ω-3 Fatty Acid Supplementation Does Not Affect Autism Spectrum Disorder in Children: A Systematic Review and Meta-Analysis

Background: Effective treatments for the core symptoms of autism spectrum disorder (ASD) are still lacking. Objective: We aimed to update the data on the effectiveness of ω-3 (n-3) fatty acid (FA) supplementation as a treatment for ASD. Methods: The Cochrane Library, MEDLINE, and EMBASE databases were systematically searched up until August 2016 with no language restrictions for randomized controlled trials (RCTs) comparing ω-3 FA supplementation with placebo or with no supplementation. Participants were children diagnosed with ASD. All functional outcome measures reported were considered. For dichotomous outcomes, the results for individual studies and pooled statistics were reported as RRs. Mean differences (MDs) were calculated for continuous outcomes. Results: Five RCTs (183 participants) were included. With 4 exceptions, there were no statistically significant differences in ASD symptoms between groups measured by validated scales. Among studies that used the Aberrant Behavior Checklist, parents' ratings indicated significant improvement in lethargy symptoms in the ω-3 FA group compared with the placebo group (2 RCTs) (pooled MD: 1.98; 95% CI: 0.32, 3.63). Among studies that used the Behavioral Assessment System for Children, parents' ratings indicated significant worsening of both externalizing behavior (2 RCTs) (pooled MD: -6.22; 95% CI: -10.9, -1.59) and social skills (1 RCT) (MD: -7; 95% CI: -13.62, -0.38) in the ω-3 FA group compared with the placebo group. One RCT reported a significant improvement in the ω-3 FA group for the daily-living component of the Vineland Adaptive Behavior Scale (MD: 6.2; 95% CI: 0.37, 12.03). Adverse effects were similar in both groups. Conclusions: Because of the limited number of included studies and small sample sizes, no firm conclusions can be drawn. However, the limited data currently available suggest that ω-3 FA supplementation does not enhance the performance of children with ASD.