TY - JOUR
T1 - Garlic supplementation reduces circulating C-reactive protein, tumor necrosis factor, and interleukin-6 in Adults
T2 - A systematic review and meta-analysis of randomized controlled trials
AU - Mofrad, Manije Darooghegi
AU - Milajerdi, Alireza
AU - Koohdani, Fariba
AU - Surkan, Pamela J.
AU - Azadbakht, Leila
N1 - Funding Information:
Supported by Tehran University of Medical Sciences, Tehran, Iran (no.97-01-161-38111). Author disclosures: MDM, AM, FK, PJS, and LA, no conflicts of interest. Supplemental Figures 1–10 are available from the “Supplementary data” link in the online posting of the article and from the same link in the online table of contents at https://academic.oup.com/jn/. Address correspondence to LA (e-mail: l-azadbakht@tums.ac.ir). Abbreviations used: AGE, aged garlic extract; CRP, C-reactive protein; CVD, cardiovascular disease; RCT, randomized clinical trial; WMD, weighted mean difference.
Publisher Copyright:
© 2019 American Society for Nutrition. All rights reserved.
PY - 2019/4/1
Y1 - 2019/4/1
N2 - Background: Conflicting findings on the effects of garlic supplementation on inflammatory biomarkers have been observed in randomized clinical trials (RCTs). Objectives: The aim of this study was to summarize study results regarding the effects of garlic supplementation on serum inflammatory biomarkers in adults. Methods: We searched Scopus, PubMed, Google Scholar and Cochrane library databases for relevant papers published until April 2018, using keywords such as “garlic” and “inflammatory biomarker.” We included RCTs that 1) were conducted in adults, 2) examined the effects of garlic supplementation on inflammatory biomarkers compared to a control group, and 3) reported sufficient data on inflammatory biomarkers. Results were reported as weighted mean differences (WMD) with 95% CI using random effects models. Cochrane's Q and I-squared (I2) tests were used to determine heterogeneity among studies. Funnel plots and Egger's regression test were used to assess publication bias. Results: Sixteen RCTs were included. Garlic doses ranged from 12 to 3600 mg/d, and intervention duration ranged from 2 to 52 wk. Garlic administration significantly reduced serum C-reactive protein (CRP) (n = 13) (WMD: −0.61 mg/L, 95% CI: −1.12, −0.11, P = 0.018, I2 = 76.9%), IL-6 (n = 5) (WMD: −0.73 ng/L, 95% CI: −1.06, −0.40, P < 0.001, I2 = 0%), and TNF (n = 7) (WMD: −0.26 ng/L, 95% CI: −0.41, −0.12, P < 0.001, I2 = 0.0%), compared to controls. However, the effect of garlic supplementation on serum adiponectin (n = 3) (WMD: 0.18 μg/L, 95% CI: −0.21, 0.57, P = 0.35, I2 = 60.7%) and leptin (n = 2) (WMD: −1.25 μg/L, 95% CI: −2.64, 0.14, P = 0.07, I2 = 0.0%) concentrations were not significant. Conclusion: In this meta-analysis of RCTs, we found that garlic supplementation reduced serum concentrations of CRP, TNF, IL-6, but did not affect serum adiponectin and leptin in adults. More RCTs are needed to test the effects of garlic supplementation on inflammation.
AB - Background: Conflicting findings on the effects of garlic supplementation on inflammatory biomarkers have been observed in randomized clinical trials (RCTs). Objectives: The aim of this study was to summarize study results regarding the effects of garlic supplementation on serum inflammatory biomarkers in adults. Methods: We searched Scopus, PubMed, Google Scholar and Cochrane library databases for relevant papers published until April 2018, using keywords such as “garlic” and “inflammatory biomarker.” We included RCTs that 1) were conducted in adults, 2) examined the effects of garlic supplementation on inflammatory biomarkers compared to a control group, and 3) reported sufficient data on inflammatory biomarkers. Results were reported as weighted mean differences (WMD) with 95% CI using random effects models. Cochrane's Q and I-squared (I2) tests were used to determine heterogeneity among studies. Funnel plots and Egger's regression test were used to assess publication bias. Results: Sixteen RCTs were included. Garlic doses ranged from 12 to 3600 mg/d, and intervention duration ranged from 2 to 52 wk. Garlic administration significantly reduced serum C-reactive protein (CRP) (n = 13) (WMD: −0.61 mg/L, 95% CI: −1.12, −0.11, P = 0.018, I2 = 76.9%), IL-6 (n = 5) (WMD: −0.73 ng/L, 95% CI: −1.06, −0.40, P < 0.001, I2 = 0%), and TNF (n = 7) (WMD: −0.26 ng/L, 95% CI: −0.41, −0.12, P < 0.001, I2 = 0.0%), compared to controls. However, the effect of garlic supplementation on serum adiponectin (n = 3) (WMD: 0.18 μg/L, 95% CI: −0.21, 0.57, P = 0.35, I2 = 60.7%) and leptin (n = 2) (WMD: −1.25 μg/L, 95% CI: −2.64, 0.14, P = 0.07, I2 = 0.0%) concentrations were not significant. Conclusion: In this meta-analysis of RCTs, we found that garlic supplementation reduced serum concentrations of CRP, TNF, IL-6, but did not affect serum adiponectin and leptin in adults. More RCTs are needed to test the effects of garlic supplementation on inflammation.
KW - Diet
KW - Garlic
KW - Inflammation
KW - Meta-analysis
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U2 - 10.1093/jn/nxy310
DO - 10.1093/jn/nxy310
M3 - Article
C2 - 30949665
AN - SCOPUS:85064886677
SN - 0022-3166
VL - 149
SP - 605
EP - 618
JO - Journal of Nutrition
JF - Journal of Nutrition
IS - 4
ER -