Compelling research evidence links dietary fat to virtually all of the most common cancers. Most of the information comes from a study of fat consumption in various countries. Those with the highest fat intake have the highest incidence of breast, colon, prostate and kidney cancer. Of even more concern, in the past 50 years, the incidence of all these cancers has increased, whereas the incidence of heart attacks and strokes has decreased. How could this be?
In the past 50 years, the fat composition in our diets has changed. When I grew up in the 1950s, the average diet provided about 30 percent of calories from fat, 60 percent of which was saturated fats contained in red meat, milk, butter and cheese.
At that time, the link between heart attacks and cholesterol became widely known and saturated fat intake was thought to be the major dietary risk factor. Simultaneously, plant oils containing high concentrations of polyunsaturated fats were shown to lower cholesterol and significantly reduce the risk of heart attacks and strokes. As a consequence, we began to eat less red meat, cheese and saturated fat, and increased the amount of polyunsaturated fat, such as corn oil and margarine. And, as we predicted, deaths from heart attacks (that was a major killer of so many middle-aged men) decreased by about 50 percent in men and have also moderately decreased in women.
While the composition of fat consumed has changed, the total amount of daily fat intake has remained constant. Today, polyunsaturated fats constitute 60 percent of the total fat. While heart attacks and strokes have decreased, the net effect on life expectancy has not been as dramatic and, over the same period of time, the incidence of cancer has increased. This includes an increased incidence of lung (almost always related to smoking), breast, colon and prostate cancer. Could it be that the change in the composition of fat intake has reduced the risk of heart attacks but increased the risk of cancer? Clearly, the answer is yes. Numerous research studies suggest that a high intake of polyunsaturated fats increases the risk of all of these cancers and is more dangerous than saturated fats. We have replaced one serious disease with another.
More recently, a great deal of interest has focused on the Mediterranean diet, where fat intake is not much different from that noted in the United States but the risk of heart attack, stroke and cancer is less. The major difference between the two diets is clearly related to olive oil. Oil obtained from corn, sunflower, safflower and soybean is almost exclusively polyunsaturated, whereas olive oil is monounsaturated.
Whether an oil is polyunsaturated or monounsaturated is primarily related to its chemical nature. Polyunsaturated fats are readily oxidized, meaning they produce a very toxic compound called a free radical that causes severe cell damage, an initial event in eventual malignant transformation. By contrast, monounsaturated olive oil does not oxidize, does not damage cells, and hence may not contribute to an increased cancer risk.
A recent research study by scientists at the Northwestern School of Medicine in Chicago showed that olive oil might protect women from developing breast cancer. Most women who develop breast cancer have an overproduction of a specific cancer-producing gene (oncogene). In this study, scientists showed that oleic acid, the main component of olive oil, inactivates this oncogene, reducing the risk of breast cancer.
Based on all this information, the message is clear. To stay healthy we must not only reduce fat intake but must also watch the type of fat consumed. Saturated fats, trans fats (margarine and shortening) and polyunsaturated fats all have more health risks than monounsaturated fats. For this reason I suggest that you stock your kitchen with olive oil. Saute with olive oil, use it in salad dressings, add pepper, and use it on bread rather than butter. The benefits may well be huge and assure a better and perhaps even a longer life.
Dr. David Lipschitz is the author of the book "Breaking the Rules of Aging." To find out more about Dr. David Lipschitz and read features by other Creators Syndicate writers and cartoonists, visit the Creators Syndicate Web page at www.creators.com. More information is available at: DrDavidHealth.com.