Margarine trans fatty acid

Small amounts of trans-unsamrated fatty acids are found in ruminant fat (eg, butter fat has 2-7%), where they arise from the action of microorganisms in the rumen, but the main source in the human diet is from partially hydrogenated vegetable oils (eg, margarine). Trans fatty acids compete with essential fatty acids and may exacerbate essential fatty acid deficiency. Moreover, they are strucmrally similar to samrated fatty acids (Chapter 14) and have comparable effects in the promotion of hypercholesterolemia and atherosclerosis (Chapter 26). 

A few fatty acids with trans double bonds (trans fatty acids) occur naturally but the major source of trans fats comes from partial hydrogenation of vegetable oils m for example the preparation of margarine However the same catalysts that catalyze the... 

U shape. This has profound significance on molecular packing in membranes and on the positions occupied by fatty acids in more complex molecules such as phospholipids. Trans double bonds alter these spatial relationships. Trans fatty acids are present in certain foods, arising as a by-product of the samration of fatty acids during hydrogenation, or hardening, of natural oils in the manufacture of margarine. An additional small... 

Trans fatty acids are produced during the commercial hydrogenation of plant oils (Chapter 11). Some margarines contain these fatty acids, as do some commercially prepared snack foods (e.g. biscnits, cookies, cakes, crisps, chips). In addition, bacteria in the rnmen of rnminants prodnce trans fatty acids, which are therefore present in dairy prodnce and meat. Trans fatty acids can be incorporated into the phospholipids of the plasma membrane of endothelial and other cells, resulting in damage to the membranes. Furthermore, these abnormal fatty acids can interfere in the production of thromboxanes, prostacyclins or leucotrienes and hence interfere in control of blood clotting, immune cell activity and inflammation (Chapter 11). 

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. 

Today we know that only two fats hurt the heart. In addition to the saturated fats, trans-fatty acids formed by the partial hydrogenation of otherwise healthy oils such as soybean or sunflower are culprits. They re even worse than saturated fats, in that they lower the levels of both LDL and HDL. You find them in processed, packaged foods such as baked goods and margarines and in deep-fried... 

TABLE 9. Cis and Trans Fatty Acids in Refined Corn Oii and Corn Oii Margarines. 

The discovery of these health-promoting properties of certain trans-fatty acids (CLA) may provide incentive to undertake an objective reevaluation of the risks of the trans-fatty acids in margarines from com and other vegetable oils. 

The fat in beef, mutton, milk, and cheese contains 2-8% trans fatty acids. These naturally occurring trans fatty acids are formed in the rumen of the stomach (of ruminants) by the action of bacterial enzymes. Most of the trans fatty acids of the diet arise from the industrial hydrogenation of food oils. During this process, most of the unsaturated cis fatty acids are converted to saturated fatty acids, but a fraction is converted to trans fatty acids. In relation to all fatty acids present in the indicated food, salad oils contain 8-17% trans fatty acid, shortening contains 14-60%, and margarines 16-70% (Simopoulos, 1996). Overall, about 6% of our dietary fatty acids are trans fatty acids, where most of these are elaidic acid (McKeigue, 1995). 

---