Overview of human studies involving various olive plant products
| Product of olive plant | Food component concentration | Treatment (duration, number of participants, gender, age) | Effect/main outcome | Reference |
|---|---|---|---|---|
| EVOO | 10 g EVOO in meal | Postprandial blood sample was collected at 1:00 PM (before lunch), and 60 min and 120 min after lunch (proteins: 16–19%; carbohydrates: 53–54%; fats: 28–30%) 30 IFG patients Gender: 17 males and 13 females Age: 58.1 years ± 11.4 years | 20% decrease of blood glucose and insulin Δ change 18 mg/dL | [48] |
| EVOO | EVOO, 25mL/day (577 mg phenolic compound/kg) ROO, 25 mL/day (polyphenols not detectable) | 11 overweight DMT2 patients First four weeks “wash out” period—only ROO. Remaining four weeks EVOO (high in polyphenols) Gender: 7 men and 4 postmenopausal women Age: 64.63 years ± 8.52 years | EVOO significantly reduced fasting plasma glucose (P = 0.023), HbA1c (P = 0.039), BMI (P = 0.012), and body weight (P = 0.012) | [55] |
| Oleuropein enriched chocolate | 40 g oleuropein eriched chocolate and Mediterranean eating pattern (long before and during clinical trial) | 25 DMT2 patients (compared to 20 healthy patients; 10 males/10 females; age: 33.9 years ± 6.9 years) Gender: 12 males and 13 females Age: 69 years ±8 years After washout period (10 days) participants took oleuropein non- enriched chocolate | Administration of 40 g oleuropein enriched chocolate is associated with modest or no increase of glycaemia DMT2 patients and healthy subjects | [65] |
| EVOO | 10 mL/day at lunch and dinner | 13 patients suffering from MS Gender: 5 males and 8 females Age: 51.9 years ± 7.4 years Measures was conducted at the beginning and after 90 days | After 90 days of the study blood glucose decreased from average 93 mg/dL to average 86.0 mg/dL | [72] |
| Capsules with OLE | Period of 12 weeks Single dose (4 capsules) contains 51.1 g oleuropein and 9.7 mg HT | 45 overweight patients Gender: only men Age: 46.4 years ± 5.5 years Participants received 4 capsules with OLEs as a single dose 12 weeks once a day | After 12 weeks supplementation insulin sensitivity was significantly improved compared to placebo group (P = 0.009) | [79] |
| Capsules with olive leaf and fruit extracts | Period of 2 months Single dose (2 capsules) contains 100 mg/day oleuropein and 20 mg/day HT | 663 patients suffering from hypertension—134 prediabetic and 44 diabetic Gender: 327 males and 336 female Age: 60 years ± 12 years 2 months supplementation | After 2 months supplementation FG was significantly improved (with a decrease of 4.8%), P ˂ 0.0001 | [62] |
| Capsule with OLE | Period of 14 weeks Single dose (1 capsule) contains 500 mg OLE | 41 patient suffering from DMT2 Gender: 27 males and 14 females Age: 18–79 years 14 weeks supplementation | After 14 weeks supplementation HbA1c was significantly lower (compared to placebo group) | [88] |
BMI: body mass index; IFG: impaired fasting glucose; P: the level of statistical significance; ROO: refined olive oil