Omega-3 fish oils, particularly DHA, are touted as an important nutrient for pregnant women because of their role in fetal brain and eye development and in helping to prevent postpartum depression (PPD) in new mothers. Yet a recent randomized controlled trial—considered the “gold standard” of medical research—found that the children of women who took fish oil supplements during pregnancy had no better cognitive or language skills at 18 months than the children of women who took a vegetable oil placebo. Nor did DHA protect women from PPD, the study published in the Journal of the American Medical Association (JAMA) found.
But before you toss your fish oil supplements, experts caution that one study by no means tells the whole story. Several previous studies have shown DHA to be important to a baby’s cognitive development. For example, a 2003 Norwegian study found that at age 4, children of women who took cod liver oil (which contains high levels of DHA) during pregnancy had higher IQs than children of mothers who were given a corn oil placebo.
It’s for those reasons that organizations such as the March of Dimes recommend that pregnant and lactating women get the equivalent of least 200 milligrams of DHA daily. In the JAMA study, pregnant women took 800 milligrams daily; rather than suggest DHA isn’t important, the research may show that extra-high doses don’t provide added benefits, says Janis Biermann, senior vice president of education and health promotion for the March of Dimes.
What’s more, other research suggests that a DHA deficiency can cause big problems. For example, animal studies have found that the offspring of mothers deprived of DHA during pregnancy have vision and behavioral problems; others have found that human mothers similarly deprived have an increased PPD risk. This is a crucial distinction: DHA deficiency is common in the American diet, and pregnant women consume an average of only 73 milligrams daily.