The Effects of Lycopene and Tomato Consumption on Cardiovascular Risk Factors in Adults: A Grade Assessment Systematic Review and Meta-analysis.

BACKGROUND: In recent times, modifying dietary habits to control cardiovascular risk factors has gained significant attention. However, previous studies have yielded inconsistent results regarding the effects of lycopene and tomato consumption on cardiovascular risk factors. OBJECTIVE: The objective of this study was to assess the impact of consuming lycopene and tomatoes on various cardiovascular risks factors such as lipid profile, glycemic control markers, blood pressure, inflammation, oxidative stress, and body weight. METHODS: A systematic literature search was carried out using electronic databases, including PubMed, Web of Science, and Scopus, up to November 2022 to identify eligible Randomized Control Trials (RCTs) evaluating the effect of lycopene and tomato consumption on cardiovascular risk factors. Heterogeneity tests of the selected trials were performed using the I2 statistic. Random effects models were assessed based on the heterogeneity tests, and pooled data were determined as the weighted mean difference (WMD) with a 95% confidence interval (CI). RESULTS: Out of 27,438 records initially identified, a total of 34 studies met the eligibility criteria and were included in this meta-analysis. The results showed that lycopene consumption was associated with a significant reduction in malondialdehyde (MDA) levels, indicating a potential benefit in reducing oxidative stress. However, lycopene and tomato consumption did not have significant effects on other cardiovascular risk factors such as triglycerides (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), fasting blood glucose (FBG), systolic blood pressure (SBP), diastolic blood pressure (DBP), Intercellular Adhesion Molecule 1 (ICAM-1), c-reactive protein (CRP), interleukin 6 (IL-6), tumor necrosis factor α (TNF-α), body weight, and body mass index (BMI). CONCLUSION: Overall, the findings showed that lycopene and tomato consumption did not affect cardiovascular risk factors. However, lycopene supplementation may result in a significant improvement in MDA levels. With the view to confirming these results, further studies with long-term duration and different doses are needed.

Effect of zinc supplementation in the management of type 2 diabetes: A grading of recommendations assessment, development, and evaluation-assessed, dose-response meta-analysis of randomized controlled trials.

The question of whether zinc supplementation may improve cardio-metabolic health in patients with type 2 diabetes mellitus (T2DM) remains controversial and require further evaluation. This study aimed to summarize the effectiveness of oral zinc supplementation in improving cardio-metabolic risk markers in people with T2DM. We searched PubMed, Scopus, and Web of Science from inception to April 2023, for randomized controlled trials (RCTs). RCTs of type 2 diabetic adults (aged ≥18 years) comparing zinc supplementation with placebo were included. We excluded studies if not randomized, involved co-supplementation, and were conducted in children or pregnant women. Glycemic indices, lipid profiles, blood pressure, anthropometric measure, c-reactive protein (CRP), creatinine, and serum zinc were extracted. Certainty of evidence was assessed using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) methods. We used a random-effect model to perform the dose-response analysis. Effect sizes were presented as mean difference (MD) and 95% confidence interval (CI). 22 studies (n = 1442 participants) were included. The certainty of the evidence was rated as moderate to high. Zinc supplementation significantly reduced glycemic indices: including two-hour postprandial glucose (2hpp) (mean difference (MD): -34.34 mg/dl; 95%CI: -51.61∼ -17.07), fast blood sugar (FBS) (MD: -23.32 mg/dl; 95% CI: -33.81∼ -12.83), and hemoglobin A1c (HbA1c) (MD: -0.47; 95% CI: -0.71∼ -0.23). Zinc had a favorable effect on lipid profiles low-density lipoprotein (LDL) (MD: -10.76 mg/dl; CI: -17.79∼-3.73), triglyceride (TG) (MD: -18.23 mg/dl; CI: -32.81∼-3.65), total cholesterol (TC) (MD: -12.74 mg/dl; CI: -21.68∼-3.80), VLDL (MD: -5.39 mg/dl; CI: -7.35∼-3.43) and high-density lipoprotein (HDL) (MD: 4.04 mg/dl; CI: 0.96 ∼ 7.12). Systolic blood pressure (SBP) (MD): -3.64 mmHg; 95% CI: -6.77∼ -0.52), weight (MD: 1.00 kg; 95% CI: 0.34∼1.66), CRP (MD: -3.37 mg/l, 95% CI: -4.05∼ -2.70), and serum zinc (MD: 15.38 µg/dl; 95% CI: 10.74∼ 20.02) changed to a statistically significant extent with zinc supplementation. There was also a linear association between additional 10 mg/d zinc treatment with FBS, HbA1c, HDL, LDL, TG, TC, and serum zinc. A non-linear dose-response gradient was seen for FBS, HDL, and SBP (p < 0.05). Egger's test showed no substantial publication bias. Our findings strongly suggest a potential beneficial effect of zinc supplementation on type 2 diabetic patients. Further high-quality research is needed to determine the optimal form, dosage, and duration of zinc supplementation for this population.