Now the good news is that there are other oils available: healthful, whole, unrefined, recently cold-pressed, fresh, properly stored, good-quality oils. These (together with refined and rancid ones, let's not be naive) you can find in organic stores - and almost only there.
Unrefined vs. refined oils
"[Unrefined oils] are mechanically (expeller-) pressed only" (as opposed to using chemicals, bva) "under relatively low heats of approximately 160°F / 71°C; in some cases they are filtered once to remove the residues. (...) Unrefined oils retain their vitamin E content, which tends to preserve the oil from rancidity (...). Like other unrefined foods, unrefined oils contain numerous nutrients not found in the refined variety (...). Regardless of the oil used, it should be unrefined. (...) Of all the information printed on a bottle of oil about its processing, "unrefined" is the most important, because no refined oil of any type should be ingested. Do not be tricked into thinking other processes mean that the oil is unrefined. For example, only a small percentage of all "expeller-pressed" oils are unrefined."(2)
"[R]efined oils have been depleted of certain vital nutrients, including lecithin, chlorophyll, vitamin E, beta-carotene, calcium, magnesium, iron, copper and phosphorus.
The temperatures reached in the refining process often exceed 450°F (232°C) - far above the temperature at which the unsaturated fatty acids transform into a synthetic fat called "trans-fatty acids". (Trans-fatty acid formation begins at 320°F / 160°C). (...) [T]rans-fatty acids not only increase the likelihood of a variety of metabolic disorders including arthritis and cancer, but also contribute to heart disease.
Once refined, these and all other oils typically form more trans-fatty acids during frying or baking when temperatures exceed 320°F / 160°C. An even more serious situation arises when oil is repeatedly re-used for deep frying, as is the case in many restaurants. After two full days, other greatly toxic compounds form when the fatty acids in the oil start to break down and combine with one another into synthetic polymers (large chains of molecules - the synthetic variety are commonly found in (...) car waxes).
The overwhelming majority of vegetable oils are highly refined. In fact, the bland taste and unclouded look of these oils is what people have come to expect."(3)
Avoid hydrogenated oils
"Margarine and shortening (...) contain hydrogenated (...) vegetable oils. Hydrogenation is an extremely harmful process that creates an immune-damaging synthetic fat (...) that - to the dismay of confirmed margarine users - has also been found to actually elevate blood cholesterol (instead of lowering it, as advertised, bva). (...) Most margarines (...) sold as "natural" are also hydrogenated and just as harmful as any other margarine. However, margarines made by other processes are now becoming available. (...) These margarines are identified by checking the ingredients for the absence of "hydrogenated" or "partially hydrogenated" oils (...)." (4)
General oil guidelines (excerpt):
- "When purchasing an oil, first choose among those labeled unrefined. All other oils will almost certainly be refined, although they are never labeled as such. Unrefined oils are currently carried almost exclusively in stores that specialize in health food products and unrefined foods.
- "In general, avoid the common polyunsaturated oils such as corn, sunflower, safflower, soy, linseed/flax, and walnut. Avoid even the unrefined versions of these oils unless they are recently pressed and stored without exposure to heat, light or air. (...) All such fresh, cold-pressed polyunsaturated oils may be used as medicinal oils or as essential-fatty-acid sources in food preparation, but they must not be used as cooking oils. The shelf life of these oils is about three months, if they are kept cool (refrigerated!, bva). (...) Soy oil has the disadvantage of being difficult to digest and is regarded as slightly toxic by traditional Chinese medicine.
- "For general use in cooking, (...) we recommend most highly (...) unrefined olive and sesame [oil]. (...)
- "The popular [canola oil] is virtually always refined or at least partially refined and thus lacking in nutrients essential for proper metabolism. Refinement additionally harms its omega-3 content. In general, avoid [canola] oil. (...)
- "When high temperatures are involved in cooking, especially above 320°F / 160°C, one of the most stable oils is clarified butter. Those who wish to avoid animal products may try palm, palm kernel, or coconut oils. (...) (For those with high blood cholesterol, in moderation or to avoid, bva)
- "[S]afflower oil has few desirable properties. Not only does safflower oil [become easily rancid], it provokes ill health according to both Ayurvedic medicine of India and our own experience, regardless of the quality or freshness of the oil. (...)(5)
- Also organic peanut oil is quoted by Pitchford as being fit for cooking, even at high temperatures.(6)
- for cooking above 160°C: clarified butter, palm, palm kernel and coconut oil (also peanut oil resists high temperatures)
- for cooking under 160°C: olive oil and sesame oil
- the other oils are for medicinal use only (linseed/flax, walnut, sunflower etcetera), certainly not for cooking, and only if they have been recently cold-pressed and stored in the absence of air, light and heat (constantly refrigerated and kept in dark containers!) - from the time of extraction without interruption up until the time of consumption! Several of them are to be avoided altogether (canola, safflower and soy oil for instance).
Storage of oils
First of all, certain oils are very delicate and should always be refrigerated, stored in dark, non-reactive containers (preferably dark glass), and not be kept longer than 3 months after extraction. These oils include linseed/flax oil and others - see above point 2.
What follows applies to all other oils.
"Proper storage of oils keeps them from rancidity. (...) When oil starts to taste rank and bitter, it should of course no longer be used.
Both heat and air speed the deterioration of oil. Keep oil in a closed container at a temperature of at most 65°F / 18°C, preferably lower - the ideal is 38-45°F, or normal refrigerator temperature. [If the fact that some of them become solid at low temperatures presents a problem], simply refrigerate the oil in a wide-mouth jar, then spoon it out and melt it in the warmed pan. Remember that all saturated oils/fats such as clarified butter (and coconut and palm oil, bva) contain at least some polyunsaturated portion, and therefore these too should be kept cool.
The effect of light on oil, which is far worse than air, rapidly alters the unsaturated fatty acids into free-radical chains. Store oil in the dark, or in opaque containers.
Oil readily combines with most types of plastic to form toxic plasticides."(7) So you should never buy oil (or anything containing or prepared in oil or fat) in a plastic bottle or container!
To finish, an interesting method of using oil in pans, skillets, and so on: the water-oil-sauté:
- "cover bottom of skillet with water. Heat.
- "add a little oil on top of water.
- "sauté by the usual method, being careful not to overheat oil.
- "has the flavor of stir-fry without overheating the oil.(8)
(1) Paul Pitchford, "Healing with Whole Foods: Asian Traditions and Modern Nutrition", North Atlantic Books; 3rd edition (2002), p.176
(2) id., p.179
(3) id., 180-181
(4) id., p.181-182
(5) id., pp. 185-186
(6) id., p. 187
(7) id., pp. 186-187
(8) id., p. 451
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