A Systematic Review and Meta-analysis of Randomized Controlled Trials on the Effects of Turmeric and Curcuminoids on Blood Lipids in Adults with Metabolic Diseases

Abstract

Dyslipidemia is a global health problem and a high risk factor for atherosclerosis, which can lead to serious cardiovascular disease (CVD). Existing studies have shown inconsistent effects of turmeric and curcuminoids on blood lipids in adults. We performed this systematic review and meta-analysis to evaluate the effects of turmeric and curcuminoids on blood triglycerides (TG), total cholesterol (TC), LDL cholesterol, and HDL cholesterol. We searched the English databases of the Web of Science, PubMed, Ovid (including EMBASE and MEDLINE), Scopus, and the Cochrane Library and 2 Chinese databases, Wanfang Data and China National Knowledge Infrastructure, for randomized controlled trials (RCTs) that studied the effects of turmeric and curcuminoids on blood TG, TC, LDL cholesterol, and HDL cholesterol in subjects with metabolic diseases. With random-effects models, separate meta-analyses were conducted by using inverse-variance. The results are presented as the mean difference with 95% CIs. Evidence from 12 RCTs for TG, 14 RCTs for TC, 13 RCTs for LDL cholesterol, and 16 RCTs for HDL cholesterol showed that turmeric and curcuminoids could lower blood TG by -19.1 mg/dL (95% CI: -31.7, -6.46 mg/dL; P = 0.003), TC by -11.4 mg/dL (95% CI: -17.1, -5.74 mg/dL; P < 0.0001), and LDL cholesterol by -9.83 mg/dL (95% CI: -15.9, -3.74 mg/dL; P = 0.002), and increase HDL cholesterol by 1.9 mg/dL (95% CI: 0.31, 3.49 mg/dL; P = 0.02). In conclusion, turmeric and curcuminoids can significantly modulate blood lipids in adults with metabolic diseases. However, these findings should be interpreted cautiously because of the significant heterogeneity between included studies (I2 > 50%). There is a need for further RCTs in future.

Keywords: HDL cholesterol; LDL cholesterol; curcuminoids; lipids; total cholesterol; triglyceride; turmeric.

FIGURE 1

Database search and study selection. We searched the English databases of the Web of Science, PubMed, Ovid (including EMBASE and MEDLINE), Scopus, and the Cochrane Library, and 2 Chinese databases, Wanfang Data and CNKI, for RCTs that studied the effects of turmeric and curcuminoids on blood triglycerides, total cholesterol, LDL cholesterol, and HDL cholesterol in subjects with metabolic diseases. By reading titles, abstracts and full articles, we finally selected 16 arms.

FIGURE 2

Forest plot of the differences in changes in circulating triglycerides in adults with metabolic disease that did or did not receive turmeric or curcuminoids in 12 trials (n = 1183). With random-effect models, data were calculated through use of inverse-variance (IV) and presented as the mean difference (black squares), 95% CI (horizontal lines through gray squares), and pooled-effect sizes (black diamonds) with the unit of mg/dL.

FIGURE 3

Forest plot of the differences in changes in circulating total cholesterol in adults with metabolic disease that did or did not receive turmeric or curcuminoids in 14 trials (n = 1266). With random-effect models, data were calculated through use of inverse-variance (IV) and presented as the mean difference (black squares), 95% CI (horizontal lines through gray squares), and pooled-effect sizes (black diamonds) with the unit of mg/dL.

FIGURE 4

Forest plot of the differences in changes in circulating LDL cholesterol in adults with metabolic disease that did or did not receive turmeric or curcuminoids in 13 trials (n = 1166). With random-effect models, data were calculated through use of inverse-variance (IV) and presented as the mean difference (black squares), 95% CI (horizontal lines through gray squares), and pooled-effect sizes (black diamonds) with the unit of mg/dL.

FIGURE 5

Forest plot of the differences in changes in circulating HDL cholesterol in adults with metabolic disease that did or did not receive turmeric or curcuminoids in 16 trials (n = 1453). With random-effect models, data were calculated through use of inverse-variance (IV) and presented as the mean difference (black squares), 95% CI (horizontal lines through gray squares), and pooled-effect sizes (black diamonds) with the unit of mg/dL.