Growing numbers still incorrectly believe that infant formula is as good as breast milk, while more are becoming increasingly uncomfortable with mothers breast-feeding their infants in public, the CDC said.

"The findings underscore the need to educate the general public that breast-feeding is the best method of feeding and nurturing infants," Dr. Rowe Li and colleagues from the Centers for Disease Control and Prevention in Atlanta write in the January issue of the Journal of the American Dietetic Association.

Li and her team note that while health experts recommend infants be breast fed for at least a year, and receive breast milk alone until they reach six months of age, the percentage of US infants exclusively breast fed at six months is 14 percent, while just 18 percent continue to receive breast milk at 12 months of age. The same survey, conducted in 2004, found 71 percent of children had ever been breast fed.

To investigate public attitudes toward breast-feeding, which play a key role in whether a woman decides to initiate and persist with breast-feeding, Li and her team compared results from two nationwide surveys conducted in 1999 and 2003 by the public relations firm Porter Novelli.

In 1999, 14.3 percent of those surveyed agreed that "infant formula is as good as breast milk," compared to 25.7 percent in 2003, the researchers found.

And there was a small increase in the percentage of people who agreed with the statement that "mothers who breast-feed should do so in private places only," from 34.8 percent to 37 percent. The percentage who said they were comfortable being near a mother breast-feeding her infant in public fell from 49.9 percent to 48.1 percent.

While rates of breast-feeding among US mothers have been on the rise since 1990, Li and her team note, the percentage of women who started breast-feeding fell for the first time between 2002 and 2003, from about 70 percent to 66 percent.

"The findings imply that despite widespread information on the benefits of breast-feeding, the trend in national opinion might be that infant formula is as good as breast milk," Li and her colleagues state.

This may at least in part be due to the introduction of formulas that contain long-chain polyunsaturated fatty acids in 2002, the researchers note, which have been advertised as "mimicking the positive influence of breast milk" on brain and vision development. Also, the researchers note, spending on advertising for infant formula rose from $29 million in 1999 to $46 million in 2004.

SOURCE: Journal of the American Dietetic Association, January 2007.