Eligibility Criteria
Studies were selected by applying the following Population-Intervention-Comparator-Outcomes-Study design (PICOS) criteria 28: 1) subjects received oral soy and soy products supplementation, as a nutritional strategy; 2) original randomized-controlled trial researches and 3) reporting at least one outcome measure of adipokines (adiponectin and leptin) ; 4) presented data of interest as mean and standard deviation (SD) of adiponectin and leptin in both intervention and placebo groups; and 5) had a trial duration of more than 4 weeks. Exclusion criteria were: 1) using a mixture of soy protein or isoflavones extract only in intervention group, not including a placebo group; 2) semi experimental, nonrandomized trials and trials without control groups; 3) duplicate studies with the same population (several papers reported the same data); 4) enrolled pregnant or lactating women; 5) experimental and animal studies; and 6) reviews, letters to editor, editorial articles, or case reports.