TY - JOUR
T1 - Effects of garlic supplementation on oxidative stress and antioxidative capacity biomarkers
T2 - A systematic review and meta-analysis of randomized controlled trials
AU - Askari, Mohammadreza
AU - Mozaffari, Hadis
AU - Darooghegi Mofrad, Manije
AU - Jafari, Alireza
AU - Surkan, Pamela J.
AU - Amini, Mohammad Reza
AU - Azadbakht, Leila
N1 - Funding Information:
This study is supported by Tehran University of Medical Sciences (grant number: 97‐03‐161‐41097).
Publisher Copyright:
© 2021 John Wiley & Sons, Ltd.
PY - 2021/6
Y1 - 2021/6
N2 - Evidence suggests that garlic supplementation may have an effect on oxidative stress by augmenting the rate of enzymatic and non-enzymatic antioxidants and diminishing pro-oxidant enzymes. Given inconsistencies across studies, we aimed to systematically review the current literature and quantify the effects of garlic supplementation on oxidative stress. We conducted a systematic search with multiple databases (Scopus, PubMed, and Web of Science) to find relevant articles published prior to October 2020. Results were reported as bias-corrected standardized mean difference (Hedges' g) with 95% confidence intervals (CI) using random-effects models. Cochrane's Q and I squared (I2) tests were used to determine heterogeneity among the studies included. Twelve randomized controlled trials (RCTs) were included. Garlic doses ranged from 80 to 4,000 mg/day, and intervention duration varied between 2 and 24 weeks. Garlic supplementation increased serum level of total antioxidant capacity (TAC) (Hedges' g: 2.77, 95% CI: 1.37 to 4.17, p < 0.001) and superoxide dismutase (SOD) (Hedges' g: 13.76, 95% CI: 4.24 to 23.29, p = 0.004), while it reduced the malondialdehyde serum level (MDA) (Hedges' g: -1.94, 95% CI: −3.17 to −0.70, p = 0.002). Due to limited data available, glutathione (GSH) was not considered for the current meta-analysis. The nonlinear dose-response effect of garlic supplementation was not observed with regard to serum TAC and MDA levels (TAC: p-nonlinearity = 0.398; MDA: p-nonlinearity = 0.488). Garlic supplementation appears to improve serum levels of TAC, MDA, and SOD. Garlic supplementation may be useful to reduce oxidative stress and related diseases. Future studies with large sample sizes and longer duration are required to confirm these findings.
AB - Evidence suggests that garlic supplementation may have an effect on oxidative stress by augmenting the rate of enzymatic and non-enzymatic antioxidants and diminishing pro-oxidant enzymes. Given inconsistencies across studies, we aimed to systematically review the current literature and quantify the effects of garlic supplementation on oxidative stress. We conducted a systematic search with multiple databases (Scopus, PubMed, and Web of Science) to find relevant articles published prior to October 2020. Results were reported as bias-corrected standardized mean difference (Hedges' g) with 95% confidence intervals (CI) using random-effects models. Cochrane's Q and I squared (I2) tests were used to determine heterogeneity among the studies included. Twelve randomized controlled trials (RCTs) were included. Garlic doses ranged from 80 to 4,000 mg/day, and intervention duration varied between 2 and 24 weeks. Garlic supplementation increased serum level of total antioxidant capacity (TAC) (Hedges' g: 2.77, 95% CI: 1.37 to 4.17, p < 0.001) and superoxide dismutase (SOD) (Hedges' g: 13.76, 95% CI: 4.24 to 23.29, p = 0.004), while it reduced the malondialdehyde serum level (MDA) (Hedges' g: -1.94, 95% CI: −3.17 to −0.70, p = 0.002). Due to limited data available, glutathione (GSH) was not considered for the current meta-analysis. The nonlinear dose-response effect of garlic supplementation was not observed with regard to serum TAC and MDA levels (TAC: p-nonlinearity = 0.398; MDA: p-nonlinearity = 0.488). Garlic supplementation appears to improve serum levels of TAC, MDA, and SOD. Garlic supplementation may be useful to reduce oxidative stress and related diseases. Future studies with large sample sizes and longer duration are required to confirm these findings.
KW - diet
KW - garlic
KW - meta-analysis
KW - oxidative stress
UR - http://www.scopus.com/inward/record.url?scp=85099909373&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85099909373&partnerID=8YFLogxK
U2 - 10.1002/ptr.7021
DO - 10.1002/ptr.7021
M3 - Review article
C2 - 33484037
AN - SCOPUS:85099909373
SN - 0951-418X
VL - 35
SP - 3032
EP - 3045
JO - Phytotherapy Research
JF - Phytotherapy Research
IS - 6
ER -