Colds are no fun for anyone, but for newborns, any assault on their still-developing immune systems can be dangerous. But moms-to-be can reduce the risk that their little ones will get sick by taking fish oil supplements.
In a study published in Pediatrics, researchers at Emory University and in Mexico report that women taking 400 mg of docosahexaenoic acid (DHA), an omega-3 fatty acid found in fish oil, helped their one-month newborns to fight off more cold symptoms such as coughing, nasal congestion and runny noses than moms who took a placebo. The cold-fighting effect lasted for six months; by that time, the DHA-protected infants experienced about the same amount of cold symptoms as the babies whose mothers did not take DHA, but their symptoms didn’t last as long.
“I wouldn’t want to overplay the benefits, but the findings do suggest some benefits early in life,” says the study’s lead author Usha Ramakrishnan, a professor in the department of global health at Emory University School of Public Health. “This is one of the first studies to look at nutritional interventions during pregnancy and immune function of newborns later on.”
MORE: Fish Oil May Prevent Symptoms of Postpartum Depression
What does the mother’s diet have to do with her child’s ability to fend off colds? A developing baby’s immune system relies on cues it receives from its environment—in this case the womb—to start building a cellular defense system that can recognize friendly tissue from foreign ones such as bacteria and viruses. Much of this early arsenal comes from information from the mother, but exactly how this data is translated from mom to baby isn’t clear yet. Ramakrishnan’s study raises interesting questions about whether a pregnant woman’s diet influences her child’s immune development on a cellular level, priming it in a way that gives the baby a head start when it comes to confronting germs once it leaves the womb.
Interestingly, while at one month, babies whose moms took the DHA supplements experienced fewer cold symptoms, they also had more rashes than the babies whose mothers had taken the placebo. And at six months, while the DHA babies suffered from shorter bouts of illness, they also recorded more vomiting than the control infants.
What do these results mean? “The mechanistic functions of the immune system are fairly complex,” says Ramakrishnan. “One part is about how well we respond to pathogens from outside, and that includes how our body reacts to things like allergens. That’s why we are following up with these children to see if there are any differences in how they fall ill from infectious conditions v how they react to allergens in the environment.” She plans to continue monitoring the infants for five years to record any differences in their allergy as well as infectious disease events.
MORE: Fish Oil Pills Don’t Stall Alzheimer’s
In the meantime, she says it’s probably safe for mothers to take DHA supplements as way to protect their baby in its critical first months. The amount of fish oil the mothers in the study took, which is slightly more than the recommended daily intake of 200mg, amounts to about two to three fish meals a week.
Alice Park is a writer at TIME. Find her on Twitter at @aliceparkny . You can also continue the discussion on TIME’s Facebook page and on Twitter at @TIME.