Bloch MH, Qawasmi A (2011) Journal of the American Academy of Child & Adolescent Psychiatry 50(10): 991-1000. EPub Aug 12
Several studies have demonstrated differences in omega-3 fatty acid composition in plasma and in erythrocyte membranes in patients with attention-deficit/hyperactivity disorder (ADHD) compared with unaffected controls. Omega-3 fatty acids have anti-inflammatory properties and can alter central nervous system cell membrane fluidity and phospholipid composition. Cell membrane fluidity can alter serotonin and dopamine neurotransmission. The goal of this meta-analysis was to examine the efficacy of omega-3 fatty acid supplementation in children with ADHD.
PubMed was searched for randomized placebo-controlled trials examining omega-3 fatty acid supplementation in children with ADHD symptomatology. The primary outcome measurement was standardized mean difference in rating scales of ADHD severity. Secondary analyses were conducted to determine the effects of dosing of different omega-3 fatty acids in supplements.
Ten trials involving 699 children were included in this meta-analysis. Omega-3 fatty acid supplementation demonstrated a small but significant effect in improving ADHD symptoms. Eicosapentaenoic acid dose within supplements was significantly correlated with supplement efficacy. No evidence of publication bias or heterogeneity between trials was found.
Omega-3 fatty acid supplementation, particularly with higher doses of eicosapentaenoic acid, was modestly effective in the treatment of ADHD. The relative efficacy of omega-3 fatty acid supplementation was modest compared with currently available pharmacotherapies for ADHD such as psychostimulants, atomoxetine, or α2 agonists. However, given its relatively benign side-effect profile and evidence of modest efficacy, it may be reasonable to use omega-3 fatty supplementation to augment traditional pharmacologic interventions or for families who decline other psychopharmacologic options.
For a news article on this study and its implications, see Omega-3 Effective for Treating Child ADHD.
These findings confirm that dietary supplementation with omega-3 from fish oils can help to reduce symptoms of 'ADHD' in children - i.e. inattention, hyperactivity and impulsivity. Although the overall treatment effect size was relatively modest, the authors commented on the safety profile and lack of negative side-effects.
Importantly, these results show that benefits from an increased intake of omega-3 do not depend on a formal clinical diagnosis of ADHD, as many of the trials included in this meta-analysis involved children recruited from non-clinical populations, and/or selected for other conditions such as dyslexia or dyspraxia.
However, it's important to recognise that this kind of intervention is not likely to help all children (or adults) with these conditions - hence further research is needed to identify those individuals or subgroups most likely to benefit.
The findings also indicate that of the two main long-chain omega-3 fatty acids in fish oils, EPA rather than DHA may be more effective for these purposes, although further studies would be needed to confirm this. A similar advantage of EPA over DHA has also been noted in studies of omega-3 for depression. (see Martins et al 2009)
For a review that includes discussion of the importance of study populations, treatment formulations and other relevant issues, see: