Profiling inflammatory and oxidative stress biomarkers following taurine supplementation: a systematic review and dose-response meta-analysis of controlled trials.

Taurine (Tau) has modulatory effects on inflammatory and oxidative stress biomarkers; however, the results of clinical studies are not comprehensive enough to determine the effect of different durations and doses of Tau supplementation on inflammatory and oxidative stress biomarkers. The current study was conducted based on the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. For this purpose, PubMed/Medline, Scopus, and Embase databases were systematically searched to obtain the relevant studies published before 30th March 2021. Meta-analysis was performed on controlled clinical trials by using the random-effects method. Non-linear relationship between variables and effect size was performed using dose-response and time-response analyses. The Cochrane Collaboration's tool was used to evaluate the quality of included studies. Tau supplementation can reduce the levels of malondialdehyde (MDA) (SMD = -1.17 µmol/l; 95% CI: -2.08, - 0.26; P = 0.012) and C-reactive protein (CRP) (SMD = -1.95 mg/l; 95% CI: -3.20, - 0.71; P = 0.002). There have been no significant effects of Tau supplementation on the levels of tumor necrosis factors-alpha (TNF-α) (SMD = -0.18 pg/ml; 95% CI: -0.56, 0.21; P = 0.368), and interleukin-6 (IL-6) (SMD = -0.49 pg/ml; 95% CI: -1.13, 0.16; P = 0.141). Besides, Tau has more alleviating effect on oxidative stress and inflammation on 56 days after supplementation (P < 0.05). Tau can decrease the levels of CRP and MDA. Based on the currently available evidence, Tau has no significant effect on the level of TNF-α and IL-6. Eight-week of Tau supplementation has more beneficial effects on inflammatory and oxidative stress biomarkers.

Dietary total antioxidant capacity (TAC), general and central obesity indices and serum lipids among adults: An updated systematic review and meta-analysis.

Background: In the present meta-analysis, we aimed to summarize the relationship between dietary total antioxidant capacity (TAC), general and central obesity indices and lipid profile in adult population. Methods: The electronic databases of Web of Sciences, PubMed, Scopus and Cochrane library were searched for relevant studies from inception to October 2019. The effect size was indicated as weighted mean difference (WMD) and 95% confidence intervals (CI) by using random effects model. The I2 index and Cochran's Q-test were used for evaluating heterogeneity. Results: From 2,469 studies identified, thirty-four studies (nineteen cross-sectional studies, thirteen cohort studies, two case-control studies) were included in the meta-analysis. According to our results, higher categories of TAC were associated with significantly lower serum triglyceride concentartions (TG; WMD: -7.58; CI: -11.42, -3.75; P < 0.001) and waist circumference (WC; WMD: -1.17; 95% CI: -1.47, -0.87; P < 0.001); while no significant change in body mass index (BMI; WMD: -0.17; 95% CI: -0.35, 0.01; P = 0.12), high density lipoprotein cholesterol (HDL-C; WMD: 0.61; 95% CI: -0.16, 1.40; P = 0.12), low density lipoprotein cholesterol (LDL-C; WMD: 1.34; 95% CI: -0.61, 3.30; P = 0.17) and total cholesterol (TC; WMD: 1.19; 95% CI: -1.46, 3.855; P = 0.37) was reported. Conclusion: Higher dietary TAC was related to reduced prevalence of central obesity, reduced WC and TG concentrations in the current meta-analysis. Moreover, subgroup analysis showed that TAC measurement index, geographical area, dietary assessment tool, health status and gender were potential sources of heterogeneity.