Truth About Fats II : Vegetable Oil

For the last fifty years, the public has been bombarded with propaganda about the benefits of vegetable oil. Pork fat, beef tallow, and butter have been vilified and blamed for high cholesterol, heart attacks, cancer, obesity, etc. In this post I will attempt to trace the history of the vegetable oil and question whether it is indeed as heart-healthy as all the advertisements make it out to be. I will begin by introducing the different kinds of fatty acids:


Saturated fats - found in animal fats and tropical oils. They have no double bonds between individual atom carbons. All the bonds are "saturated" with hydrogen atoms. Saturated fats are stable at room temperature, and ideal for cooking at high temperatures.

Monounsaturated fats - found in olive, avocado, macadamia, and almond oil. They have one unsaturated carbon bond. They are not as stable as saturated fats, and thus they stay liquid at room temperature. However, they can be used for cooking as long as the temperature is medium to low.

Polyunsaturated fats - found in all vegetable oils, fish oil, etc. They have two or more unsaturated carbon bonds. These oils are extremely sensitive to heat and they go rancid very easily.

There are two essential polyunsaturated fatty acids that are vital to human growth and health: omega-3 and omega-6. Unfortunately our bodies cannot manufacture them and thus the only way to obtain them is through  food. We get omega-3 fatty acids mostly from cold water fish and we get omega-6 fatty acids from seeds, nuts, and the oils extracted from them. There are two important omega-3 fatty acids the body needs to function properly: eicosapentaenoic acid, called EPA, and docosahexaenoic called, DHA. Flaxseeds contain ALA (alpha linolenic acid), which the body converts into EPA and DHA. These fatty acids support cell function, immune system hormones, blood clotting, etc. 
There is one important omega-6 fatty acid: linoleic acid, or LA. Archidonic acid, AA, can actually be synthesized from LA in the body. They help maintain healthy skin, bones, and help regulate metabolism.

These two amazing teams of omega-3 and omega -6 fatty acids work together to maintain a balance within our bodies. The jury is still out on what the correct ratio of the two ought to be. Some scientists claim that it is 1:1 others 3:1 and others 4:1. Yet they all agree that omega-3's should outnumber omega-6's. The Center of Genetics, Nutrition, and Health, Washington DC released an article in the journal of Experimental Biology and Medicine in the early two thousands stating that:

Several sources of information suggest that human beings evolved on a diet with a ratio of omega-6 to omega-3 essential fatty acids (EFA) of ~1 whereas in Western diets the ratio is 15/1–16.7/1. Western diets are deficient in omega-3 fatty acids, and have excessive amounts of omega-6 fatty acids compared with the diet on which human beings evolved and their genetic patterns were established. Excessive amounts of omega-6 polyunsaturated fatty acids (PUFA) and a very high omega-6/omega-3 ratio, as is found in today’s Western diets, promote the pathogenesis of many diseases, including cardiovascular disease, cancer, and inflammatory and autoimmune diseases, whereas increased levels of omega-3 PUFA (a lower omega-6/omega-3 ratio), exert suppressive effect.

 In Nourishing Traditions Sally Fallon states that:

This disruption can result in increased tendency to form blood clots and to inflammation, high blood pressure, irritation of the digestive tract, depressed immune function, sterility, cell proliferation, cancer and weight gain.  Page 11

Unfortunately the reason this essential balance of fatty acids has become so lop-sided since the turn of the century is due to the high consumption of vegetable oil. We have stopped cooking with butter, lard, tallow, duck fat, etc and switched to canola oil, cotton seed oil, and margarine. 

The problem with vegetable oils does not end here though. Most of the vegetable oil we consume is processed at high temperatures, which oxidizes the sensitive polyunsaturated fats, producing free radicals.

 The commercial oils that most of Americans consume are extracted by toxic chemicals at high temperatures, a process that turns them rancid, destroys their nutrients, and produces free radicals (reactive molecules fragments that steal electrons from molecules in a process called oxidation, which damages the cells). These free radicals can contribute to a host of diseases, digestive disorders, and infertility. 

Mary Ennig, PhD, Eat Fat, Loose Fat, Page 50

I wish vegetable oil companies like Crisco or Wesson had giant wedge presses and extracted the delicate oils through this ancient tradition. It would be one of the few ways that we can ensure the preservation of all the antioxidants, vitamins, and minerals. In fact, most of us would not be able to handle some of these cold pressed oils because of the amount of  vitamins, fatty acids, and minerals that gives them a strong smell and a overbearing taste that we are not used to anymore. Instead, similarly to the process of pasteurization, the extraction of various oils at very high temperatures not only kills antioxidants but oxidizes healthy fatty acids. Some extraction processes go even farther. Certain seeds, like cottonseed, soy seed, and rape seeds, get treated with chemical solvents in order to get rid of the horrible stench they release when treated at such temperatures.

In fact one of the initial steps involves the use of hexane, a component of gasoline. If you were to get up close and catch the stench of the initial extract, you might never imagine it can be cleaned up. Making these stinky oils palatable requires a degree in chemical engineering; it takes twenty or so additional stages to bleach and deodorize the dark, unlucky muck. 

Katherine Shanahan, Deep Nutrition, Page 180

So not only are vegetable oils full of oxidized fats but they contain chemical solvents that stay as residue in the liver and leech in the blood stream. Of course most oil companies will argue that there is a very small percentage of chemical solvents. Unfortunately any amount of heptane, pentane, hexane is toxic.  If you start reading labels while you are at the store, you will discover that there is some sort of vegetable oil in almost everything: from mayo to dried blueberries, to shampoos to cleaning supplies. Our liver is one of the most vital organs in our bodies. Unlike the heart which has one main function the liver has more than five hundred.

The liver is the most complex of the body's organs. It preforms more than 500 functions and is critical to most of our metabolism. I once heard heard the dean of a medical school say, "I'd rather run all of the operations on General Motors for a day than be my own liver." Your four -and-a half pound liver manufactures 13,000 chemicals and has 2,000 enzyme systems, plus thousands of synergists that help the body functions. [...] The liver also stores environmental toxins like radioactive substances, pesticides, herbicides, food preservatives, and dyes. The liver will detoxify what it can, but if it can't break down a particular substance, it stores it there and in tissues throughout the body.

Liz Lipski, PhD, Digestive Wellness, Page 21

Treat your liver gently and remember how much it has to do in order to maintain balance in your body. If you can help it, stay away from chemicals that will retard its functions. You will be doing yourself a favor in the long run. While things like solvents wreak havoc on our livers and the rest of our bodies, reactive molecules from the rancid oils convert healthy cells into oxidized, damaged cells. Doctor Kate Shanahan compares it to "a zombie invasion" into your bloodstream.

Imagine a zombie movie, filmed at the molecular level, except that the mutated fattys don't stumble through your bloodstream in slow motion. Using free radicals, mutated polyunsaturated fatty acids convert normal fatty acids into yellow ghouls at the rate of billions per second. I call this conversion-on-contact the Zombie effect. [...]Frying in vegetable oil doesn't much cook your food as blast them with free radicals - fusing molecules together to make the material solid. Chemists call this series of reactions a free radical cascade. Free radical cascades damage normal polyunsaturated fats, turning them into ugly molecular ghouls. 

Kate Shanahan, MD, Deep Nutrition, Page 183

This reaction causes more abrasion and tearing of the arterial walls than any saturated fat from grass fed butter or beef tallow ever would. The oxidized fat, or damaged lipoproteins, goes unrecognized by cells and as a result it does not get utilized as energy. Instead, it continues to float through your blood stream disintegrating and collecting in the lining of your arteries.

When fat coats your arteries, it does not automatically cause a heart attack or stroke. If the fats are in any way useful, the endothelial cell may simply absorb them. However, if your diet is high in vegetable oil, then the fallen lipoprotein particles are useless debris, polluting every avenue, side street and alley of your circulatory system. 

Katherine Shanahan, Deep Nutrition, Page 95

This oxidation of the vegetable oil happens first at the factories where they are processed, and again when we fry, bake, or saute it at high temperatures. While much blame has been placed on animal fat for increasing cholesterol levels and arterial damage, let us not forget that almost every household, restaurant, and fast food chain today cooks with vegetable oil instead of animal fat. Yet the rate of heart attacks, obesity, and cancer seems to be going up.

My purpose in this post is not to vilify vegetable oil. It has amazing properties that are extremely vital for our health. Unfortunately we are not taking advantage of its wonderful fatty acids, polyphenols, and antioxidants. The best vegetable oils are the ones that have been cold pressed and used in their raw state. If an oil cannot be extracted from a seed, e.g. cotton seeds, unless high heat is applied, not to mention chemical solvents, then humans probably aren't adapted to eat it! Saturated fatty acids, which are the main components of butter, animal fat, and coconut oil, are wonderful options for cooking because all of their carbon bonds are saturated and can resist heat. Cold pressed vegetable oils and fish oils are a wonderful additions of omega -3 and omega-6. Our body needs a balance of all these fats. It is the way we have evolved to eat. When we begin eating only animal fat, or only vegetable oil, or only fish oil, we will offer our bodies a very limited supply of nutrients. I suggest eating a little of all of these wonderful fatty acids in their most optimal form.

In the next post, we will take a walk in the vegetable oil aisle and decode labels. We will hunt down cold pressed oils, expeller pressed oils, and solvent-containing oils in an attempt to judge the good oils from the rancid oxidized ones.

 You can find part one of the Truth About Fats series here.