Oils such as olive, canola, vegetable, etc. are not often discussed when it comes to the subject of health and healthy foods. What oil you choose to cook with and add to your foods can play a dramatic role in your health and wellness, and choosing the wrong types can negatively affect you. Not only are there different types of oils, but also the quality of these oils is a very important factor as well.

Types of oils

Oils fall under three categories:

Saturated fats
These oils are considered “heavy” and are solid even at room temperature. These oils are considered the most stable and are the best for high-heat cooking since they do not turn rancid as easily. Saturated oils can include Coconut (92% saturated), Palm Kernel (83% saturated), and Clarified Butter (ghee) (65% saturated). Saturated fats began to be demonized in the 50's, leading to the current cholesterol scare that we have today. The topic of cholesterol is another one entirely (take a look at my other posts), but I will say this: anyone who has a balanced diet does not need to worry about cholesterol problems.

Monounsaturated oils
Monounsaturated oils offer a balance between the three oils. They do not become rancid as quickly as polyunsaturated oils and do not have the potential “cholesterol problems” that can come from saturated fats. Monounsaturated oils are popular in the Mediterranean diet, and it's been noted how despite the high-fat content, there is a low incidence of heart disease. It's also important to note that monounsaturated oils such as olive oil can also help with insulin resistance (diabetes); this is what The Zone diet is based around. Monounsaturated oils can include olive oil, avocado oil, almond oil, peanut oil, and others.

Polyunsaturated oils
These oils are the most problematic; many people have thought that by switching to polyunsaturated products (including margarine and shortening) that they would be healthier since these oils are free of cholesterol and low in saturated fat. The opposite is true actually, as numerous studies have shown that those who consume polyunsaturated vegetable oils actually have a greater risk of heart attack and cancer. These oils can become rancid very easily under heat and should never be used for cooking or frying. Polyunsaturated oils can include safflower oil, walnut oil, sunflower oil, soy oil, and others. These oils should only be used sparingly

 
Oil quality

Oils go through a method of processing to extract the oils from the fruit/nut/seed and transform it into what we buy at the market as a food product. Understanding the methods used is very important because the quality of the food we buy is the most important part of the deciding factor.

Refined
Refined oils fall under two categories: solvent extracted and expeller pressed. While neither are ideal, solvent extracted oils are by far the worst. These oils make up the most common (read: cheapest to  produce, cause health problems, and save giant corporations lots of money) and should always be avoided. Solvent extracted oils are treated with high heat (thus creating rancidity) and harsh chemicals such as hexane. Such oils  are bleached and chemically treated to ensure an oil that looks pretty (colorless, tasteless) and has a long shelf life. Paul Pitchford notes in his book Healing With Whole Foods:

The taste of rancidity has been removed, but the harmful effects remain (This is a metaphor for most of our food industry)(emphasis mine). A smaller but growing percentage of refined oils are expeller – rather than chemically extracted; at least these contain no traces of chemical solvents. Nevertheless, these oils are subjected to several steps beyond extraction, involving high heat and alkaline chemical solutions          

Another problem with refined oils – both expeller pressed and solvent extracted – is that the refining process has a reduction of some vital nutrients including lecithin, chlorophyll, vitamin E, beta-carotene, calcium, magnesium, iron, copper, and phosphorus. Again and again I go back to the point that we want whole foods, not disease-causing refined foods.  To complicate matters further, the refining process heats the oils at temperatures exceeding 450°F, thus transforming the unsaturated fatty acids in the oil into trans-fatty acids, aka trans-fats or hydrogenated oils. Trans-fatty acids have been linked to a variety of metabolic disorders including arthritis and cancer, and also contributes to heart disease.

(from Healing With Whole Foods) Once refined, these and all other oils typically form more trans-fatty acids during frying or baking when temperatures exceed 320°F. 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 products such as the most durable car waxes)

Unfortunately, the overwhelming majority of vegetable oils are highly refined. With their clear, unclouded look and bland taste, it is sadly what most have come to expect from oils these days. In Healing With Whole Foods, Paul Pitchford recounts a story of a woman who had originally lived in mainland China and since moving here to the States, she was proud to say that she used these “better quality” clear oils. She had come to his clinic because since she left mainland China, she had developed stomach ulcers. She was given an herbal decoction and was instructed to stop using the refined oils and suer enough her ulcers soon healed and they did not return.

Unrefined
Unrefined oils are mechanically (expeller-) pressed, using low heat at approximately 160°F. These oils are ideal and contain the key indicators of real oils – they retain their original taste, aroma, color, and sometimes will appear cloudy as well. These oils retain their vitamin E content which helps protect them from rancidity.  Because these oils are unrefined, they contain numerous nutrients that are lost in other products that are refined.  It must be emphasized that regardless of the oil used, it should be unrefined.

Expeller and Cold-pressed
Not too long ago, the term “cold-pressed” was often a misleading label which was used as a tool (marketing aid) to confuse customers. The vegetable oil industry has known for a very, very long time that heat damages oil, but sadly, the almighty dollar has prevailed for generations now. When a oil is processed using lower temperatures, it is of a better quality. Almost all oils are heated for commercial extraction, and those formerly labeled as “cold-pressed” are not exempt from this (save for high quality olive and coconut oils). Previously, so-called “cold-pressed” oils were really expeller-pressed and extracted using chemical solvents. Expeller-pressed oils are a lower-quality and are often refined.

Paul Pitchford adds in his book that:

In the last few years, major vegetable oil distributors decided on self-regulation, dropped the misleading phrase “cold-pressed” and replaced it with “expeller-pressed” or similar terms. Far less than 1% of all oil is actually processed at temperatures considered “cold”; some companies have suggested a reference point of 100°F, or about body temperature, as the temperature below which an oil may be termed “cold pressed”. Many firms that now use the term “cold-pressed” in this more accurate way also list on the container the maximum temperature the oil reaches during processing.

Non-oil substitutes and solutions

For those looking to use a non-oil for cooking, are unable to purchase higher-quality oils, or simply want something more healthful, there are other options.

Clarified butter
Otherwise known as “ghee”, clarified butter is a butter with the milk solids removed and offers healing properties not found in other saturated fats. In Ayurveda (a traditional east-Indian medicine),  clarified butter is said to enhance the ojas, which is an essence that governs the tissues of the body and balances the hormones as well. Ayurvedic teachings suggest that an abundance of ojas ensure a strong mind and body, disease resistance, and is essential for longevity. Clarified butter actually promotes the healing of injuries and gastro-intestinal inflammations such as ulcers and colitis.

My esteemed mentor adds to this by mentioning:

The ability of clarified butter to support physical and mental renewal has been substantiated to some degree by science. Accourding to Rudolph Ballentine, M.D., clarified butter contains butyric acid, a fatty acid that has antiviral and anti-cancer properties, and which raises the level of the antiviral chemical interferon in the body.  Butyric acid also has characteristics found to be helpful in the prevention and treatment of Alzheimer's disease.

Ayurveda describes clarified butter as one of the finest cooking oils; it is said to increase “digestive fire” and thereby improves assimilation and enhances the nutritional value of foods. Clarified butter can be easily made at home (I have written about it here), and it is actually the best way to use butter for sautéing, stir frying, and similar cooking needs.

I have posted an easy to follow recipe on how to make clarified butter, which can be viewed here.

Oil Guidelines

It is important to keep oils away from heat, air, and light; these will speed their potential rancidity. Always stay away from refined oils and only buy oils that are clearly cold-pressed and unrefined. Polyunsaturated oils should never be used for heating because they will become rancid way too quick; use them for other purposes. Coconut oil is by far the best oil for cooking and it is recommended by many health experts. More information on Coconut oil itself can be found on Dr. Joseph Mercola's site, here. Olive oil and Sesame oil are two other highly recommended monounsaturated oils for regular use.  it would be easy to write even more on the subject of oils and their usage, so I must recommend Healing With Whole Foods to anyone who would like to know more about using oils as well as further guidelines.

update: A recent meta-analysis published by the American Journal of Clinical Nutrition has shown that there is no strong evidence linking saturated fats with heart disease. Much as I figured, it was nothing but a scare all along. Based upon current research, I can see nothing unhealthy about saturated fats.

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