The olive tree (Olea europaea) has been cultivated in the Mediterranean region for millennia. While the positive properties of the olive fruit and the oil extracted from it are well known to most people, the therapeutic effects of its leaves have been almost forgotten.

The mere fact that olive trees can live for well over 1000 years, even in regions with little rain and long periods of drought, demonstrates the resilience of these trees. The fruit can be enjoyed as olives or olive oil. The olive leaves, on the other hand, are consumed as a (unfortunately very bitter) olive leaf tea, or the concentrated olive leaf extract can be taken in capsule form.

Olive leaves have a completely different effect on our health than olive oil.The latter works particularly through the properties of monounsaturated fatty acids, while the olive leaf extract consists of highly concentrated polyphenols and other plant substances. v.aOleuropein, but also hydroxytyrosol, flavonoids, phytosterols, glycosides and terpenes.

Oleuropein is a powerful antioxidant that is found in all parts of the olive tree; however, the highest concentration is found in the olive leaves. While olives contain between 4 and 350 mg of oleuropein per 100 g of olives, liquid olive leaf extracts can contain between 800 and 950 mg per 100 ml (see [reference]). https://www.internetchemie.info/substanz/Oleuropein.php).

The overall health benefits of olive leaf extract are likely due to the interplay of its numerous beneficial ingredients. They act synergistically, thus enhancing each other's effectiveness. The strong antioxidant power of olive leaf extract (see...) https://onlinelibrary.wiley.com/doi/10.1002/9781119135340.ch19 and https://www.cell.com/heliyon/fulltext/S2405-8440(18)31888-7?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS2405844018318887%3Fshowall%3Dtrue), its high chlorophyll content and the large number of secondary plant compounds it contains explain the following individual effects of olive leaf extract, which have largely been proven by initial scientific studies (especially in vitro, but there are also some human studies):

Olive leaf extract has an effect

• Antioxidant: Olive leaf extract shows 2.5 times higher antioxidant activity than the antioxidants vitamin C and E.
• antibacterial (cf. https://ann-clinmicrob.biomedcentral.com/articles/10.1186/1476-0711-13-24, https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2017.00113/full and https://www.researchgate.net/publication/320876772_The_antimicrobial_activities_of_olive_leaf_extract_against_some_pathogenic_bacteria)
• antiviral (against herpes simplex)
• antifungal (against fungi, e.g. Candida albicans) (see above). & and https://www.mdpi.com/1420-3049/21/12/1631)
• antiparasitic
• anti-inflammatory
• immune-boosting

Olive leaf extracts are characterized by exceptionally good tolerability and high bioavailability. They are free of side effects and can be safely taken as a dietary supplement for extended periods.

Biochemical mechanisms of action of olive leaf extracts

• Olive leaf extracts reduce the expression of genes that promote fat storage: PPARy, lipoprotein lipase, fatty acid binding protein 4 (see below). https://pubmed.ncbi.nlm.nih.gov/20495905/).
• Olive leaf extracts increase the differentiation of osteoblasts (increased production of osteoblast genesis markers RUNXII, Osterix, collagen type 1, osteocalcin and alkaline phosphatase) (see https://pubmed.ncbi.nlm.nih.gov/20495905/).
• Olive leaf extracts stimulate the development of blood vessels and VEGF production (see above). https://pubmed.ncbi.nlm.nih.gov/24518972/).
• Olive leaf extracts normalize MDA and blood sugar levels (see [reference]). https://www.sciencedirect.com/science/article/abs/pii/S0024320505009641).
• Olive leaf extracts lower left ventricular and systolic blood pressure and improve stroke volume, ejection fraction and cardiac output, as well as the levels of superoxide dismutase and glutathione reductase (see [reference]). https://pubmed.ncbi.nlm.nih.gov/25119867/).
• Olive leaf extracts prevent an increase in serum levels of malondialdehyde, interleukin-1β, TNF-α, creatine kinase-MB, troponin I and lactate dehydrogenase (see below). https://pubmed.ncbi.nlm.nih.gov/25119867/).
• Olive leaf extracts increase the production of proteins that prevent cell death (Bcl-2, Bcl-XL, Bim and p53) (see below). https://pubmed.ncbi.nlm.nih.gov/20568104/).

Therapeutic applications

Heart && circulation

At the University of Reading (cf. https://link.springer.com/article/10.1007/s00394-016-1188-yIn 2017, a double-blind study was conducted in Great Britain with 60 male participants suffering from pre-hypertension. They received either an olive leaf extract or a placebo for six weeks. Compared to the placebo, the olive leaf extract resulted in significantly improved blood pressure readings. The systolic value decreased by an average of almost 4 mmHg, and the diastolic value by approximately 3 mmHg. Total cholesterol, LDL cholesterol, and triglycerides were also reduced in the participants thanks to the olive leaf extract, as were the levels of the inflammatory marker interleukin-8.

In another study with 232 patients with high blood pressure, 500 mg of oleuropein twice daily for 8 weeks was as effective as the diuretic captopril at a dosage of 12.5 to 25 mg twice daily in reducing systolic and diastolic blood pressure (see [reference]). https://pubmed.ncbi.nlm.nih.gov/21036583/).

In a Swiss study from 2008 with identical twins (see... https://onlinelibrary.wiley.com/doi/10.1002/ptr.2455Participants with slightly elevated blood pressure received either 500 or 1000 mg of an olive leaf extract for eight weeks. Body weight, heart rate, blood pressure, and glucose and lipid levels were measured every 14 days. The result: Blood pressure was lowered with the olive leaf extract in a dose-dependent manner. With the higher dose of olive leaf extract, the systolic value decreased by an average of 11 mmHg (from 137 to 126), and the diastolic value by an average of 4 mmHg (from 80 to 76). With the lower dose, the values ​​decreased only slightly, while in the control group they remained unchanged or even increased slightly. Cholesterol levels also decreased significantly and in a dose-dependent manner in the olive leaf group.

The blood pressure-lowering effects of olive leaf extracts may be due to their ability to maintain the function of blood vessels, as was observed in a small study with 13 subjects with slightly elevated blood pressure (see [reference]). https://pubmed.ncbi.nlm.nih.gov/25148955/In rats with high blood pressure, an olive leaf extract reduced blood pressure, heart rate, and enlargement of the heart and kidneys, while simultaneously improving blood vessel function (see [reference]). https://pubmed.ncbi.nlm.nih.gov/26593388/).

Chronic inflammation

In a study with 18 healthy subjects, an olive leaf extract reduced the production of pro-inflammatory cytokines (IL-8) and improved the function of blood vessels (see [reference]). https://pubmed.ncbi.nlm.nih.gov/26051429/).

In another clinical study with 45 women with breast cancer, a combination of hydroxytyrosol from olive leaf extract with omega-3 fatty acids and curcumin reduced inflammation (measured via sensitive CRP) after one month of intake.

Hydroxytyrosol also reduced inflammation and pain in a small study with 25 subjects with arthritis (see [reference]). https://pubmed.ncbi.nlm.nih.gov/23746949/).

In human brain cells, an olive leaf extract prevented inflammation by reducing COX-2 production (see [reference]). https://pubmed.ncbi.nlm.nih.gov/26410343/The phenolic components of olive leaf extracts also show significant effects against polyarthritis and soft tissue rheumatism, and all types of respiratory inflammation.

Blood sugar levels

The blood sugar-lowering effect of oleuropein is based on its ability to block the formation of free radicals by Nox2, as a small study with 20 healthy subjects showed (see [reference]). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6470561/).

In a small study with 20 healthy subjects, oleuropein from olive leaf extract reduced blood sugar levels after meals by blocking the production of free radicals by Nox2 (see [reference]). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6005585/).

In another study with 46 overweight, middle-aged men at increased risk of developing type 2 diabetes, supplementation with olive leaf extract for 12 weeks improved insulin sensitivity and the activity of insulin-producing pancreatic cells (see [reference]). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3596374/).

Bone

In a clinical study with 64 women with osteoporosis, the consumption of an olive leaf extract for 12 months was able to maintain bone density and increase the blood levels of bone-forming cells (osteocalcin) (see [reference]). https://pubmed.ncbi.nlm.nih.gov/25560820/).

In a study using human bone marrow stem cells, it was observed that oleuropein increased bone cell production (see [reference]). https://pubmed.ncbi.nlm.nih.gov/20495905/).

Neurodegenerative diseases

Amyloid diseases such as Alzheimer's are at least partially caused by the build-up of misfolded proteins in tissue, which cause inflammation and tissue damage (see...). https://pubmed.ncbi.nlm.nih.gov/26092624/Olive leaf extracts may prevent these misfolded proteins from entering the brain. This effectively prevented toxicity and tissue damage in studies conducted with mice (see [reference]). https://pubmed.ncbi.nlm.nih.gov/25293421/Even in advanced stages of Alzheimer's disease, mice experienced an improvement in brain function after treatment with oleuropein (see [reference]). https://pubmed.ncbi.nlm.nih.gov/25293421/In rats with Parkinson's disease, an olive extract reduced cell damage and cell death (see [reference]). https://pubmed.ncbi.nlm.nih.gov/23394606/).

Oleuropein can also restart autophagy (the "cell recycling") within the cell. A deficiency in autophagy has been demonstrated, particularly in Alzheimer's disease, which can lead to the accumulation of toxins in the cells. In a study from Spain (see...) https://onlinelibrary.wiley.com/doi/10.1155/2018/5010741In 2018, brain samples from Alzheimer's patients were used to demonstrate that oleuropein is able to initiate autophagy, which could potentially trigger a healing process.

Colon

Many digestive problems are accompanied by inflammation of the intestinal lining.

In intestinal samples isolated from 14 subjects with ulcerative colitis, treatment with an olive leaf extract reduced the production of pro-inflammatory molecules (the enzyme COX-2 and the cytokine IL.17) and the infiltration of immune cells (CD3, CD4 and CD20), resulting in a reduction of inflammatory damage (see [reference]). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5409730/).

Olive leaf extract also eliminates harmful bacteria from the digestive system, thus enabling the regeneration of a healthy gut flora. Furthermore, olive leaf extract shows promise in its use against Candida fungi and parasites.

gout

A study from the University of Leipzig revealed that olive leaves contain substances that inhibit the enzyme xanthine oxidase. This enzyme, however, promotes the development of gout. This provides the first scientific evidence for what traditional folk medicine has long known. Olive leaves have been used to treat gout in Mediterranean regions for centuries.

Recommended intake

Generally, plant extracts should always be taken with or shortly after meals. ExceptionIn cases of Candida infection, bacterial digestive problems, or the presence of parasites, you could test your tolerance on an empty stomach, as the extract is more effective then. If diarrhea or nausea occurs, it is best to take the extract after a light meal.