Foods containing plenty of omega-3 fatty acids, such as oily fish, could help prevent postnatal depression if consumed during pregnancy, according to the results of a new study presented at the Experimental Biology 2011 meeting in Washington, DC on April 12.

Omega-3 fatty acids such as docosahexaenoic acid (DHA) are beneficial to the brain, nerves, and cardiovascular system, and can be found in foods such as salmon, herring, walnuts, and flaxseeds, according to WebMD.com.

Led by Dr. Michelle Price Judge of the University of Connecticut School of Nursing, a team of researchers gave 52 pregnant women either a fish oil capsule containing 300 milligrams of DHA or a placebo five days a week from weeks 24 to 40 of their pregnancies. Using a postpartum depression screening scale, depression levels were ascertained at two and six weeks, and then three months and six months after birth.

The team found that those women who took fish oil capsules had lower scores on the depression scale and significantly fewer symptoms. They concluded that “DHA consumption during pregnancy—at levels that are reasonably attained from foods—has the potential to decrease symptoms of postpartum depression,” according to a press statement.

Although the study was too small to draw any definite conclusions about fish oil’s effects on postnatal depression, the press release recommended that women eat at least one serving of high omega-3 fish two to three days per week.

Registered dietitian Cassie Vanderwall at the Rush University Medical Center in Chicago routinely provides nutritional advice to pregnant women.

“I don’t say this will prevent postpartum depression, but fatty fish and other omega-3-rich foods will benefit them and their child’s development,” she told WebMD. “It is a good idea to discuss your diet during pregnancy with your obstetrician.”