The Oxford-Durham Study: A Randomized, Controlled Trial of Dietary Supplementation With Fatty Acids in Children With Developmental Coordination Disorder

Design: randomized, double-blind, placebo-controlled trial with 3 months of parallel treatment followed by a 3-month one-way switch from placebo to active treatment. Participants: 117 mainstream schoolchildren aged 5–12 years with DSM-IV-defined DCD not receiving other treatment. Recruited from 12 schools in County Durham, UK. Primary outcomes measured at baseline, 3 months, and 6 months: motor function (Movement ABC-18), reading and spelling (Wechsler Objective Reading Dimensions), and ADHD-related behavior (CTRS-L). Analysis was intention-to-treat with last observation carried forward.

Active supplement: dietary oil capsules containing 80% fish oil and 20% evening primrose oil; six capsules daily (three divided doses of 2 capsules each on weekdays at school; weekend dosing at home under parental supervision). Daily intake provides 558 mg EPA and 174 mg DHA from fish oil, 60 mg gamma-linolenic acid (GLA) from evening primrose oil, and 9.6 mg natural vitamin E (α-tocopherol). Duration: 6 months total; during the first 3 months, active treatment vs placebo; after 3 months, the placebo group began active treatment for the remaining 3 months.

Active treatment did not improve motor skills versus placebo after 3 months. Reading and spelling ages improved significantly more with active treatment (reading +9.5 months vs +3.3 months; p < 0.004; spelling +6.6 months vs +1.2 months; p < 0.001). ADHD-related symptoms (CTRS-L total raw scores) decreased more with active treatment (74.7 → 58.1) than placebo (minimal change); p < 0.0001. After crossover, the placebo-to-active group showed similar gains; those continuing active treatment maintained or further improved. Authors conclude fatty acid supplementation may offer a safe and efficacious option for educational and behavioral problems in children with DCD, though motor outcomes require further investigation and durability of effects needs confirmation.

Limitations include no observed motor improvement, which may reflect measurement sensitivity or insufficient duration for motor changes; generalizability is limited to 5–12-year-old children with DCD in a single UK region; some dropout and use of last observation carried forward for missing data; no formal correction for multiple behavioral comparisons; optimal fatty acid dose and composition remain undetermined.