Impact of Omega-3 Fatty Acids on Cognitive Outcomes in Children With Autism Spectrum Disorder: A Systematic Review.

Autism spectrum disorder (ASD) is defined as a complex neurodevelopmental disorder that is characterized by a set of deficits not limited to social communication, which is restricted and repetitive behaviors. The prevalence of autism has been seen to be consistently increasing globally. Autism is multifactorial in its etiology, and it involves several physiological systems, including the central nervous system and the gut-brain axis. Omega-3 fatty acids are essential for neural development and functionality, particularly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). They both play a crucial role in not only reducing the neuroinflammation associated with autism but also supporting cognitive processing as well. Given the low levels of omega-3 noted in ASD individuals, this systematic review aims to assess the influence of omega-3 supplementation on cognitive outcomes in children with ASD. The systematic review was done following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, where different databases were assessed across PubMed, Science Direct, Cochrane Library, Google Scholar, and Scopus. MeSH terms used included keywords "Omega-3", "EPA", "DHA" AND "Autism Spectrum Disorder" OR "ASD". Articles published between 2007 and 2023 that focused on ages 2 to 18 years were screened, and cognitive outcomes relevant to omega-3 supplementation were included. Studies with inadequate access to full text excluded non-human trials and older individuals. After generating 25,312 articles, 211 were selected for further review, with 11 meeting the inclusion criteria. The articles reviewed panned over five different countries that involved omega-3 supplementation lasting up to one year. Results suggested that DHA and EPA supplementation may improve cognitive functions such as memory, attention, and executive functioning in children with ASD. The prefrontal cortex development was associated with DHA supplementation, whereas EPA showed improved emotional regulation and reduced neuroinflammation. However, conclusive results were not reached as there was variability in study designs, different dosages, and assessment methods. The power of the studies conducted was also noted to be limited. While promising, extensive research and trials are required to standardize the dosage of omega-3 and the length of intervention. Future studies should aim to identify the long-term effects of omega-3 supplementation, understand the gut-brain axis, and investigate the combination of omega-3 with other therapies to improve cognitive functioning.