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cellboyA few months ago, Dr Gupta (CNN), had a special on aging, and why is it that some people, or societies live longer than most. He visited an island somewhere between Turkey and Greece, that is known to have many living at a healthy age of 100 or older. Many reasons of course, included diet and exercise. One thing they did mention, which caught my attention, was that they used a lot of olive oil. On everything. However they did to cook, or saute with it. Once the cooking or sauteing was done, with water or wine, chicken stock, or some other liquid, they would then pour the room temperature olive oil over the food. Dr. Gupta said, that research has found that cooking olive oil at high temperatures, destroys the chemical bond, to create a more fatty, dangerous oil for our health, negating the positive properties that olive oil gives us.
There is of course contradictory views on this, but it seems that olive oil can be less damaged from heating or over heating than others. And Olive seems still to be one of the best of oil choices.
http://www.oliveoilsource.com/cooking_olive_oil.htm
(or an excerpt from http://www.oliveoilsource.com/oliveoildr-cholesterol.htm)
Heating olive oil to frying temperatures ruins its delicate flavor but can also decrease antioxidants and create a host of new chemical species. These new chemicals include hydro peroxides, alcohols, aldehydes, hydrocarbons, free fatty acids, esters, ketones, lactones, furans and others (Kiritsakis). The same is true for any oil. In a study at Ankara University in Turkey, ( Department of Biochemistry durak@pallas.dialup.ankara.edu.tr) investigators examined the effect of heating olive oil, sunflower oil and soy oil to 180 degrees C. Olive oil fared the best. It retained its natural antioxidant defense potential and formed the fewest potentially cancer causing aldehydes. This may be because of its low linolenic acid content. Researchers have found that oils high in linolenic acid develop more off-flavors during frying. During frying oils change from one shape to another, called isomers. The "cis" isomer changes to a "trans" isomer with possible harmful health effects. Trans isomer fatty acids are used differently in the body and can cause damage to proteins and enzymes, damage to lungs, formation of age pigments, disruption of cell membranes and even cancer. Repeated frying also increased the ratio of saturated to unsaturated oil. Studies showed that it took 10 to 15 heatings to create these new oil forms. Some investigators heated the oil to 200 degrees C for 25 to 100 hours to produce toxic compounds. In commercial practice, oils should be replaced before these unhealthy chemicals are formed. Frying foods higher in water content seemed to protect the oil longer.
There is of course contradictory views on this, but it seems that olive oil can be less damaged from heating or over heating than others. And Olive seems still to be one of the best of oil choices.
http://www.oliveoilsource.com/cooking_olive_oil.htm
(or an excerpt from http://www.oliveoilsource.com/oliveoildr-cholesterol.htm)
Heating olive oil to frying temperatures ruins its delicate flavor but can also decrease antioxidants and create a host of new chemical species. These new chemicals include hydro peroxides, alcohols, aldehydes, hydrocarbons, free fatty acids, esters, ketones, lactones, furans and others (Kiritsakis). The same is true for any oil. In a study at Ankara University in Turkey, ( Department of Biochemistry durak@pallas.dialup.ankara.edu.tr) investigators examined the effect of heating olive oil, sunflower oil and soy oil to 180 degrees C. Olive oil fared the best. It retained its natural antioxidant defense potential and formed the fewest potentially cancer causing aldehydes. This may be because of its low linolenic acid content. Researchers have found that oils high in linolenic acid develop more off-flavors during frying. During frying oils change from one shape to another, called isomers. The "cis" isomer changes to a "trans" isomer with possible harmful health effects. Trans isomer fatty acids are used differently in the body and can cause damage to proteins and enzymes, damage to lungs, formation of age pigments, disruption of cell membranes and even cancer. Repeated frying also increased the ratio of saturated to unsaturated oil. Studies showed that it took 10 to 15 heatings to create these new oil forms. Some investigators heated the oil to 200 degrees C for 25 to 100 hours to produce toxic compounds. In commercial practice, oils should be replaced before these unhealthy chemicals are formed. Frying foods higher in water content seemed to protect the oil longer.
