The effects of green tea extract supplementation on body composition, obesity-related hormones and oxidative stress markers: a grade-assessed systematic review and dose-response meta-analysis of randomised controlled trials.

Research indicates that green tea extract (GTE) supplementation is beneficial for a range of conditions, including several forms of cancer, CVD and liver diseases; nevertheless, the existing evidence addressing its effects on body composition, oxidative stress and obesity-related hormones is inconclusive. This systematic review and meta-analysis aimed to investigate the effects of GTE supplementation on body composition (body mass (BM), body fat percentage (BFP), fat mass (FM), BMI, waist circumference (WC)), obesity-related hormones (leptin, adiponectin and ghrelin) and oxidative stress (malondialdehyde (MDA) and total antioxidant capacity (TAC)) markers. We searched proper databases, including PubMed/Medline, Scopus and Web of Science, up to July 2022 to recognise published randomised controlled trials (RCT) that investigated the effects of GTE supplementation on the markers mentioned above. A random effects model was used to carry out a meta-analysis. The heterogeneity among the studies was assessed using the I2 index. Among the initial 11 286 studies identified from an electronic database search, fifty-nine studies involving 3802 participants were eligible to be included in this meta-analysis. Pooled effect sizes indicated that BM, BFP, BMI and MDA significantly reduced following GTE supplementation. In addition, GTE supplementation increased adiponectin and TAC, with no effects on FM, leptin and ghrelin. Certainty of evidence across outcomes ranged from low to high. Our results suggest that GTE supplementation can attenuate oxidative stress, BM, BMI and BFP, which are thought to negatively affect human health. Moreover, GTE as a nutraceutical dietary supplement can increase TAC and adiponectin.

The effects of conjugated linoleic acid supplementation on anthropometrics and body composition indices in adults: a systematic review and dose-response meta-analysis.

Prior meta-analytic investigations over a decade ago rather inconclusively indicated that conjugated linoleic acid (CLA) supplementation could improve anthropometric and body composition indices in the general adult population. More recent investigations have emerged, and an up-to-date systematic review and meta-analysis on this topic must be improved. Therefore, this investigation provides a comprehensive systematic review and meta-analysis of randomised controlled trials (RCT) on the impact of CLA supplementation on anthropometric and body composition (body mass (BM), BMI, waist circumference (WC), fat mass (FM), body fat percentage (BFP) and fat-free mass (FFM)) markers in adults. Online databases search, including PubMed, Scopus, the Cochrane Library and Web of Science up to March 2022, were utilised to retrieve RCT examining the effect of CLA supplementation on anthropometric and body composition markers in adults. Meta-analysis was carried out using a random-effects model. The I2 index was used as an index of statistical heterogeneity of RCT. Among the initial 8351 studies identified from electronic databases search, seventy RCT with ninety-six effect sizes involving 4159 participants were included for data analyses. The results of random-effects modelling demonstrated that CLA supplementation significantly reduced BM (weighted mean difference (WMD): -0·35, 95 % CI (-0·54, -0·15), P < 0·001), BMI (WMD: -0·15, 95 % CI (-0·24, -0·06), P = 0·001), WC (WMD: -0·62, 95% CI (-1·04, -0·20), P = 0·004), FM (WMD: -0·44, 95 % CI (-0·66, -0·23), P < 0·001), BFP (WMD: -0·77 %, 95 % CI (-1·09, -0·45), P < 0·001) and increased FFM (WMD: 0·27, 95 % CI (0·09, 0·45), P = 0·003). The high-quality subgroup showed that CLA supplementation fails to change FM and BFP. However, according to high-quality studies, CLA intake resulted in small but significant increases in FFM and decreases in BM and BMI. This meta-analysis study suggests that CLA supplementation may result in a small but significant improvement in anthropometric and body composition markers in an adult population. However, data from high-quality studies failed to show CLA's body fat-lowering properties. Moreover, it should be noted that the weight-loss properties of CLA were small and may not reach clinical importance.

The association of ultra-processed food intake with neurodegenerative disorders: a systematic review and dose-response meta-analysis of large-scale cohorts.

OBJECTIVES: Our systematic review and meta-analysis aimed to uncover the relationship between UPFs intake and neurodegenerative disorders, including multiple sclerosis (MS), Parkinson's disease (PD), Alzheimer's disease (AD), cognitive impairment, and dementia. SETTING: A systematic search was conducted using the Scopus, PubMed/MEDLINE, and ISI Web of Science databases without any limitation until June 24, 2023. Relative risk (RR) and 95% confidence interval (CI) were pooled by using a random-effects model, while validated methods examined quality and publication bias via Newcastle-Ottawa Scale, Egger's regression asymmetry, and Begg's rank correlation tests, respectively. RESULTS: Analysis from 28 studies indicated that a higher UPFs intake was significantly related to an enhanced risk of MS (RR = 1.15; 95% CI: 1.00, 1.33; I2 = 37.5%; p = 0.050; n = 14), PD (RR = 1.56; 95% CI: 1.21, 2.02; I2 = 64.1%; p = 0.001; n = 15), and cognitive impairment (RR = 1.17; 95% CI: 1.06, 1.30; I2 = 74.1%; p = 0.003; n = 17), although not AD or dementia. We observed that a 25 g increment in UPFs intake was related to a 4% higher risk of MS (RR = 1.04; 95% CI: 1.01, 1.06; I2 = 0.0%; p = 0.013; n = 7), but not PD. The non-linear dose-response relationship indicated a positive non-linear association between UPF intake and the risk of MS (Pnonlinearity = 0.031, Pdose-response = 0.002). This association was not observed for the risk of PD (Pnonlinearity = 0.431, Pdose-response = 0.231). CONCLUSION: These findings indicate that persistent overconsumption of UPFs may have an adverse impact on neurodegenerative conditions, potentially leading to a decline in quality of life and reduced independence as individuals age.

The effect of acarbose on inflammatory cytokines and adipokines in adults: a systematic review and meta-analysis of randomized clinical trials.

BACKGROUND: Although a large number of trials have observed an anti-inflammatory property of acarbose, the currently available research remains controversial regarding its beneficial health effects. Hence, the purpose of this study was to examine the effect of acarbose on inflammatory cytokines and adipokines in adults. METHODS: PubMed, Web of Science, and Scopus were systematically searched until April 2023 using relevant keywords. The mean difference (MD) of any effect was calculated using a random-effects model. Weighted mean difference (WMD) and 95% confidence intervals (CIs) were calculated via the random-effects model. RESULTS: The current meta-analysis of data comprised a total of 19 RCTs. Meta-analysis showed that acarbose significantly decreased tumor necrosis factor-alpha (TNF-α) (weighted mean difference [WMD]) = - 4.16 pg/ml, 95% confidence interval (CI) - 6.58, - 1.74; P = 0.001) while increasing adiponectin (WMD = 0.79 ng/ml, 95% CI 0.02, 1.55; P = 0.044). However, the effects of acarbose on TNF-α concentrations were observed in studies with intervention doses ≥ 300 mg/d (WMD = - 4.09; 95% CI - 7.00, - 1.18; P = 0.006), and the adiponectin concentrations were significantly higher (WMD = 1.03 ng/ml, 95%CI 0.19, 1.87; P = 0.016) in studies in which the duration of intervention was less than 24 weeks. No significant effect was seen for C-reactive protein (CRP; P = 0.134), interleukin-6 (IL-6; P = 0.204), and leptin (P = 0.576). CONCLUSION: Acarbose had beneficial effects on reducing inflammation and increasing adiponectin. In this way, it may prevent the development of chronic diseases related to inflammation. However, more studies are needed.

Creatine supplementation and VO2max: a systematic review and meta-analysis.

Although creatine supplementation is well-known to increase exercise performance in acute high-intensity exercises, its role in aerobic performance based on VO2max is more controversial. Thus, we performed a systematic review and meta-analysis on the effects of creatine supplementation on VO2max. PubMed, Cochrane, Embase, and ScienceDirect were searched for randomized controlled trials (RCTs) reporting VO2max in creatine supplementation and placebo groups before and after supplementation. We computed a random-effects meta-analysis on VO2max at baseline, within groups following supplementation, on changes on VO2max between groups, and after supplementation between groups. Sensitivity analyses and meta-regression were conducted. We included 19 RCTs for a total of 424 individuals (mean age 30 years old, 82% men). VO2max did not differ at baseline between groups (creatine and placebo). Participants in both groups were engaged in exercise interventions in most studies (80%). Using changes in VO2max, VO2max increased in both groups but increased less after creatine supplementation than placebo (effect size [ES] = -0.32, 95%CI = -0.51 to -0.12, p = 0.002). Comparisons after creatine supplementation confirmed a lower VO2max in the creatine group compared to the placebo group (ES= -0.20, 95%CI = -0.39 to -0.001, p = 0.049). Meta-analysis after exclusion from meta-funnel resulted in similar outcomes in a subgroup of young and healthy participants. Meta-regressions on characteristics of supplementation, physical training, or sociodemographic were not statistically significant. Creatine supplementation has a negative effect on VO2max, regardless of the characteristics of training, supplementation, or population characteristics.Supplemental data for this article is available online at https://doi.org/10.1080/10408398.2021.2008864 .

Folic acid supplementation and blood pressure: a GRADE-assessed systematic review and dose-response meta-analysis of 41,633 participants.

Hypertension is a predisposing factor for cardiovascular disease (CVD). The extant literature regarding the effects of folic acid supplementation on blood pressure (BP) is inconsistent. Therefore, this systematic review and meta-analysis of randomized controlled trials was conducted to summarize the effects of folic acid supplementation on BP. A systematic search was carried out in PubMed, Scopus, ISI Web of Science, and Cochrane library, from database inception to August 2021. Data were pooled using the random-effects method and were expressed as weighted mean difference (WMD) and 95% confidence intervals (CI). The pooled results of 22 studies, including 41,633 participants, showed that folic acid supplementation significantly decreased systolic BP (SBP) (WMD: -1.10 mmHg; 95% CI: -1.93 to -0.28; p = 0.008). Subgroup analysis showed that the results remained significant when baseline SBP was ≥120 mmHg, intervention duration was ≤6 weeks, intervention dose was ≥5 mg/d, in patients with CVD, males and females, and overweight participants, respectively. Furthermore, the changes observed in diastolic BP (DBP) (WMD: -0.24 mmHg; 95% CI: -0.37 to -0.10; p < 0.001) were also statistically significant. However, subgroup analysis showed that the results remained significant in subject with elevated DBP, long term duration of intervention (>6 weeks), low dose of folic acid (<5 mg/day), CVD patients, both sexes and male, and participants with normal BMI. Dose-response analysis showed that folic acid supplementation changed SBP and DBP significantly based on dose and duration. However, meta-regression analysis did not reveal any significant association between dose and duration of intervention with changes in SBP. The present study demonstrates the beneficial effects of folic acid supplementation on BP by decreasing both SBP and DBP.

Effects of collagen peptide supplementation on cardiovascular markers: a systematic review and meta-analysis of randomised, placebo-controlled trials.

Previous studies have advocated that collagen peptide supplementation (CPS) can positively affect cardiovascular health. However, the widespread impact of CPS on CVD-related markers is not fully resolved. Consequently, the current systematic review and meta-analysis aimed to assess the efficacy of CPS on CVD-related markers. A systematic search in the Scopus, PubMed and ISI Web of Science databases were completed to identify relevant randomised, placebo-controlled trials (RCT) published up to November 2021. Mean Differences were pooled using a random-effects model, while publication bias, sensitivity analyses and heterogeneity were assessed using previously validated methods. Twelve RCT, comprising of a total of eleven measured markers, were selected for the quantitative analysis. Pooled data revealed that CPS significantly decreased fat mass (-1·21 kg; 95 % CI: -2·13, -0·29; I2 = 0·0 %; P = 0·010) and increased fat-free mass, based on body mass percentage (1·49 %; 95 % CI: 0·57, 2·42; I2 = 0·0 %; P = 0·002). Moreover, collagen peptide supplementation led to a significant decrease in serum LDL (-4·09 mg/dl; 95 % CI: -8·13, -0·04; I2 = 93·4 %; P = 0·048) and systolic blood pressure (SBP) (-5·04 mmHg; 95 % CI: -9·22, -0·85; I2 = 98·9 %; P = 0·018). Our analysis also indicated that CPS did not affect glycemic markers. Our outcomes indicate that CPS reduces fat mass, LDL and SBP while increasing fat-free mass. Future investigations with longer CPS duration are needed to expand on our results.

The effects of guar gum supplementation on lipid profile in adults: a GRADE-assessed systematic review, meta-regression and dose-response meta-analysis of randomised placebo-controlled trials.

Recent meta-analytic work indicated that guar gum supplementation might improve lipid profile markers in different populations. However, critical methodological limitations such as the use of some unreliable data and the lack of inclusion of several relevant studies, and the scarcity in assessments of regression and dose-specific effects make it difficult to draw meaningful conclusions from the meta-analysis. Therefore, current evidence regarding the effects of guar gum supplementation on lipid profile remains unclear. The present systematic review, meta-regression and dose-response meta-analysis aimed to examine the effects of guar gum supplementation on lipid profile (total cholesterol (TC), LDL, TAG and HDL) in adults. Relevant studies were obtained by searching the PubMed, SCOPUS, Embase and Web of Science databases (from inception to September 2021). Weighted mean differences (WMD) and 95 % CI were estimated via a random-effects model. Heterogeneity, sensitivity analysis and publication bias were reported using standard methods. Pooled analysis of nineteen randomised controlled trials (RCT) revealed that guar gum supplementation led to significant reductions in TC (WMD: -19·34 mg/dl, 95 % CI -26·18, -12·49, P < 0·001) and LDL (WMD: -16·19 mg/dl, 95 % CI -25·54, -6·83, P = 0·001). However, there was no effect on TAG and HDL among adults in comparison with control group. Our outcomes suggest that guar gum supplementation lowers TC and LDL in adults. Future large RCT on various populations are needed to show further beneficial effects of guar gum supplementation on lipid profile and establish guidelines for clinical practice.

The association of ultra-processed food consumption with adult mental health disorders: a systematic review and dose-response meta-analysis of 260,385 participants.

OBJECTIVE: We aimed to conduct a systematic review and meta-analysis of observational studies examining the relationship between ultra-processed food (UPF) consumption and the risk of mental health disorders. METHODS: The ISI Web of Science, PubMed/MEDLINE, and Scopus databases were searched without date restriction until 28 December 2021. Data were extracted from 26 studies, including 260,385 participants from twelve countries. Risk ratios for mental health disorders were pooled by a random-effects model. RESULTS: Meta-analyses suggested that UPF consumption was associated with an increased risk of depression (RR = 1.28; 95% CI: 1.19, 1.38; I2 = 61.8%; p = 0.022) but not anxiety (RR = 1.35; 95% CI: 0.86, 2.11; I2 = 77.8%; p = 0.198). However, when analyzed for the dietary assessment method, UPF consumption was significantly associated with an enhanced risk of depression among studies utilizing food frequency questionnaires (RR = 1.31; 95% CI: 1.21, 1.41; I2 = 60.0%; p < 0.001) as opposed to other forms of dietary recall approaches. Additionally, for every 10% increase in UPF consumption per daily calorie intake, 11% higher risk of depression (RR = 1.11; 95% CI: 1.01, 1.17; I2 = 88.9%; p < 0.001) was observed among adults. Dose-response analysis further emphasized a positive linear association between UPF consumption with depression risk (p-nonlinearity = 0.819, p-dose-response = p < 0.001). CONCLUSION: Our findings indicate that UPF consumption is related to an enhanced depressive mental health status risk. There may be different causes for this increased risk, and further studies are needed to investigate if there is a causal relationship between consumption of UPF and mental health.

Daytime napping and coronary heart disease risk in adults: a systematic review and dose-response meta-analysis.

PURPOSE: The present study investigated the association between daytime napping and coronary heart disease (CHD) risk among adults. METHODS: Articles were detected by using PubMed, ISI Web of Science, and Scopus databases until November 8th, 2021. The relevant data were found among the eight included articles and were pooled for meta-analysis in adult participants via a random-effects model. RESULTS: Among 167,025 adults, the results revealed that daytime napping was associated with an enhanced risk of CHD (risk ratios [RR] = 1.30; 95% CI: 1.06, 1.60; p < 0.001). Subgroup analysis by daytime napping duration also indicated that daytime napping for at least 1 h had three times higher influence on the enhanced risk of CHD (RR = 1.34; 95% CI: 1.14, 1.58; p < 0.001) than that of daytime napping for less than 1 h (RR = 1.10; 95% CI: 1.02, 1.19; p = 0.014). In addition, subgroup analysis by region illustrated that daytime napping was linked with an enhanced risk of CHD in Chinese (RR = 1.41; 95% CI: 1.19, 1.66; p < 0.001), but not in European or American populations. Furthermore, the subgroup analysis of napping duration and risk of CHD suggested that their relation was significant just in those studies that controlled for depressive symptoms (RR = 1.52; 95% CI: 1.29, 1.80; p < 0.001, n = 3) and night sleep duration (RR = 1.42; 95% CI: 1.21, 1.66; p < 0.001, n = 5). The linear dose-response meta-analysis revealed that each 15-min increase in daytime napping was related with a 5% higher risk of CHD (RR = 1.05; 95% CI: 1.02, 1.08; I2 = 58.7%; p < 0.001). Furthermore, nonlinear dose-response meta-analysis revealed a positive linear relationship between daytime napping and CHD risk in adults (p nonlinearity = 0.484, p dose-response = 0.003). CONCLUSION: Results showed that daytime napping was related with an increased risk of CHD in adults. The evidence from this study suggests that the public should be made conscious of the adverse outcomes of long daytime napping for CHD, notably among the Chinese population. Additional studies are required to confirm potential links between CHD risk and daytime napping.

The effects of Gymnema Sylvestre supplementation on lipid profile, glycemic control, blood pressure, and anthropometric indices in adults: A systematic review and meta-analysis.

There is a growing interest in the considerable health benefits of Gymnema Sylvestre (GS) supplementation, as some studies have reported that it may improve cardiometabolic risk factors. However, the widespread impact of GS supplementation on the parameters mentioned above is not fully resolved. Consequently, this study aimed to examine the effects of GS supplementation on lipid profile, glycemic control, blood pressure, and anthropometric indices in adults. Eligible randomized controlled trials (RCT), published up to November 2021, were identified through PubMed, Scopus, and ISI Web of Science databases. Six studies were included and analyzed using a random-effects model to calculate weighted mean differences (WMDs) with 95% confidence intervals (CI). All studies were conducted in adults that used a GC supplement (>1 week) and assessed our selected cardiovascular risk factors. Outcomes revealed that GS supplementation significantly decreased triglyceride (p < .001), total cholesterol (p < .001), low-density lipoprotein (p < .001), fasting blood sugar (p < .001), and diastolic blood pressure (p = .003). Some limitations, including notable heterogeneity, low quality of studies, and lack of diversity among research participants, should be considered when interpreting our results. Our outcomes suggest that GS supplementation may improve cardiovascular risk factors. Future large-high-quality RCTs with longer duration and various populations are needed to firmly establish the clinical efficacy of the plant.

Cardiorespiratory Fitness and Bone Turnover Markers in Adults With Metabolic Syndrome: The Mediator Role of Inflammation.

The relationship between inflammatory markers and bone turnover in adults is well known, and a negative association between cardiorespiratory fitness (CRF) and inflammatory markers has also been described. Hence, we tested whether the association between CRF and bone turnover markers is mediated by inflammatory markers in adults with metabolic syndrome. A total of 81 adults (58.5 ± 5.0 years, 62.7% women) were included in the analysis. CRF was measured by the 6-min walking test. Serum interleukin (IL)-1ß, IL-6, IL-10, tumor necrosis factor alpha, high-sensitivity c-reactive protein (hsCRP) and vascular endothelial growth factor, collagen type I cross-linked C-telopeptide, procollagen type I N-terminal propeptide (P1NP), and total osteocalcin were assessed using a sensitive ELISA kit. Body composition was assessed by dual-energy X-ray absorptiometry. Partial correlation was used to test the relationship between CRF, inflammatory markers, and bone turnover markers, controlling for sex, lean mass, and fat mass. Boot-strapped mediation procedures were performed, and indirect effects with confidence intervals not including zero were interpreted as statistically significant. CRF was positively correlated with P1NP levels (r = .228, p = .044) and osteocalcin levels (r = .296, p = .009). Furthermore, CRF was positively correlated with IL-1ß levels (r = .340, p = .002) and negatively correlated with hsCRP levels (r = -.335, p = .003), whereas IL-1ß levels were positively correlated with P1NP levels (r = .245, p = .030), and hsCRP levels were negatively correlated with P1NP levels (r = -.319, p = .004). Finally, the association between CRF and P1NP levels was totally mediated by hsCRP (percentage of mediation = 39.9). Therefore, CRF benefits on bone formation could be dependent on hsCRP concentrations in this population.

Effects of resistance training combined with a ketogenic diet on body composition: a systematic review and meta-analysis.

We evaluated the effects of ketogenic diets (KDs) on body mass (BM), fat mass (FM), fat-free mass (FFM), body mass index (BMI), and body fat percentage (BFP) compared to non-KDs in individuals performing resistance training (RT). Online electronic databases including PubMed, the Cochrane Library, Web of Science, Embase, SCOPUS, and Ovid were searched to identify initial studies until February 2021. Data were pooled using both fixed and random-effects methods and were expressed as weighted mean difference (WMD) and 95% confidence intervals (CI). Out of 1372 studies, 13 randomized controlled trials (RCTs) that enrolled 244 volunteers were included. The pooled results demonstrated that KDs significantly decreased BM [(WMD = -3.67 kg; 95% CI: -4.44, -2.90, p < 0.001)], FM [(WMD = -2.21 kg; 95% CI: -3.09, -1.34, p < 0.001)], FFM [(WMD = -1.26 kg; 95% CI: -1.82, -0.70, p < 0.001)], BMI [(WMD = -1.37 kg.m-2; 95% CI: -2.14, -0.59, p = 0.022)], and BFP [(WMD = -2.27%; 95% CI: -3.63, -0.90, p = 0.001)] compared to non-KDs. We observed beneficial effects of KDs compared to non-KDs on BM and body fat (both FM and BFP) in individuals performing RT. However, adherence to KDs may have a negative effect on FFM, which is not ameliorated by the addition of RT.

Effects of betaine supplementation on cardiovascular markers: A systematic review and Meta-analysis.

Controversy regarding the effects of betaine supplementation on cardiovascular markers has persisted for decades. This systematic review and meta-analysis compared the effects of betaine supplementation on cardiovascular disease (CVD) markers. Studies examining betaine supplementation on CVD markers published up to February 2021 were identified through PubMed, the Cochrane Library, Web of Science, Embase, and SCOPUS. Betaine supplementation had a significant effect on concentrations of betaine (MD: 82.14 µmol/L, 95% CI: 67.09 to 97.20), total cholesterol (TC) (MD: 14.12 mg/dl, 95% CI%: 9.23 to 19.02), low-density lipoprotein (LDL) (MD: 10.26 mg/dl, 95% CI: 6.14 to 14.38)], homocysteine (WMD: -1.30 micromol/L, 95% CI: -1.61 to -0.98), dimethylglycine (DMG) (MD: 21.33 micromol/L, 95% CI: 13.87 to 28.80), and methionine (MD: 2.06 micromol/L, 95% CI: 0.23 to 3.88). Moreover, our analysis indicated that betaine supplementation did not affect serum concentrations of triglyceride (TG), high-density lipoprotein (HDL), fasting blood glucose (FBG), C-reactive protein (CRP), liver enzymes [alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyl transferase (GGT)], and blood pressure. Our subgroup analysis suggested that a maximum dose of 4 g/d might have homocysteine-lowering effects without any adverse effect on lipid profiles reported with doses of ≥4 g/d. In conclusion, the present systematic review and meta-analysis supports the advantage of a lower dose of betaine supplementation (<4 g/d) on homocysteine concentrations without the lipid-augmenting effect observed with a higher dosage.

Beneficial effects of folic acid supplementation on lipid markers in adults: A GRADE-assessed systematic review and dose-response meta-analysis of data from 21,787 participants in 34 randomized controlled trials.

Folic acid supplementation has received considerable attention in the literature, yet there is a large discrepancy in its effects on lipid markers in adults. Therefore, this systematic review and meta-analysis of 34 randomized controlled trials (RCTs) evaluated the effects of folic acid supplementation on triglyceride (TG), total cholesterol (TC), low-density lipoprotein (LDL) cholesterol, and high-density lipoprotein (HDL) cholesterol concentrations in a cohort of 21,787 participants. A systematic search current as of March 2021 was performed in PubMed/Medline, Scopus, Web of Science, and Embase using relevant keywords to identify eligible studies. A fix or random-effects model was used to estimate the weighted mean difference (WMD) and 95% confidence intervals (CIs). Thirty-four RCTs were included in this meta-analysis. The pooled analysis revealed that serum TG (WMD: -9.78 mg/dL; 95% CI: -15.5 to -4.00; p = 0.001, I2=0.0%, p = 0.965) and TC (WMD: -3.96 mg/dL; 95% CI: -6.71 to -1.21; p = 0.005, I2=46.9%, p = 0.001) concentrations were significantly reduced following folic acid supplementation compared to placebo. However, folic acid supplementation did not affect serum concentrations of LDL (WMD: -0.97 mg/dL; 95% CI: -6.82 to 4.89; p = 0.746, I2=60.6%, p < 0.001) or HDL cholesterol (WMD: 0.44 mg/dL; 95% CI: -0.53 to 1.41; p = 0.378, I2= 0.0%, p = 0.831). A significant dose-response relationship was observed between the dose of folic acid supplementation and serum concentrations of HDL cholesterols (r = 2.22, p = 0.047). Folic acid supplementation reduced serum concentrations of TG and TC without affecting LDL or HDL cholesterols. Future large RCTs on various populations are needed to show further beneficial effects of folic acid supplementation on lipid profile.

Experimental investigation and finite element modelling of PMMA/carbon nanotube nanobiocomposites for bone cement applications.

Multi-walled carbon nanotubes (MWCNTs) are one of the preferred candidates for reinforcing polymeric nanobiocomposites, such as acrylic bone type of cement. In this study, at first, bulk samples of the reinforced polymethylmethacrylate (PMMA) matrix were prepared with 0.1, 0.25, and 0.5 wt per wt% of MWCNTs by the casting method. Tensile and three-point bending tests were performed to determine the essential mechanical properties of bone cement, such as tensile and bending strengths. The tensile fracture surfaces were investigated by scanning electron microscopy (SEM). The commercial software (Abaqus) was used to conduct finite element analysis (FEA) by constructing a representative volume element (RVE) model for numerically computing the tensile and bending parameters of PMMA-MWCNT nanocomposites. Finally, MTT assays were utilized to evaluate the cell viability on the surface of nanobiocomposites. The results show that by increasing the MWCNT amount in the PMMA-based cement, the bending strengths (BS), tensile strength (TS), and elastic modulus (EM) increased considerably. Furthermore, the disparity between the FEA and experimental TS, EM, and BS values was less than 20%. According to MTT viability experiments, adding MWCNTs to PMMA had no influence on PMMA toxicity and resulted in a negative response to interaction with mesenchymal stem cells. The cell density on the nanobiocomposite was more than pristine-PMMA.

Spirulina supplementation during gradual weight loss in competitive wrestlers.

We aimed to assess the effects of spirulina supplementation during gradual weight loss on serum concentrations of follistatin (FST), myostatin (MST), insulin-like growth factor 1 (IGF-1), aspartate aminotransferase (AST), alanine aminotransferase (ALT) and body composition in competitive wrestlers. Forty competitive wrestlers (age: 22 (sem 2) years) were randomly assigned to one of two groups: gradual weight loss + spirulina (SP; n 20) or gradual weight loss + placebo (PL; n 20). Subjects in both groups lost weight according to a designed diet over 12 d and were required to reduce baseline body mass (BM) by 4%. Subjects in the SP group received two tablets of spirulina, while subjects in the PL received two tablets of placebo before each meal. Concentrations of mentioned serum markers and body composition were measured before and after the interventions. BM (SP = -3·1 kg and PL = -2·9 kg), body fat percentage (BFP) (SP = -2·1 % and PL = -0·6 %), fat mass (FM) (SP = -2·2 kg and PL = -0·9 kg) and skeletal muscle mass (SP = -1·4 kg and PL = -1·5 kg) significantly decreased in both groups (P < 0·05). The changes in BFP and FM were significantly greater in SP compared with the PL group (P < 0·001). Additionally, MST (SP = -0·1 ng/ml), AST (SP = -2·1 u/l) and ALT (SP = -2·7 u/l) concentrations significantly diminished in SP group (P = 0·005), while FST (PL = -0·1 ng/ml) and IGF-1 (PL = -2·6 ng/ml) concentrations significantly decreased in PL group (P < 0·05). Spirulina supplementation during gradual weight loss is beneficial in reducing BFP, FM, MST and liver enzymes while maintaining IGF-1 and FST concentrations in competitive wrestlers.

Ketogenic diets, physical activity and body composition: a review.

Obesity remains a serious relevant public health concern throughout the world despite related countermeasures being well understood (i.e. mainly physical activity and an adjusted diet). Among different nutritional approaches, there is a growing interest in ketogenic diets (KD) to manipulate body mass (BM) and to enhance fat mass loss. KD reduce the daily amount of carbohydrate intake drastically. This results in increased fatty acid utilisation, leading to an increase in blood ketone bodies (acetoacetate, 3-ß-hydroxybutyrate and acetone) and therefore metabolic ketosis. For many years, nutritional intervention studies have focused on reducing dietary fat with little or conflicting positive results over the long term. Moreover, current nutritional guidelines for athletes propose carbohydrate-based diets to augment muscular adaptations. This review discusses the physiological basis of KD and their effects on BM reduction and body composition improvements in sedentary individuals combined with different types of exercise (resistance training or endurance training) in individuals with obesity and athletes. Ultimately, we discuss the strengths and the weaknesses of these nutritional interventions together with precautionary measures that should be observed in both individuals with obesity and athletic populations. A literature search from 1921 to April 2021 using Medline, Google Scholar, PubMed, Web of Science, Scopus and Sportdiscus Databases was used to identify relevant studies. In summary, based on the current evidence, KD are an efficient method to reduce BM and body fat in both individuals with obesity and athletes. However, these positive impacts are mainly because of the appetite suppressive effects of KD, which can decrease daily energy intake. Therefore, KD do not have any superior benefits to non-KD in BM and body fat loss in individuals with obesity and athletic populations in an isoenergetic situation. In sedentary individuals with obesity, it seems that fat-free mass (FFM) changes appear to be as great, if not greater, than decreases following a low-fat diet. In terms of lean mass, it seems that following a KD can cause FFM loss in resistance-trained individuals. In contrast, the FFM-preserving effects of KD are more efficient in endurance-trained compared with resistance-trained individuals.

Betaine supplementation fails to improve body composition: a systematic review and meta-analysis.

Previous studies evaluating the effects of betaine supplementation on body composition offer contradictory findings. This systematic review and meta-analysis assessed the effects of betaine supplementation on body composition indices (body mass (BM), BMI, body fat percentage (BFP), fat mass (FM), fat-free mass (FFM)), and dietary intakes. Studies examining the effects of betaine supplementation on body composition and dietary intakes published up to August 2021 were identified through PubMed, the Cochrane Library, Web of Science, Embase, SCOPUS and Ovid databases. Betaine supplementation failed to significantly affect BM ((weighted mean difference (WMD): -0·40 kg, 95 % CI -1·46, 0·64), P = 0·447), BMI ((WMD: -0·05 kg/m2, 95 % CI -0·36, 0·25), P = 0·719), BFP ((WMD: 0·26 %, 95 % CI -0·82, 1·36), P = 0·663), FM ((WMD: -0·57 kg, 95 % CI -2·14, 0·99), P = 0·473) and FFM ((WMD: 0·61 kg, 95 % CI -1·27, 2·49), P = 0·527). Subgroup analyses based on participant's age (< 40 and > 40 years), sex, BMI, trial duration (< 8 and ≥ 8 weeks), betaine supplementation dosage (< 4 and ≥ 4 g) and health status (healthy or unhealthy) demonstrated similar results. Other than a potential negligible increase in protein intake (WMD: 3·56 g, 95 % CI 0·24, 6·88, P = 0·035), no changes in dietary intakes were observed following betaine supplementation compared with control. The present systematic review and meta-analysis does not show any beneficial effects of betaine supplementation on body composition indices (BM, BMI, FM and FFM).

Effects of Icelandic yogurt consumption and resistance training in healthy untrained older males.

Due to the important roles of resistance training and protein consumption in the prevention and treatment of sarcopenia, we assessed the efficacy of post-exercise Icelandic yogurt consumption on lean mass, strength and skeletal muscle regulatory factors in healthy untrained older males. Thirty healthy untrained older males (age = 68 ± 4 years) were randomly assigned to Icelandic yogurt (IR; n 15, 18 g of protein) or an iso-energetic placebo (PR; n 15, 0 g protein) immediately following resistance training (3×/week) for 8 weeks. Before and after training, lean mass, strength and skeletal muscle regulatory factors (insulin-like growth factor-1 (IGF-1), transforming growth factor-beta 1 (TGF-ß1), growth differentiation factor 15 (GDF15), Activin A, myostatin (MST) and follistatin (FST)) were assessed. There were group × time interactions (P < 0·05) for body mass (IR: Δ 1, PR: Δ 0·7 kg), BMI (IR: Δ 0·3, PR: Δ 0·2 kg/m2), lean mass (IR: Δ 1·3, PR: Δ 0·6 kg), bench press (IR: Δ 4, PR: 2·3 kg), leg press (IR: Δ 4·2, PR: Δ 2·5 kg), IGF-1 (IR: Δ 0·5, Δ PR: 0·1 ng/ml), TGF-ß (IR: Δ - 0·2, PR: Δ - 0·1 ng/ml), GDF15 (IR: Δ - 10·3, PR: Δ - 4·8 pg/ml), Activin A (IR: Δ - 9·8, PR: Δ - 2·9 pg/ml), MST (IR: Δ - 0·1, PR: Δ - 0·04 ng/ml) and FST (IR: Δ 0·09, PR: Δ 0·03 ng/ml), with Icelandic yogurt consumption resulting in greater changes compared with placebo. The addition of Icelandic yogurt consumption to a resistance training programme improved lean mass, strength and altered skeletal muscle regulatory factors in healthy untrained older males compared with placebo. Therefore, Icelandic yogurt as a nutrient-dense source and cost-effective supplement enhances muscular gains mediated by resistance training and consequently may be used as a strategy for the prevention of sarcopenia.