Background Health related quality of life (HRQOL) is a potent indicator of individual’s happiness and life satisfaction. The way in which the HRQOL is affected by the diet is a topic of constant interest and debate among researchers. Evaluating the association between single nutrients or foods and HRQOL fails to take into consideration the complex interactions between nutrients. Also, the findings from previous investigations on the relationship between dietary patterns and HRQOL have been inconsistent. Therefore, our aim was to assess the existing evidence regarding the relationship between the dietary patterns and HRQOL by conducting a systematic review. Methods A literature search was conducted in PubMed, Scopus, Web of Sciences and Google scholar databases from inception to March 2020, to identify studies that investigated associations between the dietary patterns (regardless of methods used to define dietary patterns) and HRQOL domains. Two researchers independently checked titles and abstracts, evaluated full-text studies, extracted data, and appraised their quality using the Newcastle–Ottawa Scale (NOS). Results Thirteen studies (four longitudinal, and nine cross-sectional studies), with a total of 43,445 subjects, were included. Of the studies included in this review, eight studies evaluated the association between "Mediterranean" dietary patterns (MDP) and HRQOL, while five studies examined the association between different dietary patterns ("Healthy", "Unhealthy", "Western", "Fruit and vegetable", "Bread and butter" and etc.) and HRQOL. Excluding three studies which showed no significant association, healthy dietary patterns such as MDP, "Healthy" and "Fruit and vegetable" dietary patterns were associated with better HRQOL in physical and mental components scores. The quality assessment of included studies according to NOS criteria were ranged between medium to high quality. Conclusion According to the current evidence, "Healthy" dietary patterns and “Mediterranean” dietary patterns are associated with better dimension scores of HRQOL in both physical and mental summaries. While, unhealthy dietary patterns and "Western" dietary patterns are associated with lower scores of HRQOL. Further longitudinal studies are required to clarify the association between dietary patterns and HRQOL

Aims: Several epidemiological studies have examined the association between trimethylamine N-Oxide (TMAO) and stroke risk; however, the results are still inconclusive. The purpose of this meta-analysis was to evaluate the relationship between TMAO concentrations and stroke risk. Methods: PubMed, Scopus, Cochrane and ProQuest search engines were systematically searched up to 18 June 2019. All of the studies that evaluated the relationship between TMAO and stroke were included in the systematic review and eligible studies were included into the meta-analysis. Meta-regression and subgroup analysis were also employed to find the source of heterogeneity. Results: Eight studies (two cross-sectional studies, two cohort studies, three case-control studies and one nested case-control study) with a total of 6150 participants were included in the meta-analysis. The overall result showed that being in the highest category of TMAO increased the odds of stroke by 68% (OR: 1.675; CI: 0.866-3.243; P = 0.047) and mean TMAO concentrations was 2.201 μmol/L higher in patients with stroke rather than non-stroke controls (weighted mean difference (WMD): 2.20; CI: 1.213-3.188; P < 0.001). Furthermore, we observed revealed a non-linear association between increased TMAO levels and increased odds of stroke (P-for nonlinearity < 0.001). In addition, visual inspection of the funnel plot revealed a significant asymmetry among studies examining the differences in TMAO in patients with stroke versus control group. Conclusion: This is the first meta-analysis to show positive dose-dependent relations between circulating TMAO concentration and stroke risk. However, further interventional studies and long-term studies are needed to better explain causality.

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Background Metabolic syndrome (MetS) is one of the main public health problems worldwide. Although some relations between dietary intakes and MetS have been found, few studies have focused on association between dietary nutrients interactions and the risk of the MetS and its components. The aim of the present study was to examine the association between nutrient patterns and MetS and its components among Iranian adult population. Methods A total of 588 subjects (aged 18–64 years, 271 males and 317 females) enrolled in the cross sectional study. Dietary consumption was evaluated using an 80-item food frequency questionnaire (FFQ). Biochemical assessments including fasting blood sugar (FBS), aspartate aminotransferase (AST), alanine amino transferase (ALT) and serum lipids were performed by enzymatic methods. Nutrient patterns were obtained by factor analysis procedure using principal component method. Multinational logistic regression analysis was used to evaluate the association between nutrient patterns and MetS and its components. Results Three nutrient patterns explaining 53.66% of the variance in dietary nutrients intake, were recognized in the current study. Animal-sourced nutrient pattern was significantly associated with the higher odds of MetS and high triglyceride (TG) levels. Plant-sourced nutrient pattern (high intake of fiber, carbohydrate, vitamins B6, B3, C, B1, E, D, magnesium, potassium, and linoleic acid) was significantly associated with lower risk of MetS and lower blood pressure (p < 0.05). Third nutrient pattern (mixed-source) was significantly related to higher risk of MetS, high waist circumference (WC) and high systolic blood pressure (SBP). Conclusion This present study confirms the important effect of nutrients and their patterns on MetS risk. Our results suggest that adherence to the nutrient pattern rich in fiber, carbohydrate, vitamins D, B6, B3, C, B1, E, magnesium, potassium, linoleic acid, and docosahexaenoic acid (DHA) is associated with a lower risk of MetS, while animal- and mixed-sourced nutrient patterns are positively associated with greater odds of MetS; However, further longitudinal and interventional studies are required to make a clear conclusion.

Background: The relationship between sugar-sweetened beverages (SSBs) intake and serum lipids among children and youth has been reported in several studies, but the results are still controversial.Objective: In the current study, we summarized the results of studies that assessed the relationship between SSBs consumption and serum lipids among children and youth in a systematic review and dose-response meta-analysis.Methods: The PubMed, Web of Sciences, Cochrane and Scopus electronic databases were searched for observational studies reporting an association between SSBs intake and serum lipids among children and youth that were published before May 2020. For data extracted from cohort studies, only cross-sectional baseline data were included in the current meta-analysis. The Random effects model was used to estimate the pooled weighted mean difference (WMD) and 95% confidence intervals (CI). Heterogeneity was assessed with the Cochran Q test and I 2 statistics.Results: In our search, 1845 studies were retrieved of which 13 studies (two cohorts and eleven cross-sectional) were included. High SSB consumption was associated with 1.21 mg/dL increase in low-density lipoprotein cholesterol (LDL-C; pooled WMD: 1.21 mg/dL; 95% CI: 0.23, 2.20; P = .01), 1.45 mg/dL decrease in high-density lipoprotein cholesterol (HDL-C, pooled WMD: −1.46 mg/dL; 95% CI, −2.25, −0.67; P < .0001) and 2.49 mg/dL decrease in total cholesterol (TC, pooled WMD: −2.49 mg/dL; 95% CI, −2.89, −2.10; P < .0001). In dose-response meta-analysis, there was an evidence of departure from linearity in the relationship between SSB consumption and change in LDL-C (Pnonlinearity = .03) and TC (Pnonlinearity = .01). However, no departure from linearity was observed between SSB intake and change in HDL-C (Pnonlinearity = .56) or triglyceride (TG) values (Pnonlinearity = .85). Conclusion:According to our results, high SSB consumption was significantly associated with higher LDL-C and lower HDL-C and TC among children and youth.