Most edible vegetable oils also have industrial applications, including lubrication, soaps and detergents, etc ... The casein from milk, which is what gives cheese it's wonderful texture .. is used for paints and adhesives. Flax oil, also called linseed oil, has been used for centuries for its drying and sealing properties in paints. Tallow from animal fat is used in soap. Hemp and olive oil are used in cosmetics ... etc, etc.

Rapeseed is a member of the brassica family ... cabbage, broccoli, radish, etc .. and mustard as well. ALL of these plants produce a substance which can be toxic to insects and some animal species, including humans, if ingested in large amounts. It's this property that appeals to gardeners, since these plants are therefore relatively pest-free... .. Note - this toxic substance .. glucosinolate ... is found in the stem and roots of the plants.

Natural rapeseed oil, and mustard oil have been used for centuries in Indian and Asian cooking, with no ill effect. In the late 70's, it was discovered that these oils contained a high level of Erucic acid, which proved harmful to rats. So, rapeseed was bred and cross-pollenated to be low in erucic acid. This "miracle" seed was coined Canola, for "Canadian Oil". By any name, it's still Low Erucic Acid Rapeseed, or LEAR. Since then scientists have discovered that erucic acid is toxic to rats specifically, and is NOT toxic to humans as once thought. Udo Erasmus devotes a chapter to this in "Fats That Heal, Fats That Kill", pp 116-118.

LEAR, or canola oil ... has useful nutritional benefits. Karen brings up an excellent point though. Processed and refined oils have pretty much anything that's good about them removed in the refining process. Canola, soy, sunflower or safflower oils ... that are sold on most grocery shelves .. have been solvent-extracted, heat-processed, bleached and deodorized to make them nice and clear, "light tasting" (ie, tasteless), and to give a long shelf life. The essential fatty acids have been destroyed in the process. Extra-virgin olive oil is pretty much the only cold-pressed unrefined oil that is commonly sold in grocery stores. Note that plain olive oil, golden in colour, is highly refined and processed.

Canola or rapeseed, as well as just about everything we eat, especially oil-seeds .. has been genetically modified ... to either change something about the oil yield itself, or to make the plant resistant to the elements, for better or for worse. It is possible to find organically grown, non-GMO, cold-pressed and unrefined canola/rapeseed oil, and other oils ... in health food stores and some large supermarkets that carry natural foods. Unrfined, unprocessed oil will taste like the seed, nut, fruit it came from.

There is another fat that is natural, healthy and minimally processed. It's called BUTTER. It's stable when heated, doesn't turn to harmful trans-fat, and has a good fatty acid profile. And it tastes good

On the subject of poyunsaturate vs. monounsaturate ... these fats both have health benefits. Polyunsaturated fatty acids can lower LDL "bad" cholesterol levels. Monounsaturates keep arteries from clogging, lower LDL, and raise HDL "good" cholesterol. Polys -- if consumed exclusively, and in excess -- have been linked to colon cancer. Eating natural fats and oils from a variety of sources will keep this in balance.

Sources of mononunsaturates - olives, canola, avocadoes, almonds, peanuts, macadamias and their oils

natural polyunsaturates - corn, soy, hemp, flax, sunflower, safflower, borage, fish oil, evening primrose, egg yolks

man-made polyunsaturates (ie, TRANS fats) - margarine, hydrogenated coconut and palm oil, vegetable shortening

hope this has been helpful

Doreen