Supplementation of omega 3 fatty acids may improve hyperactivity, lethargy, and stereotypy in children with autism spectrum disorders: a meta-analysis of randomized controlled trials

Abstract

Aim: Deficiency of omega 3 fatty acids may be linked to autism spectrum disorder (ASD). Evidence about the potential therapeutic effects of supplementation of omega 3 fatty acids is lacking in ASD patients.

Methods: We searched major electronic databases from inception to June 21, 2017, for randomized clinical trials, which compared treatment outcomes between supplementation of omega 3 fatty acids and placebo in patients with ASD. An exploratory random-effects meta-analysis of the included studies was undertaken.

Results and conclusion: Six trials were included (n=194). Meta-analysis showed that supplementation of omega 3 fatty acids improved hyperactivity (difference in means =-2.692, 95% confidence interval [CI] =-5.364 to -0.020, P=0.048, studies =4, n=109), lethargy (difference in means =-1.969, 95% CI =-3.566 to -0.372, P=0.016, studies =4, n=109), and stereotypy (difference in means =-1.071, 95% CI =-2.114 to -0.029, P=0.044, studies =4, n=109). No significant differences emerged between supplementation of omega 3 fatty acids and placebo in global assessment of functioning (n=169) or social responsiveness (n=97). Our preliminary meta-analysis suggests that supplementation of omega 3 fatty acids may improve hyperactivity, lethargy, and stereotypy in ASD patients. However, the number of studies was limited and the overall effects were small, precluding definitive conclusions. Future large-scale randomized clinical trials are needed to confirm or refute our findings.

Keywords: autism; omega 3; pediatric; poly-unsaturated fatty acid.

Figure 1

Flowchart of the selection strategy for the current meta-analysis.

Figure 2

Meta-analysis of difference of primary outcome, in aspects of (A) changes of ABC, (B) clinical improvement, and (C) changes of SRS total scores, in ASD children treated with omega 3 and placebo. Notes: (A) The treatment effect is significantly better by omega 3 than by placebo in subscales of lethargy (P=0.018) and stereotypy (P=0.032), trend of better response by omega 3 than by placebo in hyperactivity (P=0.064), but no any significance between omega 3 and placebo in inappropriate speech (P=0.366) or irritability (P=0.931). (B) There was no any significant difference of clinical improvement between children with ASD receiving omega 3 and those receiving placebo (P=0.569). (C) There was trend of better response by placebo than by omega 3 in changes of SRS total scores (P=0.066). Abbreviations: ABC, Aberrant Behavior Checklist; ASD, autism spectrum disorder; CGI-I, Clinical Global Impression – Improvement; CI, confidence interval; SRS, Social Responsiveness Scale.

Figure 2

Meta-analysis of difference of primary outcome, in aspects of (A) changes of ABC, (B) clinical improvement, and (C) changes of SRS total scores, in ASD children treated with omega 3 and placebo. Notes: (A) The treatment effect is significantly better by omega 3 than by placebo in subscales of lethargy (P=0.018) and stereotypy (P=0.032), trend of better response by omega 3 than by placebo in hyperactivity (P=0.064), but no any significance between omega 3 and placebo in inappropriate speech (P=0.366) or irritability (P=0.931). (B) There was no any significant difference of clinical improvement between children with ASD receiving omega 3 and those receiving placebo (P=0.569). (C) There was trend of better response by placebo than by omega 3 in changes of SRS total scores (P=0.066). Abbreviations: ABC, Aberrant Behavior Checklist; ASD, autism spectrum disorder; CGI-I, Clinical Global Impression – Improvement; CI, confidence interval; SRS, Social Responsiveness Scale.

Figure 3

Meta-analysis of difference of (A) dropout rate and (B) rate of discontinuation from study due to side effect in ASD children treated with omega 3 and placebo. Notes: (A) There was no any significant difference between the dropout rate in ASD children receiving omega 3 and those receiving placebo (P=0.795). (B) There was no any significant difference between the rate of discontinuation from study due to side effect between ASD children receiving omega 3 and those receiving placebo (P=0.707). Abbreviations: ASD, autism spectrum disorder; CI, confidence interval.