Dr. Mericle's Diet Health Weight Loss and Exercise Blog

Essential Fatty Acids EFA's

Fats (triacylglycerols) and Essential Fatty Acids

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 ...

posted by John Mericle M.D. D.A.B.R. @ 6:55 PM