Numerous studies have indicated that low levels of serum adiponectin are linked with the development of various chronic diseases. While some recent research has suggested that soy has a positive impact on serum adiponectin levels, the results are inconsistent. Therefore, we aim to conduct a thorough systematic review and meta-analysis of randomized controlled trials (RCTs) that investigate the effects of soy on serum adiponectin levels in adults. The search was conducted until March 2024 on PubMed, Scopus, Web of Science, and Cochrane Library databases to identify RCTs that studied the effects of soy supplementation on serum adiponectin levels. A random-effects model was used to pool the weighted mean differences (WMDs). Ten and nine RCTs were selected for the systematic review and meta-analysis, respectively. After analyzing data from 9 eligible RCTs, it was found that soy supplementation did not significantly impact the concentrations of adiponectin (WMD = −0.24 μg/mL; 95% confidence interval, −1.56 to 1.09; p = 0.72). However, there was significant heterogeneity between the studies (I2 = 89.8%, p < 0.001). Sensitivity analysis showed that overall estimates were not affected by the elimination of any study. We did not observe any evidence regarding publication bias. In conclusion, soy supplementation did not have a significant effect on adiponectin levels in adults. However, further RCTs are needed with longer intervention duration, higher doses, and studies conducted in different countries.
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The prevalence of metabolic syndrome caused by diets containing excessive fatty acids is increasing worldwide. Patients with metabolic syndrome exhibit abnormal lipid profiles, chronic inflammation, increased levels of saturated fatty acids, impaired insulin sensitivity, excessive fat accumulation, and neuropathological issues such as memory deficits. In particular, palmitic acid (PA) in saturated fatty acids aggravates inflammation, insulin resistance, impaired glucose tolerance, and synaptic failure. Recently, adiponectin, brain-derived neurotrophic factor (BDNF), and glucose-like peptide-1 (GLP-1) have been investigated to find therapeutic solutions for metabolic syndrome, with findings suggesting that they are involved in insulin sensitivity, enhanced lipid profiles, increased neuronal survival, and improved synaptic plasticity. We investigated the effects of adiponectin, BDNF, and GLP-1 on neurite outgrowth, length, and complexity in PA–treated primary cortical neurons using Sholl analysis. Our findings demonstrate the therapeutic potential of adiponectin, BDNF, and GLP-1 in enhancing synaptic plasticity within brains affected by metabolic imbalance. We underscore the need for additional research into the mechanisms by which adiponectin, BDNF, and GLP-1 influence neural complexity in brains with metabolic imbalances.
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Literature showed that soluble fiber has beneficial effects on cardiometabolic risk factors and leptin and adiponectin serum levels. Our aim in this meta-analysis was to determine the effect of soluble fiber supplementation on leptin and adiponectin serum levels. A systematic search was conducted using PubMed, Scopus, and ISI Web of Science for eligible trials up to December 2021. A random-effects model was used to pool calculated effect sizes. Our analysis showed that soluble fiber supplementation did not significantly affect adiponectin (standardized mean difference [SMD], −0.49 Hedges’s, 95% confidence interval [CI], −1.20, 0.21, p value = 0.167; I2 = 95.4, p value < 0.001) and leptin (SMD, −0.8 Hedges’s, 95% CI, −1.70, 0.08, p value = 0.076; I2 = 94.6, p value < 0.001) concentrations in comparison with placebo. However, in the subgroup, soluble fiber supplementation had a significant improvement in leptin concentration in overweight and obese patients (SMD, −0.22 Hedges’s, 95% CI, −0.43, −0.01, p value = 0.048) and a non-significant beneficial effect in adiponectin level in female (SMD, 0.29 Hedges’s, 95% CI, −0.13, 0.71, p value = 0.183) and diabetic patients (SMD, 0.32 Hedges’s, 95% CI, −0.67, 1.32, p value = 0.526). A non-linear association between soluble fiber dosage and adiponectin (pnon-linearity < 0.001) was observed. Soluble fiber supplementation could not change the circulatory leptin and adiponectin levels. However, beneficial effects were seen in overweight and obese leptin, and increases in adiponectin may also be observed in female and diabetic patients. Further studies are needed to confirm this results.
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Our aim was to conduct a systematic review and meta-analysis on randomized controlled trials (RCTs) evaluating the effect of garlic on serum adiponectin levels. We searched Scopus, Web of Science, PubMed, and Cochrane Library to databases up to January 2021. RCTs investigating the effects of garlic on serum adiponectin levels in adult participants were included. The change in serum adiponectin levels was estimated using weighted mean differences (WMD) and standard deviations (SD). The random effects model was used to provide a summary of mean estimates and their SDs. Out of 386 records, 6 trials with 8 arms treatment which enrolled 266 subjects were included. Garlic supplementation resulted in a non-significant increase in adiponectin concentrations when compared to placebo, according to the pooled data (WMD, 0.27 Hedges' g; 95% confidence interval [CI], −0.07, 0.62; p = 0.124). Greater effects on adiponectin were observed in trials with supplementation dose less than 1.5 gram per day (WMD, 0.71 Hedges' g; 95% CI, −0.01, 1.43; p = 0.600) and in trials with female subset (WMD, 0.62 Hedges' g; 95% CI, −0.96, 2.21; p = 0.441). Garlic boosts adiponectin levels in general. However, due to different target population, various units for reporting adiponectin level and few eligible studies in final analysis, more research is needed to get a firm conclusion about the influence of garlic on adiponectin levels.
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Adiponectin, and leptin are adipose tissue derived hormones affecting metabolic status. This study aimed to investigate the relationship between circulating adiponectin and leptin levels, and cardiometabolic parameters by obesity status among healthy women without metabolic disease. Finally 141 participants were included in the analyses and categorized into three groups by their body mass index (kg/m2) (normal weight: 18.5 ≤ body mass index [BMI] < 23.0, n=65; overweight: 23.0 ≤ BMI < 25.0, n=26; obesity: 25.0 ≤ BMI, n=50). Overweight and obesity groups were older, and had significantly higher levels of adiposity, blood pressure, fasting glucose, triglyceride, and high sensitivity C-reactive protein (hs-CRP), and lower levels of high density lipoprotein (HDL)-cholesterol than normal weight group. Circulating leptin levels, and leptin to adiponectin ratio were highest in obesity group, but circulating adiponectin levels were not statistically different among the three groups. Circulating leptin levels were negatively correlated with adiponectin levels, and leptin to adiponectin ratio. In addition, leptin levels were positively correlated with waist circumference, systolic blood pressure, insulin resistance, and hs-CRP, and negatively with HDL-cholesterol. However, circulating adiponectin levels were negatively correlated only with waist circumference, and hs-CRP. These patterns were retained after adjusted for confounding factors such as age, smoking and drinking habits, menopausal status and total calorie intake. In conclusion, circulating adiponectin and leptin levels according to obesity status were differently observed among healthy women, and circulating leptin levels may be a more sensitive parameter for cardiometabolic risk in healthy women.
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The prevalence and progression of non-alcoholic fatty liver disease (NAFLD) is mediated via several factors correlating with hepatic necroinflammation (adipokines/cytokines). This study was performed to analyze the level of inflammatory markers according to the presence of NAFLD and to identify related nutritional factors. A total of 80 adults were classified into 2 groups (healthy and NAFLD), and their body composition, blood tests, and eating habits were evaluated. In addition, inflammatory markers (adiponectin, high-sensitivity C-reactive protein [CRP], and tumor necrosis factor-alpha [TNF-α]), nutrient intake status, and dietary quality were compared. The quality of diet was assessed according to the nutrient adequacy ratio and the mean adequacy ratio (MAR). The NAFLD group had a higher body mass index (p < 0.001) than the healthy group and also carried significantly higher CRP levels (p < 0.001) but lower adiponectin (p = 0.001). TNF-α levels increased significantly with fatty liver grade (p = 0.023). The NAFLD group showed significantly higher intake of energy, carbohydrates, iron, sodium, vitamin A and saturated fatty acids, but significantly lower intake of zinc and vitamin E than the healthy group. The MAR values were slightly higher in the NAFLD group but without any significant difference. The levels of adiponectin and vitamin E showed a significant inverse correlation (p < 0.05). Nutritional management of NAFLD patients is important, and the intake of antioxidant and anti-inflammatory nutrients such as zinc and vitamin E should be emphasized.
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Gestational diabetes mellitus (GDM) is an impaired fasting glucose condition during pregnancy. Adiponectin is a polypeptide hormone that is extensively released by adipocytes which regulates energy homeostasis and carbohydrate and lipid metabolism. In addition, adiponectin has antidiabetic and anti-inflammatory properties. The aim of our research was to study about the relationship of adiponectin levels to GDM and glucose intolerance. We selected 25 GDM women and 35 healthy pregnant subjects (18–46 years) who were screened between 24 and 28 weeks of gestation based on the result of oral glucose tolerance test (OGTT). We designed a case-control study and measured the concentrations of serum adiponectin and compared the concentrations between the groups. Serum adiponectin concentration was measured using enzyme-linked immunosorbent assay (ELISA). Sociodemographic data were collected by personal interview. Serum adiponectin concentrations were significantly lower in the subjects with GDM (5.10 ± 2.15 ng/mL vs. 7.86 ± 3.52 ng/mL, p = 0.001) than in healthy pregnant subjects. The mean concentration of fasting blood glucose was considerably lower in control subjects (86.9 ± 9.0 mg/dL vs. 175.9 ± 20.1 mg/dL, p < 0.001) in comparison to GDM subjects. Our findings showed that serum concentrations of adiponectin were significantly lower in gestational diabetic women and this may help to predict the risk of GDM.
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Quercetin, found abundantly in onion peel, has been known to have antioxidant and anti-obesity effects and improves endothelial function. The purpose of this study was to evaluate the effects of a quercetin-rich onion peel extract (OPE) on the inflammatory mediators in overweight and obese women. This study was a randomized double-blind, placebo-controlled study. Thirty-seven healthy overweight and obese women were randomly assigned to two groups, and one group was given a soft capsuled OPE (100 mg quercetin/day, n = 18) and the other group a same capsuled placebo (n = 19) for 12 weeks. Fat mass was measured by bioimpendance method at baseline and after 12 weeks of intervention. The levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were measured with colorimetric assay kits. The concentrations of leptin, adiponectin, visfatin, tumor necrosis factor (TNF)-α and interleukin (IL)-4 in plasma were determined by using enzyme-linked immunosorbent assay kits. Baseline characteristics of anthropometric indicators and blood metabolic profiles were not significantly different between placebo and OPE groups. Compared with baseline value, both placebo and OPE supplementation significantly decreased the percent of body fat mass and induced plasma adiponectin levels while ALT and AST activities as well as leptin, visfatin, TNF-α, and IL-4 levels in plasma were not significantly different between two groups after 12 weeks of the supplementation. These findings suggest that 12-week supplementation of OPE do not affect modulators of systemic inflammation in overweight and obese women.
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