The study, appearing in the journal Child Development, indicates that infants receiving formula supplemented with DHA performed better on a cognitive test than infants who were given formula without it. DHA occurs naturally in breast milk.
But while doctors say the evidence may support formula containing a DHA supplement over formula without one, they are concerned that the study may be the first test toward marketing a replacement for breast milk. The formula used in the study was provided to the researchers by a manufacturing company for free.
One pediatrician notes that in her own practice, some mothers are convinced that formula with DHA can be superior to breast milk.
"The marketing has actually dissuaded mothers from choosing exclusive breast-feeding, which is preferred from all the outcomes that we understand," said Dr. Lori Feldman-Winter, a pediatrician with Cooper University Hospital in Camden, N.J.
She noted that simply adding DHA -- while it may top other infant formula -- would not make it superior to breast milk.
"There are many other factors in human milk that also support neurocognitive development and visual acuity," said Feldman-Winter.
And she was not alone in her skepticism for the apparent reasons behind the study.
"It is clear that the food industry fascination with nutraceuticals (strategically fortified food products) is now spreading into infant formula," said Barbara Moore, president and CEO of Shape Up America!, in an e-mail to ABCNews.com. "This is a disturbing new development. We have parents thinking that sticking their tiny infants in front of a Baby Einstein video will improve their child's mental development when the data suggest that parent-child interactions (and plenty of them) are the most critical factor for such development. Moore said in the e-mail. "Now parents will be encouraged to forego breast-feeding -- which is optimal for both mothers and babies -- in favor of a hyped up infant formula."
Breast milk has other benefits not related to mental development, Moore said. "Breast-feeding confers protection against infection, including viral infections, and the CDC promotes breast-feeding to confer maximal protection against swine flu and other infections."
James Drover, the study's lead author, did not respond to a request from ABC News for comment.
In a press release, he noted that "Our results clearly suggest that feeding infants formula supplemented with high concentrations of DHA provides beneficial effects on cognitive development.
Furthermore, because infants who display superior performance on the means-end problem solving task tend to have superior IQ and vocabulary later in childhood, it's possible that the beneficial effects of DHA extend well beyond infancy.
In the contentious field of breast-feeding, sharp replies to anything suggesting a replacement for breast milk are almost inevitable. Journalist Hanna Rosin waded into that this past spring, when she wrote "The Case Against Breast-Feeding" for The Atlantic magazine.
In that article, Rosin said that after having her third child, she looked at evidence for breast-feeding and did not find it to be as strong as she would have believed. Despite the fact that she herself continues to breast-feed her third child -- "I actually don't hate it," she told ABCNews.com, countering assumptions many reading her article had made -- she has received a backlash of comments criticizing her, including some from the American Academy of Pediatrics.
Action Over Substance
Rosin said the mistake breast-feeding proponents made was focusing on the substance, rather than the act.
"The formula companies tend to advertise their formulas by saying as close to breast milk as possible," she said. "Everyone accepts that breast milk is the standard."
Adding DHA would just be the latest attempt to supplement formula by adding a substance from breast milk.
"By turning breast milk into a magic vaccine, the breast milk people made themselves vulnerable to that," said Rosin.
Instead, Rosin said advocates would need to emphasize other parts of breast-feeding, such as spending time and cuddling with the infant, if they want to discourage choosing formula over breast milk.
"The formula companies can never say it's just like breast-feeding," she said.
Formulaic Infant Food
Dr. Miriam Labbok, a professor of public health at the University of North Carolina Chapel Hill, expressed some skepticism with the findings.
"It might be reasonable from these industry-funded studies to consider that this would be a good additive to formula if you are forced to stop breast-feeding," she said in an e-mail. "However, 1) none of these studies compare to continued breast-feeding, 2) you could also get these [nutrients] from other sources if you stop breast-feeding, and 3) there are hundreds, if not thousands, of other components in human milk that cannot be replaced."
Dr. Ruth Lawrence, a neonatologist at the University of Rochester Medical Center and the American Academy of Pediatrics pokeswoman on breast-feeding, said that DHA may contribute to better formula, but that won't replace breast milk.
"The important point is not let mothers think it's as good as their milk," she said.