TABLE 1.
Characteristics of included studies.
| First author (year)/location | Study design | Subjects' characteristics | Sample size | Types of supplementation | Period (weeks) | Evaluation markers |
|---|---|---|---|---|---|---|
| Choi et al. (2015)/Republic of Korea | RCT, Parallel |
Overweight to obese – BMI >23 kg/m2 |
62 – Test, n = 36 – Placebo, n = 28 |
Onion peel extract 228 mg (100 mg quercetin) or placebo | 12 |
Anthropometry – BW, BMI Biochemistry – TC, TG, LDL‐C, HDL‐C, glucose Endothelial function – FMD, EPCs |
| Choi et al. (2020) /Republic of Korea | RCT, Parallel |
Overweight to obese – BMI >23 kg/m2 |
61 – Test, n = 31 – Placebo, n = 30 |
Onion peel extract 468.4 mg (100 mg quercetin) or placebo | 12 |
Anthropometry – BW, BMI, BFM, %BF, FFM, ARFATP, LEFATP, TRFATP, AndFATP, FATP |
| Jeong et al. (2020)/Republic of Korea | RCT, Parallel |
Obese – BMI 25–30 kg/m2 |
56 – Test, n = 28 – Placebo, n = 28 |
Steamed onion capsules 900 mg or placebo | 12 |
Anthropometry – BW, BMI, WC, HC, WHR, %BF, BFM, LBM CT – Abdominal fat area (visceral, subcutaneous) Biochemistry – TC, TG, LDL‐C, HDL‐C Hormones – Adiponectin, leptin, T3, T4, TSH |
| Kim and Yim (2015, 2016)/Republic of Korea | RCT, Parallel |
Overweight to obese – BMI >23 kg/m2 |
37 – Test, n = 18 – Placebo, n = 19 |
Onion peel extract 100 mg (28.6 quercetin) or placebo | 12 |
Anthropometry – BW, BMI, WC, HC Biochemistry – TC, TG, LDL‐C, HDL‐C Oxidative stress – ROS, SOD |
| Lee et al. (2016)/Republic of Korea | RCT, Parallel |
Overweight to obese – BMI >23 kg/m2 |
72 – Test, n = 36 – Placebo, n = 36 |
Onion peel extract 340 mg (100 mg quercetin) or placebo | 12 |
Anthropometry – BW, BMI, WC, HC, Tricep, ARFAT, LEFAT, TRFAT, FATP, FAT, BP Biochemistry – TC, TG, LDL‐C, HDL‐C, glucose, insulin Hormones – leptin |
Abbreviations: 8‐iso‐PGEF2α, 8‐iso‐prostaglandin F2α; ACE, angiotensin‐converting enzyme; AI, augmentation index; ALP, alkaline phosphatase; ALT, alanine aminotransferase; AMDA, asymmetric dimethylarginine; AndFATP, android fat percentage; Apo‐AI, apolipoprotein‐I; Apo‐B, apolipoprotein‐B; ARFATP, arm fat percentage; AST, aspartate aminotransferase; BFM, body fat mass; BMI, body mass index; BP, blood pressure; BW, body weight; CT, computerized tomography; EPCs, endothelial progenitor cells; FATP, total fat percentage; FFM, fat free mass; FMD, flow‐mediated dilation; HbA1c, hemoglobin A1c; HC, hip circumference; HDL‐C, high‐density lipoprotein cholesterol; HR, heart rate; hs‐CRP, high‐sensitivity C‐reactive protein; ICAM‐1, intercellular adhesion molecule 1; IsoP, isoprostanes; LBM, lean body mass; LDL‐C, low‐density lipoprotein cholesterol; LEFATP, leg fat percentage; oxLDL, oxidized low lipoprotein; %BF, percent body fat; RCT, randomized controlled trial; RHI, reactive hyperemia index; ROS, reactive oxygen species; SOD, superoxide dismutase; T3, triiodothyronine; T4, thyroxine; TC, total cholesterol; TG, triglyceride; TRFATP, trunk fat percentage; TSH, thyroid‐stimulating hormone; VCAM‐1, vascular cell adhesion molecule 1; WC, waist circumference; WHR, waist‐to‐hip ratio.