Nonessential fatty acids

Severe negative nitrogen balance may occasionally have to be corrected by hyperalimentation or total parenteral nutrition (TPN). Intravenous solutions used in TPN contain essential and nonessential amino acids, plus a source of calories in the form of fat and carbohydrate. They "spare" the administered amino acids and allow them to be used for tissue repair. The TPN fluid must also contain all other nutritional factors required for life, including essential fatty acids, vitamins, and minerals. Severe metal and essential fatty acid deficiencies have been observed in situations in which such inclusions had not been made. 

Holman, R. T., Adams, C. E., Nelson, R. A., Grater, S. J-, Jaskicwicz, J. A., Johnson, S. B., and Erdman, J. W. (1995). Patients with anorexia nervosa demonstrate deficiencies nf selected essential fatty acids, compensatory changes in nonessential fatty acids and decreased fluidity of pla.sma lipids. / Nutr. 125,901-S107. 

The RDA for the essential fatty acids is 1 to 2% of total energy intake. Generally, between 5 and 10% of our energy intake consists of EFAs. Because of our ample intake of fat, a deficiency in EFAs is quite rare. The biochemical steps in the modification of nonessential fatty acids, such as oleic add, and essential fatty adds (linoleic add and linolenic acid) are generally the same. These steps include elongation and desaturation. Modification of fatty adds by their repeated desatu-... 

In EFA deficiency, oleic acid can be dehydrogenated to yield polyunsaturated fatty acids (PUFAs) that are nonessential and do not substitute for the essential fatty acids. One suchPUFA is 5,8,11-eicosatrienoic acid, which occurs in significant amounts in heart, liver, adipose tissue, and erythrocytes of animals fed diets deficient in EFAs but decreases after supplementation with linoleic or linolenic acids. Its appearance in tissues and plasma has been used in the assessment of EFA deficiency. 

The answer is c. (Klurray, pp 505-626. Scriver, pp 4029-4240. Sack, pp 121-138. Wilson, pp 287-320.) In mammals, arachidonic (5,8,11,15-eicosatetraenoic) acid can only be synthesized from essential fatty acids derived from the diet. Linoleic (9,12-octadecadienoic) acid produces arachidonic acid following two desaturations and chain elongation. While linolenic (9,12,15-octadecatrienoic) acid also is an essential fatty acid, desaturation and elongation produce 8,11,14,17-eicosatetraenoic acid, which is distinct from arachidonic acid. Oleic, palmitic, and stearic acids are all nonessential fatty acids that cannot give rise to arachidonic acids in mammals. 

Patients with severe hver failure may be at increased risk for essential fatty acid deficiency the ratio of nonessential to essential fatty acids was found to be increased in patients with acute and chronic hver failure. Poor oral intake of fat and dietary fat malabsorption in patients with cirrhosis both contribute to essential fatty acid deficiency. These changes were due to decreased hnoleic acid and increased serum... 

Fatty acids make the list, especially lauric acid and unsaturated oleic acid. Flavianic acid is a precursor in the preparation of the essential amino acid arginine and the nonessential amino acid tyrosine. Moss (1992) has a chapter about using arginine in the treatment of cancer. Tyrosine interestingly enters the picture as a component of the enzyme tyrosine kinase, the latter in the role of an inhibitor for cancerous stem cells, to be described in Chapter 10. 

Many nonpolar substances, such as drugs and inert gases, probably diffuse through the endothelial cell membranes. A large number of other compounds are transported through the endothelial capillaries by facilitative transport, whereas others, such as nonessential fatty acids, cannot cross the blood-brain barrier. Essential fatty acids, however, are transported across the barrier. 

Essential fatty aids (EFA) are required for the structure of cell membranes, reproduction, growth, and the regulation of cell function via a group of hormone-like derivatives, the eicosanoids. These properties of EFA are more important than other nonessential functions [19]. EFA can be allocated to two fatty acid families according to the position of the first double bound from the methyl end at carbon 3 or carbon 6, the most important representatives being linoleic acid (C18 2 co-6) and a-linolenic acid (C18 3 0)-3). In contrast, oleic acid (C18 1 (o-9) and its derivatives with the first double bound at carbon 9 can be synthesized in the body and are not essential. 

In sharp contrast to the ease of synthesis of the monoethenoid acids from the corresponding saturated fatty acids, Bernhard and Schoenheimer (1940) demonstrated in an unequivocal manner that the rat is unable to synthesize either the diethenoid acid, linoleic, or the triethenoid acid, linol c, from carbohydrate, although large amounts of stearic and palmitic acids were shown to originate concomitantly from this foodstuff. Thus, saturated and monoethenoid acids, which have most important functions in the animal, are considered to be nonessential from a dietary standpoint, since they can be synthesized even on nonfat diets. On the other hand, linoleic, linolenic, and arachidonic acids are regarded as essen-... 

Especially this last experiment again points to the important metabolic relations between vitamins E and D and the unsaturated fatty acids including both the essential and the nonessential ones. Some may even be toxic as is probably the case in cod liver oil. It is known that a high intake of unsaturated fatty acids increases the need for vitamin E, possibly because there is more need for antioxidant. The need for vitamin A has been said to increase as well. There are also relations with pyridoxine, which is necessary in the production of arachidonic acid from linoleic acid, etc. (Leitner, 1957 Hove and Harris, 1951 Hove, 1955 Sinclair, 1956 ... 

From experiments mainly with laboratory animals, it has been demonstrated that relatively high intakes of trans fatty acids in the diet in conjunction with marginal intakes of essential fatty acids (less than 2% dietary energy from linoleic acid) can lead to the presence of Mead acid (cis-5,8,11-20 3) in tissue lipids and an increase in the ratio of 20 3 n-9 to 20 4 n-6. This has been interpreted to suggest early signs of essential fatty acid deficiency, with potentially increased requirements for essential fatty acids. Mead acid can accumulate in the presence of linoleic acid, if large amounts of nonessential fatty acids are also present. Two mechanisms have been suggested to explain these observations in relation to intake of trans fatty acids ... 

Kwashiorkor— The specific features which distinguish this disorder from marasmus are (1) a significantly subnormal albumin concentration in plasma, (2) swollen parotid glands (just under and in front of the ears), (3) a depressed ratio of essential to nonessential amino acids in the blood plasma, (4) fatty liver (which often may be palpated, and (5) a moderate deficit in weight for height and age (the weight is usually 80% or more of normal). 

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