Docosahexaenoic acid for reading, cognition and behavior in children aged 7-9 years: a randomized, controlled trial (the DOLAB Study)

Abstract

Background: Omega-3 fatty acids are dietary essentials, and the current low intakes in most modern developed countries are believed to contribute to a wide variety of physical and mental health problems. Evidence from clinical trials indicates that dietary supplementation with long-chain omega-3 may improve child behavior and learning, although most previous trials have involved children with neurodevelopmental disorders such as attention-deficit/hyperactivity disorder (ADHD) or developmental coordination disorder (DCD). Here we investigated whether such benefits might extend to the general child population.

Objectives: To determine the effects of dietary supplementation with the long-chain omega-3 docosahexaenoic acid (DHA) on the reading, working memory, and behavior of healthy schoolchildren.

Design: Parallel group, fixed-dose, randomized, double-blind, placebo-controlled trial (RCT).

Setting: Mainstream primary schools in Oxfordshire, UK (n = 74).

Participants: Healthy children aged 7-9 years initially underperforming in reading (≤ 33(rd) centile). 1376 invited, 362 met study criteria.

Intervention: 600 mg/day DHA (from algal oil), or taste/color matched corn/soybean oil placebo.

Main outcome measures: Age-standardized measures of reading, working memory, and parent- and teacher-rated behavior.

Results: ITT analyses showed no effect of DHA on reading in the full sample, but significant effects in the pre-planned subgroup of 224 children whose initial reading performance was ≤ 20(th) centile (the target population in our original study design). Parent-rated behavior problems (ADHD-type symptoms) were significantly reduced by active treatment, but little or no effects were seen for either teacher-rated behaviour or working memory.

Conclusions: DHA supplementation appears to offer a safe and effective way to improve reading and behavior in healthy but underperforming children from mainstream schools. Replication studies are clearly warranted, as such children are known to be at risk of low educational and occupational outcomes in later life.

Trial registration: ClinicalTrials.gov NCT01066182 and Controlled-Trials.com ISRCTN99771026.

Conflict of interest statement

Competing Interests: The authors have read the journal's policy and have the following conflicts: Funding for the trial was provided by Martek Biosciences Inc., who also provided product and placebo. PM, JRB, and RPS declare that no other competing interests exist. AJR acts as an occasional paid consultant (lectures and advisory work) for companies and organisations involved in producing, selling, or promoting foods or supplements containing ω-3. None of these issues alter the authors' adherence to all the PLoS ONE policies on sharing data and materials.

Figures

Figure 1. Flow of participants from invitation to randomization.

Figure 2. Change in reading scores between baseline and post-intervention.

Figure 3. Change in working memory scores (recall of digits forward) between baseline and post-intervention.

Figure 4. Change in working memory scores (recall of digit backwards) between baseline and post-intervention.