2/7/2005 Philippine Daily Inquirer - A GENERATION ago, importedvegetable oil producers told Filipino consumers to replace traditionalcoconut oil with their "healthier" soybean and corn oils. Now, independentnutritional biochemists are finding otherwise.
Saturation of hydrogen atoms in fat molecules gives oil stability andshelf life. Oxygen, heat and light cause unsaturated oils to (1) turnrancid, (2) form trans fats, (3) create free radicals.
Dietary oils are to be timely consumed, sealed tight, bottled in glass,and stored in cabinets.
Vegetable oils, as defined by the US food oil industry, exclude saturatedtropical oils like coconut, palm and palm kernel oil along with saturatedanimal fats.
61% Polyunsaturated Soybean Oil
Polyunsaturated fat molecules have more than 2 pairs of hydrogen atomsmissing in theirchemical structure to make the food oil highly vulnerable to oxidationthat can cause free-radical damage in the body, and susceptible to transfat formation.
Being highly refined makes soybean, corn, cottonseed and safflower oilseven more detrimental to health.
In the 1930s, soybean oil was originally used in the US as a valued basefor paints and varnishes. But when chemists learned how to make cheaperpaints from petroleum, producers shifted to selling the oil as food.
To make it fit for human consumption, soybean oil, as well as otherpolyunsaturated oils that are as difficult to extract, has to be refined,bleached and deodorized under high heat in hydraulic presses and solventextraction methods. To retard oxidation, chemical preservatives are added.
In late 1940, soybean and corn oils were partially hydrogenated to makethem stable for use in processed foods.
60 years in food agriculture
In the 1950s, when saturated fats were being linked to heart disease,vegetable oil producers seized the opportunity to push their oil as ahealthy substitute to all saturated fats including tropical vegetableoils.
Foodmakers and restaurants were convinced to switch from natural saturatedoils to partially hydrogenated soybean oil.
By the time biochemists found out its ill health effects, nearly 80% ofall the vegetable oils used in the United States is soybean, three fourthsof which is hydrogenated.
Cause cholesterol oxidation
Polyunsaturated oils turn rancid easily in oxygen, heat and light, more sowhen they are highly refined. For this reason, soybean, corn andcottonseed oils are not ideal for cooking as monounsaturates and saturatesare. Even when taken fresh, these ols will oxidize faster in the bodywhere they mix with an abundance of oxygen. Cold-pressed flaxseed, almondand sesame oils make healthier polyunsaturates.
Polyunsaturates are bad for the heart.
Dr. Enig found that the studies (1965) showing unsaturated oils aslowering cholesterol, ignored the bad side effect on the heart.Cholesterol had simply migrated out of the blood into surrounding tissuesto fix cell walls made more leaky by the polyunsaturated oils. Whencholesterol gets oxidized by rancid oils, it becomes artery-clogging.
Polyunsaturated oils raise cancer risk
Researches (1978, 1984, 1991, 1993) by biochemist Dr. Raymond Peat revealthat (1) as unsaturation of dietary oil increases, cancer rates increases,mental ability diminishes, (2) general aging is increasingly associatedwith fat oxidation, and (3) refined vegetable oil intake exceeding 10% oftotal calories can lead to blood disease, cancer, liver damage, andvitamin deficiencies.
Refined polyunsaturated oils form the most trans fats in hydrogenationPartially hydrogenated soybean oil results in shortenings containing about40% trans fats, higher by 5% over cottonseed oil, and 15% over corn oil.