Fats (triacylglycerols) ... Some basic terminology ... fat or fatty acid ... In the human most of the important fatty acids are between 14 and 24 carbon atoms in length with the most common being 16 or 18 carbon atoms. There is a carboxy.. (acid) group at one end (COOH) and a methyl group at the other end (CH3). Carbon number one is the carbon atom in the carboxy.. group and the omega(w) carbon is the carbon atom in the methyl(CH3) group at the other end. (For purposes of this discussion we will use the w symbol for the omega symbol). saturated fat ... A carbon atom can have four atoms attached(bonded) to it. Methane gas for example is CH4. There is one carbon atom with four attached hydrogen (H) atoms. When a fatty acid is termed "saturated" this means that all the bonds between the carbon atoms are "single" bonds. All the four available spots for bonds are either taken up by an adjacent carbon atom or a hydrogen (H) atom. For example the omega end of linolenate would look like this ... CH3-CH2-CH=CH-CH2...rest of the molecule There is a single bond between the omega carbon (first from the left) and the next carbon. The second carbon atom has two hydrogen atoms and two carbon atoms bonded to it. But, what about the third carbon from the left? Unsaturated fats ... If we look at the above example the third and the fourth carbon atoms have a "double" bond between them and only one hydrogen atom each. This is an example of an unsaturated bonding, ie not as many hydrogen atoms are bonded to the carbon atom as there could be. If we make the rest of this molecule linolenate and name this according to the location of the double bond what would we call this fatty acid? Polyunsaturated fatty acids ... These are fatty acids that have more than one "double" bond. Lineolate is a good example of one having double bonds at the 9th and 12th carbon atoms (from the acid end) or the 9th, 12th and 15th carbon atoms. Essential fatty acids ... "Mammals lack the enzymes to introduce double bonds at carbon atoms beyond C-9 in the fatty acid chain." Stryer Biochemistry 4th Edition p623 This can be a source of confusion since the above statement is counting from the acid end and the omega acids are counting from the omega end. The two main "essential" fatty acids are: linolenate (w-3)also known as alpha linolenic acid(LNA) linoleate (w-6)also known as linoleic acid (LA) The w-3 tells you that the first double bond will be at the third carbon atom from the w- end. The w-6 tells you that the first double bond will be at the sixth carbon atom from the w- end. These acids are termed "essential" because human (mammalian) biochemistry cannot synthesize them. Insulin and Glucagon revisited ... Just an aside here, but it is worth mentioning again in this discussion of fat metabolism. In starvation the level of free fatty acids rises because of the hormones glucagon and epinephrine. Glucagon "mobilizes / utilizes" fat and stimulates the breakdown of fat in the fat cells. Insulin by contrast however, inhibits the breakdown of fat and actually promotes the storage of fat / energy. The good fats ... Both of the above fats are "good" fats and necessary for human biochemistry to proceed normally. The omega-6 linoleic acid can be found in more foods than the omega-3 linolenic acid. People are typically deficient in the omega-3 linolenic acid. The good fatty acids "compete" with the bad fatty acids (saturated animal fat, trans-fats etc) and diets that are too heavy in the bad fats make it difficult for the good fats to do their required biochemistry. Also, it is felt that there should be a balance maintained between the omega-3 and the omega-6 fatty acids. The ideal intake ratio of omega-6 to omega-3 should be close to 1:1. However, most Americans get a ratio closer to 25:1 (too much omega-6 relative to omega-3). What do EFA's do ... EFA's are integral to cell wall maintainance, the immune system, nervous system, cardiovascular and reproductive systems. They are precursors to the fatty acids necessary for prostaglandin formation, which control vital functions heart rate, blood pressure, immune function, fertility and blood clotting. Symptoms of omega3/6 imbalance and or deficiency ... Omega 6/3 imbalance is associated with many symptoms including depression, insulin resistance, diabetes, cancer, heart disease, aging, obesity and schizophrenia. Food sources ... Flaxseed oil is probably the easiest and best way to cover your EFA requirement. One tablespoon of flaxseed oil per day will give you the necessary omega-3 linolenic acid you need. This is also an excellent source of omega-6 linoleic acid. Other sources of omega-3 linolenic acid are: walnuts, pumpkin seeds, Brazil nuts, sesame seeds, avocados, some dark leafy green vegetables (kale, spinach, purslane, mustard greens, collards, etc.), canola oil (cold-pressed and unrefined), soybean oil, wheat germ oil, salmon, mackerel, sardines, anchovies, albacore tuna Sources of linoleic acids (omega-6) are Flaxseed oil, flaxseeds, flaxseed meal, grapeseed oil, pumpkin seeds, pine nuts, pistachio nuts, sunflower seeds (raw), olive oil, olives, borage oil, evening primrose oil, black currant seed oil, chestnut oil, chicken, corn, safflower, sunflower, soybean, cottonseed oils (Thank PamRotilla.com for these sources) Refined oils ... It must be stressed here that any oil that has been refined will have no EFA activity. The essential fatty acids are very unstable and will not tolerate either light or increased temperature. Your flaxseed (or any) oil should not be refined. While refining may produce a pretty, clear oil, it destroys most of the good things found in oils including vitamin E. Make sure your source for EFA's is kept in the refrigerator section of your grocery, in an opaque bottle. Thank you for your time. Copyright John Mericle M.D. All Rights Reserved |
