July 16, 2004 -- Research has suggested that increasing intake of dietary omega-3 fatty acids may have a number of health benefits. And babies whose diets include an abundance of essential fats seem to have an edge in terms of early development. Now new research shows that the same is true for infants born to mothers whose diets contain plenty of this essential fatty acid.
Researchers found that infants born to mothers with higher blood levels of the omega-3 fatty acid docosahexaenoic acid (DHA) at delivery had advanced levels of attention spans well into their second year of life. During the first six months of life, these infants were two months ahead of those babies whose mothers had lower DHA levels.
Attention is considered an important, but not the only, component of intelligence early in life, lead researcher John Colombo, PhD, tells WebMD.
"This adds to the mounting evidence that DHA plays an important part in brain development," he says.
DHA is important for the developing brain, which accumulates large amounts of it during the first two years of life. Compared to the rest of the body, the brain and nervous system contains very high levels of DHA but its exact role in the brain is not fully known.
DHA is found naturally in breast milk and is now available in infant formulas and some baby foods. Atlantic salmon, Pacific cod fish, and tuna are some of the best food sources of the omega- 3 fatty acid, but algae-derived DHA supplements are also now available.
The study involved some 70 mothers and infants. At the ages of 4-, 6-, and 8-months of age, the babies were tested for visual learning ability. The testing involved showing them pictures and recording their reactions.
"We know from past research that when we show babies pictures during the first year of life, as they get older they look less and less," Colombo says. "The reason is that they are taking in the information faster as they develop."
Babies born to mothers who had higher blood levels of DHA scored better on the attention tests until 6 months of age, and they scored better on different tests designed to measure visual learning in older babies at 1 year and 18 months. The findings are reported in the July/August issue of the journal Child Development.
Not So Fishy Food Sources
While Colombo says he encourages his pregnant friends to add salmon to their diets, he adds that it is not yet clear how much DHA a woman needs during pregnancy. He hopes to answer this question in future studies with nutritionist and co-author Susan Carlson, PhD.
"What we can say right now is that authorities are concerned that pregnant women are not getting enough omega-3 in their diets," Carlson tells WebMD. "A number of observational studies suggests a link between DHA levels during pregnancy and a baby's behavioral performance."
But getting DHA from food sources can be problematic for pregnant women. The FDA recommends eating up to 12 ounces (two average meals) a week of a variety of fish and shellfish that are low in mercury, such as shrimp, canned light tuna, salmon, pollock, and catfish.
Mercury is less of an issue with salmon than tuna, but concerns have been raised about unsafe levels of the toxic chemical dioxin and polychlorinated byphenols (PCBs) in farmed salmon. PCBs have been linked to cancer and birth defects.
Nutritionist Barbara Levine, PhD, recommends that pregnant women get their DHA through algae-derived supplements, available in health food stores. Omega-3-fortified eggs are another good source of DHA.
Levine says studies suggest that women need about 250 mg of DHA daily during pregnancy, but very few are getting it.
"It is true that we don't get a lot of DHA in our diets," she says. "It took forever to get the message across about the importance of folic acid early in pregnancy, but now it is in our wheat products and most women get what they need. Now we are trying to get the message out about DHA."
SOURCES: Colombo et al., Child Development, July/August 2004, Vol. 75: pp. 1254-1267. John Colombo, PhD, professor of psychology, University of Kansas; associate director of cognitive neuroscience, Schiefelbusch Institute for Lifespan Studies at the University of Kansas, Lawrence. Susan E. Carlson, PhD, Midwest Dairy Professor of Nutrition, University of Kansas Medical Center. Barbara Levine, PhD, associate professor of nutrition in medicine at Weill Medical College at Cornell University, New York, NY.