Babies fed formula experimentally supplemented with the essential fatty acid DHA appear to have higher cognitive skills than infants given standard formula, a study has found.

Previous research has shown breastfed babies have more advanced cognitive skills than formula-fed babies, and those capabilities appear to persist into later childhood. Scientists have suggested the difference could be due to high levels of DHA found naturally in breast milk.

'What we found was the children that were fed the DHA-supplemented formula were more likely to show these goal-directed behaviours. They had higher intentions scores. Not only that, but they were more likely to be successful on each trial.'— James Drover

To test the theory, researchers at the Retina Foundation Southwest and the University of Texas studied more than 200 infants randomly assigned to be fed either DHA-fortified formula or standard formula.

The study, which appears in the September-October 2009 issue of the journal Child Development, included three groups of babies at different ages given one formula or the other: the first group within days of birth; the second group after six weeks of being breast-fed and weaned; and the third following four to six months of breastfeeding and weaning.

All the children were assessed at nine months of age using a problem-solving test in which they had to complete a sequence of steps to reach and grab hold of a rattle.

In the two-step test, the babies had to remove a cloth covering the rattle and pull another cloth on which the toy was placed so it was close enough to pick up, said James Drover, who helped conduct the study during a post-doctoral fellowship at the Retina Foundation in Dallas.

"So it's very goal-directed," Drover, now an assistant professor of psychology at Newfoundland and Labrador's Memorial University, said Tuesday from St. John's. "They have to carry out those behaviours in order to get the toy.

"And what we found was the children that were fed the DHA-supplemented formula were more likely to show these goal-directed behaviours. They had higher intentions scores. Not only that, but they were more likely to be successful on each trial."

Important nutrient in infants

DHA, or docosahexaenoic acid, is found in high concentrations in the human brain and retina of the eyes. Dietary sources include oily fish, eggs and meat.

Dr. Robert Issenman, chief of pediatric gastroenterology and nutrition at McMaster Children's Hospital, could not comment specifically on the study, but said DHA has long been suspected of being "a very important nutrient in infants in terms of their neuro-cognitive development."

In fact, DHA has routinely been added to formula given to premature infants and recently manufacturers began selling DHA-enhanced formula for all babies "on the premise that if it's good for the premature babies, it might be good for [full-]term babies."

Issenman, a spokesman for the Canadian Paediatric Society, said researchers would need to study children over time to determine whether inclusion of DHA in formula for infants actually has lasting effects on their cognitive abilities compared with kids who didn't get DHA-added formula.

"The Canadian Paediatric Society would say that one way to assure that you're getting appropriate levels of nutrients for infants is to breastfeed," he said from Hamilton. "And we encourage breastfeeding of all babies, exclusively for six months and at least to a year."

As to the benefits of adding DHA to formula, Issenman said the CPS "doesn't have a position on that at this time."

Add fish to mom's diet

Bruce Holub, a professor of nutritional sciences at Ontario's University of Guelph, said the study used amounts of DHA in its enhanced formula that are rarely seen in the breast milk of Canadian mothers — but should be.

Holub, an expert in DHA and other Omega-3 fatty acids, said studies have shown that on average, pregnant and lactating women in Canada have DHA levels far below optimal.

Breastfeeding, when possible, is certainly recommended, he stressed. But women need to add more DHA-rich foods to their diets — especially fish — so their babies get enough of the nutrient in the breast milk.

Drover said the Retina Foundation is among those continuing to study the issue of DHA supplementation.

"We need to take notice and decide whether or not we should be putting DHA in the formulas," he said. "Is there consistent advantage? And if there is a consistent advantage, maybe it should be standard for DHA to be in infant formula."