Olive Oil Fights Heart Disease, Breast Cancer, Studies Say

Stefan Lovgren
for National Geographic News
March 21, 2005
They may smoke more than Americans and their health care system is far from perfect, but Greeks usually live longer than their U.S. counterparts, and they have some of the world's lowest rates of heart disease and cancer.

The secret may be their olive-oil-drenched diet.

Scores of scientific studies in the past decade have shown that olive oil, which is high in monounsaturated fat—the "good" fat—may prolong life by combating coronary heart disease and different types of cancer.

No wonder the Greek physician Hippocrates, known as the father of medicine, is said to have referred to olive oil as "the great therapeutic."

FDA Approval

For 4,000 years in the Mediterranean cultures, olive oil has served as everything from money to medicine. Today 99 percent of all olive oil is produced in the countries that rim the Mediterranean Sea.

It is the only vegetable oil that can be created simply by pressing the raw material—in this case, olives. The quality of the oil depends on the amount of processing involved. Extra virgin olive oil is considered the best. The oil from the first pressing of the olives, it is the least processed.

Once considered an "ethnic food" in the U.S., olive oil experienced rapid popularity growth in the 1980s. Today the U.S. imports more than 50 million gallons (189 million liters) a year.

A few months ago the U.S. Food and Drug Administration credited olive oil with decreasing the risk of coronary heart disease.

Up to 80 percent of olive oil is made up of monounsaturated fatty acids, which resist oxidation (the process by which fatty acids are degraded) better than polyunsaturates. Monounsaturated fatty acids help keep HDL—so-called good cholesterol—levels up and LDL, "bad" cholesterol, down.

In addition, the presence of phenols, tocopherols, and other natural antioxidants in olive oil also prevent the formation of certain free radicals (highly reactive molecules) that may cause cell destruction within the human body.

"Indeed, it is the only added lipid [fat] that has not been associated with increased risk of cancer," said Dimitrios Trichopoulos, an epidemiology professor at Harvard University in Cambridge, Massachusetts.

Other Studies

Olive oil may actually prevent cancer, according to a study released earlier this year. The study showed that oleic acid, the main monounsaturated fatty acid in olive oil, can cripple a cancer gene responsible for 25 to 30 percent of all breast cancers.

The study found that oleic acid not only suppressed the levels of the gene, called Her-2/neu, but also improved the efficiency of the drug trastuzumab (sold under the brand name Herceptin), which is used to treat many women with breast cancer.

"Our findings underpin epidemiological studies that show that the Mediterranean diet has significant protective effects against cancer, heart disease, and aging," said one of the study's authors, Javier Menendez of Northwestern University's Feinberg School of Medicine in Chicago, Illinois.

Other studies have found that olive oil has a favorable effect on both ovarian cancer and bowel cancer. In addition, olive oil is well tolerated by the stomach. It appears to prevent the formation of gallstones as well as have a therapeutic effect on ulcers.


Despite all the apparent health benefits of olive oil, scientists do not consider it a miracle food.

There may be other reasons why Mediterranean populations have lower rates of cancer and heart disease.

While olive oil is a central characteristic of the Mediterranean diet, people in that region tend to eat far more vegetables, fruit, and fish—and lower amounts of meat and dairy—than the average American.

"It may be a healthier overall diet," Trichopoulos, the Harvard epidemiologist, said.

John Deane, a medical doctor and the editor of the Web site the Olive Oil Source, said that he gets inundated with e-mails every month from people asking about the health effects of olive oil.

"People ask how many teaspoons a day they must consume to cure a certain illness, as if it was some sort of medicine," Deane said. "But caution must be used in extrapolating these many studies in animal models or cell cultures to human diseases."

Deane says olive oil should be eaten and enjoyed along with other healthy fats and foods.

"The doctor in me likes the fact that it has been consumed and available over the counter for several thousand years with a great safety profile," he said.

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