Written by Tatjana Djakovic, Staff Writer. In a double-blind study, 1000 mg of olive leaf extract exhibited significant reductions in blood pressure and cholesterol in stage I hypertension.
High blood pressure also known as “the silent killer” is a major issue in the in the United States, affecting approximately 50 million individuals. In fact, by the middle age, only a minority (about 20%) of Americans have optimal systolic blood pressure and diastolic blood pressure (120/80 mmHg) (I). As the population ages, the prevalence of high blood pressure increases and so does the risk for cardiovascular disease. High blood pressure can be lowered through lifestyle changes; nevertheless people often require additional supplementation to get their blood pressure under control. They are often prescribed medicine that has high adverse effects and is very costly, which leads individuals to consider herbal medicines.
In this randomized, double-blind study, researchers tested the extract from the leaves of the olive tree, which contain large amounts of the substance oleuropein, known for its antioxidant properties. Olive tree leaves have been used since ancient times to fight high blood pressure, hardening of the arteries, and diabetes (2). The purpose of the study was to observe if olive leaf extract was as effective in lowering blood pressure as a commonly used blood pressure lowering drug Captopril. There were 148 subjects with stage I hypertension defined by systolic blood pressure of 140-150 mmHg and diastolic blood pressure 90-99 mmHg. The subjects were randomized to receive either 500 mg of olive leaf extract twice daily or Captopril tablets at 12.5 mg once or twice daily (3).
The olive leaf extract showed a comparable blood pressure lowering effect (-11.5 and -4.8 mmHg for systolic and diastolic blood pressure, respectively) to that shown by Captopril (-13.7 and -6.4 mm Hg for systolic and diastolic blood pressure, respectively) (p<0.05).
The administration of olive leaf extract also significantly reduced total cholesterol and triglyceride levels, while such beneficial effects were not found in the Captopril group. The researchers also observed higher incidence of adverse effects such as coughing, which occurred in 7% of the subjects taking Captopril, compared to 4.6% of the participants taking olive leaf extract (3).
| Variables | Baseline | After 8 Months | %Change | P value |
| Olive group (n=72) | ||||
| Systolic Blood Pressure(mm Hg) | 145 | 133.5 | -6.89% | <0.001 |
| Diastolic Blood Pressure (mm Hg) | 91.3 | 86.6 | -5.14% | <0.001 |
| Total cholesterol (m~ldl) | 202.2 | 196.4 | -2.86% | 0.033 |
| Triglycerides (mg/dl) | 140.3 | 128.4 | -8.48% | 0.032 |
| Captopril group (n=76) | ||||
| Systolic Blood Pressure (mm Hg) | 144.7 | 130.9 | -9.50% | <0.001 |
| Diastolic Blood Pressure (mm Hg) | 89.9 | 83.4 | -7.23% | <0.001 |
| Total Cholesterol (mg/ dl) | 183.6 | 184.1 | +0.27% | 0.808 |
| Triglycerides (mgldl) | 119.5 | 118.2 | + 1.08% | 0.800 |
The mechanism of action by which olive leaf extract lowers blood pressure has not been clearly elucidated. It is believed that the major component of olive leaf, oleuropein, inhibits the angiotensin converting enzyme(ACE), which decreases the constriction of blood vessels, thus lowering blood pressure (4). The study demonstrates that the effect of olive leaf extract in lowering blood pressure was comparable to a pharmaceutical drug and it also improved the patient’s lipid profile where as Catpopril did not.
Source: Susalit, Endang, et al. “Olive (Olea europaea) leaf extract effective in patients with stage-1 hypertension: comparison with Captopril.” Phytomedicine 18.4 (2011): 251-258.
© 2010 Elsevier GmbH. All rights reserved.
Posted February 20, 2014.
References:
- I. Stamler, J. “Blood pressure and high blood pressure. Aspects ofrisk.” Hypertension 18.3 Suppl (1991): 195.
- Cherif, S., et al., A clinical trial of a titrated Olea extract in the treatment of essential a1terial hypertension. I 996. J.Pharm. Bel g. 51 , 69-71.
- Susalit, Endang, eta!. “Olive (Olea europaea) leaf extract effective in patients with stage-! hype1tension: Comparison with Captopril.” Phytomedicine 18.4 (20 II): 251-258.
- Hansen K., et al, Isolation of an angiotensin converting enzyme (ACE) inhibitor for Olea europaea and Olea lancea.1996. Phytomedicine 2 (4), 319-325.
