Dietary requirements essential fatty acids

Recent evidence from both animal and human studies suggests that oral detection of fatty acids occurs via a gustatory pathway [3]. As opposed to the five primary taste stimuli, fat taste appears to have no discrete taste quality [40]. However, humans do possess a dietary requirement for fatty acids. Essential fatty acids such as linoleic acid are important for plasma membrane formation, and for the absorption of fat-soluble vitamins [41]. Due to the importance of fatty acids in the diet, the generation of a specific taste quality by fatty acids is a reasonable hypothesis. 

The perturbation of the incorporation of linoleic add metabolites into mammary gland lipids by CLA metabolism may lead to the hypothesis that CLA is able to create a mild arachidonic acid deficiency condition, in particular in the mammary tissue which is composed mainly of neutral lipids. In fact, because CLA and some of its metabolites are preferentially incorporated into neutral lipids (15), unlike linoleic acid, which is instead incorporated mainly into phospholipids, the preponderance of neutral lipids in the mammary tissue renders the competition between these two fatty acids more favorable toward CLA. It has been demonstrated that mammary tumorigenesis requires essential fatty acids, and eicosanoid inhibitors are able to reduce tumor incidence in experimental models (22). CLA, likely by decreasing the supply of arachidonic acid and inhibiting eicosanoid formation through its metabolites, may counteract arachidonic acid-derived eicosanoid action. Because the decrease of arachidonic acid, CLA metabolite incorporation, TEB density, and tumor incidence correlated with the (XA dietary intake, we can speculate that TEB density could also be modulated by eicosanoids. More data are required, however, to substantiate this hypothesis and to identify which eicosanoid(s) may be responsible for such effects. 

Prostaglandins arise from unsaturated C20 carboxylic acids such as arachidonic acid (see Table 26 1) Mammals cannot biosynthesize arachidonic acid directly They obtain Imoleic acid (Table 26 1) from vegetable oils m their diet and extend the car bon chain of Imoleic acid from 18 to 20 carbons while introducing two more double bonds Lmoleic acid is said to be an essential fatty acid, forming part of the dietary requirement of mammals Animals fed on diets that are deficient m Imoleic acid grow poorly and suffer a number of other disorders some of which are reversed on feed mg them vegetable oils rich m Imoleic acid and other polyunsaturated fatty acids One function of these substances is to provide the raw materials for prostaglandin biosynthesis... 

Essential fatty acid one of a family of polyunsaturated fatty acids that are essential dietary requirements. 

The carcinogenicity of af la toxin is reduced by protein deficiency, presumably because of reduced metabolic activation to the epoxide intermediate, which may be the ultimate carcinogen, which binds to DNA (Fig. 5.14). A deficiency in dietary fatty acids also decreases the activity of the microsomal enzymes. Thus, ethylmorphine, hexobarbital, and aniline metabolism are decreased, possibly because lipid is required for cytochromes P-450. Thus, a deficiency of essential fatty acids leads to a decline in both cytochromes P-450 levels and activity in vivo. 

Holman, R. T., Caster, W. O. and Wiese, H, F. 1964. The essential fatty acid requirement of infants and the assessment of their dietary intake of linoleate by serum fatty acid analysis. Am. J. Clin. Nutr. 14, 70-75. 

It is noteworthy that virtually all of the naturally occurring polyunsaturated fatty acids contain 18-22 carbon atoms. Linoleic acid is the predominant polyunsaturated fatty acid. It is of considerable interest that most animals cannot synthesize linoleic acid and must take it in the diet. If insufficient amounts of this acid are present in the diet of animals, severe symptoms, such as skin lesions, kidney damage, cataracts, increased permeability to water, and so on, can occur. Thus, the term essential fatty acids has been applied to these compounds. It is not certain, however, that dietary unsaturated fatty acids are needed by the human adult, but there is evidence of such a requirement by the human infant. 

Dietary fat is also important as a source of the fat-soluble vitamins, A, D, E, and K. Requirements for the fat-soluble vitamins are several orders of magnitude lower than that of the essential fatty acids, being measured in micrograms rather than grams per day. Since the fat-soluble vitamins are required for growth and development, much interest has been focused on the concentration and availability of these vitamins in human milk. 

Linoleic acid (18 3 -6 and a-linolenic acid (18 3n-3) are metabolically essential fatty acids, but linoleic acid is the only essential fatty acid for which a dietary requirement has been established. Characteristic EFA deficiency symptoms observed in poultry include an increased need for water and decreased resistance to disease. A dietary requirement for linoleic acid has been set at 1% of diet dry matter. No major special considerations are mentioned for turkeys, ducks, ringnecked pheasants, Japanese quail, and bobwhite quail (16). 

Human body is unable to synthesise all fatty acids found in the body. Those fatty acids that are not s)mthesized in the body but required for normal body growth and maintenance are called as essential fatty acids. These fatty acids are to be supplied through diet. Linoleic and linolenic acids are essential fatty acids. The longer chain fatty acids can be s)mthesized by the body from dietary linoleic and a-linolenic acids. Arachidonic acid is essential but it can be synthesised by the body from linolenic acid. It is also present in the meat. Linoleic acid is grouped under n-6 family because the 6th carbon from methyl end possesses the double bond. 

The relationship between vitamin E and the polyunsaturated fatty acids, including the essential fatty acids, is quite dose, ft has been said that, if the body did not need or use PUFAs, there would also be no need for itamin E. A dietary relationship exists between PUFAs and vitamin E. Greater intakes of PUFAs tend to increase the requirement for vitamin E. An increase in intake of PUFAs, however, does not necessarily mean that vitamin E supplements are needed, because the foods highest in PUFAs (vegetable oils are also good sources of vitamin E. 

Polyunsaturated fatty acids containing 20 carbons and three to five double bonds (e.g., arachidonic acid) are usually esterified to position 2 of the glycerol moiety of phospholipids in cell membranes. These fatty acids may require dietary linoleic acid (18 2,A9 12), an essential fatty acid, for their synthesis. 

Blockage of the bile duct caused by problems such as cholesterol-containing gallstones or duodenal or pancreatic tumors can lead to an inadequate concentration of bile salts in the intestine. Digestion and absorption of dietary lipids is diminished. Certain diseases that affect the pancreas can lead to a decrease in bicarbonate and digestive enzymes in the intestinal lumen. (Bicarbonate is required to raise the intestinal pH so that bile salts and digestive enzymes can function.) If dietary fats are not adequately digested, steatorrhea may result. Malabsorption of fats can lead to caloric deficiencies and lack of fat-soluble vitamins and essential fatty acids. 

Belch JJF, Ansell D, Madhok R, O Dowd A, Sturrock D. Effects of altering dietary essential fatty acids on requirements for non-steroidal anti-inflammatory drugs in patients with rheumatoid arthritis a double blind placebo controlled study. Ann Rheum Dis 1988 47 96-104. 

Copper is recognized as an essential metalloelement like sodium, potassium, magnesium, calcium, iron, zinc, chromium, vanadium and manganese [1]. Like essential amino acids, essential fatty acids and essential cofactors (vitamins), essential metalloelements are required for normal metabolic processes but cannot be synthesized de novo and daily dietary intake and absorption are required. The adult body contains between 1.4 mg (22 pmol) and... 

Onr diet also must contain the compounds we cannot synthesize, as well as all the basic building blocks for compounds we do synthesize in our biosynthetic pathways. For example we have dietary requirements for some amino acids, but we can synthesize other amino acids from our fuels and a dietary nitrogen precursor. The compounds required in our diet for biosynthetic pathways include certain amino acids, vitamins, and essential fatty acids. 

Other Dietary Requirements In addition to providing energy, the diet provides precursors for the biosynthesis of compounds necessary for cellular and tissue structure, function, and survival. Among these precursors are the essential fatty acids and essential amino acids (those that the body needs but cannot synthesize). The diet must also supply vitamins, minerals, and water. 

Although most hpids required for cell structure, fuel storage, or hormone synthesis can be synthesized from carbohydrates or proteins, we need a minimal level of certain dietary hpids for optimal health. These hpids, known as essential fatty acids, are required in our diet because we cannot synthesize fatty acids with these particular arrangements of double bonds. The essential fatty acids a-linoleic and a-linolenic acid are supphed by dietary plant oils, and eicosapentaenoic acid (ERA) and docosa-hexaenoic acid (DHA) are supplied in fish oils. They are the precursors of the eicosanoids (a set of hormone-like molecules that are secreted by cells in small quantities and have numerous important effects on neighboring cells). The eicosanoids include the prostaglandins, thromboxanes, leukotrienes, and other related compounds. 

The essential fatty acid linoleic acid is required in the diet for at least three reasons (a) It serves as a precursor of arachidonic acid from which eicosanoids are produced, ib) It covalently binds another fatty acid attached to cerebrosides in the skin, forming an unusual lipid (acylglucosylceramide) that helps to make the skin impermeable to water. This function of linoleic acid may help to explain the red, scaly dermatitis and other skin problems associated with a dietary deficiency of essential fatty acids, (c) It is the precursor of C22 6o)3, an important neuronal fatty acid. 

Recommended dietary allowances for a male adult (daily intake, in foods and food supplements) of some nutrients, usually the amounts estimated as needed to prevent overt manifestation of deficiency disease in most persons. For the substances listed in smaller amounts the optimum intake, leading to the best of health, may be somewhat greater. Not shown, but probably or possibly required, are the essential fatty acids, />aminobenzoic acid, choline, vitamin D, vitamin K, chromium, manganese, cobalt, nickel, zinc, selenium, molybdenum, vanadium, tin, and silicon. 

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