Fish Oil Supplements in Pregnancy No Help for Cognition or Depression
Manufacturers of prenatal vitamins add docosahexaenoic acid (DHA), an omega-3 fatty acid found in fish oil, as it is thought that the nutrient helps with infant cognition and may prevent postpartum depression. However, a recent study published in the Journal of the American Medical Association has found DHA supplements to have no benefit in fighting either condition. Despite the findings, some experts still say they will encourage the dietary supplements because there are few side effects and the nutrient may have other benefits.
Healthy Diet More Beneficial than DHA Supplements in Pregnancy
Researcher Maria Makrides of the Women’s and Children’s Health Research Institute in Australia and colleagues conducted a multicenter, randomized trial that included almost 2,400 women who were less than 21 weeks pregnant through 5 Australian maternity hospitals between October 2005 and January 2008. The women received either capsules containing 800 milligrams of DHA, which were taken once a day, or a placebo made with vegetable oil.
Levels of depression at a six-month follow-up were measured using the Edinburgh Postnatal Depression Scale, a 5-minute test of 10 questions developed in 1987 for screening postpartum women. A score of 9 or above indicates the need for immediate follow-up by a mental health professional. The researchers found no statistically significant difference between the two groups of women in the reporting high levels of depression symptoms.
Infants were also assessed at the follow-up for cognitive and language development using the Bayley Scales of Infant and Toddler Development. Neither average cognitive scores nor average language scores of the children born to women taking DHA differed from those born to women in the placebo group. Other developmental outcomes were also assessed, including motor development and social-emotional behavior, but no difference was found.
DHA is important for both vision and brain during fetal development; however this research suggests that supplements may not be necessary. Dr. Makrides suggests that it is likely that infants receive what they need from the mother during pregnancy through her normal healthy diet.
Some health experts have said that they will continue to recommend that pregnant women to get at least 200 milligrams per day of DHA, either through diet or supplements. Low-mercury fish such as Pollock, whitefish, perch, scallops, flounder, salmon, and freshwater trout are recommended during pregnancy to reduce the risk of mercury contaminants affecting brain and nervous system development in the growing infant.
Makrides M, et al "Effect of DHA supplementation during pregnancy on maternal depression and neurodevelopment of young children: A randomized controlled trial" JAMA2010; 304: 1675-1683.
Oken E, Belfort MB "Fish, fish oil, and pregnancy" JAMA 2010; 304: 1717-1718.