ABSTRACT
Evidence suggests that adopting a healthy diet, such as the Mediterranean Diet (MD), can positively affect mental health. To further explore this, a study was conducted to determine the impact of MD instruction over 12 weeks on depression, anxiety, stress, and anthropometric indices. The study is a randomized, double-blind, controlled clinical trial with sixty participants who reported stress, anxiety, and depression conducted in Tabriz, Iran (2022-2023). They were randomly assigned to either the intervention group (n = 30), which received MD instruction, or the control group (n = 30), which received standard healthy nutrition education. Both groups were asked to follow their respective nutrition education plans for 12 weeks. After 12 weeks, depression, anxiety, and stress levels were measured using the DASS-21 questionnaire, and anthropometric indices were assessed. Initially, the unadjusted DASS-21 scores for depression, anxiety, and stress did not show significant differences between the two groups. However, after adjusting for baseline variables (model 2), all scores decreased significantly (the P-value for all scores was < 0.001). There was no significant difference in weight and BMI between the intervention and control groups. However, after adjusting the results based on baseline values (Model 2) and adherence to the program (Model 3), weight and BMI were significantly reduced in the MD group (P-values for both cases and both models were < 0.001). Overall, despite some significant findings, the results were not noticeable from a clinical perspective. The study provides some indications that following the Mediterranean diet may lead to improvements in weight and mental well-being.
ABSTRACT
Oxidative stress is a contributing factor to many chronic diseases. It has been investigated that zinc (Zn) may enhance the antioxidant defense. The current dose-response and time-response meta-analysis aims to determine the efficacy of Zn supplementation in improving antioxidant defense. Scopus, PubMed/Medline, Web of Science, and Embase databases were searched systematically up to December 30, 2020. Meta-analysis was performed on human controlled clinical trials using random effects method. To find any source of heterogeneity, subgroup analysis and meta-regression were performed. Trim and fill analysis was used for adjusting the publication bias. To find any non-linear relationship between variables and effect size, dose-response and time-response analyses were performed. Cochrane Collaboration's tool was used for evaluating the quality assessment. A total of 23 controlled clinical trials were analyzed. The range of Zn supplementation duration in various studies was within 4-24 weeks. Zn supplementation did not have beneficial effects on glutathione peroxidase (GPx) activity (SMD = -0.34 U/g; 95% CI: -0.93, 0.25; P = 0.258). There were significant increasing effects of Zn supplementation on glutathione (GSH) (SMD = 1.28 µmol/l; 95% CI: 0.42, 2.14; P = 0.003) and total antioxidant capacity (TAC) levels (SMD = 1.39 mmol/l; 95% CI: 0.44, 2.35; P = 0.004). Zn had ameliorative effects on superoxide dismutase (SOD) activity after elimination of publication bias (SMD: 0.84 U/g; 95% CI: 0.12, 1.56, P < 0.05). Zn could also elevate GSH and TAC levels, plus SOD activity after modifying the publication bias. Finally, Zn had no significant effect on GPx activity.
