Olive leaf extract may help lower blood pressure, according to the results of a recent study published in the September issue of the journal, Phytotherapy Research. The study, conducted by researchers in Germany and Switzerland, was designed to determine the effects of olive leaf extract on blood pressure and cholesterol levels in adult twins diagnosed with borderline hypertension.

When study volunteers took 500 milligrams of olive leaf extract daily for eight weeks, their systolic blood pressure — the "top" number of the blood pressure reading — fell by 5 points. Among those who took 1,000 milligrams daily, systolic blood pressure fell by an average of 11 points.

Medicinal use of the olive leaf is by no means new. Since the time of the ancient Greeks, the olive leaf has been revered for its long list of healing properties, including its purported ability to abate high fevers, reduce inflammation and ward off infection.

The leaf of the olive tree isn't the only part of the plant with proven health benefits. Olive oil has been shown to offer a measure of protection against heart disease, gastrointestinal ulcers, osteoporosis and certain cancers.

The oil is the principal source of fat in the Mediterranean diet, popularized in the United States as a cardio-protective nutritional regimen. Phenolic compounds in olive oil, known for their antioxidant, anti-inflammatory and anti-clotting properties, may help explain the cardiovascular benefits associated with the Mediterranean diet.

Olive oil is rich in monounsaturated fats, which are considered to be far superior to the trans fats and saturated fats found in many junk foods, fried foods and animal products. Unlike other fats, olive oil can reduce levels of total cholesterol and low-density lipoprotein (LDL) cholesterol.

Regular consumption of the oil may also protect against certain gastrointestinal diseases, including cancer. After analyzing cancer rates and dietary patterns in 28 countries, researchers found that diets rich in olive oil were associated with a reduced risk of colon cancer.

In a study published last year in the Journal of Agricultural and Food Chemistry, Spanish researchers reported their findings that olive oil may play a role in the prevention and treatment of gastritis and peptic ulcer disease. Both conditions are caused by infection with a bacterium known as Helicobacter pylori.

In laboratory experiments, the phenolic compounds in olive oil demonstrated strong antibacterial effects against eight strains of the ulcer-causing bacteria, including those that were resistant to antibiotic drugs commonly used to eradicate them. Unlike many therapeutic agents, the active ingredients in the oil remained stable in highly acidic conditions typical of the human stomach.

A naturally occurring chemical found in extra virgin olive oil has anti-inflammatory properties similar to those provided by the non-steroidal anti-inflammatory drug ibuprofen. Named oleocanthal by the researchers who discovered it, the compound inhibits the inflammatory activity of cyclo-oxygenase (COX) enzymes in the body.

A growing body of scientific evidence supports the theory that inflammation is a causative factor in many chronic diseases, including heart disease, stroke and certain dementias. Some experts believe that many of the Mediterranean diet's positive effects are attributable to the oleocanthal in olive oil.

While the health benefits of consuming olive oil may be easy to appreciate, choosing among the various grades of the oil — including extra virgin, virgin and refined — can be a bit confusing.

Olive oil is traditionally produced by pressing or crushing olives to extract their oil. The amount of processing involved in the extraction determines the quality of the final product.

Extra virgin olive oil is generally considered best, as it is obtained from the first pressing and is subjected to the least amount of processing. Because it's closer to the natural state, it's typically richer in flavor and in disease-fighting polyphenols.

Virgin olive oil is the product of the second pressing. Since it undergoes more processing, including filtering and refining, is generally considered to be of lower quality than oil of the extra virgin variety, but is still superior to refined olive oil.

Although olive oils typically have a shelf life of about one to two years under ideal conditions, fresher oils tend to taste better and offer greater health benefits. Because oils may degrade and become rancid when exposed to heat and light, it's best to store them in a cool, dark place.

Quality olive oil can be a bit pricier than other oils, but in terms of health benefits, it's undoubtedly a worthwhile investment.

Rallie McAllister is a board-certified family physician, speaker and the author of several books, including "Healthy Lunchbox: The Working Mom's Guide to Keeping You and Your Kids Trim." Her website is www.rallieonhealth.com. To find out more about Rallie McAllister, M.D., and read features by other Creators Syndicate writers and cartoonists, visit the Creators Syndicate Web page at www.creators.com.

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