Impact of omega-3 fatty acid supplementation on clinical manifestations in autism spectrum disorders: an umbrella review of meta-analyses.

Autism spectrum disorder (ASD) is a neurodevelopmental condition. Omega-3 fatty acid insufficiency has been linked to ASD. This umbrella meta-analysis was performed to investigate the effects of omega-3 supplementation on clinical manifestations in participants with ASD. Based on the PRISMA statement, databases including Web of Science, PubMed and Scopus were systematically searched for published meta-analyses on the effect of omega-3 supplementation on ASD up to December 2023. To assess the risk of bias, the assessment of multiple systematic reviews (AMSTAR)-2 was utilised. The outcomes were core and non-core symptoms of ASD including social withdrawal/lethargy, cluttering speech, hyperactivity, irritability and stereotypy. Seven meta-analyses eventually remained in the umbrella review. The results revealed that omega-3 fatty acid supplementation caused a significant reduction in cluttering speech in studies conducted on age ≤8 years (effect size (ES) -0·30; 95% confidence interval (CI) -0·55, -0·06; P = 0·02). Omega-3 supplementation caused a significant reduction in hyperactivity in participants ≤8 years (ES -0·30; 95% CI -0·55, -0·06; P = 0·02) and in participants who received the supplements for more than 14 weeks (ES -0·30; 95% CI -0·55, -0·06; P = 0·02). A dosage of ≤1000 mg/d of omega-3 supplementation led to a significant increase in the stereotypy/restricted and repetitive interests and behaviours (ES 0·19; 95% CI 0·03, 0·35; P = 0·02). This umbrella review revealed that omega-3 fatty acid may be a beneficial supplement to control cluttering speech and hyperactivity in children with ASD who are 8 years old or younger.