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1.
Zinc Supplementation and Body Weight: A Systematic Review and Dose-Response Meta-analysis of Randomized Controlled Trials.
Abdollahi, S, Toupchian, O, Jayedi, A, Meyre, D, Tam, V, Soltani, S
Advances in nutrition (Bethesda, Md.). 2020;(2):398-411
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Abstract
The aim of this study was to determine the effect of zinc supplementation on anthropometric measures. In this systematic review and dose-response meta-analysis, we searched PubMed, Scopus, ISI Web of Science, and the Cochrane Library from database inception to August 2018 for relevant randomized controlled trials. Mean differences and SDs for each outcome were pooled using a random-effects model. Furthermore, a dose-response analysis for zinc dosage was performed using a fractional polynomial model. Quality of evidence was evaluated using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology. Twenty-seven trials (n = 1438 participants) were included in the meta-analysis. There were no significant changes in anthropometric measures after zinc supplementation in the overall analysis. However, subgroup analyses revealed that zinc supplementation increased body weight in individuals undergoing hemodialysis (HD) [3 trials, n = 154 participants; weighted mean difference (WMD) = 1.02 kg; 95% CI: 0.38, 1.65 kg; P = 0.002; I2 = 11.4%] and decreased body weight in subjects who are overweight/obese but otherwise healthy (5 trials, n = 245 participants; WMD = -0.55 kg; 95% CI: -1.06, -0.04 kg; P = 0.03; I2 = 31.5%). Dose-response analyses revealed a significant nonlinear effect of supplementation dosage on BMI (P = 0.001). Our data suggest that zinc supplementation increases body weight in patients undergoing HD and decreases body weight in individuals who are overweight/obese but otherwise healthy, although after normalization for study duration, the association observed in subjects who are overweight/obese disappeared. Although more high-quality studies are needed to reach a definitive conclusion, our study supports the view that zinc may be associated with body weight.
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The effect of berberine supplementation on obesity indices: A dose- response meta-analysis and systematic review of randomized controlled trials.
Xiong, P, Niu, L, Talaei, S, Kord-Varkaneh, H, Clark, CCT, Găman, MA, Rahmani, J, Dorosti, M, Mousavi, SM, Zarezadeh, M, et al
Complementary therapies in clinical practice. 2020;:101113
Abstract
BACKGROUND and purpose: Clinical studies investigating the effects of berberine supplementation on anthropometric indices in humans have generated inconsistent results. Thus, the objective of this systematic review and meta-analysis was to clarify the effects of berberine supplementation on obesity indices in human subjects. METHODS Several online medical databases were systematically searched up to February 2019. All clinical trials exploring the effects of berberine supplementation on indices of obesity were included. The combined weighted mean difference (WMD) of eligible studies was assessed using a random-effects model. We evaluated publication bias by using the Egger's test. RESULTS Overall, 10 studies were included. The combined outcomes suggested a significant influence of berberine administration on body mass index (BMI) (WMD: -0.29 kg/m2, 95% CI: -0.51 to -0.08, p = 0.006) and waist circumference (WC) (WMD: -2.75 cm, 95% CI: -4.88 to -0.62, p = 0.01). However, berberine supplementation yielded no significant decline in body weight (BW) (WMD: -0.11 kg, 95% CI: -0.99 to 0.76, p = 0.79). Following the dose-response evaluation, berberine intake was found to significantly reduce BMI (r = -0.02) and WC (r = -0.72) based on treatment duration. CONCLUSION The results of the current study support the use of berberine supplementation for the improvement of obesity indices.
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The effect of psyllium consumption on weight, body mass index, lipid profile, and glucose metabolism in diabetic patients: A systematic review and dose-response meta-analysis of randomized controlled trials.
Xiao, Z, Chen, H, Zhang, Y, Deng, H, Wang, K, Bhagavathula, AS, Almuhairi, SJ, Ryan, PM, Rahmani, J, Dang, M, et al
Phytotherapy research : PTR. 2020;(6):1237-1247
Abstract
Water-soluble dietary fibers have been shown to improve lipid profile and glucose metabolism in diabetes. The aim of this study was to review the effects of psyllium consumption on weight, body mass index, lipid profiles, and glucose metabolism in diabetic patients in randomized controlled trials. A comprehensive systematic search was performed in PubMed/MEDLINE, Web of Sciences, Cochrane, and Scopus by two independent researchers up to August 2019 without any time and language restrictions. The DerSimonian and Laird random-effects model method performed to calculate the pooled results. Inclusion criteria were randomized controlled trial design, adult subjects, and studies reporting the mean differences with the 95% confidence interval for outcome. Eight studies containing nine arms with 395 participants were identified and included in final analysis. Combined results found a significant reduction in triglycerides, low-density lipoprotein, fasting blood sugar, and hemoglobin A1c following psyllium consumption (weighted mean differences [WMD]: -19.18 mg/dl, 95% CI [-31.76, -6.60], I2 = 98%), (WMD: -8.96 mg/dl, 95% CI [-13.39, -4.52], I2 = 97%), (WMD: -31.71 ml/dl, 95% CI [-50.04, -13.38], I2 = 97%), and (WMD: -0.91%, 95% CI [-1.31, -0.51], I2 = 99%), respectively. There was no significant change in high-density lipoprotein, body mass index, cholesterol, and weight. In conclusion, the results demonstrated a significant reduction in triglycerides, low-density lipoprotein, fasting blood sugar, and hemoglobin A1c by psyllium intervention among diabetic patients.
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The effects of psyllium supplementation on body weight, body mass index and waist circumference in adults: A systematic review and dose-response meta-analysis of randomized controlled trials.
Darooghegi Mofrad, M, Mozaffari, H, Mousavi, SM, Sheikhi, A, Milajerdi, A
Critical reviews in food science and nutrition. 2020;(5):859-872
Abstract
Background: Previous studies reported inconsistent findings regarding the effects of psyllium supplementation on obesity measures. This systematic review and meta-analysis was performed to summarize data from available randomized clinical trials (RCTs) on the effect of psyllium supplementation on body weight, body mass index (BMI), and waist circumference (WC) in adults.Methods: PubMed, SCOPUS, Cochrane Library, and Google Scholar were searched to identify relevant articles up to August 2018. The effect sizes were presented as weighted mean difference (WMD) and 95% confidence intervals (CI) by using random effects model. To detect dose-response relationships, we used fractional polynomial modeling.Results: A total of 22 RCTs were included. Meta-analysis did not find any significant effect of psyllium supplementation on body weight (MD: -0.28 kg, 95% CI: -0.78, 0.21, p = 0.268), BMI (MD: -0.19 kg/m2, 95% CI: -0.55, 0.15, p = 0.27) and WC (MD: -1.2 cm, 95% CI: -2.6, 0.2, p = 0.09). Subgroup analysis showed that psyllium dosage, kind of psyllium administration, duration of trial, study design, sample size, and gender were potential sources of heterogeneity. Moreover, there was nonlinear association between duration of psyllium consumption, BMI and WC.Conclusion: Psyllium supplementation does not reduce body weight, BMI, and WC significantly.
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Effect of lifestyle modifications on anthropometric, clinical, and biochemical parameters in adolescent girls with polycystic ovary syndrome: a systematic review and meta-analysis.
Abdolahian, S, Tehrani, FR, Amiri, M, Ghodsi, D, Yarandi, RB, Jafari, M, Majd, HA, Nahidi, F
BMC endocrine disorders. 2020;(1):71
Abstract
BACKGROUND Polycystic ovary syndrome (PCOS) is the most common endocrine disorder in women of childbearing age. This study aimed to compare the effects of lifestyle interventions on anthropometric, clinical, and biochemical parameters in adolescent girls with PCOS. METHODS PubMed, Scopus, and Web of Science was systematically searched to retrieve studies investigating the effects of lifestyle modifications in adolescent girls with PCOS, which were published up to December 2019. The primary outcome was Body Mass Index (BMI) and secondary outcomes were all manifestations of PCOS, including clinical, metabolic, and hormonal parameters. Random effect meta-analysis was applied for significant results. Publication bias was assessed using the Egger test. RESULTS This study showed significant improvements in luteinizing hormone (LH) (Pooled SMD = - 0.1.23; 95% CI, - 2.44 to - 0.03), and Free Androgen Index (FAI) levels (Pooled SMD = - 0.78 95% CI, - 0.1.42 to - 0.13) in adolescent girls receiving lifestyle intervention compared to baseline. This study also revealed that diet modifications alone were associated with a significant decrease in Body Mass Index (BMI) (Pooled SMD = - 0.45; 95% CI, - 0.76 to - 0.13), and FG score (Pooled SMD = - 0.81; 95% CI, - 1.33 to - 0.28). Exercise interventions were associated with significant changes in the menstrual cycles (Pooled SMD = 1.16; 95% CI, 0.72 to 1.61), Ferriman-Gallwey (FG) score (Pooled SMD = - 0.57; 95% CI, - 0.99 to - 0.15), LH (Pooled SMD = - 056; 95% CI, - 0.98 to - 0.14), Anti-Müllerian Hormone (AMH) (Pooled SMD = - 0.81; 95% CI, - 0.1.24 to - 0.38), and Triglyceride (TG) levels (Pooled SMD = - 0.32; 95% CI, - 0.62 to - 0.02). CONCLUSION This meta-analysis concluded lifestyle interventions, such as diet and exercise, can improve some clinical, metabolic, and hormonal parameters in adolescent girls with PCOS.
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A systematic review, meta-analysis, and meta-regression of the impact of diurnal intermittent fasting during Ramadan on body weight in healthy subjects aged 16 years and above.
Jahrami, HA, Alsibai, J, Clark, CCT, Faris, MAE
European journal of nutrition. 2020;(6):2291-2316
Abstract
PURPOSE Studies on the effect of Ramadan diurnal intermittent fasting (RDIF) on body weight have yielded conflicting results. Therefore, we conducted a systematic review and meta-analysis to estimate the effect size of body weight changes in healthy, non-athletic Muslims practicing Ramadan fasting, and to assess the effect of covariates such as age, sex, fasting time duration, season, and country, using subgroup analysis, and meta-regression. Covariate adjustments were performed to explain the variability of weight change in response to Ramadan fasting. METHODS CINAHL, Cochrane, EBSCOhost, EMBASE, Google Scholar, ProQuest Medical, PubMed/MEDLINE, ScienceDirect, Scopus, and Web of Science databases were searched from date of inception in 1950 to the end of August 2019. RESULTS Eighty-five studies, conducted in 25 countries during 1982-2019, were identified. RDIF yielded a significant, but small reduction in body weight (K = 85, number of subjects, N = 4176 (aged 16-80 years), Hedges' g =- 0.360, 95% confidence interval (CI) - 0.405 to - 0.315, I2 = 45.6%), this effect size translates into difference in means of - 1.022 kg (95% CI - 1.164 kg to - 0.880 kg). Regression analysis for moderator covariates revealed that fasting time (min/day) is a significant (P < 0.05) moderator for weight change at the end of Ramadan, while age and sex are not. Variable effects for the season and country were found. CONCLUSION RDIF may confer a significant small reduction in body weight in non-athletic healthy people aged 16 years and above, directly associated with fasting time and variably correlated with the season, and country.
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The effect of green coffee extract supplementation on anthropometric measures in adults: A comprehensive systematic review and dose-response meta-analysis of randomized clinical trials.
Asbaghi, O, Sadeghian, M, Rahmani, S, Mardani, M, Khodadost, M, Maleki, V, Pirouzi, A, Talebi, S, Sadeghi, O
Complementary therapies in medicine. 2020;:102424
Abstract
BACKGROUND AND AIM Two meta-analyses summarized data on the effects of green coffee extract (GCE) supplementation on anthropometric measures. However, the accuracy of those meta-analyses is uncertain due to several methodological limitations. Therefore, we aimed to conduct a comprehensive systematic review and dose-response meta-analysis to summarize all available evidence on the effects of GCE supplementation on anthropometric measures by considering the main limitations in the previous meta-analyses. METHODS We searched available online databases for relevant publications up to January 2020, using relevant keywords. All randomized clinical trials (RCTs) investigating the effects of GCE supplementation, compared with a control group, on anthropometric measures [including body weight, body mass index (BMI), body fat percentage, waist circumference (WC) and waist-to-hip ratio (WHR)] were included. RESULTS After identifying 1871 studies from our initial search, 15 RCTs with a total sample size of 897 participants were included in the systematic review and meta-analysis. We found a significant reducing effect of GCE supplementation on body weight (weighted mean difference (WMD): -1.23, 95 % CI: -1.64, -0.82 kg,P < 0.001), BMI (WMD: -0.48, 95 % CI: -0.78, -0.18 kg/m2, P = 0.001), and WC (WMD: -1.00, 95 % CI: -1.70, -0.29 cm, P = 0.006). No significant effect of GCE supplementation on body fat percentage and WHR was seen. In the dose-response analyses, there was no significant association between chlorogenic acid (CGA) dosage, as the main polyphenol in green coffee, and changes in anthropometric measures. CONCLUSION We found that GCE supplementation had a beneficial effect on body weight, BMI and WC. It provides a cost-effective and safe alternative for the treatment of obesity. Additional well-designed studies are required to further confirm our findings.
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A Systematic Review and Meta-Analysis Comparing Heterogeneity in Body Mass Responses Between Low-Carbohydrate and Low-Fat Diets.
Smith, ES, Smith, HA, Betts, JA, Gonzalez, JT, Atkinson, G
Obesity (Silver Spring, Md.). 2020;(10):1833-1842
Abstract
OBJECTIVE An important notion in personalized medicine is that there is clinically relevant treatment response heterogeneity. Low-carbohydrate (CHO) and low-fat diets are widely adopted to reduce body mass. To compare individual differences in responses between two dietary interventions, a formal statistical comparison of response variances between study arms in a randomized controlled trial (RCT) is crucial. METHODS The change in variances in RCTs for the body mass responses to low-CHO dietary interventions versus change variances for the low-fat groups (typically considered as the comparator intervention) were compared. A literature search identified relevant RCTs (n = 25; 3,340 participants). The means and SDs of body mass change in low-CHO and low-fat study arms were extracted to calculate the variances of individual responses. These were meta-analyzed in a random-effects model and converted to the SD for individual responses. RESULTS The pooled SD for individual responses for body mass was 1.4 kg (95% CI: -1.1 to 2.3) with a wide 95% prediction interval of -6.3 to 10.4 kg. CONCLUSIONS Evidence is insufficient to suggest the response heterogeneity to low-CHO diets differs from that observed with low-fat diets.
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Effects of nonnutritive sweeteners on body weight and BMI in diverse clinical contexts: Systematic review and meta-analysis.
Laviada-Molina, H, Molina-Segui, F, Pérez-Gaxiola, G, Cuello-García, C, Arjona-Villicaña, R, Espinosa-Marrón, A, Martinez-Portilla, RJ
Obesity reviews : an official journal of the International Association for the Study of Obesity. 2020;(7):e13020
Abstract
There is an ongoing debate about the possible influences of nonnutritive sweeteners (NNS) on body weight. We conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) with NNS to assess their impact on body weight. We systematically searched for RCTs at least 4 weeks in duration, evaluating the effect of NNS on body weight, both in subjects with healthy weight and in subjects with overweight/obesity at any age, and compared the effects of NNS vs caloric and noncaloric comparators. The primary outcome was the difference in body weight between NNS and comparators. Twenty studies were eligible (n = 2914). Participants consuming NNS showed significant weight/BMI differences favouring NNS compared with nonusers. Grouping by nature of comparator revealed that NNS vs placebo/no intervention and NNS vs water produced no effect. When comparing NNS vs sucrose, significant weight/BMI differences appeared favouring NNS. Consumption of NNS led to significantly negative weight/BMI differences in unrestricted energy diets, but not in weight-reduction diets. Participants with overweight/obesity and adults showed significant favourable weight/BMI differences with NNS. Data suggest that replacing sugar with NNS leads to weight reduction, particularly in participants with overweight/obesity under an unrestricted diet, information that could be utilized for evidence-based public policy decisions.
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Association of anthropometry and weight change with risk of dementia and its major subtypes: A meta-analysis consisting 2.8 million adults with 57 294 cases of dementia.
Lee, CM, Woodward, M, Batty, GD, Beiser, AS, Bell, S, Berr, C, Bjertness, E, Chalmers, J, Clarke, R, Dartigues, JF, et al
Obesity reviews : an official journal of the International Association for the Study of Obesity. 2020;(4):e12989
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Abstract
Uncertainty exists regarding the relation of body size and weight change with dementia risk. As populations continue to age and the global obesity epidemic shows no sign of waning, reliable quantification of such associations is important. We examined the relationship of body mass index, waist circumference, and annual percent weight change with risk of dementia and its subtypes by pooling data from 19 prospective cohort studies and four clinical trials using meta-analysis. Compared with body mass index-defined lower-normal weight (18.5-22.4 kg/m2 ), the risk of all-cause dementia was higher among underweight individuals but lower among those with upper-normal (22.5-24.9 kg/m2 ) levels. Obesity was associated with higher risk in vascular dementia. Similarly, relative to the lowest fifth of waist circumference, those in the highest fifth had nonsignificant higher vascular dementia risk. Weight loss was associated with higher all-cause dementia risk relative to weight maintenance. Weight gain was weakly associated with higher vascular dementia risk. The relationship between body size, weight change, and dementia is complex and exhibits non-linear associations depending on dementia subtype under scrutiny. Weight loss was associated with an elevated risk most likely due to reverse causality and/or pathophysiological changes in the brain, although the latter remains speculative.