Olive is a small evergreen tree native to Mediterranean regions. The characteristic green to blue-black fruit of this tree yields a useful, edible oil. Both the oil and the dried green-grayish colored leaves are used medicinally.1, 2
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3 StarsReliable and relatively consistent scientific data showing a substantial health benefit.
2 StarsContradictory, insufficient, or preliminary studies suggesting a health benefit or minimal health benefit.
1 StarFor an herb, supported by traditional use but minimal or no scientific evidence. For a supplement, little scientific support.
This supplement has been used in connection with the following health conditions:
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In animal studies oleuropein, one of the constituents of olive leaf, has decreased blood pressure and dilated arteries surrounding the heart, when given by injection or intravenously.5 Olive leaf has been used traditionally to treat people with hypertension,6 In a double-blind trial, the blood pressure-lowering effect of an extract of olive leaf was nearly as great as that of captopril, a drug used to treat hypertension. The olive leaf extract used in the study was EFLA 943, and the amount given was 500 mg twice a day for 8 weeks.7
Olive leaf extracts have been used experimentally to lower elevated blood-sugar levels in diabetic animals.8 These results have not been reproduced in human clinical trials.
Type 2 Diabetes
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Olive leaf extracts have been used experimentally to lower elevated blood-sugar levels in diabetic animals.9 These results have not been reproduced in human clinical trials.
Traditional Use (May Not Be Supported by Scientific Studies)
The olive tree has been held in high esteem throughout history. Moses reportedly decreed that men who cultivated the leaf be exempt from serving in the army. The oil is symbolic of purity and goodness, while the olive branch represents peace and prosperity. Winners in the Greek Olympic games were crowned with a wreath of olive leaves.3 Historically, medicinal use of olive leaf has been for treatment of fevers and for the topical treatment of wounds or infection. As a poultice, it was also used by herbalists to treat skin rashes and boils.4
How It Works
How It Works
Olive leaf has a wide number of constituents, including oleuropein and several types of flavonoids (e.g., rutin, apigenin, luteolin).10 While olive leaf is traditionally associated with a wide number of medicinal claims, few of these have been verified by experimental study. In an animal study oleuropein (when given by injection or in intravenous form) was found to decrease blood pressure (e.g., systolic and diastolic) and dilate the coronary arteries surrounding the heart.11 This ability to lower blood pressure may justify the traditional use of olive leaf in the treatment of mild to moderate hypertension.12 However, human studies are needed to clearly establish olive leaf as a potential treatment for high blood pressure.
In addition, a test tube study has revealed that oleuropein inhibits the oxidation of LDL (“bad”) cholesterol. LDL oxidation is one part in a series of damaging events that, if left unchecked, can lead to the development of atherosclerosis.13 This action may provide one clue as to why those consuming a Mediterranean-based diet may lower their risk of developing atherosclerosis.
Oleuropein from olives may also have antibacterial properties. When unheated olives are brined to preserve them, oleuropein is converted into another chemical called elenolic acid. Elenolic acid has shown antibacterial actions against several species of Lactobacilli and Staphylococcus aureus and Bacillus subtilus in a test tube study.14 Whether or not the oleuropein in the leaf undergoes such a transformation is open to question at this point, raising some question as to its antibacterial effects and potential use for this purpose in humans.
Olive leaf extracts have been employed experimentally to lower elevated blood-sugar levels in animals with diabetes.15 These results have not been reproduced in human clinical trials and as such, no clear conclusions can be made from this animal study in the treatment of diabetes.
How to Use It
The effective amount of olive leaf for human use is not established. To make a tea, steep 1 teaspoon (5 grams) of dried leaves in 1 cup (250 ml) of hot water for 10–15 minutes.16 Dried leaf extracts containing 6–15% oleuropein are available commercially, but no standard amount has been established.
Interactions with Supplements, Foods, & Other Compounds
At the time of writing, there were no well-known supplement or food interactions with this supplement.
Interactions with Medicines
As of the last update, we found no reported interactions between this supplement and medicines. It is possible that unknown interactions exist. If you take medication, always discuss the potential risks and benefits of adding a new supplement with your doctor or pharmacist.
The Drug-Nutrient Interactions table may not include every possible interaction. Taking medicines with meals, on an empty stomach, or with alcohol may influence their effects. For details, refer to the manufacturers’ package information as these are not covered in this table. If you take medications, always discuss the potential risks and benefits of adding a supplement with your doctor or pharmacist.
The safety of olive leaf has not been established in pregnancy. Olive leaf can be irritating to the stomach lining and should be taken with meals.17
The information presented in Aisle7 is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. For many of the conditions discussed, treatment with prescription or over the counter medication is also available. Consult your doctor, practitioner, and/or pharmacist for any health problem and before using any supplements or before making any changes in prescribed medications. Information expires June 2014.
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