Good oils, be they coconut, olive, avocado or other can make you sick when they start to go rancid! Why is rancid oil bad (aside from the fact that you get nauseous hearing the words in your head)? Oil, when it’s overheated, deteriorates chemically. The rate of the breakdown (and total formation of toxic compounds) is dependent on the type of oil and temperature.
Initially, the oil’s decomposition results in the creation of hydroperoxids and then increasing levels of aldehydes. (Aldehydes are toxic compounds and recognized “markers of oxidative stress in cells” and are known contributors to “degenerative illnesses.” What does this mean for anyone who eats rancid oil? They just invited in a Trojan Horse of free radicals galore that are now beginning their violent pillaging of the person’s innards. This is true of overheated oils that appear to have not been overheated, just stored in a warm environment too long!
Nuts and seeds that are stored in containers on the counter in most homes will begin to smell rancid after some time, because their oils go bad just from exposure to air and the warmth of your room (especially shelled ones). Cashews and walnuts are some of the first to decompose. These are rancid oils and they can make you sick! One oil that is considered healthy, is Flax Seed oil. This, even refrigerated goes bad quickly, just from contact with air (oxidation). I do not use flax oil for that reason, though grinding and eating the seeds is a great source of good oils and excellent fiber, just be sure it is fresh. If you use flax meal, keep it in the freezer as it will go rancid quickly too!
Research on the effects of heating oils has been geared toward understanding safe practices for deep-frying and industrial purposes. In a study published in 2010 by the “Food Chemistry” journal, researchers studied the emissions from four commonly used oils — safflower, canola, extra virgin olive and coconut. Each was heated to four temperature levels, and its emissions were analyzed for certain toxic fumes, including aldehydes, which are known to be cancer-causing. When an oil exceeded its smoke point, the amount of toxic fumes increased significantly, according to the study. Canola oil, with the highest smoke point, gave off the lowest levels of toxic fumes. Coconut oil, which has the lowest smoke point of the four studied, emitted the greatest amount of total volatile fumes at all but the lowest temperature. (This report is from LiveStrong.com).
Coconut oil, my favorite, or olive oil? Back in the 1930s, a dentist named Dr. Weston Price traveled throughout the South Pacific, examining traditional diets and their effect on dental and overall health. He found that those eating diets high in coconut products were healthy and trim, despite the high fat concentration in their diet. The first, extra-virgin olive oil, is a better monounsaturated fat. It works great as a salad dressing. However, it is not the best oil to cook with. Due to its chemical structure, cooking makes it susceptible to oxidative damage. Coconut oil does much better under moderate heat (none are good for high temperatures and one reason to not fry foods). A refined coconut oil may be better than the extra virgin variety for cooking. If you choose to cook with oils at moderate temperatures, seek out the refined variety that is not overly processed with things such as toxic chemicals or hydrogenated in the refining by over heating.
What to look for in buying coconut oil:
- Certified organic by USDA standards
- No refining
- No chemicals added (including hexane)
- No bleaching
- No deodorization
- No hydrogenation
- Made from traditional coconut palms only, no hybrid or genetically modified (GMO) varieties
- Made from fresh coconuts, not the dried “copra” used in cheap oils
- Made without heat processing
Here is a list of when oils start to smoke and rapidly deteriorate under cooking. Canola oil would seem to be the best but many argue that it is an unhealthy oil especially since it is almost always a GMO.