Fatty Acid Dietary Supplements in Treatment of Developmental Coordination Disorder and ADHD

Abstract

Source: Richardson AJ, Montgomery P. The Oxford-Durham study: a randomized, controlled trial of dietary supplementation with fatty acids in children with developmental coordination disorder. Pediatrics. 2005;115:1360–1366.The effects of dietary supplementation with fish oil and evening primrose oil (in a ratio of 80% to 20%) compared to placebo were assessed, in a randomized, 1-way crossover, controlled trial in 117 children with developmental coordination disorder (DCD), aged 5-12 years, at the University of Oxford, UK. Conners’ Teacher Rating Scale-L (CTRS-L) scores were obtained at baseline on 102 study children; there were 32 children with scores compatible with a diagnosis of ADHD. Six capsules of the supplement provided ω-3 fatty acids (558 mg of eichosapentaenoic acid and 174 mg of docosahexaenoic acid), the ω-6 fatty acid γ-linoleic acid (60 mg), and 9.6 mg of vitamin E (natural form, α-tocopherol) daily. Placebo capsules contained olive oil.Compared to placebo recipients, significant improvements in reading age (mean increase 9.5 months vs 3.3 months), spelling age (mean increase 6.6 months vs 1.2 months), and behavior (reduction on CTRS-L 74.7 to 58.1 vs 69.5 to 67.9) occurred over a 3-month treatment with the fatty acid supplement. Similar improvements were subsequently noted in the placebo group when they were given the active supplement for 3 months after crossover: mean reading age improved by 13.5 months, mean spelling age improved by 6.2 months, and CTRS-L decreased to 57.8. During this 3- to 6-month follow-up phase, children continuing active treatment showed additional improvements in mean reading age of 10.9 months, a mean spelling gain of 5.3 months, and a further decrease of the mean CTRS-L score from the baseline of 74.7 to 52.6.Motor skills were not benefited; mean Movement Assessment Battery scores in children receiving fatty acid supplements were below the 6th percentile at baseline and at the 12th percentile after 3 months of treatment. These scores were not different from those of placebo recipients. No adverse effects were reported. On active treatment, the gain in reading age was 3 times that expected and spelling advanced at twice the normal expected rate, reaching values above normal for age at follow-up.Dr. Millichap has disclosed no financial relationships relevant to this commentary.Developmental coordination disorder (DCD) is a motor skills disorder, not due to cerebral palsy or muscular dystrophy, that impairs a child’s performance in sports or handwriting and interferes with academic achievement or activities of daily living (ADL).1 In neurologic terms, DCD is equivalent to an ideokinetic (adextrous) dyspraxia, or clumsiness, in writing, dressing, using scissors, and other ADL, despite normal muscle power (a dominant parietal lobe dysfunction). There is overlap between DCD and the syndromes of ADHD and DAMP (deficit in attention, motor control and perception).2 Treatment involves occupational therapy, special education, and when indicated, medication. The above authors demonstrated a beneficial effect of fatty acid supplements in the diet of children with reading, spelling, and attention and behavior disorders, but without improvement in coordination. These findings confirm earlier reports of the benefit of docosahexaenoic acid supplements in dark adaptation (scotopic vision) and improvements in reading ability in some dyslexics.3 They also corroborate the report of a significant decrease in serum essential fatty acids (docosahexaenoic acid, etc.) found in 44 hyperactive children compared to 45 age- and sex-matched controls.4 The hyperactive children in that study had a greater incidence of learning disabilities and dyslexia than controls, but a double-blind, placebo-controlled, crossover study of evening primrose oil in 31 patients showed only modest improvements in behavior.The present authors cite more recent references to successful trials of ω-3/ω-6 fatty acid supplements in children with dyslexia or ADHD, but a lack of response to ω-3 fatty acid (docosahexaenoic acid) alone. The combination of ω-3 and ω-6 (γ-linoleic) fatty acids appears to be essential, and the dosage is probably also important in the duplication of the authors’ encouraging results. Dietary modifications or supplements in the treatment of learning and behavior disorders of children have frequently fallen short of initial expectations after closer and more prolonged study. These have included the additive-salicylate-free, hypoallergenic, sugar-restrictive, megavitamin, and mineral and trace element diets.5 Despite the excellent experimental design of the Oxford-Durham study, further controlled trials are indicated before advocating fish, with its attendant mercury exposure, or fatty acids as a general substitute for medication. However, the introduction of a relatively safe and well-tolerated dietary treatment could, if successful, serve as a complementary or substitute treatment, and offset the increase in concern regarding side effects of drug therapies.