Pregnant women need to worry a lot when it comes to keeping their bodies and developing babies healthy. Now researchers in Australia are reporting that fish oil supplements, a popular nutritional boost that many expectant mothers thought improved their moods and their little ones brain development, don’t do much either.
In a study of more than 2,300 pregnant women in five Australian hospitals between 2005 and 2008, scientists found that those who took fish oil supplements – mostly in the form of docosahexaenoic acid or DHA, a breakdown product of the original fatty fish oil -. had the same rates of postpartum depression as those who took a placebo. ((More on Time.com: 5 pregnancy taboos explained (or debunked)
In addition, the children of women who took DHA did not show any significant improvements in cognitive development after 18 months compared to those born to women who did not take the supplements.
The results contradict previous results in population-based studies in which women were asked about their DHA consumption after giving birth. These studies showed that women who consumed more fish oil had a 6% to 7% reduction in depressive symptoms after giving birth than women who ate less. However, the results of the current study are believed to be more reliable as the researchers randomly took women with either DHA or placebo and then observed the rate of postpartum depression and measured the developmental markers for children such as language and other cognitive skills.
However, the fact that no mood or cognitive benefits were found for the fish oil supplements in the study does not mean that women should stop eating fish or stop taking fish oil supplements. The authors found a positive correlation between the use of DHA and a lower risk of premature birth before 34 weeks (doctors consider 39 weeks full-time). “There is no clear evidence of the benefits of these supplements,” says Dr. Emily Oken, Professor of Population Medicine at Harvard Medical School, who wrote an editorial on the article in the Journal of the American Medical Association. “But my personal advice as a doctor and mom is to encourage people to try and eat fish that are less mercury and more DHA, like salmon, trout, herring, and anchovies. If women eat a serving or two of these fish per week, they are getting the recommended DHA intake of 200 mg per day. “((More on Time.com: Photos: Pregnant Belly Art)
Although this particular study found no benefits for postpartum depression, Oken notes that about a third of the women who originally signed up for the study were ineligible because they were already consuming the recommended amount of DHA. These women may have already supplemented their diets with fish oil because they were at higher risk for depression, and she says these women may benefit most from higher doses of DHA – in the study, volunteers took 800 one mg daily.
Regarding the benefits of fish oil for cognitive development in children, other smaller studies found that the effects of DHA exposure during pregnancy in young children may not appear until several years of age, once language skills are more established.
While the new study might discourage pregnant women from adding fish oil to their diets, Oken notes that there are other known benefits of the oil, such as protection against heart disease, as well as the possibility that it may improve cognitive development in older children . “I don’t think women should feel like they are harming their children if they don’t eat fish or include fish in their diet,” she says. “At the same time, as doctors and public health officials, we could better let women know that they can properly consume fish while pregnant without having to worry about mercury.”
At the very least, women should continue to aim to consume at least the recommended 200 mg per day. The study showed no harm from this and could help prevent premature births, which could put the baby and mother at risk for additional health problems.
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