When you think of dietary fats, what generally comes to mind is that you must limit or avoid consuming them. However, fat is a necessary component of the human diet. There are two essential fatty acids -- linoleic acid and alpha-linolenic acid. They are deemed essential because the body cannot make them and must obtain them from the food you eat.
Identification
A polyunsaturated fatty acid is made up of a long chain of carbon atoms, in which there are two or more double bonds between the carbon atoms, notes Udo Erasmus, Ph.D., in his bestselling book "Fats that Heal, Fats that Kill." "Poly" means more than one, and "unsaturated" means that instead of each carbon atom in the chain being saturated with hydrogen atoms, some of the atoms have formed double bonds with one another.
Linoleic Acid
Linoleic acid is an essential polyunsaturated fatty acid that has two double bonds in its hydrocarbon chain. The first of the double bonds begins on the sixth carbon atom in the chain, and that is why linoleic acid is considered an omega-6 fatty acid. It is abundant in safflower, sunflower, corn, sesame and other oils. A dietary deficiency in linoleic acid can result in growth retardation, heart problems, miscarriage, sterility in males, liver degeneration, hair loss, eczema-like skin eruptions and increased susceptibility to infection, reports Erasmus. Because linoleic acid is essential, he writes, if it is absent from the diet for a prolonged period of time it is fatal.
Alpha-Linolenic Acid
Alpha-linolenic acid is an essential polyunsaturated fatty acid that has three double bonds in its hydrocarbon chain. The first of the double bonds begins on the third carbon atom in the chain, and thus, alpha-lenolenic acid is considered an omega-3 fatty acid. It is abundant in flaxseeds, flaxseed oil, pumpkin seeds, walnuts and walnut oil. A diet deficient in alpha-linoleic acid can result in symptoms that include growth retardation, weakness, vision impairment, high triglycerides, high blood pressure, tissue inflammation, edema and dry skin, notes Erasmus in his book.
Caring for Essential Fatty Acid Rich Oils
Oils containing both alpha-linolenic acid and linoleic acid are temperamental, and are degraded by light, air and heat. Light produces free radicals in oils, resulting in rancid oil; light can also break these essential fatty acids into other compounds. Oxygen breaks down these oils and results in rancid oil. Heat destroys essential fatty acids by destroying the shape, and therefore disrupts the shape-dependent function of these essential fatty acids in the body, notes Erasmus. Essential fatty acid rich oils should be pressed and packaged in the dark in the absence of oxygen and with minimal heat, and put in opaque containers. They should be stored in the fridge in air-tight opaque containers and consumed raw.
References
- University of Maryland Medical Center: Alpha-linolenic acid
- "Fats that Heal, Fats that Kill"; Udo Erasmus, Ph.D.; 2007
Member Comments