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Essential Fatty Acids
By: Dr. Randy Wysong - [health]
For the most part, organisms can satisfy their own fatty acid needs. In mammals, however, those
enzymes which insert double bonds into the chains of fatty acids cannot insert them into the
omega-3 and omega-6 positions. Linoleic and linolenic acid contain omega-6 and 3 bonds and are
necessary for mammalian metabolism. These two fatty acids are therefore essential fatty acids
(EFA) and must be supplied by the diet.
Variations among species and within species occur in terms of what is or is not essential and at
what levels. For example, the cat is limited in its ability to synthesize arachidonic acid (AA,
18:4w6). 1,2 Humans are unable to synthesize sufficient fatty acids with double bonds closer to
the methyl end than omega-9. Varying capabilities occur even within species. 3 A diet satisfactory
for one individual may not be for another, since enzyme systems regulating synthesis and
metabolism vary with individual genetics.
Varying environmental circumstances may also alter needs. A sufficient diet this week may not be
so next week if circumstances change. The consumption of alcohol or medications, the presence
of disease, atrophy, increased stress, increased consumption of trans- fatty acids (present in all
foods containing partially hydrogenated oils), dieting, obesity, allergy, young age, old age, high
cholesterol, and so forth can all alter nutrient requirements. 4 There is no such thing as an
average requirement which fits everyone all the time.
Some factors affect dietary intake while others affect the ability of essential fatty acids, once
consumed, to convert through the steps necessary to form their physiologically important end
products. For example, LA (18:2w6) consumed must first be converted to gamma linolenic acid
(GLA, 18:3w6) by desaturase enzymes, and then on to other products by enzymes to form important
eicosanoids such as prostaglandins. Many factors (stress, disease, allergy, etc.) can interfere
with this first step mediated by delta-6-desaturase to create GLA. 5 Therefore, for some
individuals, GLA or its progeny may have to be directly supplied to the diet thus by-passing the
need for this enzyme. This is the rationale for the use of the supplement evening primrose oil since
it contains high levels of GLA. Other oil sources such as black currant seed, borage, and fish also
supply fatty acids which skip several steps in these metabolic pathways and thus may be
important dietary components for some individuals (animals and people). (Fig. 13)
[ Fatty Acid Essentiality Image ]
http://www.wysong.net/articles/lipid/figures/figure13.jpg
An important component of fish oil, for example, eicosapentaenoic acid (EPA, 20:5w3) may
become a dietary essential if age or other factors limit the ability to convert dietary plant-derived
LNA (l8:3w3) into EPA, which is the precursor to several important omega-3 derived eicosanoids.
Although not considered essential fatty acids in the sense of LA and LNA, there are at least four
other unsaturated fatty acids in nutrition now recognized as playing key biochemical roles, and for
which there may be an essential requirement for some individuals. These are oleic acid (OA, 18:
1w9), gammalinolenic acid (GLA, 18:3w6), eicosapentaenoic acid (EPA, 20:5w8), and
docosahexaenoic acid (DHA, 22:6w3). This list is surely incomplete.
Note that OA is a mono-unsaturated compound (one double-bond), GLA has three double bonds,
and EPA and DHA have five and six double bonds, respectively. (Fig. 5) Linolenic acid
(manufactured only in plant chloroplasts) as well as EPA and DHA belong to the omega-3 family of
fatty acids; LA and GLA, as well as arachidonic acid (AA: 20: 4w6), are members of the omega-6
family. Oleic acid is a member of the omega-9 family. All these fatty acids have great biochemical
significance and the understanding of their metabolic roles is increasingly demonstrating their
link to health and disease.
The essentiality of fatty acids, like that of all other nutrients, is linked to many variables. Required
amounts and types of fatty acids can vary among species and even for the same individual. Diets
rich in unaltered fatty acids (particularly raw whole foods) and specific properly prepared fatty
acid supplements (a second choice) can provide sufficient fatty acid substrate for optimal health.
References available within book text, click the following link to view this article on wysong.net:
http://www.wysong.net/articles/lipid/04articlelipidchapterfouressentialfattyacids.shtml
For further reading, or for more information about, Dr Wysong and the Wysong Corporation please
visit www.wysong.net or write to wysong@wysong.net. For resources on healthier foods for
people including snacks, and breakfast cereals please visit www.cerealwysong.com.
--------------------------------------------------------------------------------
Dr. Wysong: A former veterinary clinician and surgeon, college instructor in human anatomy,
physiology and the origin of life, inventor of numerous medical, surgical, nutritional, athletic and
fitness products and devices, research director for the present company by his name and founder
of the philanthropic Wysong Institute. http://www.wysong.net. Also check out
http://www.cerealwysong.com.
By: Dr. Randy Wysong - [health]
For the most part, organisms can satisfy their own fatty acid needs. In mammals, however, those
enzymes which insert double bonds into the chains of fatty acids cannot insert them into the
omega-3 and omega-6 positions. Linoleic and linolenic acid contain omega-6 and 3 bonds and are
necessary for mammalian metabolism. These two fatty acids are therefore essential fatty acids
(EFA) and must be supplied by the diet.
Variations among species and within species occur in terms of what is or is not essential and at
what levels. For example, the cat is limited in its ability to synthesize arachidonic acid (AA,
18:4w6). 1,2 Humans are unable to synthesize sufficient fatty acids with double bonds closer to
the methyl end than omega-9. Varying capabilities occur even within species. 3 A diet satisfactory
for one individual may not be for another, since enzyme systems regulating synthesis and
metabolism vary with individual genetics.
Varying environmental circumstances may also alter needs. A sufficient diet this week may not be
so next week if circumstances change. The consumption of alcohol or medications, the presence
of disease, atrophy, increased stress, increased consumption of trans- fatty acids (present in all
foods containing partially hydrogenated oils), dieting, obesity, allergy, young age, old age, high
cholesterol, and so forth can all alter nutrient requirements. 4 There is no such thing as an
average requirement which fits everyone all the time.
Some factors affect dietary intake while others affect the ability of essential fatty acids, once
consumed, to convert through the steps necessary to form their physiologically important end
products. For example, LA (18:2w6) consumed must first be converted to gamma linolenic acid
(GLA, 18:3w6) by desaturase enzymes, and then on to other products by enzymes to form important
eicosanoids such as prostaglandins. Many factors (stress, disease, allergy, etc.) can interfere
with this first step mediated by delta-6-desaturase to create GLA. 5 Therefore, for some
individuals, GLA or its progeny may have to be directly supplied to the diet thus by-passing the
need for this enzyme. This is the rationale for the use of the supplement evening primrose oil since
it contains high levels of GLA. Other oil sources such as black currant seed, borage, and fish also
supply fatty acids which skip several steps in these metabolic pathways and thus may be
important dietary components for some individuals (animals and people). (Fig. 13)
[ Fatty Acid Essentiality Image ]
http://www.wysong.net/articles/lipid/figures/figure13.jpg
An important component of fish oil, for example, eicosapentaenoic acid (EPA, 20:5w3) may
become a dietary essential if age or other factors limit the ability to convert dietary plant-derived
LNA (l8:3w3) into EPA, which is the precursor to several important omega-3 derived eicosanoids.
Although not considered essential fatty acids in the sense of LA and LNA, there are at least four
other unsaturated fatty acids in nutrition now recognized as playing key biochemical roles, and for
which there may be an essential requirement for some individuals. These are oleic acid (OA, 18:
1w9), gammalinolenic acid (GLA, 18:3w6), eicosapentaenoic acid (EPA, 20:5w8), and
docosahexaenoic acid (DHA, 22:6w3). This list is surely incomplete.
Note that OA is a mono-unsaturated compound (one double-bond), GLA has three double bonds,
and EPA and DHA have five and six double bonds, respectively. (Fig. 5) Linolenic acid
(manufactured only in plant chloroplasts) as well as EPA and DHA belong to the omega-3 family of
fatty acids; LA and GLA, as well as arachidonic acid (AA: 20: 4w6), are members of the omega-6
family. Oleic acid is a member of the omega-9 family. All these fatty acids have great biochemical
significance and the understanding of their metabolic roles is increasingly demonstrating their
link to health and disease.
The essentiality of fatty acids, like that of all other nutrients, is linked to many variables. Required
amounts and types of fatty acids can vary among species and even for the same individual. Diets
rich in unaltered fatty acids (particularly raw whole foods) and specific properly prepared fatty
acid supplements (a second choice) can provide sufficient fatty acid substrate for optimal health.
References available within book text, click the following link to view this article on wysong.net:
http://www.wysong.net/articles/lipid/04articlelipidchapterfouressentialfattyacids.shtml
For further reading, or for more information about, Dr Wysong and the Wysong Corporation please
visit www.wysong.net or write to wysong@wysong.net. For resources on healthier foods for
people including snacks, and breakfast cereals please visit www.cerealwysong.com.
--------------------------------------------------------------------------------
Dr. Wysong: A former veterinary clinician and surgeon, college instructor in human anatomy,
physiology and the origin of life, inventor of numerous medical, surgical, nutritional, athletic and
fitness products and devices, research director for the present company by his name and founder
of the philanthropic Wysong Institute. http://www.wysong.net. Also check out
http://www.cerealwysong.com.