DHA delivered via mothers’ breast milk may enhance development in premature infants; Boys’ failure to benefit may be due to metabolic differences
by Craig Weatherby
Australian researchers have reported the hopeful findings of a large, controlled clinical trial, which indicates that premature infant girls enjoy improved mental development when mother's breast milk delivers high doses of the omega-3 fatty acid called DHA.
No effect was seen in premature infant boys.
DHA is an essential component of cell membranes, and is proven to enhance mental development.
The body can make DHA from a plant source omega-3 called ALA, but this is a very inefficient process. The only known food sources of DHA are seafood, algae and fish oil.
But fetuses cannot perform this conversion from ALA to DHA, and must rely on their mother to provide DHA via the placenta.
Because premature infants are born before their brains have fully developed, some may lack adequate DHA while their brains are still growing.
Breast milk and infant formula contain some DHA, but the amount may be insufficient for building brain matter in preemies.
Aussie trial portends new hope for preemies
The Australian scientists hypothesized that adding DHA to the diet of a preterm infant could improve mental development in such kids.
The new findings, which flow from the largest trial ever to test omega-3s randomly in preterm babies, bolster that idea (Makrides M et al. 2009).
Study co-author Maria Makrides and her colleagues identified 657 premature infants born at 23 to 33 weeks gestation— roughly 5 1/4 to 7 1/2 months into a pregnancy—at five medical centers across Australia.
The babies were randomly assigned to get either a typical amount of DHA, as found in breast milk or formula, or a dose triple that amount (1000mg of DHA).
In bottle-fed babies, half received regular formula and half received formula fortified with added DHA.
Breast-feeding mothers took six capsules daily, with half the women getting fish oil and the others soy, which doesn’t add any DHA. The scientists tested the formula and breast milk to ascertain DHA levels.
Each mother was instructed to maintain her assigned regimen until her preterm baby reached its expected birth date.
The researchers examined each baby at 18 months from the child’s due date, using standard cognitive and behavioral tests that measure the baby’s alertness, curiosity, ability to do simple tasks for a reward and other behavior.
The researchers adjusted the data to account for differences between the groups in gestational age at delivery, gender, education level of the mother and birth order.
Girls receiving extra DHA either in formula or breast milk scored higher on the tests and were 57 percent less likely to have a mild delay in mental development and 83 percent less likely to have a severe delay, compared with girls not getting the supplement.
Boys didn’t show any cognitive benefit from the DHA supplements.
Makrides hypothesized that the male-female finding could be traced to the fact that boys have a higher metabolic rate and thus may burn more DHA as energy, needing more in their diets to keep their brains fully supplied
Infants weighing one-third the weight of a full-term baby who were fed high-DHA breast milk scored better on mental development tests, with a 40 percent reduction in the incidence of “mild mental delay”.
A new gold standard for preemies
Science Digest quoted Kanwaljeet Anand, a physician and neurobiologist at the University of Arkansas for Medical Sciences in Little Rock on the significance of the results: “This is a very well-designed and well-executed study. Differences in children’s development at age 18 months are actually quite significant” (Seppa N 2009).
According to Dr. Anand, a higher score on these cognitive tests predicts a different trajectory for the female children receiving DHA supplements. For example, he noted that children with higher scores may be more likely to go to college.
Anand serves on two advisory committees to the Food and Drug Administration, which is among several bodies that make recommendations for use of supplements such as DHA. “I think these results are quite compelling,” he says. “I will be bringing this up with the other committee members” (Seppa N 2009).
As Maria Makrides said, “We think the level of DHA used in [this] study should become the new ‘gold standard’ for preterm infants, whether it is supplied through breast milk or infant formula” (Seppa N 2009).
The Australian group plans to monitor the children for seven years.
- Makrides M, Gibson RA, McPhee AJ, Collins CT, Davis PG, Doyle LW, Simmer K, Colditz PB, Morris S, Smithers LG, Willson K, Ryan P. Neurodevelopmental outcomes of preterm infants fed high-dose docosahexaenoic acid: a randomized controlled trial. JAMA. 2009 Jan 14;301(2):175-82.
- Seppa N. Omega-3 fatty acid is early boost for female preemies. Science News, January 13th, 2009. Accessed online at http://www.sciencenews.org/view/generic/id/39849/title/Omega-3_fatty_acid_is_early_boost_for_female_preemies_