Olive oil is a staple in the diet of Mediterranean countries. It's used not only in cooking, but also mixed with vinegar as a dressing, and even with cracked black pepper as a dipping sauce. In fact, it's become a favorite for chefs, the health-conscious, and even gourmet cooks.

But there's much more to this delicious, nutritious oil... Forty years ago, when studying Greeks living on the island of Crete, researchers found that despite the high fat content in their traditional diet, the residents had an exceptionally low occurrence of heart disease. As researchers continued to examine the diets of the Greek people, their goal was to determine what factors contributed to these results. Their conclusion? Olive oil! The Greeks use very little transfats like margarine, substituting olive oil instead.

A scientific project called the Seven Countries Study determined that 46 percent of middle aged deaths in American men were due to heart disease, while the percentage of deaths in Crete were only 4 percent — over 10 times lower. In addition to the benefits of the monounsaturated fats in olive oil, there are several other compounds that can benefit your health. These can stop damage in your arteries before it starts. Polyphenols are powerful antioxidants found in olive oil. These antioxidants disable the free radical oxygen molecules produced naturally by your body. This keeps the free radicals from attacking the low-density lipoprotein cholesterol (LDL) which lowers the chances that they will stick to artery walls, clogging them and causing heart disease. The conclusion? Adding olive oil to your diet can help to keep your arteries clear.

Oleic acid-rich olive oil, an important component of the Mediterranean diet, may also be a key ingredient in the fight against breast cancer, U.S. researchers have discovered.

The findings, which are reported in the January 10, 2005 issue of Annals of Oncology, may lead to promising new treatments for the disease.

The researchers have demonstrated in a series of laboratory experiments on breast cancer cell lines that oleic acid dramatically cuts the levels of an oncogene called Her-2/neu, also known as erb B-2. High levels of Her-2/neu occur in over a fifth of breast cancer patients and are associated with highly aggressive tumors that have a poor prognosis.

Not only did oleic acid suppress over-expression of the gene, other tests on the cell lines showed that it also boosted the effectiveness of trastuzumab (Herceptin), the monoclonal antibody treatment that targets the Her-2/neu gene and has helped to prolong the lives of many breast cancer patients.

Over the last few years, researchers at the Harvard School of Public Health and the Athens School of Public Health studied the effects of olive oil on more than 2,300 women. They discovered that women who consumed olive oil more than once a day had a 25% lower risk of breast cancer, and in fact the female population of Greece is much less likely to die from breast cancer than women in the United States. They believe that the high concentration of vitamin E, found in olive oil, which has been proven to slow or stop cell damage, as well as the polyphenols in the oil mentioned earlier contribute to this benefit.

To get the most benefit from olive oil, make sure to look for extra virgin olive oil. This oil comes from the very first cold press of the olive and contains the highest and purest amounts of disease fighting polyphenols. Also, unlike other oils, olive oil should be kept cool to avoid becoming rancid, either in the refrigerator of other dark cool spot. This will make sure your olive oil maintains its protective qualities, as well as its great taste.