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Essential Fatty Acids -The Good Fats
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 methylgroup 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 symbolfor 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 carbonatom with four attached hydrogen (H) atoms. When a fatty acid is termed "saturated" this means that all the bondsbetween the carbon atoms are "single" bonds. All the fouravailable spots for bonds are either taken up by an adjacent carbon atom or a hydrogen (H) atom. For examplethe 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 fromthe 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 fourthcarbon atoms have a "double" bond between them and onlyone hydrogen atom each. This is an example of an unsaturated bonding, ie not as many hydrogen atoms arebonded to the carbon atom as there could be. If we makethe rest of this molecule linolenate and name this according to the location of the double bond what wouldwe call this fatty acid?
Polyunsaturated fatty acids ... These are fatty acids thathave more than one "double" bond. Lineolate is a good example of one having double bonds at the 9th and 12thcarbon atoms (from the acid end) or the 9th, 12th and 15th carbon atoms.
Essential fatty acids ... "Mammals lack the enzymes tointroduce double bonds at carbon atoms beyond C-9 in thefatty acid chain."
Stryer Biochemistry 4th Edition p623
This can be a source of confusion since the above statementis 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 atthe third carbon atom from the w- end. The w-6 tells youthat 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 thisdiscussion of fat metabolism. In starvation the level of free fatty acids rises because of the hormones glucagonand epinephrine. Glucagon "mobilizes / utilizes" fat andstimulates the breakdown of fat in the fat cells. Insulinby 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 linoleicacid can be found in more foods than the omega-3 linolenicacid. People are typically deficient in the omega-3 linolenicacid. 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 fatsto do their required biochemistry. Also, it is felt that thereshould be a balance maintained between the omega-3 and the omega-6 fatty acids. The ideal intake ratio of omega-6 toomega-3 should be close to 1:1. However, most Americans geta 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 immunesystem, nervous system, cardiovascular and reproductivesystems. They are precursors to the fatty acids necessaryfor prostaglandin formation, which control vital functionsheart rate, blood pressure, immune function, fertility andblood 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 coveryour EFA requirement. One tablespoon of flaxseed oil perday will give you the necessary omega-3 linolenic acid you need. This is also an excellent source of omega-6linoleic acid. Other sources of omega-3 linolenic acidare:
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 refinedwill have no EFA activity. The essential fatty acidsare very unstable and will not tolerate either light orincreased temperature. Your flaxseed (or any) oil should notbe refined. While refining may produce a pretty, clear oil,it destroys most of the good things found in oils includingvitamin E. Make sure your source for EFA's is kept inthe refrigerator section of your grocery, in an opaque bottle.
Thank you for your time.
Copyright © John Mericle M.D. All Rights Reserved
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