Dietary modifications of animal fats: status and future perspectives

The purpose of modifying animal fats is to product high quality products, w hich meet the dietary recommendations for a reduced intake of fat in the hu man diet, notably that of certain saturated fatty acids and cholesterol, an d an increased intake of mono- (MUFA) and polyunsaturated fatty acids (PUFA ) in order to minimize the risk for obesity, cancer, cardiovascular, and ot her life-style diseases. The body fat of farm animals is partly synthesized from dietary carbohydrat es, partly from dietary fatty acids. In monogastric animals, preruminants a nd poultry PUFAs are readily absorbed and deposited in the edible parts of the body and incorporated into egg yolk lipids. In ruminants, however. PUFA s are hydrogenated to mainly saturated fatty acids by the rumen microorgani sms with some formation of MUFAs, trans-, odd-, branched chain, and conjuga ted fatty acids. The latter fatty acids are absorbed, deposited in adipose and muscle tissue and incorporated into milk lipids, unless dietary PUFAs a re protected against hydrogenation. Thus, it is relatively easy to change t he fatty acid composition of pork, poultry meat, lamb, and veal, whereas be ef and milk can only be enriched significantly with PUFAs by manipulation. Products enriched with PUFAs are, however, prone to oxidation, and enrichme nt with antioxidants, notably with dietary vitamin E, is necessary in order to prevent the risk of oxidative damage.