Effects of Bioactive Compound Supplementation on Insulin Resistance and Systemic Inflammation in Overweight and Obese Adults: A Systematic Review and Meta-Analysis of Randomized Controlled Trials
- 1Department of Land, Environment, Agriculture and Forestry, Università degli Studi di Padova, Viale dell’Università 16, 35020 Legnaro, Italy
- 2Department of Statistics, Università di Bologna, Via Belle Arti, 41, 40126 Bologna, Italy
- 3Department of Medicine (DIMED), Università degli Studi di Padova, Via Niccolò Giustiniani 2, 35028 Padova, Italy
Abstract
Background/objectives: Obesity is characterized by chronic low-grade inflammation and insulin resistance. This systematic review and meta-analysis evaluated oral supplementation with curcumin, green tea extract, resveratrol and omega-3 fatty acids on homeostatic model assessment of insulin resistance (HOMA-IR) and C-reactive protein (CRP) in adults with overweight or obesity. Methods: PubMed and Scopus were searched on 22 July 2026 for randomized controlled trials (RCTs) of isolated oral supplementation versus placebo or control, lasting ≥4 weeks, in adults with BMI ≥25.0 kg/m2 without type 2 diabetes. Risk of bias was assessed with RoB 2 and certainty of evidence with GRADE. Random-effects meta-analyses were performed separately for each compound and biomarker, using mean difference (MD). Results: Fifty-nine RCTs (3263 participants) were included (omega-3: 23; curcumin: 13; green tea: 13; resveratrol: 10). Most trials had some concerns or high risk of bias. Only curcumin significantly reduced HOMA-IR (MD = −0.30 [−0.53, −0.07], p = 0.019; moderate certainty), with low heterogeneity. Green tea extract yielded a non-significant CRP reduction (MD = −0.43 mg/L [−0.87, 0.02], p = 0.057; low certainty) with substantial heterogeneity. Resveratrol and omega-3 showed no significant effect on either outcome (low certainty). Significant heterogeneity was observed in five of eight analyses. Conclusions: Curcumin may modestly improve insulin resistance in this population, potentially as a complementary strategy in obesity management. Green tea’s anti-inflammatory effect requires confirmation. Heterogeneous formulations and doses, small samples and risk of bias limit interpretation; future RCTs should use standardized formulations with documented bioavailability.
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BibTeX
@article{nichele2026effects,
title = {{Effects of Bioactive Compound Supplementation on Insulin Resistance and Systemic Inflammation in Overweight and Obese Adults: A Systematic Review and Meta-Analysis of Randomized Controlled Trials}},
author = {Sarah Nichele and Lucas Moneró Prates and Luca Busetto},
journal = {Nutrients},
year = {2026},
month = oct,
doi = {10.3390/nu18213638},
url = {https://www.mdpi.com/2072-6643/18/21/3638},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Effects of Bioactive Compound Supplementation on Insulin Resistance and Systemic Inflammation in Overweight and Obese Adults: A Systematic Review and Meta-Analysis of Randomized Controlled Trials
AU - Sarah Nichele
AU - Lucas Moneró Prates
AU - Luca Busetto
PY - 2026
DA - 2026/10/31
JO - Nutrients
DO - 10.3390/nu18213638
UR - https://www.mdpi.com/2072-6643/18/21/3638
AB - Background/objectives: Obesity is characterized by chronic low-grade inflammation and insulin resistance. This systematic review and meta-analysis evaluated oral supplementation with curcumin, green tea extract, resveratrol and omega-3 fatty acids on homeostatic model assessment of insulin resistance (HOMA-IR) and C-reactive protein (CRP) in adults with overweight or obesity. Methods: PubMed and Scopus were searched on 22 July 2026 for randomized controlled trials (RCTs) of isolated oral supplementation versus placebo or control, lasting ≥4 weeks, in adults with BMI ≥25.0 kg/m2 without type 2 diabetes. Risk of bias was assessed with RoB 2 and certainty of evidence with GRADE. Random-effects meta-analyses were performed separately for each compound and biomarker, using mean difference (MD). Results: Fifty-nine RCTs (3263 participants) were included (omega-3: 23; curcumin: 13; green tea: 13; resveratrol: 10). Most trials had some concerns or high risk of bias. Only curcumin significantly reduced HOMA-IR (MD = −0.30 [−0.53, −0.07], p = 0.019; moderate certainty), with low heterogeneity. Green tea extract yielded a non-significant CRP reduction (MD = −0.43 mg/L [−0.87, 0.02], p = 0.057; low certainty) with substantial heterogeneity. Resveratrol and omega-3 showed no significant effect on either outcome (low certainty). Significant heterogeneity was observed in five of eight analyses. Conclusions: Curcumin may modestly improve insulin resistance in this population, potentially as a complementary strategy in obesity management. Green tea’s anti-inflammatory effect requires confirmation. Heterogeneous formulations and doses, small samples and risk of bias limit interpretation; future RCTs should use standardized formulations with documented bioavailability.
SN - 2072-6643
ER -