Effect of Omega-3 Polyunsaturated Fatty Acid Supplements on Cognitive Performance in Patients with Mild Cognitive Impairment or Alzheimer’s Disease: A Systematic Review and Meta-Analysis

Context A positive effect of omega-3 polyunsaturated fatty acids (n-3 PUFAs) on brain activity has been observed within subjects who have Alzheimer’s disease (AD) or mild cognitive impairment (MCI). However, inconsistent findings have been reported regarding the efficacy or ineffectiveness of an n-3 PUFA dietary intervention for cognitive improvement. Objective To address this problem, our thorough investigation and statistical analysis sought to assess the impact of n-3 PUFA dietary intake on cognitive function among persons diagnosed with AD or MCI. Data Sources The databases consulted included PubMed, PubMed Central Library, and the Cochrane Library. Data Extraction Nine articles reporting on the findings of randomized controlled trials that looked at the link between n-3 PUFA intake and cognitive performance-related outcomes were included in the comprehensive evaluation, with the meta-analysis utilizing 7 of these. Key details such as author, publication year, study area, research type, pathology (MCI or AD), were incorporated into the data extraction procedure. Data Analysis Evaluation of the included studies used Cochrane risk-of-bias instruments, a random-effects model, standardized mean differences (SMDs) and 95% CIs. Results Our findings have provided evidence of the effectiveness of an n-3 PUFA treatment in improving Full-Scale IQ (FSIQ) (SMD −0.82; 95% CI: −1.57, −0.08; P = .000), information processing (SMD −2.90; 95% CI: −5.25, −0.56; P = .000), and digit span/working memory/attention aspects of cognitive functioning (SMD −1.89; 95% CI: −3.27, −0.51; P = .000). No evidence was found for the effectiveness of an n-3 PUFA treatment in improving image completion (SMD −0.07; 95% CI: −0.50, 0.35; P = .000), picture layout (SMD −0.08; 95% CI: −0.32, 0.16; P = .075), block design SMD −0.15; 95% CI: −0.37, 0.03; P = .123), or arithmetic aspects of cognitive functioning (SMD −0.33; 95% CI: −0.61, 0.04; P = .007). Conclusion In summary, n-3 PUFAs have been found to significantly affect some domains of cognitive function, such as FSIQ, information processing, and digit span/working memory/attention in subjects with MCI. However, no significant effect was observed for some domains, such as picture completion, picture arrangement, or block design.