Linoleic acid adults

Quinlan, G.J., Evans, T.W. and Gutteridge, J.M.C. (1994). Linoleic acid and protein thiol changes suggestive of oxidative damage in the plasma of patients with adult respiratory distress syndrome. Free Bad. Res. Commun. 20, 299-306. 

The essential fatty acids in humans are linoleic acid (C-18 2 N-6) and a-linolenic acid (C18 3 N-3). Arachidonic acid (C20 4 N-6) is also essential but can be synthesized from linoleic acid. Administration of 2% to 4% of total daily calories as linoleic acid should be adequate to prevent essential fatty acid deficiency in adults (e.g., infusion of 500 mL of 20% intravenous lipid emulsion once weekly).7 Biochemical evidence of essential fatty acid deficiency can develop in about 2 to 4 weeks in adult patients receiving lipid-free PN, and clinical manifestations generally appear after an additional... 

Emken, E.A., Adlof, R.O., and Gulley, R.M. 1994. Dietary linoleic acid influences desaturation and acylation of deuterium-labeled linoleic and linolenic acids in young adult males. Biochim. Bio-phys. Acta 1213, 277-288. 

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. 

Funk, C. D., and Powell, W. S. 1983. Metabolism of linoleic acid by prostaglandin endo-peroxide synthase from adult and fetal blood vessels. Biochim. Biophys. Acta, 754, 57-71. 

Vitamin K is a fat-soluble vitamin. The RDA for the adult man is 10 mg of a-loeophenol, or its biological equivalent. The RDA for infants should also be mentioned, as vitamin E deficiency, when it occurs, tends to strike this population. The RDA for the newborn is 5 mg of a-tocopherol, or its equivalent. The vitamin needs of the infant have been expressed in terms of the amount of polyunsaturated faltj acids (as fats and oils) in the diet, for example, 0,7 mg of a-tocopherol per gram of linoleic acid. A common level of dietary intake is about 10 mg per day. A deficiency iit the vitamin is quite rare. 

If sufficient scientific evidence is not available to calculate an Estimated Average Requirement, a reference intake called an Adequate Intake (Al) is used instead of a Recommended Dietary Allowance. The Al is a value based on experimentally derived intake levels or approximations of observed mean nutrient intakes by a group (or groups) of healthy people. The Al for children and adults is expected to meet or exceed the amount needed to maintain a defined nutritional state or criterion of adequacy in essentially all members of a specific healthy population LA = linoleic acid LNA = n-linolenic acid DHA = docosahexaenoic acid EPA = eicosapentaenoic acid TRANS-EA = trans fatty acids SAT = saturated fatty acids MONOs = monounsaturated fatty acids. 

Salem N Jr, Pawlosky R, Wegher B, Hibbeln J. In vivo conversion of linoleic acid to arachidonic acid in human adults. Prostaglandins Leukotrienes Essential Fatty Acids 1999 60(5-6) 407 10. 

The AI for men and women for fat is 1.6 and 1.1 g of a-linolenic acid daily, respectively, and for linoleic acid is 17 g/day for adult men and 12 g/day for adult women. Overall, fat should represent no more than 20% to 35% of total calories with the recommendation that saturated fatty acids, trans fatty acids, and dietary cholesterol intake be kept as low as possible while consuming a nutritionally adequate diet. As mentioned previously, fat intake in children less than 2 years of age is critical for proper central nervous system growth and development therefore, no fat restriction (e.g., skim milk) should be imposed until after the age of 2 years. 

The requirement of man for (o-6 fatty acids can be fullfilled with the supply of linoleic acid. Taking into account normal linoleic add levels and normal 20 3/20 4 ratios in hpids of serum and blood cells, the requirement for normal adults is 6-10 g linoleic acid per day or 3 energy % [27]. In infancy a similar supply of 1-3 energy % is recommended [8]. To determine the Unoleic acid requirement for healthy people the amount of saturated and trans fatty acids in the diet, - which will increase the requirement - must be taken into account [30]. In patients with heavy injuries, the requirement for linoleic acid can be increased by up to the five fold the amount for healthy people [28, 29] (Fig. 1). 

Mushtaq, S., Mangiapane, E.H., Hunter, K.A. 2010. Estimation of cis-9, trans-11 conjugated linoleic acid content in UK foods and assessment of dietary intake in a cohort of healthy adults. British Journal of Nutrition 103, t366-t374. 

Sluijs, I., Plantinga, Y., de Roos, B., Mennen, L.I., Bots, M.L. 2010. Dietary supplementation with cis-9, trans-11 conjugated linoleic acid and aortic stiffness in overweight and ohese adults. American Journal of Clinical Nutrition 91, 175-183. 

In the body, linoleic acid is converted to longer-chain fatty acids with three, four, and five double bonds, which are essential components of membranes. In infants fed formulas, the primary symptom noted in essential fatty acid deficiency is drying and flaking of the skin. A fatty acid deficiency in adult humans was unknown until recently. In the past several years, there have been numerous reports of such deficiency being produced inadvertently in hospitalized patients, both infants and adults, fed exclusively by intravenous fluids not containing fat. 

Corn, cottonseed, safflower, soybean, and sunflower oils are excellent sources of linoleic acid, which comprises about one-half of the fatty acid contentof these oils. Hence, about 1 Tbsp per day of any of them will provide the requirement for adults. 

Available evidence indicates that only around 5-10% of the daily intake of linoleic acid can be converted to GLA and beyond. For a 60 kg adult with a dietary intake of 5-20 g/day of linoleic acid, the endogenous rate of formation of GLA will be 250-1000 mg/day or around 4-17 mg/kg body weight/day. Human breast milk contains 10C)-400 mg/1 of GLA-f-DGLA. A 5 kg baby consuming 1 litre of milk per day receives 20-80 mg/kg body weighl/day of these two acids combined (Horrobin, 1992). 

Essential Fatty Acids. The higher unsaturated fatty acids are indispensable for the rat. Deprivation of these fatty acids results in loss of hair, disturbances of fluid balance, loss of reproductive faculty, and ultimately in death. Similar deficiency symptoms have not been observed in man, because the amounts required are so small (in the rat only 20 mg linoleic acid per day) and an absolutely fat-free diet is practically unknown. It is established, however, that man cannot synthesize the higher unsaturated fatty acids either. They should be particulary important in the nutrition of infants the adult organism has large reserves to draw on. 

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