Understanding Oils and Fats
Let’s start with oils- they are fats. It’s just that some are more solid than others. So, really we’ll be talking about fats in general here. It’s the amount of hydrogen saturation of the fatty acids in the oils that makes them different. So, what are the differences in these oils and fats and which ones are better for us? Let’s explore this.
Basically, the most saturated ones we call "saturated fats". In general, these stay solid at normal room temperatures and melt when heated. They are very shelf stable, meaning they don’t easily spoil. Examples are lard and tallow and also the tropical oils like palm and coconut. The least hydrogenated fats, we call "polyunsaturated fats". These are the most fragile and are more likely to spoil or become rancid. Examples are vegetable oils like corn and soybean oil. In between these, we have monosaturated fats like olive oil, ghee and butter, which are very soft or even liquid at normal room temperature and semi-solid when cold. According to Dr. Mary Enig, PhD, who is a board certified nutritionist, researcher, author and expert in the field of lipids (fats and oils), "none of the naturally occurring fats and oils is made up of only all saturated or all unsaturated fatty acids; rather they are a mixtures of different amounts of various fatty acids." (From Dr. Enig’s book, "Know Your Fats: The Complete Primer for Understanding the Nutrition of Fats, Oils, and Cholesterol", page 17.)
Fats are the most nutrient dense of all foods. They are a source of energy for our bodies and fats help transport the important fat soluble vitamins, A, D, E, and K, which are stored in the fats we eat. People throughout the world have traditionally used fats like butter, ghee, lard, tallow, chicken fat, olive oil, coconut oil and palm oil. These natural fats were all that was available before the 20th century. It is interesting to note that cancer and heart disease were rare back then. According to Dr. Enig, the increased use of industrially processed vegetable oils and man made fats has significantly increased health problems in our society. She says that we now have "problems of widespread obesity, runaway diabetes in adults, ever-increasing cancer incidence rates, immune dysfunction, a continuing increase in heart disease rates, and growth and development problems in our young".(1) Let’s explore what the problems are with these polyunsaturated vegetable oils next.
Problems with polyunsaturated vegetable oils
The two best known fatty acid groups that make up the polyunsaturated vegetable oils are Omega- 6 and Omega- 3. The main source for Omega-6 fatty acids is vegetable oils. The main source for Omega-3 fatty acids is from fish and shellfish. Examples of vegetable oils that are very high in the Omega- 6 fatty acid known as Linoleic acid (LA) are corn, cottonseed, soybean and canola oils. LA is an essential fatty acid, meaning our bodies can not manufacture it and it is essential for life. However, according to a study found in the American Journal of Clinical Nutrition (2), there is a growing body of evidence that suggests we need to increase our dietary intake of Omega-3 fats and decrease our intake of Omega- 6 fatty acids to decrease cardiovascular disease and mental illness.
Additionally, as previously mentioned, the polyunsaturated vegetable oils are the least stable of all the fats. But, many people still cook with these highly processed vegetable oils which can have an adverse effect on their health. Simply put, polyunsaturated oils (like corn and soybean oil) are not healthy oils to cook with. These oils have either been highly processed or cold-pressed. Some of the cold-pressed ones are all right to use in things like salad dressings. However, oils which have been highly processed have undergone treatments that are damaging to them. These harmful treatments include such things as undergoing high heat, bleaching and being treated with chemical solvents (like hexane, which is a dry-cleaning fluid). (3) Unfortunately, as we’ll discuss, this processing does not stabilize these oils and it also destroys most of the vitamins & other nutrients.
Vegetable oils that are normally liquid at room temperature are not very shelf stable; even if cold pressed, they are very susceptible to rancidity. This is why you find some packaged in dark glass with instructions to refrigerate after opening and to avoid over heating the oil. The problem is these fats are easily oxidized which begins to degrade it, adversely effecting flavor, causing a bad odor and breaking down the nutrients. Rancid oils are thought to increase cardiovascular diseases and cancer, which will be discussed more thoroughly next.
One of the problems with cooking with these polyunsaturated vegetable oils is that the unsaturated fatty acids are susceptible to breaking down and forming "free radicals" which can be very toxic to cells. Here’s what happens: when the polyunsaturated fats are reused again and again (for example, as they are in fast foods eateries that repeatedly fry foods in the same oil numerous times), they begin to break down, making them even more dangerous. The more they start to break down, the more oxidative damage there is, forming more free radicals.
Here’s a quick explanation about these scavengers or "radicals" (also known as "free radicals"). Radicals are atoms or molecules which have at least one missing electron, where there should be a pair. This is a normal occurrence in our bodies, but when you get an excess of these, you can get problems. These "out of balance" atoms or molecules are constantly trying to regain their chemical structure and balance. They will grab up the closest available free electron from some other nearby atom or molecule, which leaves in missing an electron. Now it has just become another free radical- it’s a chain-reaction process. In this way, free radicals can be causes of disease and pathology. Dr. Richard A. Bowen, DVM, PhD, explains that, "One of the best known toxic effects of oxygen radicals is damage to cellular membranes". He explains that this is started by a process known as lipid peroxidation. He says this can lead to many problems, including "increased membrane rigidity", "altered permeability" of the membrane, and that radicals can "directly attack membrane proteins"- all of which effects our cell’s membrane function. (4)
We talked about one of the Omega-6 fatty acids earlier, linoleic acid (LA), which is found in high levels in polyunsaturated vegetable oils. Another health risk with LA, according to Dr. Kent L. Erickson, shows that it actually promotes cancer in many different animal studies. "Several different dietary fats and oils have been compared with respect to carcinogen-induced tumorigenesis in animals, and the results clearly show that polyunsaturated fats caused a significant increase in primary breast and colon tumors whereas saturated fats had little effect." (5)
What about Trans fats?
To make polyunsaturated oils solid, they undergo a process known as hydrogenation. These hydrogenated and partially hydrogenated oils are known as "trans- fats". These man- made, chemically altered, liquid fats have hydrogen added to them to make them more solid and stable. This does improve their stability, increases their shelf life and makes them spreadable. (Note- there is a healthy and naturally occurring form of trans fats, conjugated linoleic acid, which will be discussed later.)
For the most part, all solid (at normal room temperatures) "fake" fats, like margarine, shortenings made from vegetable oils, and MANY other processed food products are loaded with trans- fats. Here are some of the problems with these trans fats:
In summary, saturated and monosaturated animal fats, as well as the saturated tropical oils like palm and coconut oil, were the fats traditionally used by people before the advent of man-made, polyunsaturated vegetable oils and trans fats. These traditionally used fats are more stable and not as likely to become rancid as compared to the polyunsaturated fats. Saturated fats have been shown to actually decrease Lp(a) (which was mentioned earlier as a marker for heart disease). (11) When they come from animals that have been exclusively grass-fed, they contain the important fat soluble vitamins A, D, E, and K. Vitamins that are critically important to maintaining good health.
Thus, important considerations about animal fats are if they are primarily grain fed or if they come from animals that are allowed to graze exclusively on pasture. The CLA content, as mentioned previously, is much higher when animals are pastured. They also have higher levels of vitamin A ("Know You Fats, by Dr. Mary Enig, Ph.D, page 134). And according to researcher Chris Masterjohn, this is true for Vitamin K2, which "is important for the utilization of minerals, protects against tooth decay, supports growth and development, is involved in normal reproduction, protects against calcification of the arteries leading to heart disease, and is a major component of the brain". (12)
So, to clarify this important point, any animal fats will have greater benefits if they come from grass fed sources. For example, milk, butter and butter oil which comes from grass fed animals (like cows, sheep and goats) offers more protective health benefits than milk, butter and butter oil from animals that are grain fed. Indeed, one of the oldest dietary fats made and kept by humans is butter. This traditionally came from the milk of various ruminant animals, including cows, sheep and goats. From butter, butter oil is derived. (This is also known as ghee or clarified butter, especially in India.) If very pure, ghee is 100% fat, having the other components of the butter removed from it and making it more shelf stable than butter (it can be stored for much longer and giving it a higher smoke point for high heat cooking). Ghee’s ability to withstand higher cooking temperatures makes it a favorite with cooks. In fact, if very pure, its smoke point is 485°F- higher than butter, palm oil, coconut oil and lard.
Which ever fats you choose to eat and cook with, you should now have a greater understanding of which ones are more shelf stable, which are better for higher heat cooking, which ones have the potential to cause health problems, and which ones convey greater nutrients for our health.
(1) "Fats and Oils and Their Impact on Health", by Mary G. Enig, PhD (http://www.westonaprice.org/Fats-and-Oils-and-Their-Impact-on-Health.html)
(2) American Journal of Clinical Nutrition, Vo. 83, No. 6, S1483-1493S, June 2006
(3) Vegetable Oil Processing- Food And Agricultural Industry (http://www.epa.gov/ttnchie1/ap42/ch09/final/c9s11-1.pdf)
(4) "Free Radicals and Reactive Oxygen" –R. A. Bowen DVM PhD/ Colorado State University (http://www.vivo.colostate.edu/hbooks/pathphys/misc_topics/radicals.html)
(5) Am J Clin Nutr 1998;68:5–7, by Dr. Kent L. Erickson, PhD
(6) . Trans fat is double trouble for your heart health- The Mayo Clinic (http://www.mayoclinic.com/health/trans-fat/CL00032/NSECTIONGROUP=2)
(7) Trans Fatty Acids and Coronary Heart Disease - The New England Journal of Medicine, June 24, 1999 Vol. 340, No. 25
(8) Discussion by Dr. Mary Enig on Weston A. Price Foundation web site, citing research by Barnard, Dennis, University of Maryland and USDA. (http://www.westonaprice.org/Do-Saturated-Fats-and-Trans-Fats-Cause-Type-2-Diabetes.html)
(9) Influence of pasture and concentrates in the diet of grazing dairy cows on the fatty acid composition of milk. – abstract- J Dairy Res. 2003 Aug;70(3):267-76.
(10) CLA General Information- web page. (http://www.cook.wisc.edu/Generalinfo/cla.html)
(11) "...saturated fatty acids consistently decrease Lp(a) concentrations" - Arteriosclerosis, Thrombosis, and Vascular Biology. 1997;17:1657-1661
Disclaimer: This article provides only general information about oils and fats and does not intend to endorse products of Pure Indian Foods.
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