Curcumin supplementation effect on liver enzymes in patients with nonalcoholic fatty liver disease: a GRADE-assessed systematic review and dose-response meta-analysis of randomized controlled trials

CONTEXT

Clinical evidence from investigations of the effects of curcumin on liver enzymes in patients with nonalcoholic fatty liver disease (NAFLD) have led to inconsistent results.

OBJECTIVE

The aim of this systematic review and meta-analysis was to investigate the overall effects of curcumin and curcumin plus piperine supplementation on liver enzymes such as alanine aminotransferase (ALT), alkaline phosphatase (ALP), and aspartate aminotransferase (AST) in patients with NAFLD.

DATA SOURCES

The Scopus, Web of Science, PubMed, and Cochrane Library databases were searched from inception through July 2023, using search terms representing NAFLD and liver enzymes. Articles were screened independently by 2 researchers based on PICOS inclusion criteria.

DATA EXTRACTION

The following data were extracted: first author's name, study location, year of publication, mean age, study duration, study design, participants' sex, number of participants in each group, dose of curcumin supplementation, and ALT, ALP, and AST concentrations. Risk of bias was assessed using the Cochrane Collaboration's modified risk-of-bias tool.

DATA ANALYSIS

Fixed- or random-effects meta-analysis was performed to estimate the effects of curcumin on liver enzymes, considering heterogeneity across studies. The I2 and Cochran's Q tests were used to assess heterogeneity between studies.

RESULTS

Overall, 15 randomized controlled trials comprising 905 participants were eligible for this meta-analysis. Curcumin supplementation significantly reduced ALT (weighted mean difference [WMD], -4.10, 95%CI, -7.16 to -1.04) and AST (WMD, -3.27; 95%CI, -5.16 to -1.39), but not ALP (WMD, -0.49; 95%CI, -1.79 to 0.82). Curcumin plus piperine supplementation had no significant effect on ALT (WMD, -3.79; 95%CI, -13.30 to 5.72), and AST (WMD, -1.1; 95%CI, -3.32 to 1.09).

CONCLUSIONS

Curcumin supplementation improved AST and ALT levels compared with the control group. However, better-designed randomized controlled trials with larger sample sizes and of higher quality are needed to assess the effects of curcumin on ALP.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42023448231.

Effects of therapeutic lifestyle change diets on blood lipids, lipoproteins, glycemic parameters, and blood pressure: a systematic review and meta-analysis of clinical trials

CONTEXT

Cardiovascular disease is the leading cause of death worldwide. Low-calorie, low-fat therapeutic diets (TDs) developed by the US National Cholesterol Education Program, ie, the Step I and II diets and the therapeutic lifestyle changes diet, are approximately similar and are the initial therapeutic interventional approaches for lifestyle modification.

OBJECTIVE

This systematic review with meta-analysis was undertaken to evaluate the effects of TDs diet on blood lipids, apolipoprotein A-1, apolipoprotein B, blood pressure, fasting blood glucose, and insulin.

DATA SOURCES

A comprehensive search of the PubMed/MEDLINE, Web of Science, Scopus, and Google Scholar databases until October 2022 was performed to identify clinical trials investigating the effects of TDs on the aforementioned parameters.

DATA EXTRACTION

One investigator screened the records and extracted data, and another reviewed the extracted data.

DATA ANALYSIS

A total of 910 records were retrieved. After records were screened for eligibility, 34 clinical trials met the inclusion criteria. The pooled analysis from the random-effects model revealed a significant reduction in total cholesterol, triglycerides, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, apolipoprotein A-1, and apolipoprotein B in the TD intervention group vs the control group. The overall effects of TDs on fasting blood glucose, insulin, and blood pressure were not significant, but the results of subgroup analysis revealed a significant reduction in fasting blood glucose with the Step II diet and an intervention duration of more than 24 weeks. For blood pressure, the Step I diet and an intervention duration of more than 24 weeks resulted in significant reduction. There was no evidence of publication bias, but strong heterogeneity was observed.

CONCLUSION

Therapeutic diets have promising effects on lipid profile parameters, glycemic indexes, and blood pressure, which can promote cardiovascular health.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42021259355.