Supplementation with the omega-3 fatty acid DHA may help improve reading skills and behavior in kids who need help most — those whose test scores place them in the bottom 20% of their elementary school class — according to a new controlled trial.

Researchers at Oxford University’s Center for Evidence-Based Intervention studied 362 7- to 9-year-old children who had placed in the bottom third of their class in reading scores. For 16 weeks, the children were given either a placebo or 600 mg of DHA (docosahexaenoic acid). The DHA was extracted from algae, which are the original source of the omega-3 fatty acids found in fish.

Over the 16-week trial, the children receiving placebos progressed in their reading skills as expected. But those students who received DHA and had scored in the bottom 20% of readers at the start of the study advanced by nearly an extra month, while those in the bottom 10% gained nearly two extra months of progress. Students whose reading skills were less impaired — those whose scores had placed them at the highest end of the bottom third — did not see extra improvements with DHA.

Parents of the kids who received DHA also rated their children as more attentive and less restless, as compared with those who got placebo. However, teachers did not report improvement in the children’s behavior.