DHA supplements during pregnancy don't raise kids' IQ

(Reuters Health) - Children of women who took DHA supplements during pregnancy are no smarter than peers whose mothers didn’t take the supplements, a recent study concludes.

In the third follow-up of children born during a trial of DHA supplementation in pregnancy, there were no significant differences in IQ or other cognitive processes at age 7 – the same result researchers found in earlier rounds of testing.

Docosahexaenoic acid (DHA) is a type of omega-3 fatty acid, an important nutrient for the brain, and is needed for development during pregnancy, said lead study author Jacqueline Gould, of the Child Nutrition Research Center at the South Australian Health and Medical Research Institute in Adelaide.

“The main source of DHA for the growing baby is the mother’s diet. However, the exact amount of DHA that needs to be eaten by the mother is unknown,” Gould told Reuters Health in an email.

“DHA-rich fish oil supplements have been marketed by manufacturers as beneficial for child brain development. Use of these supplements has become common in developed countries, but the effects of DHA have been unclear,” Gould said.

For the original trial, Gould and her colleagues randomly assigned pregnant women to groups that would receive either 800-milligram DHA supplements or dummy pills to be taken daily during the second half of pregnancy.

When the babies were 18 months old and again when they were 4 years old, testing showed no differences in intelligence, cognitive, language or motor skills in the two groups of children.

In the most recent follow-up, children were 7 years old, the earliest age at which intelligence testing can predict adult intelligence, the study team notes in JAMA. A total of 543 children, 85 percent of the original trial group, participated in the testing.

The kids were given IQ tests and parents answered questions about their children’s behavior and “executive function,” which includes skills like self-regulation and mental control.

The mean IQ score for both groups of children was about 97 to 98 points. Language skills, school performance and executive functioning also didn’t differ between groups.

The study team found that perceptual reasoning skills were slightly better in the DHA group. But parent-rated behavioral problems were also slightly higher in the DHA group.

Although the study didn’t find an effect on IQ, there are other possible benefits to taking DHA during pregnancy, Gould noted.

“Randomized controlled trials that have given a high-dose of DHA, or a placebo, have found that supplements may reduce the risk of preterm births and may lower the risk of a child developing allergies if they have a family history of allergy,” she said.

“Healthy pregnant women eating a balanced and varied diet are unlikely to enhance their child’s brain development by taking DHA supplements,” Gould said.

Fish is an excellent source of DHA, as well as protein and a variety of vitamins and minerals, she added.

“There is some general confusion around whether fish is safe for pregnant women to eat due to possible methyl mercury contamination, however, there are several species that are considered safe such as salmon and tinned light tuna,” Gould said. Brains and liver are also rich in DHA, and smaller amounts can be found in egg yolks and the lean tissue of red meat.

DHA has been shown in some studies to benefit cognitive development when given after a baby is born, said Susan Carlson, a researcher at the University of Kansas Medical Center in Kansas City who wasn’t involved in the study.

“If the population has adequate DHA intake and infants receive DHA and arachidonic acid postnatally, which they now do in most developed countries, increasing DHA intake during pregnancy would not necessarily show any benefit,” she said.

SOURCE: JAMA, online March 21, 2017.