Active components and clinical applications of olive oil
The olive tree, Olea europaea, is native to the Mediterranean basin and parts of Asia Minor. The fruit and compression-extracted oil have a wide range of therapeutic and culinary applications. Olive oil also constitutes a major component of the "Mediterranean diet." The chief active components of olive oil include oleic acid, phenolic constituents, and squalene. The main phenolics include hydroxytyrosol, tyrosol, and oleuropein, which occur in highest levels in virgin olive oil and have demonstrated antioxidant activity. Antioxidants are believed to be responsible for a number of olive oil's biological activities. Oleic acid, a monounsaturated fatty acid, has shown activity in cancer prevention, while squalene has also been identified as having anticancer effects. Olive oil consumption has benefit for colon and breast cancer prevention. The oil has been widely studied for its effects on coronary heart disease (CHD), specifically for its ability to reduce blood pressure and low-density lipoprotein (LDL) cholesterol. Antimicrobial activity of hydroxytyrosol, tyrosol, and oleuropein has been demonstrated against several strains of bacteria implicated in intestinal and respiratory infections. Although the majority of research has been conducted on the oil, consumption of whole olives might also confer health benefits. (Altern Med Rev 2007;12(4):331-342)
The olive tree, Olea europaea, produces the olive fruit. Olives are grown widely in the Mediterranean basin and parts of Asia Minor. References to the olive tree date back to Biblical and Roman times and to Greek mythology. Historically, the products of Olea europaea have been used as aphrodisiacs, emollients, laxatives, nutritives, sedatives, and tonics. Specific conditions traditionally treated include colic, alopecia, paralysis, rheumatic pain, sciatica, and hypertension. (1) The olive can be consumed whole as either the fully ripe black fruit or as the unripe green fruit. Olive oil, the major source of dietary fat in the countries where olives are grown, (2,3) constitutes part the commonly referred to "Mediterranean diet" of countries that surround the Mediterranean Sea and tend to have a low incidence of chronic degenerative disease. (4) Although there are dietary variations among Mediterranean countries, a common feature is the high consumption of olive oil, either uncooked or as the primary cooking fat. (4) Half the total fat consumed in the Mediterranean diet comes from cooking with olive oil, with deep fat frying being the most common method used. (4)
In the latter part of the 20th century, Keys et al conducted the Seven Countries Study, which revealed the Mediterranean diet is linked to a reduced incidence of degenerative diseases, particularly coronary heart disease (CHD) and cancers of the breast, skin, and colon. (5,6) This study inspired much research into the Mediterranean diet. In addition to olive oil, the Mediterranean diet is rich in healthful fiber, fish, fruits, and vegetables. (6) Since olive oil is the major energy source in the Mediterranean diet, recent research has focused on the contribution it makes to reported health benefits of the diet. Compared to diets of other countries, the Mediterranean diet has a relatively high fat content; however, as the diet...