| The Essential Fats are a group of fatty acids that are essential
to human health. There are two types, the omega-3 (w3) and
omega-6 (w6) families. Fatty acids (the key components of fat) are classified into two major groups: those that the body can easily make, called Non-Essential Fatty Acids, and those that the body cannot make, called Essential Fatty Acids (EFAs).
Since the body cannot make EFAs, we must consume them as part of our diets. This is not true of other types of fat, because the body can easily convert carbohydrates and protein to saturated fatty acids (SFAs) and monounsaturated fatty acids (MUFAs), but not to polyunsaturated fatty acids (PUFAs).
In this way, essential fats are similar to vitamins, which we cannot manufacture in our bodies, but must get from external sources. The difference is that we need EFAs in much larger quantities than we do vitamins. We can eat a small pill every day to get all the vitamins and minerals we need. We must eat a lot of food to get all the essential fats we need.
Types of Fats
Fats are a mixture of fatty acids:
Saturated fatty acids (SFAs), such as beef fat, form solid foods at room temperature because they are straight molecules and can pack tightly together.
Monounsaturated fatty acids (MUFAs), such as olive oil, have one “kink” or bend. They form liquid foods at room temperature, but pack together as solids when refrigerated.
Polyunsaturated fatty acids (PUFAs), like flax seed oil, have 2 or more kinks. They remain liquid even when refrigerated, because the molecules cannot pack together. Two PUFAs (w3 and w6) are EFAs. Others (w7 and w9) are not EFAs. Dr. Siguel coined the term “essential fats” to refer to the w3 and w6 PUFAs.
The human body can make MUFAs & SFAs, but not w3 or w6. It is the unique, kinked shape of PUFAs which allows them to perform their useful functions in our bodies.
PUFAs can assume many different spatial configurations. Each of these different spatial shapes is known as an “isomer.” Isomers have the same number of atoms, but they are arranged in a different way and thus form different physical structures. The highly unsaturated fatty acids can form more isomers than the less unsaturated fatty acids. Heat, light, and many physical processes can change the shape of a PUFA from one isomer to another isomer. As far as we know, only one form, known as the “cis” form, has the necessary biological effects. The cis form is usually found in natural foods.
Hydrogenation is a process that changes the location of the hydrogen carbons and causes the molecule to straighten its bend. The new form of the fatty acid is known as trans fatty acids (TFAs). TFAs are straighter than their original unsaturated fatty acid and therefore act more like saturated fat than their original unsaturated fatty acid.
Essential Fats, EFAs, PUFAs
Essential Fats (EFs), a term coined by Dr. Siguel, consist of two families, omega-3s (w3s) and omega-6s (w6s). The letter “omega”, abbreviated “w”, refers to the “kinks” or “bends” in EF chemical structure.
Each family is divided into parents (precursors) and daughters (derivatives). Using information gained by distinguishing precursors from their metabolic derivatives, nutritionists can determine fatty acid needs. Siguel distinguished these groups because there is interconversion among the derivatives, and the key limiting delta-6-desaturase enzyme separates them from their precursors.
The two EFAs (the “parents”) are linolenic acid and linoleic acid. From the EFAs, most humans can make all the EFA derivatives they need. However, some people (diabetics, alcoholics, the elderly, infants not breast fed, and people with severe fat malabsorption, AIDS, cardiovascular disease, or nutritional deficiencies) cannot make enough EFA derivatives, and must eat them.
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