If you’re a fan of Italian or Greek food, then you’re probably familiar with olives and olive oil, but the leaves from olive trees are also of use and benefit. In fact, herbal extracts from olive leaves have been used as folk remedies for thousands of years, at least as far back as ancient Egypt. As a safe and natural anti-viral and antioxidant, olive leaf extract shows medicinal potential and warrants more research.
Olive leaves are rich in oleuropein, which is a bitter compound that olive trees produce to resist disease and infestation. Oleuropein has been fairly well studied over the last 50 years or so. Scientists observed that it has the ability to lower blood pressure by relaxing blood vessels and it relieves muscle spasm and dysfunction in smooth, skeletal and cardiac muscle tissue. Furthermore, scientists eventually isolated a chemical from oleuropein called elenolic acid, which acts as a powerful antimicrobial and antioxidant. Liquid extracts of olive leaf are the most concentrated form of the herb, although powdered capsules, tablets and tea bags are also available.
The elenolic acid in olive leaf extract is a full-spectrum antimicrobial, which means it destroys or deters the growth of numerous viruses, bacteria, fungi and parasites. As an anti-viral, elenolic acid inactivates viruses by preventing virus shedding, budding and assembly, which stops their replication. Furthermore, oleuropein and elenolic acid are not toxic to people, even in very large doses. However, most of the research on olive leaf extract has been conducted in test tubes or on animals, and more human research is needed before it can be recommended for specific infectious diseases such as the common cold, influenza, herpes or pneumonia.
Elenolic acid and other compounds in oleuropein called phenolics display strong antioxidant behavior. Antioxidants destroy harmful free radicals, which are products of specific chemical reactions that are destructive to tissues such as blood vessels and organs. As such, antioxidants tend to prevent inflammation and reduce the risk of liver damage and cardiovascular diseases. Antioxidants also boost the immune system -- at least indirectly -- because they prevent precious energy from being used on tissue repair.
Olive leaf extract is also able to significantly deter pain, and some studies show that it enhances the effect of morphine, which may have important implications in hospital settings. As a painkiller, olive leaf extract is most effective when applied topically -- like on a mild skin abrasion or achy tooth. Taken internally, dosages should be at least 25 milligrams of olive leaf extract per pound of body weight to have a noticeable impact on pain, according to the "Natural Standard Herb and Supplement Reference."
- PDR for Nutritional Supplements; Sheldon Hendler and David Rorvik
- Natural Standard Herb & Supplement Reference: Evidence-based Clinical Reviews; Catherine E. Ulbricht and Ethan M. Basch
Sirah Dubois is currently a PhD student in food science after having completed her master's degree in nutrition at the University of Alberta. She has worked in private practice as a dietitian in Edmonton, Canada and her nutrition-related articles have appeared in The Edmonton Journal newspaper.