Table 3.
Meta-analyses of RCTs investigating the effect of curcumin intake on glucose control.
| Ref. | No. of Studies Included | Health Status of Subjects | No. of Subjects | Age of Subjects (Years) | Design | Period (Weeks) |
Dose | Outcomes (Effect Size) |
Quality of Primary Studies | Databases |
|---|---|---|---|---|---|---|---|---|---|---|
| Lukkunaprasit et al. 2023 [160] | 3 publications [50,161,162] | MAFLD | 231 | 26–38 | P | 8–12 | 80–500 mg/day of curcumin | ↔ HbA1c (MD = −0.24; 95% CI −0.66 to 0.18; p > 0.05) |
Cochrane risk of bias tool (68.8%) | Medline and SCOPUS |
| 12 publications [34,35,50,146,161,162,163,164,165,166,167,168] | MAFLD | 710 | 18–72 | P | 8–24 | 80–1500 mg/day of curcumin, 2000–3000 mg/day of turmeric | ↓ FBG (MD = −2.05 mg/dL; 95% CI −3.08 to −1.01; p < 0.05) |
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| Qiu et al. 2023 [22] | 9 publications [23,25,27,61,126,169,170,171,172] | Mets | 576 | 28–81 | P | 4–12 | 80–1500 mg/day of curcumin, 1000 mg/day of curcuminoids, 2400 mg/day of turmeric |
↓ FBG (MD = −8.6 mg/dL; 95% CI −15.45 to −1.75; p = 0.01) |
Cochrane risk of bias tool (71.4%) | PubMed, SCOPUS, Cochrane Library, EMBASE, Web of Science, and China Biological Medicine |
| Różański et al. 2023 [173] | 14 publications [34,35,50,55,161,164,165,166,174,175,176,177,178,179] | MAFLD | 847 | 18–70 | P | 8–12 | 70–1500 mg/day of curcuminoids, 80–1000 mg/day of curcumin, 3000 mg/day of turmeric |
↓ Insulin (MD = −1.1430 μIU/mL; 95% CI −1.5439 to −0.7421; p < 0.0001) ↓ HOMA-IR (MD = −0.2884; 95%CI −0.3950 to −0.1817; p < 0.0001) |
Cochrane risk of bias tool (90.8%) | PubMed, Web of Science, and Scopus |
| Ngu et al. 2022 [180] | 3 publications [50,177,181] | NAFLD | 238 | 18–70 | P | 8–12 | 80–1500 mg/day of curcumin | ↔ QUICKI (MD = 0.01; 95% CI −0.00 to 0.02; p = 0.30) |
Cochrane risk of bias tool (79.5%) | Cochrane Central Register of Controlled Trials, and PubMed |
| Sun et al. 2022 [100] | 23 publications [23,25,27,39,45,49,60,61,70,76,80,87,101,126,169,170,182,183,184,185,186,187,188] | T2DM, obese, nephropathy, proteinuria, hemodialysis, DFU, IFG/IGT, Mets, hyperlipidemia | 1847 | 35–68 | P, CO |
4–36 | 80–2400 mg/day of curcumin | ↓ FBG (WMD = −0.50 mg/dL; 95% CI −0.72 to −0.28) |
Cochrane risk of bias tool (69.3%) Jadad scale (77.0%) |
PubMed, Embase, Web of Science, CNKI, Wanfang and CBM |
| 16 publications [27,29,39,49,60,70,76,80,101,126,182,183,185,186,187,188] |
T2DM, obese, proteinuria, hemodialysis, DFU, IFG/IGT, Mets, hyperlipidemia | 1224 | 35–70 | P, CO |
8–36 | 80–2100 mg/day of curcumin | ↓ Hb1Ac (WMD = −0.42%; 95% CI −0.57 to −0.26) |
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| 5 publications [45,76,80,187,188] | T2DM, IGT, hyperlipidemia, hemodialysis, DFU | 247 | 35–63 | P, CO |
6–17 | 80–500 mg/day of curcumin | ↓ Insulin (WMD = −1.70 μIU/mL; 95% CI −2.03 to −1.38) |
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| 11 publications [39,45,49,60,70,76,80,101,183,188,189] | T2DM, obese, hyperlipidemia, hemodialysis, IFG, IGT, DFU | 874 | 42–63 | P, CO |
6–36 | 80–2100 mg/day of curcumin | ↓ HOMA-IR (WMD = −0.71; 95% CI −1.11 to −0.31) |
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| Tian et al. 2022 [190] | 9 publications [38,49,57,87,101,114,182,183,191] | T2DM | 604 | 41–61 | P | 4–12 | 80–1500 mg/day of curcumin, 300–1000 mg/day of curcuminoids, 1500–2100 mg/day of turmeric |
↓ FBG (WMD = −8.85 mg/dL; 95% CI −14.4 to −3.29; p = 0.002) |
Cochrane risk of bias tool (57.1%) | PubMed, EMBASE, Web of Science, and Cochrane Library |
| 8 publications [38,49,57,101,114,182,183,191] |
T2DM | 564 | 41–61 | P | 4–12 | 80–1500 mg/day of curcumin, 300–1000 mg/day of curcuminoids, 2100 mg/day of turmeric |
↓ HbA1c (WMD = −0.54; 95% CI −0.81 to −0.27; p ≤ 0.001) |
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| Nouri et al. 2022 [192] | 4 publications [58,73,193,194] | PCOS | 198 | 28–31 | P | 6–12 | 93.34–1500 mg/day of curcumin | ↓ FBG (ES = −3.62 mg/dL; 95% CI −5.65 to −1.58; p < 0.001) ↓ Insulin (ES = −1.67 mU/mL; 95% CI −3.06 to −0.28; p = 0.018) ↓ HOMA-IR (ES = −0.42; 95% CI −0.76 to −0.09; p < 0.01) |
Cochrane risk of bias tool (75.0%) | PubMed, Scopus, and ISI Web of Science |
| Khalili et al. 2022 [195] | 9 publications [34,50,161,164,165,166,177,179,196] | NAFLD | 683 | 42–67 | P | 4–12 | 50–2000 mg/day of curcumin | ↓ FBG (SMD = −0.28; 95% CI −0.46 to −0.09; p = 0.003) |
Cochrane risk of bias tool (65.5%) | Web of Science, Science Direct, PubMed, and Embase |
| Shen et al. 2022 [99] | 7 publications [58,73,193,194,197,198,199] | PCOS | 447 | 20–38 | P | 6–24 | 80–1500 mg/day of curcumin | ↓ FBG (WMD = −3.618; 95% CI −5.165 to −2.071; p < 0.001) ↓ Insulin (WMD = −1.834; 95% CI −2.701 to −0.968; p < 0.001) ↓ HOMA-IR (WMD = −0.565; 95% CI −0.779 to −0.351; p < 0.001) |
Cochrane risk of bias tool (73.5%) | PubMed, Embase, Cochrane Library, Web of Science, Scopus, Clinical Trials, Chinese Clinical Trial Registry, Chinese Biomedical Literature Database, Chinese National Knowledge Infrastructure, VIP database, and Wanfang Database |
| 4 publications [58,193,194,197] | PCOS | 266 | 23–38 | P | 6–12 | 80–1500 mg/day of curcumin | ↑ QUICKI (WMD = 0.011; 95% CI 0.005 to 0.017; p = 0.001) |
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| Ashtary-Larky et al. 2021 [111] | 7 publications [23,50,71,76,171,182,185] | Mets, NAFLD, T2DM, hemodialysis | 417 | 36–68 | P | 6–12 | 40–120 mg/day of nano-curcumin | ↓ FBG (WMD = −18.14 mg/dL; 95% CI −29.31 to −6.97; p = 0.001) |
Cochrane risk of bias tool (55.6%) | PubMed, Scopus, Embase, and Web of Science |
| 3 publications [50,76,171] | Mets, NAFLD, T2DM, hemodialysis | 180 | 36–68 | P | 12 | 40–80 mg/day of nano-curcumin | ↓ Insulin (WMD = −1.21 mg/dL; 95% CI −1.43 to −1.00; p < 0.001) |
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| 4 publications [50,171,182,185] | Mets, NAFLD, T2DM | 277 | 36–68 | P | 8–12 | 40–80 mg/day of nano-curcumin | ↓ HbA1c (WMD = −0.66 mg/dL; 95% CI −1.41 to −0.08; p < 0.001) |
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| 3 publications [50,76,171] | Mets, NAFLD, T2DM, hemodialysis | 180 | 36–68 | P | 12 | 40–80 mg/day of nano-curcumin | ↓ HOMA-IR (WMD = −0.28 mg/dL; 95% CI −0.33 to −0.23; p < 0.001) |
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| Abdelazeem et al. 2021 [115] | 5 publications [58,73,193,194,197] | PCOS | 296 | 24–39 | P | 6–12 | 80–1500 mg/day of curcumin | ↓ FBG (MD = −3.67; 95% CI −5.25 to −2.08; p < 0.00001) ↓ Insulin (MD = −1.91; 95% CI −2.97 to −0.84; p = 0.0005) ↓ HOMA-IR (MD = −0.55; 95% CI −0.83 to −0.27; p = 0.0001) |
Cochrane risk of bias tool (73.3%) | PubMed, EMBASE, Scopus, Web of Science, Cochrane Central, and Google Scholar |
| 4 publications [58,193,194,197] | PCOS | 266 | 24–36 | P | 6–12 | 80–1500 mg/day of curcumin | ↓ QUICKI (MD = 0.01; 95% CI 0.00 to 0.02; p = 0.0005) |
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| Zhang et al. 2021 [200] | 5 publications [31,60,70,183,185] | T2DM | 524 | 34–70 | P | 8–24 | 80–1500 mg/day of curcumin, 300–1500 mg/day of curcuminoids |
↓ HbA1c (WMD = −0.70; 95% CI −0.87 to −0.54; p < 0.0001) |
Cochrane risk of bias tool (69.4%) | Chinese database (CNKI, Wan Fang, VIP, CBM), PubMed, EMBASE, Cochrane Library, Web of Science, Medline Complete and, ClinicalTrials.gov |
| 1 publication [60] | T2DM | 100 | 34–51 | P | 12 | 1000 mg/day of curcuminoids | ↓ HOMA-IR in the Middle East subgroup (WMD = −0.60; 95% CI −0.74 to −0.46; p < 0.00001) |
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| 2 publications [31,183] | T2DM | 313 | 34–65 | P | 12–24 | 1500 mg/day of curcumin, 300 mg/day of curcuminoids |
↓ HOMA-IR in the Asia subgroup (WMD = −2.41; 95% CI −4.44 to −0.39; p = 0.02) |
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| 6 publications [31,60,70,87,183,185] | T2DM | 564 | 34–70 | P | 8–24 | 80–1500 mg/day of curcumin, 300–1500 mg/day of curcuminoids, 1500 mg/day of turmeric |
↓ FBG in the Asia subgroup (SMD = −0.57; 95% CI −0.79 to −0.36; p < 0.00001) ↔ FBG in the Middle East subgroup |
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| Altobelli et al. 2021 [201] | 5 publications [49,114,144,182,183] | T2DM | 333 | 18–80 | P | 8–12 | 80–1500 mg/day of curcumin, 300 mg/day of curcuminoids, 2100 mg/day of turmeric |
↓ HbA1c (ES = −0.42; 95% CI −0.77 to −0.11; p = 0.008) |
Cochrane risk of bias tool (93.8%) | Medline, EMBASE, Scopus, ClinicalTrials.gov, Web of Science, and Cochrane Library |
| 4 publications [31,49,144,183] | T2DM | 432 | 18–70 | P | 8–24 | 1500 mg/day of curcumin, 250–300 mg/day of curcuminoids, 2100 mg/day of turmeric |
↓ HOMA-IR (ES = −0.41; 95% CI −0.60 to −0.22; p < 0.001) |
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| Chien et al. 2021 [202] | 3 publications [58,193,194] | PCOS | 168 | 24–39 | P | 6–12 | 500–1500 mg/day of curcumin | ↓ FBG (MD = −2.77; 95% CI −4.16 to −1.38; p < 0.001) ↓ Insulin (MD = −1.33; 95% CI −2.18 to −0.49; p = 0.002) ↓ HOMA-IR (MD = −0.32; 95% CI −0.52 to −0.12; p = 0.002) ↓ QUICKI (MD = 0.010; 95% CI 0.003 to 0.018; p = 0.005) |
Cochrane risk of bias tool (72.2%) | PubMed, Embase, Scopus, Web of Science, and Cochrane Library |
| Jalali et al. 2020 [203] |
6 publications [34,50,161,164,165,177] | NAFLD | 407 | 33–58 | P | 8–12 | 50–1425 mg/day of curcumin | ↔ FBG (MD = −0.22; 95% CI −0.42 to −0.02; p = 0.313) |
Jadad scale (88.9%) | PubMed, Embase, Scopus, Web of Science, and Cochrane Library |
| 3 publications [50,165,177] | NAFLD | 211 | 36–58 | P | 8–12 | 80–1425 mg/day of curcumin | ↓HOMA-IR (MD = −0.37; 95% CI −0.70 to −0.03; p = 0.000) ↓ Insulin (MD = −0.49; 95% CI −0.81 to −0.16; p = 0.000) |
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| Azhda-ri et al. 2019 [204] | 5 publications [25,27,61,126,172] | Mets | 359 | 38–60 | P | 6–12 | 1000–1890 mg/day of curcumin, 1000 mg/day of curcuminoids, 2400 mg/day of turmeric |
↓ FBG (WMD = −9.18 mg/dL; 95% CI −16.70 to −1.66; p = 0.01) |
Cochrane risk of bias tool (57.1%) | Web of Science, Medline, Google Scholar, Scopus, Cochrane, and CINAHL |
| Huang et al. 2019 [205] | 13 publications [25,35,39,45,51,57,114,126,161,177,182,183,206] | T2DM, NAFLD, Mets, hyperlipidemia, CAD, high ALT | 1064 | 30–72 | P, CO |
4–12 | 70–1890 mg/day of curcumin, 294–2000 mg/day of curcuminoids, 2400–3000 mg/day of turmeric |
↓ FBG (SMD = −0.382; 95% CI −0.654 to −0.111 mg/dL; p = 0.006) |
Cochrane risk of bias tool (83.7%) | PubMed, Cochrane Library, Web of Science, and Embase |
| 7 publications [31,35,39,45,57,177,183] | T2DM, NAFLD, Mets, hyperlipidemia | 821 | 30–72 | P, CO |
4–12 | 1000 mg/day of curcumin, 294–1500 mg/day of curcuminoids, 2000–3000 mg/day of turmeric |
↓ HOMA-IR (SMD = −0.351; 95% CI −0.615 to −0.087; p = 0.009) |
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| 8 publications [39,57,114,126,161,177,182,183] |
T2DM, NAFLD, Mets | 731 | 40–74 | P | 4–12 | 80–1890 mg/day of curcumin, 300–1500 mg/day of curcuminoids, 2000 mg/day of turmeric |
↓ HbA1c (SMD = −0.370; 95% CI −0.631% to −0.110%; p = 0.005) |
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| 5 publications [35,39,45,57,177] | T2DM, NAFLD, Mets, hyperlipidemia | 507 | 31–71 | P, CO |
4–12 | 1000 mg/day of curcumin, 294–1500 mg/day of curcuminoids, 2000–3000 mg/day of turmeric |
↔ Insulin (SMD = −0.058; 95% CI −0.352 to 0.235; p = 0.697) |
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| Tabrizi et al. 2018 [207] | 19 publications [25,32,39,45,46,51,57,87,101,114,126,129,161,178,182,183,206,208,209] | T2DM, hyperlipidemia, Mets, obese, diabetic nephropathy, NAFLD, CAD | 1299 | 10–73 | P | 4–24 | 70–2000 mg/day of curcumin, 300–1000 mg/day of curcuminoids, 112–2400 mg/day of turmeric |
↓ FBG (SMD = −0.78; 95% CI −1.20 to −0.37; p < 0.001) |
Cochrane risk of bias tool (76.9%) | Cochrane Library, EMBASE, MEDLINE, and Web of Science |
| 7 publications [32,39,45,57,129,178,208] | T2DM, obese, hyperlipidemia, NAFLD | 552 | 18–68 | P | 4–36 | 294 mg/day of curcumin, 500–1000 mg/day of curcuminoids, 2000–2100 mg/day of turmeric |
↑ Insulin (SMD = 0.92; 95% CI 0.06 to 1.78; p = 0.036) |
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| 8 publications [31,32,39,45,57,178,183,208] | T2DM, obese, hyperlipidemia, NAFLD | 836 | 10–65 | P | 4–36 | 294 mg/day of curcumin, 500–1000 mg/day of curcuminoids, 300–2100 mg/day of turmeric |
↓ HOMA-IR (SMD = −0.91; 95% CI −1.52 to −0.31; p = 0.003) |
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| 10 publications [39,57,101,114,126,161,178,182,183,208] | T2DM, Mets, obese, hyperlipidemia, NAFLD |
906 | 18–73 | P | 4–36 | 70–1890 mg/day of curcumin, 300–1000 mg/day of curcuminoids, 300–2100 mg/day of turmeric |
↓ HbA1c (SMD = −0.92; 95% CI −1.37 to −0.47; p < 0.001) |
ALT, alanine aminotransferase; CAD, coronary artery disease; CI, confidence interval; CO, crossover; DFU, diabetic foot ulcer; ES, effect size; FBG, fasting blood glucose; HbA1c, glycated hemoglobin; HOMA-IR, homeostatic model assessment for insulin resistance; IFG, impaired fasting glucose; IGT, impaired glucose tolerance; MD, mean difference; Mets, metabolic syndrome; MAFLD, metabolic (dysfunction)-associated fatty liver disease; NAFLD, non-alcoholic fatty liver disease; P, parallel, PCOS, polycystic ovary syndrome; QUICKI, quantitative insulin sensitivity check index; RCTs, randomized controlled trials; SMD, standardized mean difference; T2DM, type 2 diabetes mellitus; WMD, weighted mean difference. The quality of primary studies is indicated as a percentage of low risk (Cochrane risk of bias tool) or ≥3 (Jadad scale). ↑, increase; ↓, decrease; ↔ no effect.