The impact of low advanced glycation end products diet on obesity and related hormones: a systematic review and meta-analysis

Several randomized clinical trials (RCTs) have investigated the effect of dietary advanced glycation end products (AGE) on obesity factors and related hormones in adults; results were conflicting. Therefore, a study was performed to assess the effect of low advanced glycation end products diet on obesity and related hormones. A comprehensive literature search without any limitation on language was conducted using the following bibliographical databases: Web of Science, Scopus, Ovid MEDLINE, Cochrane, and Embase up to October, 2019. From the eligible trials, 13 articles were selected for the systematic review and meta-analysis. Our systematic reviews and meta-analyses have shown a significant decrease in BMI (WMD: � 0.3 kg/m2; 95 CI: � 0.52, � 0.09, p = 0.005; I2 = 55.8), weight (WMD: � 0.83 kg; 95 CI: � 1.55, � 0.10, p = 0.026; I2 = 67.0), and leptin (WMD: � 19.85 ng/ml; 95 CI: � 29.88, � 9.82, p < 0.001; I2 = 81.8) and an increase in adiponectin (WMD: 5.50 µg/ml; 95 CI: 1.33, 9.67, p = 0.010; I2 = 90.6) levels after consumption of the low AGE diets compared to the high AGE diets. Also, the effect of intake of low AGE compared to high AGE diets was more pronounced in subgroup with duration > 8 weeks for the BMI and weight. Overall, according to our results, although low AGE diets appeared to be statistically significant in reducing the prevalence of obesity and chronic diseases compared to high consumption of dietary AGEs. But, no clinical significance was observed. Therefore, to confirm these results clinically, further prospective studies should be conducted in this regard. The study protocol was registered in the in International prospective register of systematic reviews (PROSPERO) database as CRD42020203734. © 2020, The Author(s)

Association of the insulinemic potential of diet and lifestyle with risk of diabetes incident in Tehranian adults: a population based cohort study

Background: We aimed to assess the associations between insulinemic potential of diet and lifestyle and the risk of diabetes incident, using four empirical indices including the empirical dietary index for hyperinsulinemia (EDIH), the empirical dietary index for insulin resistance (EDIR), empirical lifestyle index for hyperinsulinemia (ELIH), and empirical lifestyle index for insulin resistance (ELIR). Methods: A total of 3734 individuals, aged � 20 years old, who were free of diabetes at baseline (2008�2011), were followed for 6.2 years (2015�2018) to ascertain incident diabetes. The food frequency questionnaire was used to collect dietary intakes at baseline. Odds ratio (OR) of diabetes were calculated across quartiles of EDIH, EDIR, ELIH, and ELIR using logistic regression, which controlled for confounding factors. Results: The mean ± SD age and BMI of individuals (45.1 male) were 40.9 ± 12.0 years and 27.1 ± 4.1 kg/m2, respectively. At the end of follow-up, 253 (6.8 ) diabetes cases were identified. In the multivariable-adjusted model, individuals in the highest quartile of EDIR (1.58;95 CI:1.03�2.44, P for trend = 0.025), ELIH (1.89;95 CI:1.20�2.97, P for trend = 0.004), and ELIR (1.74; 95 CI:1.11�2.72, P for trend = 0.031) had increased the risk of diabetes. However, no significant associations were found between the score of EDIH and diabetes incident. Conclusions: Higher adherence to EDIR, ELIH, and ELIR scores were associated with increased risk of diabetes, while no significant association was found between EDIH score and diabetes incident. © 2021, The Author(s)

Dietary and lifestyle inflammatory scores and risk of incident diabetes: a prospective cohort among participants of Tehran lipid and glucose study

Background: Inflammation is a precursor of chronic disease, which is affected by lifestyle and dietary habits. Recently empirical dietary inflammatory patterns (EDIP), dietary inflammation scores (DIS), and lifestyle inflammation scores (LIS) were developed to indicate lifestyle and dietary contributions in systemic inflammation. The current study aimed to investigate the associations between these indices and the incidence of diabetes among Tehranian adults. Methods: A total of 4624 individuals, aged 20�75 years, who were free of diabetes at baseline (2008�2011), were followed for 5.71 years (2014�2017) to ascertain incident diabetes. Dietary intakes were collected at baseline using the food frequency questionnaire. The hazard ratio (HR) of diabetes was calculated by Cox proportional hazards regression across quartiles of EDIP, DIS, and LIS, adjusted for potential confounders. Results: The mean ± SD for the age and BMI of the study population (45.1 male) were 40.8 ± 12.7 years and 27.1 ± 4.1 Kg.m2, respectively. At the end of the follow-up, 329 (7.1) diabetes cases were identified. In the multivariable-adjusted model, individuals in the highest compared to the lowest quartile of EDIP (HR = 0.83; 95CI:0.59�1.15, p for trend = 0.286), and LIS (HR = 2.41; 95CI:1.61�3.60, P for trend < 0.001) had increased risk of diabetes. However, no significant associations were found between the score of DIS and diabetes incidents (HR = 0.83; 95CI:0.59�1.15, p for trend = 0.286). Conclusion: Greater adherence to EDIP and LIS scores was associated with a higher risk of diabetes, while no significant association was found between the DIS score and diabetes incident. © 2021, The Author(s)

The effect of nigella sativa on biomarkers of inflammation and oxidative stress: A systematic review and meta-analysis of randomized controlled trials

Inflammation and oxidative stress are involved in the pathogenesis of a myriad of chronic disorders. This systematic review and meta-analysis was designed to determine the effects of Nigella Sativa (NS) seed and seed oil consumption on several biomarkers of inflammation and oxidative stress. The Scopus, Web of Science, and PubMed-MEDLINE databases were systematically searched until August 2019. The quality assessment and heterogeneity of the selected randomized clinical trials (RCTs) were measured using the Jadad checklist, and Q and I2 tests, respectively. Finally, a total of 10 clinical RCTs were found to be eligible for this meta-analysis. The pooled findings showed that NS consumption significantly reduced serum high-sensitivity C-reactive protein (hs-CRP; WMD: �0.67, 95 CI: �1.29, �0.05, I2 = 95.7), tumor necrosis factor-alpha (TNF-α; WMD: �2.29, 95 CI: �4.48, �0.11, I2 = 93), and malondialdehyde (MDA; WMD: �1.18, 95 CI: �2.24, �0.12, I2 = 85.4), and significantly increased total antioxidant capacity (TAC; WMD: 0.35, 95 CI: 0.10, 0.59, I2 = 77.1), and superoxide dismutase (SOD; WMD: 66.30, 95 CI: 1.03, 131.57, I2 = 99.4) levels. Overall, the results of this systematic review and meta-analysis imply that NS consumption may decrease inflammatory response and oxidative stress markers. Practical applications: Overall, the evidence supports the consumption of NS to reduce hs-CRP, TNF-α, and MDA, and to increase SOD and TAC levels. In addition, the subgroup analyses findings concluded that lower dosages of NS, longer durations of the intervention, and the use of NS seed oil may result in more effective action on inflammatory markers, but because of the limited number of trials, the results must be analyzed with caution, especially for the subgroup analysis. However, further prospective studies regarding the effect of NS consumption on biomarkers of inflammation and oxidative stress, with larger sample sizes, from various countries and longer follow-up periods, are required to confirm whether NS possesses veritable anti-inflammatory and antioxidant effects. © 2021 Wiley Periodicals LLC

Association of dietary fiber and depression symptom: A systematic review and meta-analysis of observational studies

Background: A potential relationship between depression and the intake of dietary fiber has been hypothesized in several studies. However, no meta-analysis has been conducted so far to explore the association between these two variables. Hence, we designed the present meta-analysis to elucidate the relationship between the intake of dietary fiber and depression. Methods: A comprehensive search was performed using the PubMed/Medline, Scopus, Web of Science and Google Scholar databases to identify any relevant studies published from inception to October 2019. Observational studies (cross-sectional and case-control) were included in the analysis. Results: Pooled analysis from the random-effects model of four case-control studies revealed that the consumption of dietary fiber in patients with depression was significantly lower versus healthy controls (WMD: -1.41 mg/dl, 95 CI: �2.32, �0.51, P = 0.002). No significant heterogeneity was demonstrated among the analyzed studies (I2 = 4.0 , P = 0.37). By pooling 5 effect sizes of cross-sectional studies (with a total of 97,023 subjects), we demonstrated that a higher dietary consumption of fiber was associated with significantly lower odds of depression (OR = 0.76; 95 CI: 0.64, 0.90; P = 0.010), with a low heterogeneity seen among the retrieved studies (I2 = 43.9 ; P = 0.12). Conclusion: An increased intake of total dietary fiber is associated with lower odds of depression. Further studies are needed to evaluate the relationship between the different types of dietary fiber and depression. © 202

The Impact of Low Advanced Glycation End Products Diet on Metabolic Risk Factors: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Several randomized clinical trials have investigated the effect of dietary advanced glycation end products (AGEs) on metabolic syndrome risk factors in adults. However, the results of these studies were conflicting. Therefore, our aim was to assess the effect of dietary AGEs on metabolic syndrome risk factors. We searched the PubMed-MEDLINE, Scopus, Cochrane Databases, Google Scholar, Web of Science, and Embase databases for papers published up to October 2019 that investigated the effect of dietary AGEs on metabolic syndrome risk factors. From the eligible trials, 13 articles were selected for inclusion in this systematic review and meta-analysis. The meta-analysis was performed using a random-effects model. Heterogeneity was determined by I2 statistics and Cochrane Q test. Pooled results from the random-effects model showed a significant reduction for insulin resistance weighted mean difference (WMD): -1.204; 95% CI: -2.057, -0.358; P = 0.006, fasting insulin (WMD: -5.472 μU/mL; 95% CI: -9.718, -1.234 μU/mL; P = 0.011), total cholesterol (WMD: -5.486 mg/dL; 95% CI: -10.222, -0.747 mg/dL; P = 0.023), and LDL (WMD: -6.263 mg/dL; 95% CI: -11.659, -0.866 mg/dL; P = 0.023) in the low-AGEs groups compared with the high-AGEs groups. There were no changes in the other components of the metabolic syndrome. The results of this review suggest that a diet with a low AGEs content has beneficial effects on insulin resistance, fasting insulin, total cholesterol, and LDL. Moreover, following a diet low in AGEs may be a helpful strategy to decrease the burden of metabolic syndrome risk factors in adults and particularly in patients with diabetes. © 2020 The Author(s). Published by Oxford University Press on behalf of the American Society for Nutrition

The Impact of Chromium Supplementation on Blood Pressure: A Systematic Review and Dose�Response Meta�Analysis of Randomized�Controlled Trials

Introduction: Potential effects of chromium supplementation on blood pressure (BP) have been examined in several interventional studies. Nevertheless, findings in this context are controversial. Aim: Therefore, the current systematic review and meta-analysis aimed to comprehensively assess the impact of chromium supplementation on BP. Methods: Five online databases including Web of Science, Scopus, Embase, Google Scholar, and PubMed were systematically searched from inception to March 2020. We included all randomized clinical trials (RCTs) evaluating the effects of chromium supplementation on systolic blood pressure (SBP) and/or diastolic blood pressure (DBP) in humans. Results: The random-effects meta-analysis of 11 eligible RCTs with 637 participants demonstrated the significant decline in both SBP (WMD � 2.51 mmHg; 95 CI � 4.97 to � 0.05, p = 0.04) and DBP (WMD � 1.04 mmHg; 95 CI � 1.96 to � 0.12, p = 0.026) following supplementation with chromium. In subgroup analysis, studies that were administered chromium yeast and brewer's yeast, showed greater decrease in SBP. Also, in stratification based on participants' health status, significant reduction in SBP only was seen in diabetic patients with chronic heart disease (CHD). Nonlinear dose-response analysis revealed a significant influence of chromium dosage on SBP changes. Conclusion: The current meta-analysis, indicated that supplementation with chromium significantly decrease SBP and DBP. In subgroup analysis, administration of chromium yeast and brewer�s yeast resulted in greater reduction in SBP. Further large-scale RCTs with better design are needed to confirm these findings. © 2021, Italian Society of Hypertension

The effect of nigella sativa on biomarkers of inflammation and oxidative stress: A systematic review and meta-analysis of randomized controlled trials

Inflammation and oxidative stress are involved in the pathogenesis of a myriad of chronic disorders. This systematic review and meta-analysis was designed to determine the effects of Nigella Sativa (NS) seed and seed oil consumption on several biomarkers of inflammation and oxidative stress. The Scopus, Web of Science, and PubMed-MEDLINE databases were systematically searched until August 2019. The quality assessment and heterogeneity of the selected randomized clinical trials (RCTs) were measured using the Jadad checklist, and Q and I2 tests, respectively. Finally, a total of 10 clinical RCTs were found to be eligible for this meta-analysis. The pooled findings showed that NS consumption significantly reduced serum high-sensitivity C-reactive protein (hs-CRP; WMD: �0.67, 95 CI: �1.29, �0.05, I2 = 95.7), tumor necrosis factor-alpha (TNF-α; WMD: �2.29, 95 CI: �4.48, �0.11, I2 = 93), and malondialdehyde (MDA; WMD: �1.18, 95 CI: �2.24, �0.12, I2 = 85.4), and significantly increased total antioxidant capacity (TAC; WMD: 0.35, 95 CI: 0.10, 0.59, I2 = 77.1), and superoxide dismutase (SOD; WMD: 66.30, 95 CI: 1.03, 131.57, I2 = 99.4) levels. Overall, the results of this systematic review and meta-analysis imply that NS consumption may decrease inflammatory response and oxidative stress markers. Practical applications: Overall, the evidence supports the consumption of NS to reduce hs-CRP, TNF-α, and MDA, and to increase SOD and TAC levels. In addition, the subgroup analyses findings concluded that lower dosages of NS, longer durations of the intervention, and the use of NS seed oil may result in more effective action on inflammatory markers, but because of the limited number of trials, the results must be analyzed with caution, especially for the subgroup analysis. However, further prospective studies regarding the effect of NS consumption on biomarkers of inflammation and oxidative stress, with larger sample sizes, from various countries and longer follow-up periods, are required to confirm whether NS possesses veritable anti-inflammatory and antioxidant effects. © 2021 Wiley Periodicals LLC

Association between abnormal maternal serum levels of Vitamin B12and preeclampsia: A systematic review and meta-analysis

Context: Some evidence has shown an association between maternal Vitamin B12 levels and the development of preeclampsia in pregnant women, but the relationship between preeclampsia and Vitamin B12 is not clear. Objective: The aim of this systematic review was to compare serum Vitamin B12 levels in women with preeclampsia with those in normotensive pregnant women. Data Sources: The PubMed/MEDLINE, Scopus, and Web of Science databases were searched up to August 2019, along with the reference lists of included articles. Study Selection: The literature was searched for observational studies that investigated Vitamin B12 levels in women with preeclampsia. Data Extraction: Data were extracted independently by 2 authors. Data were pooled using a random-effects model. Results: Vitamin B12 levels in women with preeclampsia were significantly lower than those in healthy women (mean,-15.24 pg/mL; 95CI,-27.52 to-2.954; P < 0.015), but heterogeneity between studies was high (I2â=â97.8; P = 0.0103). Subgroup analyses based on folic acid supplementation, homocysteine concentrations, and gestational age at the time of sampling for Vitamin B12 assessment did not identify the sources of heterogeneity. Conclusions: Women with preeclampsia had significantly lower Vitamin B12 concentrations than normotensive pregnant women. © 2020 The Author(s) 2020. Published by Oxford University Press on behalf of the International Life Sciences Institute. All rights reserved

Association between glycemic index and Helicobacter pylori infection risk among adults: A case-control study

Objectives: The aim of this case-control study was to investigate the relationships between carbohydrate consumption, glycemic load (GL), glycemic index (GI), and the risk of Helicobacter pylori infection among adults admitted to an Iranian hospital. Methods: In this case-control study, we recruited 150 participants with H. pylori infection and 302 healthy participants ages 18 to 55. Dietary GI and GL were assessed using a validated 168-item quantitative food frequency questionnaire. Dietary GL was calculated as a function of GI, carbohydrate content, and the frequency of intake of certain foods. Results: After adjustment for potential confounders, and comparing the highest tertile with the lowest tertile, a significant direct association was observed between the consumption of carbohydrates (odds ratio OR = 2.87; 95% confidence interval CI, 1.18�6.96; P for trend = 0.017), GI (OR = 3.70; 95% CI, 2.01�6.81; P for trend < 0.001), GL (OR = 3.06; 95% CI, 1.43�6.54; P for trend = 0.001), the consumption of bread and refined-grain products (OR = 4.24; 95% CI, 2.22�8.11; P for trend < 0.001), and the odds of H. pylori infection (OR = 2.22; 95% CI, 1.30�3.79; P for trend = 0.003). Conclusions: Our data suggest that a high dietary GL, high GI, and high consumption of dietary carbohydrates significantly elevate the risk of H. pylori infection. Also, the amount of bread and refined-grain products consumed had a significant positive relationship with H. pylori infection. © 202