| |
Essential Fatty Acids
By Dr. Wysong
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.
About the Author
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.
Article Source: http://www.simplysearch4it.com/article/44264.html
| If you wish to add the above article to your website or newsletters then please include the "Article Source: http://www.simplysearch4it.com/article/44264.html" as shown above and make it hyperlinked. |
| Some other articles by Dr. Wysong | Fatty Acid Pathways
Fatty acids exist in the body primarily as triglycerides and phospholipids. Phospholipids make up the bilipid membrane of cells and the membranes of organelles within the cytoplasm. Fatty acids are split from the triglyceride ...
Lipid Digestion
Most natural whole foods have inherent enzymes capable of completely or partially digesting lipids if the enzymes are not destroyed through heat and ...
Lipid Biochemistry
FATTY ACIDS
Fatty acids are long-chain "carboxylic" acids, that is, hydrocarbon (alkyl) chains containing the terminal -COOH chemical group. (Fig. 2)
[ ...
Lipid Functions
It can be argued that lipids may be the most important of all dietary constituents since they are required in ...
|
|
| |
|
