Table 1.
General characteristics of randomized controlled trials included in the systematic review.
| Reference | Sample Size; % Female | Age (Years, Mean ± SD) | BMI (kg/m2, Mean ± SD) | Duration (Weeks), Design | Diseases/Health Status/Medication | Olive Oil Intervention | Comparison Group | Outcome Parameters |
|---|---|---|---|---|---|---|---|---|
| Casas et al., 2014 [19] | 164; olive oil: 56.4, control: 59.3 | Olive oil: 68.1 ± 6, control: 67.4 ± 4 | Olive oil: 27.9 ± 3.4, control: 26.5 ± 3.7 | 52, parallel | High risk for CVD (type 2 diabetes mellitus or 3 or more major cardiovascular risk factors) | MedD + extra virgin olive oil (50 mL/day) | Low-fat diet | CRP, sE-selectin, sP-selectin, sVCAM-1 |
| Ceriello et al., 2014 [20] | 24; olive oil: 25, control: 33 | n.d. | Olive oil: 29.8 ± 1.4, control: 29.2 ± 1.1 | 3 months, parallel | Type 2 diabetes mellitus | MedD + extra virgin olive oil (50 mL/day) | Low-fat diet | FMD |
| Damasceno et al., 2010 [17] | 18; 50 | 56 ± 13 | 25.7 ± 2.3 | 4, cross-over | Moderate hypercholesterolemia, no medication, no hormone replacement therapy | MedD + 30–50 g/day virgin olive oil (polyphenols 34.3 mg/100g) | MedD + walnuts (polyphenols 1.3 mg/100g); MedD + almonds (polyphenols 1.1 mg/100g) | CRP, sICAM-1, sVCAM-1 |
| Damsgaard et al., 2008 [21] | 64; 0 | Olive oil high linoleic acid: 24.9 ± 3.8, olive oil low linoleic acid: 25.5 ± 4.4, control high linoleic acid: 26.3 ± 4.8, control low linoleic acid: 24.9 ± 4.9 | Olive oil high linoleic acid: 23.1 ± 1.9, olive oil low linoleic acid: 23.3. ± 1.9, control high linoleic acid: 21.9 ± 1.8, control low linoleic acid: 22.9 ± 1.9 | 8, 2 × 2 factorial | Healthy, no medication | 5 mL/day unrefined extra virgin olive oil capsules | 5 mL/day fish oil capsules | adiponectin, CRP, IL-6, VCAM-1 |
| Damsgaard et al., 2009 [22] | 63; 0 | Olive oil high linoleic acid: 24.9 ± 3.8, olive oil low linoleic acid: 25.5 ± 4.4, control high linoleic acid: 26.3 ± 4.8, control low linoleic acid: 24.9 ± 4.9 | Olive oil high linoleic acid: 23.1 ± 1.9, olive oil low linoleic acid: 23.3. ± 1.9, control high linoleic acid: 21.9 ± 1.8, control low linoleic acid: 22.9 ± 1.9 | 8, 2 × 2 factorial | Healthy, no intensive sports | 5 mL/day unrefined extra virgin olive oil capsules | 5 mL/day fish oil capsules | |
| Eschen et al., 2004 [23] | 60; olive oil: 82, control: 66 | Olive oil: 39 ± 10, control: 38 ± 11 | Olive oil: 24.6 ± 3.7, control:25.1 ± 2.9 | 12, parallel | Healthy, no medication | 10 g/day olive oil capsules | 6.6 g/day n-3 PUFA capsules; 2.0 g/day n-3 PUFA + 7 g/day olive oil capsules | ICAM-1, VCAM-1, P-selectin |
| Eschen et al., 2010 [24] | 138; olive oil: 22, control: 13 | Olive oil: 61 ± 8, control: 58 ± 10 | Olive oil: 27.1 ± 0.4, control: 27.1 ± 0.5 | 24, parallel | Chronic heart failure and left ventricular ejection fraction<40 or stable oral medication | 1 g/day olive oil capsules | 0.9 g/day n-3 PUFA capsules | SICAM-1, sVCAM-1, sP-selectin |
| Esposito et al., 2004 [25] | 180; olive oil: 46, control: 44 | Olive oil: 44.3 ± 6.4, control: 43.5 ± 5.9 | Olive oil: 27.9 ± 3.4, control: 28.1 ± 3.2 | 104, parallel | ≥3 criteria of metabolic syndrome, no medication, no intensive sports | MedD + olive oil | Generally healthy diet | hsCRP, IL-6 |
| Esposito et al., 2009 [26] | 195; olive oil: 50, control: 51.5 | n.d. | n.d. | 208, parallel | Overweight, newly diagnosed type 2 diabetes mellitus, no medication | MedD + 30–50 g olive oil/day | Low-fat diet | adiponectin |
| Flynn et al., 2010 [27] | 28; n.d. | 59.2 ± 6.1 | 27.9 ± 2.8 | 8 weight loss, 24 follow-up, cross-over | Overweight women with invasive breast cancer, stable medication | Plant-based olive oil diet with at least 3 tablespoons extra virgin olive oil/day | National Cancer Institute diet with canola oil | CRP |
| Fuentes et al., 2008 [28] | 20; n.d. | 23.3. ± 1.5 | 24.65 ± 2.91 | 4, cross-over | Healthy, no medication, no intensive sports | MUFA diet based on extra virgin olive oil (38% fat) | SFA diet; low-fat n-3 enriched diet based on α-linoleic acid | sVCAM-1, sICAM-1 |
| Gammelmark et al., 2012 [29] | 50; olive oil: 52, control: 52 | Olive oil: 58.0 ± 17.4, control: 55.4 ± 9.5 | Olive oil: 30.8 ± 4.2, control: 29.5 ± 3.3 | 6, parallel | Abdominally obese, women postmenopausal, no medication except NSAIDs | 2 g/day olive oil capsules | 2 g/day fish oil capsules | Adiponectin, CRP, IL-6 |
| Konstantinidou et al., 2010 [30] | 90; olive oil: 67, control: 63 | Olive oil: 45 ± 10, control: 44 ± 10 | Olive oil: 25 ± 4, control: 26 ± 5 | 12, parallel | Healthy | MedD + virgin olive oil (phenolic content 328 mg/kg) | MedD + washed virgin olive oil (phenolic content 55 mg/kg); habitual diet | sP-selectin |
| Kontogianni et al., 2013 [31] | 37; 78 | 25.6 ± 5.9 | 21.9 ± 2.5 | 6, cross-over | Healthy, no medication, no intensive sports | 15 mL/day extra virgin olive oil | 15 mL/day flaxseed oil | Adiponectin, CRP, TNF-α |
| Maki et al., 2009 [32] | 76; olive oil: 80, control: 88 | Olive oil: 49.6 ± 1.4, control: 49.4 ± 1.7 | Olive oil: 31.1 ± 1.1, control: 32.6 ± 1.5 | 4, parallel | Healthy, abdominally obese | 2 g/day olive oil capsules | 2 g/day krill oil capsules; 2 g/day menhaden oil capsules | CRP |
| Mena et al., 2009 [33] | 106; olive oil: 84, control: 76 | Olive oil: 66 ± 11, control: 66 ± 7 | Olive oil: 28.0 ± 2.9, control: 27.8 ± 3.2 | 12, parallel | Type 2 diabetes mellitus or ≥3 CVD risk factors, ACE inhibitors, diuretics, anti-hypertensive agents, statins, lipid-lowering agents, insulin, oral glucose-lowering agents, aspirin or anti-platelet drugs | MedD + virgin olive oil (1 L/week) | MedD + nuts (30 g/day); low-fat diet | sE-selectin, sP-selectin, sVCAM-1, sICAM-1, IL-6, CRP |
| Mori et al., 2003 [34] | 51; olive oil: 25, control: 28 | Olive oil: 61.5 ± 1.9, control: 60.9 ± 1.9 | Olive oil: 29.9 ± 1.0, control: 28.6 ± 0.7 | 6, parallel | Hypertension, type 2 diabetes mellitus, anti-hypertensive therapy, oral glucose-lowering agents but no insulin | 4 g/day olive oil capsules | 4 g/day EPA capsules; 4 g/day DHA capsules | CRP, IL-6, TNF-α |
| Perez-Martinez et al., 2007 [2] | 16; 0 | n.d. | n.d. | 4, cross-over | Healthy, no medication, no intensive sports | MedD + virgin olive oil | SFA diet; diet high in carbohydrates | VCAM-1 |
| Pfeuffer et al., 2011 [35] | 85; olive oil: 0, control: 0 | n.d. | Conjugated linoleic acid: 28.3 ± 2.3, safflower oil: 28.2 ± 2.0, heated safflower oil: 28.9 ± 2.6 | 4, parallel | Overweight or obese, metabolic syndrome, coronary heart disease | 4.5 g/day olive oil capsules | 4.5 g/day conjugated linoleic acid mixture capsules; 4.5 g/day safflower oil capsules; 4.5 g/day heated safflower oil capsules | CRP, sICAM, sVCAM, sE-selectin |
| Sanders et al., 2011 [18] | 367; olive oil: 61, control: 56 | Olive oil: 55 (range: 54–57), control: 55 (range: 54–57) | Olive oil, males: 27 (range: 26–28), olive oil, females: 26 (range: 25–27), control, males: 26 (range: 25–27), control, females: 25 (range: 24–26) | 52, parallel | No CVD, medication: statins, anti-hypertensive medication, hormone replacement therapy, thyroxine | 3 g/day refined olive oil capsules | 0.45/0.9/1.8 g/day EPA + DHA capsules | CRP, FMD |
| Singhal et al., 2013 [36] | 324; olive oil: 60, control: 66 | Olive oil: 27.6 ± 4.7, control: 28.2 ± 4.8 | Olive oil: 23.6 ± 3.5, control: 23.6 ± 34.3 | 16, parallel | Healthy, no medication | 4 g/day olive oil capsules | 1.6 g/day DHA + 2.4 g/day carrier oil capsules | CRP, FMD |
| Sofi et al., 2010 [37] | 11; olive oil: 0, control: 33 | Olive oil: 54 (range: 42–70), control: 55 (range: 30–41) | Olive oil: 29.3 ± 3.9, control: 29.3 ± 4.1 | 52, parallel | Non-alcoholic fatty liver disease | 6.5 mL/day olive oil | 6.5 mL/day olive oil enriched with n-3 PUFA | adiponectin |
| Stirban et al., 2010 [38] | 34; n.d. | 56.8 ± 8.3 | 31.3 ± 4.1 | 6, cross-over | Type 2 diabetes mellitus, aspirin, angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, calcium channel blockers, ß-blockers, diuretics, statins | 2 g/day olive oil capsules | 2 g/day n-3 PUFA capsules | FMD |
| Taylor et al., 2005 [39] | 40; olive oil: 0, control: 0 | Olive oil: 47 ± 8, control: 45 ± 6 | Olive oil: 33 ± 3, control: 33 ± 3 | 12, parallel | Overweight, healthy | 4.5 g/day olive oil capsules | 4.5 g/day conjugated linoleic acid mixture capsules | adiponectin, CRP, FMD, TNF-α |
| Theobald et al., 2007 [40] | 39; 50 | Male: 51.1 ± 7.4, female: 46.2 ± 4.9 | Male: 51.1 ± 7.4, females: 46.2 ± 4.9 | 12, cross-over | Healthy, no medication | 1.5 g/day refined olive oil capsules | 0.7 g/day DHA capsules | IL-6, CRP, sE-Selectin |
| Tholstrup et al., 2008 [41] | 69; olive oil: 100, control: 100 | Olive oil: 59.9 ± 4.9, control: 62.3 ± 5.0 | Olive oil: 25.5 ± 3.3, control: 25.6 ± 3.1 | 16, parallel | Healthy, postmenopausal women, no medication | 5.5 g/day olive oil capsules | 5.5 g/day conjugated linoleic acid mixture capsules; 5.5 g/day conjugated linoleic acid milk capsules | IL-6, ICAM-1, VCAM-1 |
| Thomazella et al., 2011 [42] | 40; olive oil: 0, control: 0 | Olive oil: 55.0 ± 4.6, control: 54.6 ± 5.0 | Olive oil: 26.5 ± 1.9, control: 26.3 ± 2.5 | 12, parallel | ≥1 coronary event, clinical stablility, aspirin, anti-platelet drugs, statins (+ezetimibe), nitrates, ACE inhibitors, ß blockers | MedD + extra virgin olive oil (30 mL/day) | Low-fat therapeutic lifestyle changes diet | CRP, sICAM-1, sVCAM-1, FMD |
| Urpi-Sarda et al., 2012 [43] | 516; n.d. | n.d. | n.d. | 52, parallel | Type 2 diabetes mellitus or ≥3 CVD risk factors | MedD + virgin olive oil (1 L/week) | MedD + nuts; low-fat diet | ICAM-1, IL-6 |
| Voon et al., 2011 [44] | 45; 80 | 30.1 ± 8.3 | 30.1 ± 8.3 | 5, cross-over | healthy | Olive oil (2/3 of total fat) | Coconut oil (2/3 of total fat); palm olein (2/3 of total fat) | CRP, IL-6, TNF-α |
| Wong et al., 2010 [45] | 97; olive oil: 58, control: 53 | Olive oil: 59.0 ± 8.3, control: 61.2 ± 9.0 | Olive oil: 26.4 ± 4.4, control: 25.2 ± 3.7 | 12, parallel | Type 2 diabetes mellitus, no cardiovascular events, oral glucose-lowering agents/insulin | 4 g/day olive oil capsules | 4 g/day fish oil capsules | CRP, FMD |
| Woodman et al., 2003 [46] | 59; olive oil: 25, control: 28 | Olive oil: 61.5 ± 7.6, control: 60.9 ± 8.2 | Olive oil: 29.9 ± 4.0, control: 30.6 ± 3.1 | 6, parallel | Obese, type 2 diabetes mellitus and hypertension, oral glucose-lowering agents and treatment for hypertension | 4 g/day olive oil capsules | 4 g/day EPA capsules; 4 g/day DHA capsules | FMD, P-selectin |
ACE = angiotensin converitng enzyme; CRP= C-reactive protein; CVD = cardiovascular disease; DHA = docosahexaenoic acid; EPA = eicosapentaenoic acid; FMD = flow-mediated dilatation; ICAM-1 = intercellular adhesion molecule-1; IL-6 = interleukin-6; MedD = Mediterranean diet; NSAIDs = non-steroidal anti-inflammatory drugs; PUFA = polyunsaturated fatty acids; TNF-α = tumor necrosis factorα; VCAM-1 = vascular cell adhesion molecule-1.