina Global Breastfeeding Institute.

Researchers agree that nothing beats the nutritive superpowers of breast milk or the health benefits of breastfeeding. But marketers of infant formula are really good at their jobs. Their ads can be misleading for parents, Parry found, and often undermine the advice most doctors give patients about what’s best for new babies.

As part of her work at the institute, Parry recruited dozens of women, many of whom were pregnant or already had babies, and analyzed their reactions to various packaging and advertisements for infant formulas. She wanted a better understanding of how the ads influence the choices mothers make about how and what to feed their infants.

Parenting magazines and websites are teeming with such ads, but new parents also see them in hospitals and doctors’ offices and, Parry found, frequently confuse them for medical advice.

Even more baffling for new parents, she says, are the goody bags many hospitals send home with them, each one stuffed with formula samples, pamphlets, coupons, and sweepstakes.

One study participant’s reaction: “I think it’s crazy because…the doctors encourage you to breastfeed, but then, you know, ‘Enter to win $100 free formula…’.”

Infant formula ads list the nutrients they offer, such as DHA, vitamin D, and various proprietary ingredients. (Enfamil’s newborn formula, for example, includes “Natural Defense Dual Prebiotics Blend.”) But certain ingredients sound so scientific that some women wonder whether their breast milk can compete.

“Is my breast milk doing all those things, too?” one participant asked. “I’m starting to feel a little bit of doubt when I look at this.”

In the 1970s, the World Health Organization became concerned that manufactured breast milk substitutes were becoming more popular while breastfeeding in many parts of the world was declining.

So in 1981 the International Code of Marketing of Breast-milk Substitutes came into being. The code offers legislative tactics that governments can put into place to keep marketers honest and promote adequate nutrition for their nations’ babies. These include requirements for accurate product labeling and for health care workers to educate parents and encourage breastfeeding.

Unfortunately, Parry says, the United States has never adopted the code. (A list of countries that have and have not adopted the code (PDF).)

Little research has been done on the effects of TV and magazine marketing on breastfeeding, Parry says. But her study illustrates that many women are misled by the statements marketers make in infant formula ads.