What are Essential Fats?

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.

“Essential Fats” (EFs)

= EFA precursors + EFA derivatives

= linolenic (w3) + linoleic (w6) + (w3 derivatives) + (w6 derivatives).

PUFAs =  PUFA w3 + PUFA w6 + some w9, mostly with EFA deficiency

Fats in Health and Disease

The following factors influence the effects of fats and oils upon your health: the total and proportionate amounts that you eat of saturated, monounsaturated and essential fats, trans fatty acids and other isomers, the amounts of antioxidants in your diet, your exercise level, your metabolism, the state of your health, and your body’s fatty acid composition. In general, small amounts of saturated fatty acids from butter or tropical oils are harmless, particularly if you have adequate levels of essential fats. TFAs are never harmless, but small amounts cause insignificant changes in health status. Isomers, which are other types of fatty acids produced by food processing, may be even more dangerous than TFAs because the body may not be able to eliminate them. We know very little about where the isomers and TFAs accumulate in the body, if they do. Very small amounts of these unusual fatty acids could have an effect out of proportion to their size if they affect some organs, like the heart, more than other organs. It is very important to have the right quantity and balance of EFs in your body. If you eat foods low in EFs, most of the fat in your body will be solid, your arteries will become hard, and you will develop hypertension. Eating foods high in EFs maintains soft arteries and prevents clots. EFs are used for energy, to make cell membranes, and to modulate the balance of eicosanoids (hormones which regulate many body functions). Eicosanoid balance is critical to life (for clot formation, immune defenses, inflammation, etc.). Nutrients (vitamins and minerals) protect EFs from oxidation.

How much EFs do we need?

Dr. Siguel suggests consuming about 1/3 gram EFs per kg of ideal body weight [20-30 grams per day for the average man that weighs 150 lbs; and 15-25 grams for the average woman that weighs 120 lbs]. The proportion of w3:w6 should be between 1:1 and 1:10. Because EFs accumulate in the body, one may eat more some days and less other days. There is huge variability in individual needs. The need for EFs increases with increased cell turnover (i.e. burns, pregnancy, gastrointestinal disease, inflammation, growth). Growing children and pregnant women need proportionately more EFs, particularly w3s, than average adults. To reduce your chances of becoming deficient in EFs, you should eat more natural foods in their unprocessed state. These foods are high in cell membranes, which contain plenty of EFs and the appropriate antioxidants. Green vegetables, many seeds and oils such as soybean oil, flax, and wheat germ are often high in EFs. Fish, poultry, and egg yolks contain mixtures of EFs. Lean meats and eggs from animals fed EF-rich feeds are high in w3s and w6s. EFs can be added to spreads, desserts, baked products, salad dressings + many other foods. In general, the diet that works best for prevention or treatment of CAD may also work to prevent other diseases, including cancer. A low-fat diet can be healthy, but only when eating foods that are intrinsically low in fat and high in EFs.