Effects of traditional fermented food (Ash-Kardeh) consumption on blood glucose, blood pressure, and lipid profile in type 2 diabetes: a study protocol for a randomized clinical trial

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.

Effects of an Iranian traditional fermented food consumption on blood glucose, blood pressure, and lipid profile in type 2 diabetes: a randomized controlled clinical trial

BACKGROUND

Ash-Kardeh is one of the few fermented foods without a dairy base in Iran, which is traditionally prepared from cereals and plants in the presence of microorganisms (mainly lactic acid bacteria).

PURPOSE

This study aimed to assess the effects of Ash-Kardeh consumption on blood glucose, lipid profile, and blood pressure in type 2 diabetic patients.

METHODS

Forty-six patients with type 2 diabetes were studied in this randomized controlled clinical trial. Subjects were randomly allocated into intervention (n = 23) and control (n = 23) groups. Individuals of both groups received the usual treatment of diabetic patients, while those in the intervention group, in addition to the usual treatment, received 250 g of Ash-Kardeh daily for 6 weeks. Fasting blood glucose, blood pressure, and lipid profiles were measured before and after the intervention.

RESULTS

Compared to the control group, Ash-Kardeh consumption led to a significant decrease in fasting blood glucose (P = 0.003), total cholesterol (P = 0.025), triglyceride (P = 0.003), systolic (P < 0.001), and diastolic blood pressure (P = 0.014) in the intervention group. Also, a significant increase in the concentrations of high-density lipoprotein cholesterol (P = 0.048) was observed after Ash-Kardeh consumption.

CONCLUSION

It seems that Ash-Kardeh consumption could improve high blood glucose, lipid profile, and hypertension in type 2 diabetic patients but does not affect low-density lipoprotein cholesterol concentrations. This study was registered on 2019-09-15 in the Iranian Registry of Clinical Trials ( www.irct.ir ) with the code number IRCT20170202032367N3.