This is a critically important topic to our health, and as I stated in previous tips, it is one the nutrition pundits have got wrong. They are suggesting we use polyunsaturated vegetable oils for cooking. Now think back to high school chemistry and remember what, by definition, a "polyunsaturated molecule" means. It means that the molecule is unstable - that it has more than one double bond, and would prefer to share those electrons with other atoms to help the molecule become saturated and stable. Oxygen is missing two electrons in its outer shell, and so it is fairly reactive and would be happy to bind with the extra electrons in the polyunsaturated molecule. The more unsaturated the molecule is, the less stable the molecule, and the more reactive it is. So, when polyunsaturated vegetable oils are heated, they react with oxygen, and oxidize, which makes them rancid. This is why a monounsaturated oil like olive oil is more stable and okay for low temperature cooking, and saturated fats are the most stable and therefore the best for cooking.

The kicker is that most of the vegetable oils on the market are heated in the processing in order to get the oil out of the seed. (Can you imagine how difficult it would be to squeeze oil out of a grape seed?) Therefore they are already rancid on the store shelves. They are then bleached so they look nice, and deodorized so they don't smell bad and the consumer will not know the oil is rancid. It is worth noting that flax oil is usually treated properly - unrefined, packaged in a dark bottle and kept in the fridge like all polyunsaturated vegetable oils should be.

Polyunsaturated oils like canola oil, sunflower oil, safflower oil, corn oil, etc. can be used for salad dressings as long as the bottle says "unrefined" on it and it is stored in a dark bottle. In my neck of the woods in western Canada, I can buy Rapunzel, Orphee, and Spectrum organic unrefined oils. What brands of organic unrefined oils are near you? Please post them here - let's help our clients and patients choose well. Make sure the bottles are dark, and keep them in the fridge.

It is worth noting however that most people consume far too much omega 6 fatty acids, the ones found in vegetable oils, compared to omega 3 fatty acids, the ones found in fish oils. We tend to consume a ratio of 20 /1 omega 6 to omega 3, which is highly inflammatory to the body, and we should get that ratio down to closer to 1/1 or at least 4/1. This will encourage the cox 1 pathway rather than the cox 2 pathway in the body, and create less need for cox 2 inhibitors. This is another valid reason to reduce our consumption of vegetable oils. So, consume your fish oils, but stay away from vegetable oils as much as possible. One can get enough omega 6 from nuts, seeds and whole grains, and when they are consumed whole, they have the antioxidants in them to prevent any problems.

Trans fats are known to be very devastating to the body, and are implicated in heart disease, so avoid margarine and shortening. Don't be fooled by the fake buttery spreads that are touted as healthy, even if they say "no trans fats" on the label. Either the manufacturer has lowered the percentage of transfats in the product so that legally they can claim it is transfat free (but it is not!), or they are using another form of manufactured fats called interesterified fats, which are equally dangerous. Use real butter instead. Be suspect of any food that has vegetable oils listed on the label, and yet the product is semi-solid (like ice cream) or dry (like crackers or spices). That is a give-away that the fats inside should not be consumed.

For cooking, saturated fats are the way to go. They are stable and contrary to popular belief, healthy for the body. So use extra virgin coconut oil (Omega nutrition is a great brand), free-range organic chicken, beef fat or butter, and don't worry about clogging your arteries. These fats are not the problem. Remember that heart disease was virtually non-existent in the late 1800s when everything was cooked with these saturated fats. Animal fats, whole raw milk, eggs and butter had been consumed and prized for their healthfulness for thousands of years by primitive cultures all over the world. The first heart attack on record happened in 1921, just as the vegetable oil industry was picking up steam, and sugar and white flour were becoming more plentiful. (See this study published in the Lancet which shows that most arterial plaques are actually made up of unsaturated fats rather than saturated fats, contrary to popular belief.) Since then saturated fat consumption has plummeted, so it is illogical to blame saturated fat for heart disease.

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Enig, Mary; Know Your Fats: The Complete Primer For Understanding the Nutrition of Fats, Oils, and Cholesterol Bethesda Press, Silver Spring, MD, 2003.

Online by Mary Enig, PhD, fats, oils and lipids researcher The importance of saturated fats for biological functions

Online by Mary Enig, PhD, fats, oils and lipids researcher Fats and Oils and their impact on health

Online by Mary Enig, PhD, fats, oils and lipids researcher An Example of Junk Science

Felton C. et al. Dietary polyunsaturated fatty acids and composition of human aortic plaques Lancet, 1994, 344:1195

German, B and Dillard, C Saturated Fats: What dietary intake? American Journal of Clinical Nutrition, Vol. 80, No. 3, 550-559, Sept. 2004.

Knopp RF Saturated fat prevents coronary artery disease? An American paradox American Journal of Clinical Nutrition, Vol. 80, No. 5, 1102-1103,
Nov 2004.

Mozaffarian D. et al. Dietary fats, carbohydrate, and progression of coronary atherosclerosis in postmenopausal women American Journal of Clinical Nutrition, Vol. 80, No. 5, 1175-1184, November 2004

Ravnskov, Uffe, MD, PhD The Cholesterol Myths: Exposing the Fallacy that Saturated Fat and Cholesterol Cause Heart Disease, New Trends Publishing Inc., Washington D.C., 2000.

Krumholz HM and others. Lack of association between cholesterol and coronary heart disease mortality and morbidity and all-cause mortality in persons older than 70 years. Journal of the American Medical Association 272, 1334-1340, 1994.

Shestov DB and others. Increased risk of coronary heart disease death in men with low total and low-density-lipoprotein cholesterol in the Russian Lipid Research Clinics prevalence follow-up study. Circulation 88, 846-853, 1993.

Soriquer F. et al. Hypertension is related to the degradation of dietary frying oils Am J Clin Nutr Dec;78(6):1092-7, 2003.

de Roos NM et al. Replacement of dietary saturated fatty acids by trans fatty acids lowers serum HDL cholesterol and impairs endothelial function in healthy men and women Arterioscler Thromb Vasc Biol, Jul; 21(7):1233-7, 2001

de Roos NM et al. Consumption of a solid fat rich in lauric acid results in a more favorable serum lipid profile in healthy men and women than consumption of a solid fat rich in trans fatty acids Journal of Nutrition Feb:131(2):242-5, 2001.

de Roos et al. Replacement of dietary saturated fat with trans fat reduces serum paraoxonase activity in healthy men and women Metabolism Dec;51(12):1534-7, 2002.

Temme EH. et al.Individual saturated fatty acids and effects on whole blood aggregation in vitro Eur J Clin Nut Oct:52(10):697-702, 1998.

Online by Mary Enig, PhD, fats, oils and lipids researcher
Trans Fatty Acids are not formed by heating vegetable oils

Price, Weston Nutrition and Physical Degeneration Pottenger Price Foundation, 1945.

Alexander JC et al. Biological observations from feeding heated corn oil and heated peanut oil to rats Journal of Toxicology and Environmental Health 21, 295-309, 1987.

Pinckney ER, The potential toxicity of excessive polyunsaturates. Do not let the patient harm himself American Heart Journal 85, 723-726, 1973.

West, CE et al. Reservations on the use of polyunsaturated fats in human nutrition Search 5, 90-96, 1974.