Jump within page to Essential Fatty Acids
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We have already mentioned that essential fatty acids are nutrients we must have to stay healthy. To really understand essential fatty acids, we must get down to the molecular level. But then I'm `getting the cart before the horse.' Lets talk about a couple of non-essential fatty acids first.
Introduction: This isn't an essential fatty acid, but its a close cousin, Stearic acid. (It's
a saturated fat, a subject we'll talk a lot about later.) It is very
stable, and beef is one of the places it's found. To help you understand
the above diagram, the row of C's in the middle are carbon atoms. There are
18 of them in this fatty acid. Common fatty acids can have from 4 to 22 carbon
atoms in their chains. The H's around the outside are hydrogen atoms, and
the O and OH on the end are what is called the `Carboxyl End.' This forms
the acid group of the molecule. The O is an oxygen atom, and the OH is an
oxygen atom and a hydrogen atom. The vertical and horizontal dash marks show
the bonds. Notice on the Carboxyl end there is a double bond with the lone
oxygen atom. (It looks like an equal sign.) Stearic acid, one of the long
chain saturated fatty acids is sticky. This means the individual molecules
tend to stick together. If we eat too many saturated fatty acids, they
will eventually do a lot of harm to our cardiovascular system.
Oleic acid: The fatty acid in this diagram isn't an essential fatty acid ,either. It's called Oleic
acid and is also a fairly stable 18 carbon molecule. At least some of it
is found in almost everything we eat which contains fats or oils; plant or
animal. Notice that it is very similar to Stearic acid, except it has a double
bond in the middle, between the 9th and 10th carbon atoms. We see that it
is now missing a couple of hydrogen atoms. It's called a mono-unsaturated
acid because of its one double bond and two missing hydrogen atoms. Also
notice that it is bent. It bends because of the opposing charges of the hydrogen atoms. If you have ever played with magnets, you have recognized that the
North and South poles of two magnets pull towards each other. But when you
turn one of the magnets over and try to put the two North poles or the two
South poles together, they push apart. The same thing happens here. The hydrogen
atoms carry a negative charge and repel each other. Because Oleic acid is
missing two hydrogen atoms on one side, the upper two hydrogen atoms push
against each other and bend the fatty acid in the middle. This creates amazingly
important implications. For example, Stearic acid has a melting point of
158 degrees F (70C). Oleic acid melts at 55 degrees F (13C). This is because
Oleic acid molecules are more difficult to align and aggregate less easily.
Linoleic Acid: With the above background information, we move to the Essential Fatty Acids (EFAs).
This EFA is called Linoleic Acid (LA) and is poly-unsaturated. You will
see that LA is an 18 carbon chain fatty acid with two double bonds in the
middle and is missing four hydrogen atoms, all on one side. The first double
bond occurs after the 6th carbon atom. Because of this, LA is sometimes referred
to as the W6 EFA. Because of the four missing hydrogen atoms, LA is even
more bent than Oleic Acid, giving it a melting temperature of 23 degrees
F (-5C). LA is fairly unstable, reacting with light and oxygen. Now lets
look at the second EFA.
This is Alpha Linolenic Acid (LNA). It is an 18 carbon fatty acid with three double
bonds at the 3, 6, and 9 carbon positions. LNA is missing 6 hydrogen
atoms, again all from one side. Because of the first double bond occurring
at the 3rd carbon atom, LNA is sometimes referred to as the W3 EFA. It
is sometimes referred to as a super unsaturated fatty acid (SUFA), even though it is also
poly-unsaturated. Because LNA is bent more than the others, it has the lowest
melting point of the three, 10 degrees F (-12 C). (I have a bottle of it
in my freezer and it is still liquid!). LNA is 5 times more unstable than
LA and quickly goes rancid if exposed to light or oxygen. It is so unstable,
in fact, that when it is pressed from the seeds that possess it, the pressing
must be done in the total absence of light and oxygen. It must be handled
in this way right through to the packaging stage, then quickly refrigerated
or frozen.
Essential: LA and LNA are essential in our diets because our bodies cannot make them, yet use them to make many other fatty acids our bodies must have. Therefore, without LA and LNA, our bodies miss out on a bunch of fatty acids we must have to be healthy.
EFA Functions: So, what do they accomplish in our systems? "...EFAs are involved with producing life energy in our bodies from food substances, and moving that energy throughout our systems. They
govern growth, vitality, and mental state. They hook up oxygen, electron
transport, and energy in the process of oxidation. Oxidation, the central
and most important moment-to-moment living process in our body, is the `burning'
of food to produce the energy required for life
processes."
Linoleic Acid: For good health, LA intake should be 3 to 6% of our total calories. At 9 calories per gram, this is about 6-12 grams, or about a tablespoon. The higher our intake of saturated fats, the more LA we need to both counteract the saturated fat, and also provide the nutrients our body needs to perform its functions.
Alpha-Linolenic Acid: We need somewhere from 1/5th to 1/2 as much LNA as LA. That comes to about 1 to 2 teaspoons per day. LNA is even more valuable in dispersing saturated fats.
Remember: To be healthy, we must get all 50 essential nutrients our body requires. Essential fatty acids especially need Vitamins A, B3, B6, C, E, and the minerals magnesium, and zinc to perform their numerous roles.
References:
1. Fats that Heal and Fats that Kill pg. 47
2. Ibid.
pg 44-45
Home Page: http://waltonfeed.com/
Much of the information for the EFA pages was taken from Fats that Heal Fats that Kill by Udo Erasmus, Published by Alive Books, Burnaby, BC, Canada 1-800-661-0303
All contents copyright (C) 1995, Al Durtschi. All rights reserved.
Revised: 8 May 96
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