Sorry, moms: Prenatal vitamins with DHA won’t boost your kids’ IQ after all

Children fill in workbooks in a classroom.
Many women take prenatal vitamins with DHA to boost their babies’ brains, but a new study of 7-year-olds who were part of a clinical trial finds no evidence that the supplement made a difference in IQ scores.
(Katie Falkenberg / Los Angeles Times)

Researchers have some bad news for moms who used DHA supplements while they were pregnant in hopes of boosting their baby’s brains:

It didn’t work.

At age 7, kids whose mothers took DHA scored no higher on an IQ test than kids whose moms swallowed capsules that were DHA-free.

The results are the latest findings from a study assessing the benefits — if any — of giving DHA to babies in utero. They appear in Tuesday’s edition of the Journal of the American Medical Assn.


DHA, short for docosahexaenoic acid, is an omega-3 fatty acid that plays a key role in brain health. It’s essential throughout our lives, and especially during infancy when the brain, eyes and nervous system are developing.

DHA is a natural component of breast milk, and manufacturers often add it to infant formula. So it was probably just a matter of time before it took off as a component of prenatal vitamins.

But does it work?

To find out, researchers in Australia recruited 2,399 pregnant women to participate in a randomized clinical trial. Some of the women were given capsules that contained 800 milligrams of DHA per day. Others got a placebo that had vegetable oil instead. The women didn’t know which group they were in.

That was back in 2010, 2011 and 2012. Now the oldest children in the study have reached the age of 7, making them eligible to take an IQ test.

The test — the Wechsler Abbreviated Scale of Intelligence, Second Edition — was administered to 259 children whose mothers took DHA during pregnancy and 284 children whose moms received the placebo. An “average” score on the test is 100; the minimum score to qualify as “gifted” is typically 130.

As a whole, neither group came close to that mark. The average score for the kids in the DHA group was 98.31, compared with an average score of 97.32 for kids in the placebo group, according to the JAMA report. That difference wasn’t large enough to be considered statistically significant.


Breaking things down, children in both groups scored the same for “language, academic functioning and executive functioning,” the researchers wrote. The one exception was for perceptual reasoning — kids who got DHA scored “slightly higher” than kids who got the placebo.

However, questionnaires filled out by parents revealed that the DHA kids had more behavior problems than their counterparts. The children in the DHA group also had higher scores for executive dysfunction, according to the study.

This isn’t the first time the researchers have checked in on the kids and seen DHA come up short.

When the children were 18 months old, the researchers assessed their “cognitive, language and motor development” and found no differences between the groups, they wrote.

Then, when the kids were 4 years old, the researchers saw no sign that the ones in the DHA group had any advantage in general intelligence, executive functioning or language compared with the kids in the placebo group.

With the first IQ results in hand, the researchers now say they have “strong evidence for the lack of benefit of prenatal DHA supplementation.”


The study was funded by Australia’s National Health and Medical Research Council. The pills used in the trial were provided by Croda Chemicals, whose product lineup includes DHA supplements.

Follow me on Twitter @LATkarenkaplan and “like” Los Angeles Times Science & Health on Facebook.


Why global warming could lead to a rise of 100,000 diabetes cases a year in the U.S.

Your kids aren’t killing you; one day they may actually help you live longer


These three drugs may boost your thinking skills but cost you time-wise