Table 1.
Characteristics of eligible randomized controlled trials that investigated the effect of OLE intervention on cardiovascular-risk factors in adults
| Author, year | Country | Participants (I, C)/sex | Design/duration (weeks) | Mean age | Health status | Intervention protocol/control protocol | Outcome | ||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Obesity | HTN | Dyslipidemia | T2DM | Other | |||||||
| Araki, 2019 [19] | Japan | (28, 29)/B | P/12 | 52 | Y | N | N | Y | – | 1000 ml OLT (32.4 mg/100 g Oleuropein, 1.2 mg/100 g Hydroxytyrosol)/0.5 g LOLT ((2.4 mg/100 g Oleuropein, 0.3 mg/100 g HT) | FBS, HbA1c, HOMA-IR, LDL-C, HDL-C, |
| Araki, 2018 [34] | Japan | (20, 19)/B | P/12 | 52 | N | N | Y | N | – | 1000 ml OLT (425 mg/L Oleuropein,6.4 mg/L Hydroxytyrosol)/Green tea (0 mg/L Oleuropein, and 4.9 mg/L Hydroxytyrosol) | FBS, HbA1c, LDL-C, HDL-C, TG |
| de Bock, 2013 [20] | New Zealand | (45, 45)/M | C/12 | 46.5 | Y | N | N | N | – | 4 Cap (51.1 mg Oleuropein, 9.6 mg HT)/ Pl | LDL-C, HDL-C, TG, TC, SBP, DBP, hs-CRP, IL-6, IL-8, TNF-α, LDL-ox, |
| Filip, 2015 [42] | Netherlands | (32, 32)/F | P/48 | 59.7 | N | N | N | N | Postmenopausal women with osteopenia | 250 mg Cap (40% ≤ Oleuropein) + 400 mg Ca/400 mg Ca | LDL-C, HDL-C, TG, TC, hs-CRP, IL-6, ALP, Cr |
| Javadi, 2019 [35] | Iran | (30, 30)/B | P/12 | 54 | N | Y | N | N | – | 500 mg Tab (16% Oleuropein, 0.62 mg luteolin)/Pl | FBS, Ins, HOMA-IR, IL-6, IL-8, TNF-α, AST, ALT, ALP, Cr |
| Lockyer, 2017 [17] | Australia | (31, 30)/M | C/6 | 45.3 | Y | Y | N | N | – | 20 ml/day OLE liquid (equaled to 136.2 mg/day oleuropein and 6.4 mg/day Hydroxytyrosol)/Pl | FBS, Ins, HOMA-IR, LDL-C, HDL-C, TG, TC, SBP, DBP, hs-CRP, IL-6, IL-8, TNF-α, LDL-ox |
| Perrinjaquet-Moccetti, 2008 [21] | Switzerland | (10, 10)/B | P/8 | 36 | N | Y | N | N | – | 500 mg Tab OLE (e 18–26%) oleuropein, 30–40% polyphenols and luteolin-7-glucoside)/Pl | LDL-C, HDL-C, TC, SBP, DBP |
| Saberi, 2018 [24] | Iran | (32, 32)/B | P/NM | 54 | N | Y | N | N | – | 1000 mg Cap OLE/Pl | SBP, DBP, |
| Stevense, 2021 [43] | Netherlands | (39, 38)/B | P/8 | 56.5 | Y | N | Y | N | – | 500 mg OLE (16.7%, and 83.5 mg oleuropein)/Pl | FBS, Insulin, LDL-C, HDL-C, TG, TC, SBP, DBP, LDL-ox, AST, ALT, ALP |
| Susalit, 2011 [36] | Indonesia | (72, 76)/B | P/8 | 50 | N | Y | N | N | – | 500 mg Caplet (19.9%) oleuropein)/12.5 mg captopril | FBS, Insulin, LDL-C, HDL-C, TG, TC, AST, ALT, Cr, SBP, DBP |
| Wainstein, 2012 [44] | Israel | (41, 38)/ | P/14 | ≥ 55 | N | N | N | Y | – | 500 mg Tab OLE /Pl | HbA1c |
| Yaghoobzadeh, 2020 [37] | Iran | (30, 30)/B | P/12 | 54.5 | N | Y | N | N | – | 500 mg Tab OLE (16% and 0.6 luteolin)/Pl | LDL-C, HDL-C, TG, TC, SBP, DBP |
P, parallel design; C, crossover design; HTN, hypertension; T2DM, type-2 diabetes mellitus; OLT, olive leaf extract; OLT, olive leaf tea; LOLT, low concentration of olive leaf tea; FBS, fasting blood glucose; HbA1c, glycated hemoglobin; HOMA-IR, homeostatic model assessment for insulin resistance; LDL-C, low-density lipoprotein cholesterol; HDL-C, high-density lipoprotein cholesterol; TG, triglycerides; TC, total cholesterol; SBP, systolic blood pressure; DBP, diastolic blood pressure; hs-CRP, high-sensitivity C-reactive protein; IL-6, interleukin-6; IL-8, interleukin-8; TNF-α, tumor necrosis factor alpha; LDL-ox, oxidized low-density lipoprotein; AST, aspartate transaminase; ALT, alanine transaminase; ALP, alkaline phosphatase; Cr, creatinine; Cap, capsule; Tab, tablet; Ca, calcium, PI, per intervention