Effect of dietary lipids on circulating adiponectin: a systematic review with meta-analysis of randomised controlled trials

Different dietary interventions have been identified as potential modifiers of adiponectin concentrations, and they may be influenced by lipid intake. We identified studies investigating the effect of dietary lipids (type/amount) on adiponectin concentrations in a systematic review with meta-analysis. A literature search was conducted until July 2013 using databases such as Medline, Embase and Scopus (MeSH terms: adiponectin', dietary lipid', randomized controlled trials (RCT)'). Inclusion criteria were RCT in adults analysing adiponectin concentrations with modification of dietary lipids. Among the 4930 studies retrieved, fifty-three fulfilled the inclusion criteria and were grouped as follows: (1) total dietary lipid intake; (2) dietary/supplementary n-3 PUFA; (3) conjugated linoleic acid (CLA) supplementation; (4) other dietary lipid interventions. Diets with a low fat content in comparison to diets with a high-fat content were not associated with positive changes in adiponectin concentrations (twelve studies; pooled estimate of the difference in means: -004 (95% CI -082, 074)g/ml). A modest increase in adiponectin concentrations with n-3 PUFA supplementation was observed (thirteen studies; 027 (95% CI 007, 047)g/ml). Publication bias was found by using Egger's test (P=001) and funnel plot asymmetry. in contrast, CLA supplementation reduced the circulating concentrations of adiponectin compared with unsaturated fat supplementation (seven studies; -074 (95% CI -138, -010)g/ml). However, important sources of heterogeneity were found as revealed by the meta-regression analyses of both n-3 PUFA and CLA supplementation. Results of new RCT would be necessary to confirm these findings.Foundation for Research Support of the State of Rio Grande do Sul (FAPERGS)Hospital de Clinicas de Porto Alegre Research FundConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)International Scholarship Program of the Endocrine SocietyUniv Fed Rio Grande do Sul, Fac Med, Postgrad Endocrinol Program, Porto Alegre, RS, BrazilHosp Clin Porto Alegre, BR-90035003 Porto Alegre, RS, BrazilUniv Fed Rio Grande do Sul, Dept Internal Med, Porto Alegre, RS, BrazilHosp Clin Porto Alegre, Div Endocrinol, Metab Unit, Porto Alegre, RS, BrazilHosp Clin Porto Alegre, Exercise Pathophysiol Res Lab, Porto Alegre, RS, BrazilUniversidade Federal de São Paulo, Endocrinol Unit, São Paulo, BrazilUniversidade Federal de São Paulo, Endocrinol Unit, São Paulo, BrazilHospital de Clinicas de Porto Alegre Research Fund: FIPE 11-226Web of Scienc