The therapeutic effects of soy consumption on adipokine concentrations have yielded inconsistent results in previous meta-analyses. This umbrella meta-analysis aims to investigate the impact of soy and its isoflavones on serum adiponectin and leptin levels in adults. We searched the Cochrane Central, Web of Science, PubMed, and Scopus databases until October 10, 2024. The articles were restricted to those written in English. We included meta-analysis studies that evaluated the effects of soy and its isoflavones on levels of adiponectin and leptin and reported effect sizes (ES) and corresponding confidence intervals (CI). Two independent reviewers screened all articles based on eligibility criteria and extracted the required data from the included meta-analyses. The meta-analysis was performed using a random-effects model in STATA software. Six meta-analyses of randomized controlled trials meeting the inclusion criteria were included in the current umbrella meta-analysis. The findings indicated that soy and its isoflavones did not have a significant effect on adiponectin (ES= 0.10; 95% CI: -0.22, 0.41; P=0.55; I2= 51.8%) and leptin (ES= -0.37; 95% CI: -1.35, 0.61; P=0.46; I2= 71.2%) concentrations. Subgroup analysis based on participants’ mean age, total sample size, and duration was conducted. Results showed that the effect is not statistically significant in any of the subgroups. In conclusion, soy and its isoflavones could not improve the adipokines mentioned above. However, further high-quality research in different countries is required to substantiate these findings.

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.

Several meta-analyses investigating the efficacy of n-3 PUFA in alleviating depression symptoms have reported conflicting findings. In the present study, we aimed to perform an umbrella meta-analysis to provide a definite conclusion. A comprehensive systematic search of PubMed, Scopus, Embase, Web of Science and Cochrane Central Library was performed up to June 2021. Meta-analysis studies evaluating the effects of n-3 PUFA on depression symptoms were included. The quality of the included meta-analyses was assessed using AMSTAR questionnaire. Out of 101 studies, twenty-two studies with twenty-six effect sizes (ES) were eligible for inclusion. Sixteen ES showed significant improving effect of n-3 supplementation on depression symptoms among which eleven ES had small ES. The other studies observed no significant effect. Available evidence suggests that n-3 PUFA (EPA, DHA) supplementation could be considered as an effective add-on therapeutic approach in relieving depression symptoms.