Curcumin effects on glycaemic indices, lipid profile, blood pressure, inflammatory markers and anthropometric measurements of non-alcoholic fatty liver disease patients: A systematic review and meta-analysis of randomized clinical trials.

OBJECTIVES: Curcumin has antioxidant properties and has been proposed as a potential treatment for NAFLD. The aim of current systematic review and meta-analysis was to evaluate previous findings for the effect of curcumin supplementation on glycaemic indices, lipid profile, blood pressure, inflammatory markers, and anthropometric measurements of NAFLD patients. METHODS: Relevant studies published up to January 2024 were searched systematically using the following databases: PubMed, SCOPUS, WOS, Science Direct, Ovid and Cochrane. The systematic review and meta-analysis were conducted according to the 2020 PRISMA guidelines. The quality of the papers was assessed the using the Joanna Briggs Institute (JBI) Critical Appraisal Checklist. Pooled effect sizes were calculated using a random-effects model and reported as the WMD and 95% CI. Also, subgroup analyses were done to find probable sources of heterogeneity among studies. RESULTS: Out of 21010 records initially identified, 21 eligible RCTs were selected for inclusion in a meta-analysis. Overall, 1191 participants of both genders, 600 in the intervention and 591 in the control group with NAFLD were included. There are several limitations in the studies that were included, for instance, the results are weakened substantially by potential bias or failure to account for potential adulteration (with pharmaceuticals) or contamination (with other herbs) of the curcumin supplements that were tested. However, previous studies have reported curcumin to be a safe complementary therapy for several conditions. Our study indicated that curcumin supplementation in doses of 50-3000 mg/day was associated with significant change in FBG [WMD: -2.83; 95% CI: -4.61, -1.06), I2 = 51.3%], HOMA-IR [WMD: -0.52; 95% CI: -0.84, -0.20), I2= 82.8%], TG [WMD: -10.31; 95% CI: -20.00, -0.61), I2 = 84.5%], TC [WMD: -11.81; 95% CI: -19.65, -3.96), I2 = 94.6%], LDL [WMD: -8.01; 95% CI: -15.79, -0.24), I2 = 96.1%], weight [WMD: -0.81; 95% CI: -1.28, -0.35), I2= 0.0%] and BMI [WMD: -0.35; 95% CI: -0.57, -0.13), I2= 0.0%] in adults with NAFLD. There was no significant change in HbA1C, plasma insulin, QUICKI, HDL, SBP, DBP, CRP, TNF-α and WC after curcumin therapy. Subgroup analysis suggested a significant changes in serum FBG, TG, SBP, WC in RCTs for intervention durations of ≥ 8 weeks, and SBP, TG, LDL, HDL, BMI, WC in RCTs with sample size > 55 participants. CONCLUSION: Curcumin supplementation in doses of 50-3000 mg/day over 8-12 weeks was associated with significant reductions in levels of FBG, HOMA-IR, TG, TC, LDL, weight and BMI in patients with NAFLD. Previous studies have reported curcumin as a safe complementary therapy for several diseases. We would suggest that should curcumin supplements be used clinically in specific conditions, it should be used with caution. Also, difference in grades of NAFLD may effect the evaluated outcomes, so it is suggested that future studies be conducted with an analyses on subgroups according to their NAFLD grade. Furthermore, because of the failure to conduct independent biochemical assessment of the turmeric/curcumin product used in most studies as well as potential sources of bias, results should be interpreted with caution.

Effects of Bread with Nigella Sativa on Blood Glucose, Blood Pressure and Anthropometric Indices in Patients with Metabolic Syndrome.

Nigella sativa (N. sativa) is one of important herbal foods in traditional medicine and many studies have conducted to show the effects of this plant on several diseases. The goal of this study was the evaluation of effects of bread with N. Sativa on clinical parameters such as blood glucose, blood pressure (BP) and anthropometry indices in subjects with metabolic syndrome (MetS). A study as double-blind, cross-over, randomized clinical trial was performed in 51 MetS patients in Chalus, north region of Iran. After dividing of patients randomly in 2 groups, in phase 1, intervention group (A, n = 27) used daily a bread with N. sativa and control group (B, n = 24) used the same bread but without N. sativa for 2 months. After considering of 15 day wash out period, phase 2 was began with changing of position of 2 groups. Measuring of parameters including fasting blood glucose (FBG), systolic blood pressure (SBP), diastolic blood pressure (DBP), weight, body mass index (BMI), and waist circumference (WC) was done before and after of 2 phases. After evaluation of treatment, sequence and time effects of intervention on parameters, it is shown that consumption of this bread has not significant treatment effect (as main effect) on FBG, SBP, DBP, WC, weight, and BMI (p > 0.05). Sequence effect on FBG, weight, WC, and BMI was significant (p < 0.05), but was not on BP. Time effect was only significant for DBP. Consumption of bread with N. sativa in MetS patients has not significant effect on FBG, BP, weight, WC, and BMI. TRIAL REGISTRATION: Iranian Registry of Clinical Trials Identifier: IRCT2015041821815N1.

Effects of Nigella sativa supplementation on blood parameters and anthropometric indices in adults: A systematic review on clinical trials.

BACKGROUND: Nigella sativa (N. sativa) has been used in traditional medicine and several studies have been performed in the last decades to reveal the effects of it on different medical disorders such as diabetes, dyslipidemia, hypertension, and obesity. We evaluated the effects of N. sativa supplementation on lipid profiles, glycemic control, blood pressure (BP), and some anthropometric indices in humans. MATERIALS AND METHODS: A search on published studies was done by using databases including PubMed, Google Scholar, Thomas Reuters Web of Science, and Cochrane. Medical subject headings (MeSH) terms searched included "N. sativa," "Black seed," "Black cumin," "kalonji," and "Triglycerides," "Cholesterol," "Lipoproteins," "LDL," "Lipoproteins," "HDL," "Blood glucose," "Hemoglobin A," "Glycosylated," "Blood pressure," "Body mass index," "Waist circumference". Initially 515 articles were extracted. Four hundred ninety-two papers that were unrelated, reviews, animal studies, and combined and duplicated studies were excluded, 23 articles were eligible for this review. RESULTS: After analyzing 23 articles including 1531 participants, these results were achieved: In 4 trials, N. sativa reduced BP, but in 5 trials it could not. Fasting blood sugar (FBS) was reduced significantly in 13 studies. In addition, N. sativa reduced levels of glycosylated hemoglobin (HbA1c). Although weight and waist circumference (WC) in 2 articles were reduced significantly, in 6 articles they were not. Fluctuation in lipid profile in the articles was very controversial, being significant in many of them but not in others. CONCLUSION: Our systematic review revealed that N. sativa supplementation might be effective in glycemic control in humans.