Olive Oil - What are its advantages?

New studies show some surprising benefits for olive oil, including a possible protective effect on bone. Spanish research, to be published in the October issue of the Journal of Clinical Endocrinology and Metabolism, shows that consumption of a Mediterranean diet enriched with olive oil is associated with increased serum osteocalcin and other bone formation markers. Osteocalcin is produced by bone cells called osteoblasts, and is used as a marker for bone formation. Prior to this study, it had been noted that the incidence of osteoporosis in Europe was lower in the Mediterranean basin. All subjects in this study were instructed to eat a Mediterranean diet, rich in fruits and vegetables, lean protein from fish, poultry, and beans, and whole grains instead of white flour bread and pasta. Olive oil was their added fat.

Another Spanish study in 2010 showed that the phenolic compounds in extra virgin olive oil change how genes function. Phenols are chemical compounds found in plants that have many unique properties. In conjunction with a Mediterranean diet, genes related to atherosclerosis were down regulated, and there was a positive impact on oxidation of fats and DNA, insulin resistance, inflammation, carcinogenesis and tumor suppression. Atherosclerosis is a disorder that occurs when fat, cholesterol and other substances build up in the walls of arteries and form hard structures called plaques. This diminishes blood flow and can lead to heart attack and stroke.

Breast cancer risk may also be modified by virgin olive oil. Spanish scientists at the University of Barcelona decoded the signals within breast tumor cells activated by olive oil, concluding that benefits include decrease in activity of an oncogene, and stimulation of tumor cell death. An oncogene is a gene that has the potential to cause cancer, if activated by mutations in another gene or certain environmental factors. Olive oil also showed ability to prevent DNA damage. Corn oil and some other vegetable oils high in polyunsaturated fatty acids, can increase the aggressiveness of cancers.

Virgin olive oil is oil produced by crushing olives mechanically, with no chemical treatment. It has an acidity of less than 1.5%. Extra virgin olive oil comes from virgin olive oil and is lower in acidity (less than 0.8%) and is judged to have the best taste. Virgin olive oils contain the highest levels of phenolic compounds and anti-oxidants that have been linked with better health.

Using olive oil or canola oil on your salads will give you the best absorption of carotenes from colorful vegetables, according to a new study from Purdue University. Low fat and non-fat salad dressings resulted in minimal carotene absorption. Carotenes are pigments that occur in vegetables and fruits and have multiple healthy properties. Avocado is another healthy fat that enhances carotene absorption. If you do use canola oil, make sure that it is organic. Otherwise you will be using genetically modified canola that may be high in pesticides and herbicides, as ‘superweeds’ and resistant insects have evolved to make the application of Roundup less effective. More spraying is necessary.

Your vote in support of Proposition 37 in November will help to ensure that genetically modified food products are labeled in California. This is a huge issue for food companies, who have raised millions against the proposition. Stay tuned, and read the arguments on your ballot carefully.

Sadja Greenwood, MD, MPH back issues on this blog