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Evidence mounts for Olive Leaf Extract health benefits

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Evidence mounts for Olive Leaf Extract

Olive Leaf Extract (OLE) has many properties -antimicrobial, antifungal, antiviral, anti-inflammatory and therefore a wide variety of uses, from blocking Herpes to killing cancer cells, restricting dementia and helping heart health.

Olive leaves are eaten in some Mediterranean Countries and also powdered olive leaves are made into a tincture, which is drunk or rubbed on the skin. There are many polyphenols in OLE, but the main active ingredient is Oleuropein (1), according to researchers from Rome, who produced a major overview on the herb and suggested the active ingredient was more concentrated in the leaf than in olive oil. This phenol has free-radical scavenging benefits and even anti-cancer properties.

Six science-proven benefits of Olive Leaf Extract

1. Olive Leaf Extract can treat Herpes

Research has shown Olive Leaf Extract (OLE) to have antifungal, antiviral and antibacterial actions (2). This research showed its effects against HSV-1 herpes, which causes genital disease. OLE can be taken orally, or placed on the sores using cotton wool. On every sample of the virus tested, OLE was 2 to 10 times more effective than the antiviral drug acyclovir. OLE appears to stop the virus spreading and invading adjacent cells. Wiley Online Library has a Case Report on OLE’s effects here.

2. Olive Leaf Extract kills pathogens

In research (5), a concentration of 62.5 mg/ml OLE almost completely inhibited the growth of three food-borne pathogens – Listeria monocytogenes, Salmonella Enteritidis and Escherichia coli O157;H7. L monocytogenes also lost mobility – electron microscopy shown the OLE had caused it to lose its flagella. Finally, OLE inhibited biofilm formation from all three.

3. Olive Leaf Extract reduces cardiovascular risk

The Oleuropein in OLE and olive oil can reduce cholesterol levels (especially LDL), blood pressure and atherosclerosis resulting in an improvement in heart health and cardiovascular health (3). It can also reduce damage resulting from strokes. It also has strong anti-inflammatory effects reducing levels of damaging cytokines. Finally, a study in rats showed that is could even correct arrhythmia (Source: WebMD).

4. Olive Leaf Extract and brain health

The same research overview (3) listed neuroprotective benefits including a reduced risk of Dementia and Alzheimer’s. It seems to prevent dopamine loss and treated rats have more neurons (1). It also seems to restrict the damaging formation of Amyloid plaque. Oleuropein has been described as one of the most important and neuroprotective polyphenols.

5. Olive Leaf Extract has anticancer effects

OLE and oleuropein have been shown to prevent UVB skin damage in rats(4). They have been shown to inhibit angiogenesis, metastasis and cause apoptosis. Oleuropein has been shown to inhibit the growth of all types of cancer cells (1). 

6. Olive Leaf Extracts has benefits with diabetes

A randomized, placebo-controlled clinical trial across 14 weeks in 70 humans with type-2 diabetes (6) showed that this taking 500 mg pills of olive leaf extract had significantly lowered plasma glucose levels (HbA1c) and fasting plasma insulin levels. However, after food, the insulin levels were similar in the OLE group and the placebo group. Parallel research with sand rats indicated lowered digestion and absorption may be the reason for the reduced  figures.

In a 2014 study (7), olive leaf extract administered to two groups of rats for 8 weeks (at 200 or 400 mg/kg body weight), showed that those rats given the higher dose had significantly lower blood glucose, serum total cholesterol, and triglyceride levels (7). Further analysis suggested that the OLE at both levels caused a reduction in insulin resistance by inhibiting MRNA expression of inflammatory cytokines.

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  1. Effects of the Olive-Derived Polyphenol Oleuropein on Human Health; Int J Mol sci, 2014, October 15 (10). Barbara Barbaro et al.
  2. Anti-HSV type-1 activity of Olive Leaves; Rania Abdelmonem Khattab et al, Cairo University; 26 May 2016.
  3. Saudi Pharm J 2010 July; Sayed Haris Omar; Cardioprotective and neuroprotective roles of oleuropein in olive
  4. OLE and UVB damage in Rats; https://pubmed.ncbi.nlm.nih.gov/19776181/
  5.  Assessment of antimicrobial activity of Olive Leaf extract; 2017; 8, 113; Front Microbiol. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5288333/  
  6.  J Med Food 2012, July 15(7), Olive Leaf Extract as a hypoglycemic agent, Julio Wainstein et al.
  7. Nutr Res 2014 May 34 (5) Ya Nan Liu et al. Olive Leaf Extract suppresses messenger RNA.