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.