A previous meta-analysis provided convincing evidence for an inverse association between adherence to a Mediterranean diet (MedDiet) and the risk of all-cause mortality. Since then, 19 prospective studies have been published. We updated the evidence from these prospective studies and conducted a dose-response meta-analysis to test the linear and potential nonlinear dose-response associations between adherence to a MedDiet and the risk of all-cause mortality. The PubMed, Scopus, ISI Web of Knowledge, and Embase bibliographic databases were systematically searched up to August 24, 2018. Summary HRs were estimated with the use of a random-effects meta-analysis to assess the association between a 2-point increment in MedDiet adherence and the risk of all-cause mortality. Sensitivity and subgroup analyses were performed and potential publication bias was tested. Twenty-nine prospective studies with 1,676,901 participants and 221,603 cases of all-cause mortality were included in the final analysis. The pooled HR of all-cause mortality was 0.90 (95% CI: 0.89, 0.91; I2 = 81.1%) for a 2-point increment in adherence to a MedDiet. Subgroup analyses showed that a significant inverse association was stronger in participants who lived in the Mediterranean region compared with non-Mediterranean areas (HRs: 0.82 compared with 0.92, respectively), and in studies that used the Panagiotakos MedDiet score. A nonlinear dose-response meta-analysis indicated that the risk of all-cause mortality linearly decreased with the increase in adherence to a MedDiet. The robustness of findings was confirmed in the sensitivity analyses. In conclusion, low-quality evidence from prospective cohort studies suggests an inverse association between adherence to a MedDiet and the risk of all-cause mortality, especially in Mediterranean regions. An inverse linear dose-response relation was also observed between adherence to a MedDiet and the risk of all-cause mortality.

Background: Although previous investigations have proposed an association between Dietary Approaches to Stop Hypertension (DASH)-style diet and lower mortality from chronic diseases, the exposure-response relationship is not clear. The present systematic review andmeta-analysis aimed to explore the linear and non-linear dose-responseassociation between adherence to the DASH diet andall-cause and cause-specific mortality.Methods: Database search was performed in PubMed, Scopus, and EMBASE for prospective cohort studies investigating the association between adherence to the Dietary Approaches to Stop Hypertension (DASH) diet and risk of mortality. Summary hazard ratios (HRs) and 95% confidence intervals (CI) were estimated with the use of a random-effects model for the linear and nonlinear relationships. The two-stage hierarchical regression model was applied to test the potential non-linear dose-response associations.Results: The inclusion criteria were met by 17 studies (13 publications). The scores reported for adherence to the DASH diet in different studies were converted to a conventional scoring method in which the adherence score might range between 8 to 40. The linear analysis revealed that summary HRs were 0.95 (95% CI: 0.94–0.96, I² = 91.6%,n = 14) for all-cause, 0.96 (95% CI: 0.95–0.98, I² = 82.4%,n = 12) for CVD, 0.97 (95% CI: 0.96–0.98, I² = 0.00%,n = 2) for stroke, and 0.97 (95% CI: 0.95–0.98, I² = 63.7%,n = 12) for cancer mortality per each 5-point increment of adherence to the DASH diet. There was also evidence of non-linear associations between the DASH diet and all-cause and cause-specific mortality as the associations became even more evident when the adherence scores were more than 20 points (P < 0.005).Conclusion: Even the modest adherence to the DASH diet is associated with a lower risk of all-cause and cause-specific mortality. The higher adherence to the diet also strengthens the risk-reducing association.Registration: This review was registered in the international prospective register of systematic reviews (PROSPERO) database (registration ID: CRD42018086500).

The aim was to systematically review and meta-analyze prospective cohort studies investigating the relation between maternal dietary patterns during pregnancy with pregnancy and birth outcomes. PubMed, Scopus, and ISI Web of Science were searched from inception until October 2019 for eligible studies. Studies reporting relative risk, ORs, or incidences (for binary data) or means ± SDs or B-coefficients (for continuous outcomes) comparing the highest and lowest adherence with maternal dietary patterns were included. Dietary patterns were categorized as "healthy," "unhealthy," or "mixed." No language restrictions were applied. Study-specific effect sizes with SEs for outcomes of interest were pooled using a random-effects model. Quality of evidence was assessed using Grading of Recommendations Assessment, Development, and Evaluation (GRADE). Sixty-six relevant publications were included. A higher maternal adherence to a healthy diet was associated with a reduced risk of gestational hypertension (14%, P < 0.001), maternal depression (40%, P = 0.004), low birth weight (28%, P = 0.001), preterm birth (56%, P < 0.001), higher gestational weight gain (Hedges' g: 0.15; P = 0.01), and birth weight (Hedges' g: 0.19; P = 0.007). Higher maternal adherence to an unhealthy or a mixed diet was associated with higher odds of gestational hypertension (23%, P < 0.001 for unhealthy, and 8%, P = 0.01 for mixed diet). In stratified analyses, a higher healthy eating index was associated with reduced odds of being large based on gestational age (31%, P = 0.02) and a higher head circumference at birth (0.23 cm, P = 0.02). The Mediterranean and "prudent" dietary patterns were related to lower odds of being small based on gestational age (46%, P = 0.04) and preterm birth (52%, P = 0.03), respectively. The overall GRADE quality of the evidence for most associations was low or very low, indicating that future high-quality research is warranted. This study was registered at http://www.crd.york.ac.uk/PROSPERO as CRD42018089756.

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.

An emerging body of evidence has demonstrated the beneficial effects of probiotics on various mental health conditions. In this systematic review and meta-analysis, we sought to examine the effects...