Trans-fatty acid

Elner, VM, 2002. Retinal pigment epithelial acid lipase activity and lipoprotein receptors Effects of dietary omega-3 fatty acids. Trans Am Ophthalmol Soc 100, 301-338. 

Trans fatty acids Trans fatty acids (Figure 27.13) are chemically classified as unsaturated fatty acids, but behave more like saturated fatty acids in the body, that is, they elevate serum LDL (but not HDL), and they increase the risk of CHD. Trans fatty acids do not occur naturally in plants and only occur in small amounts in animals. However, trans fatty acids are formed during the hydrogenation of liquid vegetable oils, for example, in the manufacture of margarine. 

Interesting research assessing the influence of select nutrients on apo A-I expression has been published (reviewed in Mooradian et al.36). Among some of the nutrients associated with decreased expression of the apo A-I gene in cell culture or animal models are polyunsaturated fatty acids, trans-fatty acids, omega-3 fatty acids, glucose, antioxidant vitamins, and zinc deficiency. In contrast, monounsaturated fatty acids, soy proteins, alcohol, and copper deficiency are associated with increased expression of the human apo A-I gene. 

Gas chromatography is the most accurate means of quantifying the trans isomers present in fatty acid mixtures. In the GC trace the trans peaks appear broader because they contain isomers whose complete resolution is difficult. Virgin olive oils may show, in the sum of the trans-oleic acid-isomers, a maximum value of 0.05% and in the sum of /ran.v-linoleic and linolenic acid the same maximum value of 0.05%. Lower grade olive oils and refined olive oils are allowed wider limits for fatty acid trans isomers (see Table 2.2). 

Offer, N.W., Marsden, M., Dixon, J., Speake, B.K. and Thacker, F.E. (1999) Effect of dietary fat supplements on levels of n-3 polyunsaturated fatty acids, trans acids and conjugated linolenic acid in bovine milk. Animal Sci., 69, 613—625. 

Fatty acid triesters of glycerol containing the unnatural trans isomers of fatty acids. Trans fats are often formed as by-products in the partial hydrogenation of vegetable oils to produce margarine and vegetable shortening, (p. 1205)... 

Canakci, M., and Van Gerpen, J. 2001. Biodiesel production from oils and fats with high free fatty acids. Trans. ASAE, 44(6), 1429-1436. 

No hydrogenated oil and no trans-fatty acids. Trans-fats can raise LDL bad cholesterol and lower HDL good cholesterol. 

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. 

Phosphates Ore with Fatty Acids, Trans. AIME, 208, 70 (1957). 

Problem 19.7. Why do cis double bonds lower the melting points of fatty acids Trans double bonds do not have the same effect as cis double bonds. Why Hint Use appropriate drawings to show the effect of double bonds on molecular shape and indicate how molecular shape affects melting point. 

Printing Office, 2010. EFSA. Scientific opinion on Dietary Reference Values for fats, including saturated fatty acids, polyimsaturated fatty acids, monounsaturated fatty acids, trans fatty acids, and cholesterol. EFSA Journal. 2010,8(3) l46l. 

Cis and trans isomers of dietary fats and oils are suspected to play a role in human health. All unprocessed fats and oils contain only cis isomers. During processing, some of the cis isomers are converted to trans isomers, called trans fatty acids. Trans fatty acids are suspected of raising the amount of serum cholesterol in the blood stream, which can cause health problems. 

In nature most, but not all, unsaturated fatty acids are in the cis configuration. The major source of fats containing trans vmsaturated fatty acids (trans fats) in the diet of developed nations is... 

See also Coronary Heart Disease Prevention. Fatty Acids Trans Fatty Acids. 

In addition to geometrical isomerism (cis and trans), unsaturated fatty acids also exhibit positional isomerism, where the double bonds can occur in different positions along the chain in fatty acids which have identical chemical formulae. As with cis fatty acids, trans fatty acids also occur as mixtures of positional isomers. 

PUFA, polyunsaturated fatty acids. Trans fatty acid methyl esters ... 

Trans fatty acids are present in the diet in esterified form, mainly in triacylglycerols but those from ruminant sources may also be present in phospholipids. Before absorption into the body, triacylglycerols must be digested by pancreatic lipase in the upper small intestine. There is no evidence of differences in the hydrolysis and absorption of trans fatty acids, in comparison with that of cis fatty acids. Trans fatty acids are transported from the intestine mainly in chylomicrons, but some are also incorporated into cholesteryl esters and phospholipids. 

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