The olive tree (Olea europaea), which originated in the Mediterranean basin, has provided human civilization with food, lumber, cosmetics, and medicine for centuries. Containing natural antioxidants that help protect it from sun damage, insects, and pathogens, edible parts of the tree, including the olive leaf (and its extracts), may help support a strong immune system and a healthier, more balanced response to stress, among many other potential health benefits.
What is the Olive Tree, and What are Its Parts?
The olive tree is a subtropical broad-leaved evergreen tree with edible fruit from the botanical family Oleaceae. It can grow between 10 to 40 feet tall. The plant has fine branches and produces clusters of small, white flowers, as well as spear-shaped, dark green leathery leaves, and olive fruit, which may be harvested when ripe for food and pressed for oil. The olive is wind-pollinated, but in the wild, some birds swallow olives whole and may scatter their seeds. Olive trees produce good crops between 15-20 years of age until they reach 80 years old. The olive tree has great historical significance and has been cultivated for centuries for its fruit, its wood, its oil, and the olive leaf. (1)
The Significance of Olive Fruit and the Olive Leaf
Various factors are responsible for age-related illnesses, including the oxidation process, which may damage cell membranes, lipids, and DNA due to long-term exposure to environmental toxins, a poor diet, lack of exercise, and other factors. Antioxidants such as polyphenols from different parts of the olive tree may help the body neutralize free radicals that cause oxidation.
Polyphenols are plant-based, naturally occurring compounds with antioxidant properties that support the human body’s natural defense against ultraviolet (UV) radiation and pathogens. There are more than 8,000 polyphenolic compounds, including phenolic acids, flavonoids, stilbenes and lignans. Most parts of the olive tree contain polyphenols, but their concentration varies between different parts of the plant.
All classes of phenolic compounds are shown to be potent antioxidants. Olive fruit, olive oil, and olive leaf all contain various amounts of simple phenols (hydroxytyrosol, tyrosol), polyphenols (oleuropein glucoside), and other compounds with potential health benefits. Some studies suggest olive oil phenolic compounds provide more antioxidant effects than vitamin E on lipids and DNA oxidation. That’s one of the many reasons why the oil, the leaves, and extracts from olives are used medicinally. (2, 3, 4, 5)
Long-term consumption of diets rich in plant polyphenols from fruits and vegetables contributes to a daily intake of antioxidants that may offer some protection against the development of chronic diseases and health conditions related to the skin, cells, heart, brain, and bones. Fruits such as berries contain up to 200–300 mg polyphenols per 100 g weight, while a glass of red wine, a cup of tea, or a mug of coffee contains 100 mg polyphenols. It’s possible to get the recommended daily amount of polyphenols (about 1 g per day maximum) in a nutritious diet, but supplementation may help fill any nutritional gaps. That’s why it may make a difference to your health to try a Mediterranean diet of olive oil and olive leaf extract supplements. (6, 7)
About the Olive Fruit
Olive oil comes from the olive fruit (also called the table olive), which is a “drupe,” similar to cherries, peaches, and plums. Any fruit with a seed-bearing stone is known as a drupe. Each olive fruit contains a pit (also called a stone) with one or two seeds. (8)
Once an olive tree has matured, green olives are typically picked before they are ripe, and black olives are fruit that have ripened on the tree. Each type of olive has its unique flavor and nutritional value; however, phenolic compounds decrease as the fruit ripens. After olive fruit is harvested, it must be processed to neutralize its bitterness by treatments with a dilute alkali such as lye, or various salt applications.
Olive oil is pressed from the fleshy fruit of the olive tree. (The word “oil” comes from the ancient Greek word “elaia,” which means olive.) During its fertile years, 6 to 8 months after flowers have bloomed, olive fruit reaches its peak weight, of which 30% of its fleshy skin is olive oil, according to Encyclopedia.com.
Throughout the centuries, various types of olive oil have been used for cosmetics, medicine, and as fuel for lamps, including the original Olympic torch.
There are several types of olive oil. Virgin olive oil comes from the first pressing of chemical-free olives. Pure olive oil is a mixture of refined and virgin oils. Refined, or commercial, olive oil consists of inferior virgin oils that are classified as a lampante, from which acid, color, and odor have been removed. Lampante is high-acid oil obtained from a second pressing of residual pulp with hot water that is used as a lamp fuel. Sulfide is extracted with solvents and refined repeatedly. (9)
The healthiest olive oil is known as extra virgin olive oil (ranging in color from yellow to green). It is the highest-grade olive oil and comes from freshly milled or cold-pressed olives within 24 hours of harvest. It is not heat treated, it’s free from defects, and it contains no additives or fatty acids. (10) Extra virgin olive oil is used to cook and is a popular component of salad dressing. It contains up to 80% more phenolic compounds (232 mg/kg) than refined olive oil (62 mg/kg). (11)
Olive oil is good source of polyphenols and antioxidants, which promote cellular health. Research has shown that phenolic compounds such as oleuropein and hydroxytyrosol from olive oil have a positive effect on cellular and molecular activities. In addition, oleic acid, a monounsaturated fatty acid, and squalene play an important role in preventing cellular damage from oxidation. These free radical scavengers potentially inhibit oxidation and platelet aggregation (blood clots) in the human body, allowing for healthy blood circulation. (12) These active parts of olive oil are highly bioavailable. (13)
However, olive oil is very different from the extract of the olive leaf itself.
About the Olive Leaf
Similar to olive oil, the olive leaf and its extract contain polyphenolic compounds, including oleuropein and hydroxytyrosol, which are bioactive, highly bioavailable phenylethanoids (phenolic phytochemicals with antioxidant properties) that help protect the olive tree from invasive microorganisms and promote normal biological processes in the human body. The olive leaf also contains polyphenols known as flavonoids (rutin, apigenin, and luteolin), which are phytonutrients thought to provide health benefits through cell signaling pathways and antioxidant effects. (14, 15)
Oleuropein, one of the main phenolic components of olive oil, is a bitter-tasting glycoside with antioxidant effects against oxidation, which may support a healthy immune system and may support age-related brain health. Oleuropein is also found in small, young olives, where it can amount to 14% of dry matter. It can be taken as a singular supplement or blended in formulations with other nutrients in an olive leaf complex to help maintain optimal health. (16)
Hydroxytyrosol, which is present in the fruit and the leaf of the olive, plays a role in promoting heart health, according to the European Food Safety Authority, which suggests that 5 mg of hydroxytyrosol and its derivatives should be consumed daily. (17)
These olive phenolics are often found in olive leaf extract supplements designed to support healthy aging, detoxification, cardiovascular health, vascular health, a healthy immune response, healthy-looking skin, and glucose metabolism, to name a few potential health benefits. And it has been this way for centuries. (18)
Brief History of the Olive Tree, Olive Fruit, and Olive Leaf
The olive tree has had a great ecological, economical, and cultural importance, especially to Early Mediterranean civilizations.
Archeological evidence suggests Neolithic inhabitants of the Mediterranean basin collected and consumed olives from wild olive trees (namely oleasters) since The Copper Age (6th millennium BCE). New research suggests domesticated olive tree orchards may have first been cultivated on the border between Turkey and Syria. However, most species of domestic olive trees came from the Near East, the Aegean Sea, and the Strait of Gibraltar. As civilization expanded, they were then spread throughout the Mediterranean. (19)
The olive was grown on the island of Crete as far back as 3500 BCE. The ancient Egyptians used the olive leaf in the process of mummification. During the first Olympic Games in 776 BCE, the winners were awarded with an olive twig to honor the goddess Athena and as a sign of fraternity and peace. Olive oil was even used by ancient Greeks to anoint the body. (Homer, who lived between the 9th–8th Century BCE, once referred to olive oil as “liquid gold.”) In addition, the ancient Romans cultivated the olive tree in 600 BCE. (20)
Since biblical times, the olive tree has been a symbol of unity and peace, especially the offering of its branches. Its oil symbolizes purity, and the olive branch represents peace and prosperity. Destroying an enemy’s olive trees is considered an act of war. (21)
The importance of the olive has been mentioned in ancient sacred literature, including in the Bible. “The fruit thereof shall be for meat, and the leaf thereof for medicine.” (Ezekiel 47:12) (22) Pliny the Elder (24–79 CE), in his “Historia Naturalis,” listed 48 medicines made with olive oil. “Except the vine, there is no plant which bears a fruit of as great importance as the olive,” Pliny wrote. During the Middle Ages, monks used olive oil to treat skin wounds. During the Renaissance, most pharmacies offered jars of olive oil. (23)
The olive is also sometimes considered an adaptogen. Popular in Ayurvedic medicine, adaptogens are plant-based compounds that help the body become more resilient to stress. (24) In traditional Moroccan medicine, olive leaf extract in oral supplement form has been used to help maintain healthy blood sugar levels already in the normal range. In addition, the hearty trunk of the olive tree can be used for carving and furniture-making. Some trees live for hundreds of years, according to National Geographic. (25)
By the late 20th-century, Spain, Italy, and Greece became the world’s leaders in commercial olive production, according to Britannica.com, and people began taking olive leaf extract in dietary supplements. Today, the World Health Organization features olive tree branches, chosen as a symbol of peace and health, on its official seal and emblem. And the Mediterranean diet, containing olives, olive oil, and olive leaf, is as popular as ever for people seeking nutritional benefits.
Potential Health Benefits of Olive Oil and Olive Leaf Extract
There are many documented potential health benefits of olive oil and olive leaf extract.
According to an article published by the International Journal of Molecular Sciences: “Olive oil and olive leaf extract are renowned natural traditional remedies used for the treatment of different conditions, including dermatitis, wound healing and treatment of burns, stomach and intestinal pain, malaria-induced fever, different infections, alopecia, rheumatic pain, otitis, rickets, distortions, sciatica, hypertension, as a diuretic, as a laxative, and as an aphrodisiac.” (26)
The consensus of researchers claims the following:
Potential Benefits of Olive Leaf Extract, Olives, and Olive Oil
- May support healthy immune function
- May promote a healthy response to stress
- May help maintain healthy internal response
- May support brain health
- May support cardiovascular health
- May promote healthy blood pressure
- May support glucose metabolism
- May support cholesterol levels already in the normal range
- May support healthy-looking skin
Supports a Healthy Immune System
The olive has been a staple crop in the Mediterranean basin for thousands of years. The Mediterranean diet, which includes olives and extra virgin olive oil (as the principal source of dietary fat and in substitution of animal fat), healthful fiber, fish, fruits, and vegetables, is linked to a reduced incidence of degenerative diseases affecting the heart, breast, skin, and colon.
Olive oil is a source of monounsaturated fatty acids (“good fat”) containing mainly oleic acid, instead of saturated fat. Olive oil also includes some palmitic and linoleic acids. Oleic acid is the principal fatty acid of olive oil, which may help prevent oxidation. (27, 28) Linoleic acid is an omega-6 essential fatty acid, a polyunsaturated fatty acid, that may help the body maintain a healthy weight and support immune system function. (29)
As the human body ages, it is impacted by oxidative injury, mainly to mitochondria, over a lifetime. Antioxidants like oleuropein destroy free radicals, protecting the body’s cells, tissues, and DNA from oxidative stress and inhibiting the rate of growth of potentially harmful cells to support normal, healthy aging. It is believed that oleuropein prevents free radical formation through chelation of metal ions, such as copper and iron. (30)
“Oleuropein’s antioxidant potential is mainly related to its ability to improve radical stability through the formation of an intramolecular hydrogen bond between the free hydrogen of the hydroxyl group and its phenoxyl radicals… demonstrating antioxidant potential similar to those exerted by vitamin C and vitamin E.” (31)
A study on rats found that “oleuropein treatment shows an antioxidant and anti-inflammatory effects by decreasing oxidative stress.” (32) Another study found that the natural antioxidants in olive leaf extract were effective in reducing DNA damage, especially as a pretreatment to oxidative stress. (33)
Oleuropein and other phenolic compounds have also been shown to have an antibacterial effect by damaging the bacterial membrane and inhibiting its spread. Its effects may also have a similar effect on some viral pathogens. However, further clinical studies are needed to validate these health claims. (34)
Supports Brain Health
It is believed that some oxidative damage during the natural aging process may occur due to decline of antioxidant enzymes. A Mediterranean diet of antioxidant-rich foods such as olive oil and olive leaf extract may delay cognitive decline, protecting healthy aging of the brain, according to some research. (35)
A study on aging rats found that treatment with oleuropein reduced the oxidative damage of brain neurons by increasing antioxidant enzyme activities. (36) Other phenolic compounds present in the olive also show a neuroprotective effect. (37) Hydroxytyrosol, specifically, is a free radical scavenger in olive oil and olive leaf extract that crosses the blood-brain barrier to protect nerve cells in the brain and spine. (38)
Additional in vitro and epidemiological studies suggest the positive impact of olive leaf polyphenols on age-related disorders of the brain and heart. (39, 40)
Supports Heart Health
Naturally occurring dietary polyphenols such as oleuropein and hydroxytyrosol from the olive leaf and from extra virgin olive oil may promote cardiovascular health by protecting against oxidative damage and supporting vascular and cellular health.
A study on rats taking polyphenol-enriched extract from olive leaves found that oleuropein and hydroxytyrosol reversed the chronic inflammation and oxidative stress that induced the cardiovascular and metabolic symptoms of obese rats without changing their blood pressure. (41) Another study on rats confirmed the cardioprotective effect of oleuropein. (42)
In an experimental study in 1995, hydroxytyrosol was shown to inhibit low-density lipoprotein (LDL) oxidation (known as “bad cholesterol”), helping to prevent fatty deposits (plaque) from clogging arteries and prevent the hardening and narrowing of the arteries, which are risk factors for heart disease. Hydroxytyrosol supplementation also helped maintain healthy cholesterol levels already within the normal range, maintained normal blood pressure, and contributed to the body’s natural defenses against harmful microbes. (43)
Another study suggests that extracts of olive leaf may support cardiovascular health. Adult subjects took a supplement of 500 mg olive leaf extract, 100 mg green coffee bean extract, and 150 mg beet powder twice daily for six weeks. The study reported reductions of LDL cholesterol; however, further placebo-controlled trials are needed to confirm the potential health benefits of olive leaf extract in humans. (44)
Supports Healthy-Looking Skin
The olive and its constituents are considered skin protective because of their antioxidant properties that play a role in maintaining a normal, healthy aging process.
Oleuropein, hydroxytyrosol, and squalene from the olive and its various parts help protect the skin against UV light and radiation. Oleuropein acts as a free radical scavenger at the skin level, protecting healthy-looking skin. Olive leaf extract with oleuropein may help protect the skin against UVB-induced damage. Squalene plays a role in the filtration of oxygen at skin level. (45) Co-administration of hydroxytyrosol and hydrocortisone may also provide antioxidant benefits to the skin. (46)
Historically, the olive leaf was used by herbalists as a poultice to treat skin conditions and by monks during the middle Ages to treat wounds and burns. (47) Olive leaf extract may also prevent certain irritating skin flare-ups. Some people take 500-750 mg capsules, with 20 mg of oleuropein per capsule to promote digestion and detoxification, inhibiting bacteria and viruses from developing, which could cause various health disturbances, including several skin-related conditions. (48) In addition, olive leaf extract may have properties that help protect the body from invasive microorganisms. (49)
Additional Potential Benefits
A clinical trial on overweight middle-aged men at risk of developing a metabolic syndrome found that supplementation with olive leaf polyphenols for 12 weeks significantly improved insulin sensitivity. (50) In addition, a study on rats found that doses of oleuropein had protective effects on bone mass. (51)
It’s clear there is a lot of documented research indicating the positive effects of an olive diet and supplementation for maintaining optimal health. Now it’s time to try it for yourself!
How to Buy High-Quality Olive, Olive Oil, and Olive Leaf Products
The olive fruit (commonly seen as the unripe green fruit or fully ripe black fruit) can be eaten whole. Olive oil, a major source of healthy dietary fat, can be used for cooking or can be consumed uncooked. Olive leaves can be brewed in healthful teas. Olive leaf extract can be taken in various dietary supplements, including as a liquid extract, in capsule or tablet form, or in convenient powdered drink mixes.
If you’re looking for table olives to add to a salad or a Mediterranean recipe, be careful to avoid “fake” black olives, which are unripe olives treated with an alkaline solution and oxygen to darken their color. Instead, opt for fresh organic black olives or green olives. Young, small green olives have more nutrients and flavor. (52)
When shopping for olive oil, select a certified organic extra virgin olive oil, which has more nutrients than other versions. It should be 100% natural and high in antioxidants. If the oil is produced in California, look for the COOC (California Olive Oil Council) seal, which certifies freshness and purity. Avoid cheaper, lower quality olive oils, which may have been processed or mixed with additives.
True extra virgin olive oil from reputable brands has been extracted and standardized for purity. It has a distinctive taste and contains many phenolic antioxidants. Refined or light olive oils are extracted with solvents, treated with heat, or diluted with soybean or canola oils. This lack of quality standards means some cheaper, lower quality oils may be labeled incorrectly as virgin olive oil. (53)
If you’re shopping for fresh olive leaves, look for dried versions. Olive leaf tea is a non-caffeinated source of energy that is believed to provide double the antioxidant activity than that of green tea and about four times more vitamin C. (54) To make olive leaf tea, steep 1 teaspoon (5 grams) of dried leaves in 1 cup (250 ml) of hot water for 10–15 minutes. (55)
For dietary supplements, olive leaf extract containing about 6–15% oleuropein is available commercially, but no standard amount has been established for dosage. Most olive leaf extract is taken in the 500-1,000 mg range daily, although some supplements go as low as 10 mg. (56)
Sample Daily Low Dosage of Olive Leaf Extract:
- Adult: 25 mg per day divided by 1-2 doses
- 12 years - Adult: 12.5 mg per day divided into 1-2 doses
- 6 - 12 years: 7 mg per day divided into 1-2 doses
- 2 - 6 years: 5 mg per day divided into 1-2 doses
- Under 2 years: Consult your healthcare professional (57)
Olive leaf extract has a very low toxicity, especially if you follow the low dosage recommendations on product labels for health maintenance. Olive leaf extract can be harsh on an empty stomach, though, so be sure to read the nutritional label on your supplements to see how much to take and if you need to take it with food or water. You should always consult a healthcare provider before adding a supplement to your diet.
Not sure where to start? Shop for olive leaf extract supplements from Natural Healthy Concepts, where all domestic orders receive free shipment!