Formula Additives May Improve Development in Preemies
Similar Benefit of Supplemental Fatty Acids Not Seen in Term Infants
By Steve Mitchell, MS
WebMD Washington Correspondent
Reviewed by Tonja Wynn Hampton, MD
Aug. 10, 2001 -- The FDA recently decided that the long-chain polyunsaturated fatty acids docosahexaenoic acid, or DHA, and arachidonic acid, or AA, are safe ingredients and may be added to baby formulas in the U.S. But any potential benefit may be limited to premature infants, according to two new studies in the August issue of Pediatrics.
Several studies have suggested that children who were breastfed have improved intellectual development compared to children who were formula fed. Research has also shown that DHA and AA, found naturally in breast milk, are important for neurodevelopment. This has led pediatricians to debate whether formulas need to be supplemented with DHA and AA to ensure normal development for formula-fed infants.
In the largest prospective, randomized, controlled study of its kind, 470 premature infants (birthweights 750-1,800 g) were fed preemie formulas fortified with or without AA+DHA for the first 12 months of life. Various instruments were used to assess visual acuity and development at different intervals during the study period.
Overall, there was no difference on the Bayley Mental Development Index between the two groups of infants, but motor development was higher for infants who received the fortified formula than controls for infants <1,250 g. All infants who received the formula with AA+DHA had improved visual acuity from 4 to 6 months.
No adverse effects from AA+DHA were detected in the infants, according to lead author Deborah O'Connor, PhD, of the Hospital for Sick Children in Canada, and colleagues.
But fatty acid fortified formula may not carry the same benefits for term infants. In a similarly designed study, the largest study to look at AA+DHA-fortified formula in term infants, 239 infants received formula either with or without the fatty acids. Infant development was assessed at multiple intervals from birth to 14 months.
These researchers found no difference in developmental tests between the two groups of infants. In their conclusion, Marc Bornstein, PhD, of the National Institute of Child Health and Human Development, and colleagues write, "There would be no demonstrable advantage to infant development from the widespread addition of AA+DHA to infant formula."
But whether the fatty acids improve long-term cognitive function of premature or term infants remains unknown, says William C. Heird, MD, a professor of pediatrics and a researcher at USDA/ARS Nutrition Research Center at Baylor College of Medicine, in Houston.
The developmental tests used in the studies were not designed to pick up subtle differences in IQ and do not predict how a child may be functioning at 6 or 7 years of age, Heird tells WebMD.
Only a long-term study that follows these children until they are 6 or 7 will answer the question of whether the addition of AA+DHA to formulas is beneficial, says Heird.
Ross Products, the baby formula manufacturer that funded both studies, has followed infants as long as 3 years and has not detected any IQ differences between those who received AA+DHA and those who did not, says Russell Merritt, MD, PhD, the company's medical director in pediatric nutrition. The company may continue to follow them longer if enough children stay enrolled in the study, he tells WebMD.
Martek Biosciences, which manufactures DHA and AA and currently sells them to the majority of baby formula manufacturers in the U.S., recently received approval from the FDA that the fatty acids could safely be added to infant formulas.
The fatty acids are already available in baby formulas in virtually every other country except for the U.S. and Canada. But it could be a while before formulas containing the fatty acids are available here.
An FDA source who requested anonymity tells WebMD that the approval is only for Martek and only for term infants, which seem to be the least likely to benefit from AA+DHA.
Companies wishing to incorporate the ingredients into their infant formulas would have to seek FDA approval and then monitor the infants to make sure they are developing in a normal manner, the source says.
Ross is considering adding the ingredients to its formulas, Merritt tells WebMD. Two other top formula manufacturers, Mead Johnson and Carnation, tell WebMD that they have not yet made a decision in that regard.