"Fats composed mainly of saturated fatty acids are solid at room temperature, and the greater the saturated fat content, the higher will be the temperature of melting. Animals fats are highly saturated, as are the 2 vegetable fats: the oils of coconuts and palm kernals. At the opposite end of this chemical spectrum are the polyunsaturated vegetable oils, all of which stay liquid at colder temperatures. The lower the temperature at which solidification occurs, the greater the degree of unsaturation.
Corn, soy, sesame, sunflower and safflower are examples of polyunsaturated fats. In the middle of the spectrum are the vegetable oils composed primarily of monounsaturated fatty acids, those with just one double or triple bond in the chain of carbon atoms; examples are olive, canola, peanut and avocado oils.

Polyunsaturated oils are bad for us in other ways. They are chemically unstable, owing to their content of fatty acids with energetic double and triple bonds that tend to react with oxygen, resulting in toxic compounds that can damage DNA and cell membranes, promoting cancer, inflammation and degenerative changes in tissue. Moreover, when unsaturated fatty acids are heated or treated with chemical solvents and bleaches, they tend to deform from a natural curved shape (called cis-configuration) to an unnatural jointed shape (called the trans-configuration). Trans-fatty acids, or TFA's, may be extremely toxic, even though medical scientists have been very slow to recognize the danger. The body builds cell membranes out of cis-fatty acids and also uses them in synthetic pathways for hormones. We do not know what it does with TFA's; if it tries to use them in the same ways, the result might be defective membranes and hormones... Remember that TFA's are rarely found in nature, only fats that have been subjected to unusual chemical and physical treatment.... You can avoid any danger by eliminating from the diet all margarine and solid vegetable shortening and products made from them, all products listing "partially hydrogenated" oil of any kind on the label, and all commercial brands of polyunsaturated vegetable oils (corn, soy, sesame, sunflower and safflower), since these have been extracted with heat and solvents that promote the formation of TFA's.... Vegetable oils that are predominantly monounsaturated - olive, canola, peanut, avocado - do not pose the cardiovascular risk of saturated fats or the cancer risks of polyunsaturates."

(A side note - a toxic mold, called aflatoxin, is commonly found in peanuts, corn and soy. If you do use peanuts or peanut oil, please make sure it is aflatoxin free)

So we have learned which types of oils (olive, canola, peanut and avocado) are good for us and our pets, as well as the typical extraction methods (the ways to get the oil out of the seed) like chemical solvents (usually hexane) and heat are bad. So where does this leave us?

There are different types of fatty acids inside the fats themselves. We hear the most about Omega fatty acids, particularly omega 3, 6, and 9 fatty acids. You need all three for proper function, but you want more of the 3 than the 6. 9 we don't know much about. Omega 6 fatty acids can contribute to a hormone called prostaglandin E2 which, among other things, is an inflammatory agent. A wonderful benefit of the omega 3 fatty acids is the ability to inhibit some inflammation mediators. Fish oil (*not* fish liver oil) and flaxseed oil have good amounts of omega 3's. The 2 acids that make up a fatty acid that are important here are EPA (eicosapentaenoic acid) and DHA (docosahexanoic acid). These are readily available in fish oil, but do need to be converted in flaxseed oil. DHA and EPA have great anti-inflammatory effects. Flaxseed generally contains 9% saturated, 18% oleic acid, 16% omega 6 and 57% omega 3 fatty acids. However, flaxseeds themselves contain phytic acid which can hinder the the absorption of such nutrients as iron, calcium, phosphorus and zinc. A good quality oil from the flaxseeds should be without phytic acids. You will find this oil refrigerated and in a dark glass bottle. It should be labeled as cold-pressed and organic, with no heat treatments or chemical solvents. Do not vigorously shake oils as to help reduce oxidation (which makes the oil spoil) and if it tastes bitter, it has spoiled (do not use). A good quality fish oil is actually more species-specific and can be used better by our cats and dogs, but flaxseed oil is the next best thing.

Finding good quality fish oil may be a very difficult thing. Studies are showing that appreciable levels of organochlorines are showing up in almost all marketed fish oils. These killer chemicals are stored up in the fat of any animal that consumes it, and since water is the dumping ground for industrial waste, much of it ends up in the bellies of fishes. Eating contaminated fish in a high amount can be correlated with higher risks of cancer, among other things. Your best bet for fish oil is to call up the producer of the oil and ask for data on organochloride testing. I personally rotate between flaxseed oil and fish oil so that hopefully all my bases are covered without an overdose of anything toxic. I can't find really good fish oil, but I can find good flaxseed oil.

Udo Erasmus, author of the book "Fats that heal, Fats that kill" has some interesting things to say on the subject of oils.

The essential fatty acids, linoleic and linolenic acids, are necessary for the normal functioning of all cells, tissues, and organs. The richest source of alpha-linoleic acid is flaxseed.

Without EFA's, humans and animals alike would deteriorate until we die if we don't get any, degenerate if we get too little, must get at least minimum amounts to remain functional and must obtain optimal amounts from diet to remain healthy, as the body is unable to make the acids.

However, EFA's are sensitive to destruction - particularly by light, air and high temperatures (think refining, hydrogenating and frying). Oils are best unrefined because the unrefined oils contain some 'minor' ingredients (minor in proportion, major in health impact), such as phytosterols, lecithin, Vit E, carotene and hundreds of other phytochemicals. Refining destroys or leaves out these ingredients. The seeds used need to be organically grown as well to assure they are pesticide free.

Some kibble companies boast of containing EFA's. That sounds good but there are problems with that, including the fact that only one EFA is considered essential. If a kibble only contains one EFA, the balance is upset....too much of one can cause a deficiency in the other.

Udo Erasmus has done a lot of research on nutrition and oils and even has a line of products available.

A note on Beta-carotene and cats: cats can't convert the Vit A found in plants to the active Vit A (retinol) that they need to use for eyesight, skin, coordination, etc. It is necessary to supply them with an animal-based source. Good source of this (as well as taurine, another necessary supplement) are cod liver oil, eggs, meat, heart muscle and seafood. And indeed, it is hard for dogs and even humans to convert a lot of plant-based beta-carotene to retinol, so meat, etc. is important for dogs and us too. Many things can hinder the conversion from the plant-based beta-carotene to retinol, so it is best to always provide the animal tissues for good Vit A.

So this means supplementing with cod liver oil, as well as flaxseed oil and/or fish oil. I do all 3, but not all at once and not all the time.

Of course, many of the nutritional requirements for healthy cats and dogs are met by a raw and natural diet. Commercial diets can be lacking in many things, not just essential fatty acids. If you would like information on how to get started feeding a natural diet, please let me know.

I hope this gives you some idea of the why and what of supplementing with oils for ourselves and our animal companions. If you have further questions, please email me:)