Americans have come to see vegetable oils as heart healthy over the past 50 years. The Diet Heart Hypothesis raised by Ancel Keys in the 1950s, and seemingly confirmed by his Seven Country Study, implied saturated fat in the diet was to blame for the post-World War II surge in arteriosclerotic heart disease.
Saturated fat, as in butter, lard and red meat, was found to raise cholesterol, whereas vegetable oils containing polyunsaturated fats lowered the cholesterol. The theory went that cholesterol, a fatty, waxy substance, was building up in the walls of our arteries in response to excess consumption of saturated fat. This process eventually clogs up the artery, leading to reduced blood flow with a heart attack or stroke, depending on the location of the artery, in the heart or the brain.
The building blocks of fats and oils are called fatty acids. All food fats, whether solid or liquid, are triglycerides where three fatty acids are attached to glycerol, a sugar alcohol and arranged like the letter E. The additives you often see on food ingredient lists mono- and diglycerides are just triglyceride fats with one or two arms missing.
Fatty acids come in three kinds of saturation — saturated, unsaturated and polyunsaturated. Saturation refers to the amount of hydrogen on a fatty acid, if all sites are filled with hydrogen the fatty acid is fully saturated and solid at room temperature. Unsaturated fatty acids are missing some hydrogen and are liquid at room temperature. Monounsaturated fatty acids such as oleic acid in olive oil have only one hydrogen missing and are liquid at room temperature but congeal in the refrigerator.
On the other hand, a highly polyunsaturated fat — like safflower oil, with more than 75 percent of its fatty acids missing two hydrogens — will stay liquid even in the refrigerator. This tells you that olive oil has more saturated fat than safflower oil (13 percent vs 6 percent) but both are low in comparison to butter or beef fat, which contain 50 percent saturated fatty acids.
Vegetable oils, such as corn or soybean oil, have been used in margarines for more than 100 years as a cheaper alternative to butter or lard, especially in war times. In good times, however, butter and lard were preferred due to their better taste, flavor and savoriness.
However, as the medical world and especially the American Heart Association started to endorse vegetable oils as the way to better health, it became a shoo-in for the food industry. What better way to use up the huge surplus crops from our monocultures of corn, soy and rapeseed? An additional bonus was that these oils were cheaper than butter, lard or beef tallow. Beef tallow was used by McDonald’s until it was forced to change to “heart healthy canola oil.”
So what could be wrong with the vegetable oils? First, not all are bad, and some — like olive oil and fish oils — are actually good for you. But the industry has been dishing up a potpourri of oils that are “wolves in sheeps clothing.”
Let’s address Canola oil first since it got the endorsement of the USDA in 2006 to make the following health claim: “There is limited and non-conclusive evidence that eating 1.5 tablespoonful or 19 grams of canola oil daily may decrease the risk of coronary heart disease due to its content of unsaturated fats.”
Canola is derived from a variety of the rapeseed plant low in erucic acid. Rapeseed oil sold for human consumption in 1956 was a failure. This was due to its greenish color and off taste. Additionally, it contained a high amount of erucic acid, which is toxic to the heart muscle. So the oil got the big makeover by two chemists at the University of Manitoba, Canada. Its name is derived from Can for Canada and ola for oil. The main difference from the original rapeseed oil was its much lower content of erucic acid of less than 2 percent.
What drove the heart-health claim endorsed by the USDA? In its unprocessed form, Canola oil has a high content of Omega 3 fatty acids, of fish oil fame, as well as the PUFAs or PolyUnSaturatedFats, both of which are good for heart health. But, alas, there is the rub, to quote Shakespeare. When heated to high temperatures, as in frying — especially in restaurants and fast-food joints — these unsaturated fats get oxidized and converted to aldehydes such as formaldehyde — yes, the stuff to embalm corpses with! These aldehydes are toxic to the cells and damage DNA and RNA. Early experiments and trials such as the LA Veterans’ trial showed increased cancer deaths from vegetable oils with a high PUFA content. Additionally, these oils are added widely to processed foods. When people consume a large amount of processed and restaurant foods containing canola oil they may also ingest larger amounts of the erucic acid.
There are several problems associated with canola oil: Most of it is hydrogenated oil, since it has to be refined with bleaching and degumming chemical solvents. It also needs to be deodorized due to its strong odor. All this is done under high heat, which destroys most of the beneficial Omega 3 fatty acids right there, transforming them into transfats, the ones we have been told are particularly damaging to the heart due to their proinflammatory effect. Experiments in mice bred to be prone to the development of Alzheimer dementia show that when fed a diet enriched with Canola oil for several weeks, they exhibit memory problems and their brains develop increased amyloid plaque deposits, the same stuff found in human brains affected with Alzheimer-type dementia. And last but not least, it is 90 percent GMO or genetically modified and Roundup ready, which means that the plants can withstand the heavy spraying with Roundup or Glyphosite, an insecticide and herbicide.
Soybean and corn oil, the other common vegetable oils, fare not much better. They are also mostly GMO and subjected to processing under high heat and extraction with petroleum derivatives such as Hexane. They are also Roundup ready, cultivated to withstand the spraying with herbicides and pesticides. These oils are used extensively in frying and food processing as additives, also in salad dressings, mayonnaise, pastries etc. Fast foods use them making french fries. When the oils are heated to the high temperatures required, it creates oxidative damage and the formation of the toxic aldehydes.
So what oils can one use safely? Olive oil has proven itself over the centuries and most recently in the PrediMed study in Spain where the incidence of adverse coronary events was cut down by 30 percent when people in the study consumed a pint of extra virgin cold pressed olive oil per week for two years. Cholesterol-lowering drugs such as statins do not perform any better! For frying, which requires a higher burning point, you may want to consider avocado oil, which is monounsaturated similar to olive oil but can withstand being heated to 500 degrees. Additionally, it is taste-neutral. You may say olive and avocado oils are expensive, to which I counter, “Would you rather hand over $50 or more every month to a pharmaceutical company as pay for your statin drug?”
One last word of advice: be proactive in your choice of healthy fats and oils. The big agencies such as the FDA, USDA or even the AHA or American Heart Association are of no help. The AHA is even paid by food companies so they can put the “Heart Healthy” sign on the oil bottle. Canola oil being the example. Learn to pause and read labels for contents. They will tell you what oil or oils are being used. Sometimes it can be several vegetable oils in one item, such as soybean oil, canola and sunflower for example. Labels can be tricky, such as mayonnaise made with olive oil, but closer scrutiny reveals that half of the oil comes from soybean oil. Avoid deep-fried foods when you eat at restaurants or fast-food joints. All these places invariably use the cheap oils, canola, soy and corn. Additionally, the oils are reheated and reused several times, making them even more toxic.
Dr. Eva Abbo is a doctor of internal medicine in La Jolla, Calif., and former Laurel resident.