Association of Dietary Acid Load With Metabolic Syndrome and Its Components in Iranian Adults: A Cross-Sectional Study.

Introduction Metabolic syndrome (MetS) remains one of the leading health challenges worldwide. A combination of genetic and environmental factors has been implicated in the etiology of MetS. Diet is a changeable environmental risk factor, and dietary modifications could significantly reduce the incidence and mortality of numerous diseases, including MetS. Certain dietary factors may contribute to MetS by affecting the acid-base balance within the body. This study examined the association of dietary acid load (DAL) with MetS and its components in Iranian adults. Materials and methods This cross-sectional study was conducted in 2022 on 6356 Iranian adults aged 35-70 years. Potential renal acid load (PRAL) and net endogenous acid production (NEAP) as two indicators of DAL were calculated based on nutrient intake data from validated food frequency questionnaires. MetS and its components were defined according to the Adult Treatment Panel III criteria. Logistic regression analysis was used to explore the associations between DAL and MetS and its components. Age, energy intake, physical activity, education, marital status, home ownership, socioeconomic status, history of obesity-related disease, and calcium supplements were included in model I. Further adjustment in model II was made for body mass index. Results Higher NEAP scores were associated with increased odds of low high-density lipoprotein cholesterol (HDL-C) in the crude model (OR: 1.26, 95% CI: 1.01-2.56, p trend = 0.06) in women, which was confirmed in the adjusted models. In model I, women in the last quintile of NEAP had 54% greater odds of having hypertriglyceridemia compared to the first quintile (OR: 1.54, 95% CI: 1.007-2.36, p trend = 0.02). This association was still significant and even stronger after further adjustment for BMI (OR: 1.55, 95% CI: 1.01-2.40, p trend = 0.01). In addition, in model I, men in the fourth quintile of NEAP had 5.68-fold greater odds of hyperglycemia compared to the first quintile (OR: 5.68, 95% CI: 1.18-27.25, p trend = 0.11). Similar results were found in the fully adjusted model (OR: 5.89, 95% CI: 1.19-28.99, p trend = 0.54). Conclusion There was no significant association between DAL and MetS. DAL was positively associated with the odds of low HDL-C and hypertriglyceridemia in women. Moreover, moderate DAL (NEAP) was associated with an increased odds of hyperglycemia in men.

Effect of exercise as adjuvant to energy-restricted diets on quality of life and depression outcomes: a meta-analysis of randomized controlled trials.

BACKGROUND AND AIM: Obesity and related co-morbidities lead to a decrease in health-related quality of life (HRQOL) and mood. Lifestyle strategies may improve these outcomes. However, the efficacy of exercise in conjunction with a weight-loss diet on HRQOL and mood is unclear. The aim of this systematic review and meta-analysis of randomized controlled trials (RCTs) was to examine whether the addition of exercise to energy-restricted dietary programs improves HRQOL and mood status when compared with energy-restricted diets alone in overweight and obese adults. METHODS: Eligible RCTs were identified by searching PubMed/MEDLINE, EMBASE, ISI (Web of sciences), Scopus, and Google Scholar up to April 2021. Summary effects were derived using a random-effects model. The quality of evidence was assessed using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) methodology. RESULTS: The meta-analysis revealed that an energy-restricted diet plus exercise compared with an energy-restricted diet alone had no significant effects on depression (n = 6, hedges'g = - 0.04, 95% CI: - 0.28,0.20), MOS 36-Item Short-Form Health Survey (SF-36)-physical component summary scores (n = 8, weighted mean difference (WMD) = 1.51, 95% CI: - 0.16, 3.18), SF36-mental component summary scores (n = 7, WMD = 0.64, 95% CI: - 1.00, 2.28), and HRQOL disease-specific questionnaire scores (n = 5, hedges'g = 0.16, 95% CI: - 0.09, 0.40). The GRADE revealed that the quality of evidence was low for disease-specific HRQOL scores, and depression status; and high for physical and mental health assessed by SF-36. CONCLUSION: In our sample of overweight and obese adults, no beneficial effect of adding exercise to an energy-restricted diet was found in terms of HRQOL and Depression.

Does exercise beneficially affect sex hormones when added to hypo-caloric diets in adults with overweight or obesity? A systematic review and meta-analysis of controlled clinical trials.

OBJECTIVE: There is no consensus of opinion if exercise beneficially affects sex hormones if added to weight-loss diets. The purpose of this study was to perform a systematic review and meta-analysis of controlled clinical trials to evaluate the effect of adding exercise to a hypo-caloric diet during a weight-loss program, on serum testosterone, estradiol, and sex hormone-binding globulin (SHBG) in adults with overweight/obesity. DESIGN: Systematic review and meta-analysis of the literature. METHODS: Online databases including PubMed/MEDLINE, EMBASE, Scopus, ISI Web of Science, and Google Scholar were searched up to April 2021. A random-effects model was applied to compare mean changes in sex hormones and SHBG between participants undergoing a hypo-caloric diet with or without exercise. RESULTS: In total, 9 eligible clinical trials with 462 participants were included. Out of these, seven, three, and four studies illustrated changes in testosterone, estradiol, and SHBG, respectively. The meta-analysis revealed that exercise had no significant effect on circulating testosterone (WMD = -0.03 nmol/L, 95% CI: -0.11, 0.06, P = 0.51), estradiol (WMD = -0.46 pg/mL, 95% CI: -1.57, 0.65, P = 0.42), and SHBG (WMD = 0.54 nmol/L, 95% CI: -2.63, 3.71, P = 0.74) when added to low-calorie diets. CONCLUSION: The addition of exercise to a hypo-caloric diet provided no additional improvement in sex hormone profiles. Further, well-designed randomized controlled trials with longer follow-up periods in both sexes are recommended to confirm and expand the current results.

Does exercise affect bone mineral density and content when added to a calorie-restricted diet? A systematic review and meta-analysis of controlled clinical trials.

The effects of exercise in conjunction with weight-loss diets on bone health are mixed. Our objective was to systematically review and meta-analyze controlled clinical trials in adults investigating the addition of exercise to a weight-loss diet compared with a calorie-matched weight-loss diet without exercise on bone measures. Online databases including PubMed/MEDLINE, EMBASE, ISI (Web of Science), Scopus, and Google Scholar were searched up to April 2021 with no restriction. A random effects model was used to calculate the overall estimates. Quality of evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology. Fourteen eligible controlled clinical trials were included in the systematic review. The meta-analysis revealed that, compared to weight-loss diets alone, the addition of exercise did not improve total body bone mineral density (BMD) [weighted mean difference (WMD) = 0.002 g/cm2, P = 0.62, n = 8], lumbar BMD (WMD = 0.007 g/cm2, P = 0.44, n = 9), total hip BMD (WMD = 0.015 g/cm2, P = 0.14, n = 4) and total bone mineral content (BMC) (WMD = - 11.97 g, P = 0.29, n = 7). Subgroup analysis revealed that resistance exercise in conjunction with hypocaloric diets positively affects total BMD compared to an energy restrictive diet alone (WMD = 0.01 g/cm2, P = 0.003, n = 3). Overall, it appears that only resistance exercise beneficially affects total BMD during a calorie-restricted diet in adults. Further well-controlled and long-term clinical trials are still needed to confirm these results. PROSPERO registration number: CRD42020173434.

The effects of exercise and low-calorie diets compared with low-calorie diets alone on health: a protocol for systematic reviews and meta-analyses of controlled clinical trials.

BACKGROUND: Exercise and weight loss diets are two independent non-pharmaceutical strategies used to improve several aspects of body composition and health. We plan to systematically review controlled clinical trials investigating weight loss diets alone compared to weight loss diets in conjunction with exercise on energy intake, body weight, body composition, cardiometabolic risk factors, sex hormones, and mental health. METHODS AND ANALYSIS: PubMed/MEDLINE, EMBASE, ISI (Web of Science), Scopus, and Google Scholar will be searched to retrieve potential controlled clinical trials investigating the effects of exercise in conjunction with weight loss diets compared with weight loss diets alone on energy intake, body weight and composition (fat mass, fat-free mass), anthropometrics (waist circumference), cardiometabolic markers, sex hormones [testosterone, estradiol, and sex hormone binding globulin (SHBG)], liver and kidney enzymes (alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyl transferase (GGT), uric acid, blood urea nitrogen (BUN), glomerular filtration rate (GFR), quality of life, and depression in adults. The weighted mean difference (WMD) and its corresponding 95% confidence intervals (CIs) will be derived using random effects model. Several subgroup analyses based on follow-up duration, the health status of the participants, the diet used for weight loss, the exercise protocol, participants' sex, and other possible variables will be conducted to explore possible sources of heterogeneity. Publication bias will be explored by inspecting funnel plots and by conducting asymmetry tests. Overall quality of the evidence will be assessed by using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) tool. DISCUSSION: We envisage that this systematic review and meta-analysis will provide valuable information regarding the effectiveness of adding exercise to weight loss diets. No primary data is going to be collected; therefore, ethical approval is not required. The resulting manuscripts will be disseminated in peer-reviewed journals and at international and national conferences. SYSTEMATIC REVIEW REGISTRATION: The study protocol is registered in the International Prospective Register of Systematic Reviews (PROSPERO, Registration ID: CRD42020173434 ).