Pregledni rad
Polyunsatured fatty acids in diet and human health
Danijel Karolyi
; Zavod za opće stočarstvo, Agronomski fakultet Sveučilišta u Zagrebu, Svetošimunska cesta 25, 10 000, Zagreb, Hrvatska
Sažetak
Recent medical researches indicated the significanceof the role of nutritional levels of omega-6 (n-6) and omega-3 (n-3) polyunsaturated fatty acids in the development of cardiovascular and other chronical diseases in humans. Principal n-6 fatty acid is linoleic (LA, 18:2 n-6) and principal n-3 fatty acid is alpha-linolenic acid (ALA, 18:3 n-3). In organism, these fatty acids can be elongated and desaturated into their longer-chain derivates such as arachidonic acid (AA, 20:4, n-6), derived from LA, or eicosapentaenoic acid (EPA, 20:5 n-3) and docosahexaenoic acid (DHA, 22:6 n-3), derived from ALA. Polyunsaturated fatty acids with 20 carbons in the chain act as precursors for eicosanoides include prostaglandins, leukotrienes and thromboxanes. These have an important role as regulators of many physiological processes in tissues, such as blood clotting or inflammatory response. Eicosanoides derived from polyunsaturated fatty acids of different n-series have a different structure and biological effects. Thus, tromboxane A2 produced from AA (20:4 n-6) is a powerful pro-aggregatory agent in heamostasis whereas tromboxane A3 produced from EPA (20:5 n-3) is much less active. Similarly, leukotrienes derived from AA (20:4 n-6) stimulate the inflammatory response more than those derived from EPA (20:5 n-3). The levels of these eicosanoides depend on the quantities of AA and EPA in the phospholipids of tissue cells, and these amounts, in turn, depend upon the relative amounts of their precursors, LA (18:2 n-6) and ALA (18:3 n-6) in the diet. The amount of LA (18:2 n-6) in modern diet has been increased considerably by the use of vegetable oils that contain high proportion of LA. Meat, eggs and fish from industrial production, als contai nhig hamount of LA because concentrate grain-based feeds are rich source of LA. It is believed that humans evolved with nutritional ratio of n-6/n-3 of 1-2 whereas in current diet this ratio has been significantl yincreased and ranges from 10 to 20 or more. Lost of balance of n-6 and n-3 polyunsaturated fatty acids in the diet has been linked with causes of permanent growth of modern civilization diseases. Researches showed that increased intake of n-3 polyunsaturated fatty acids in relation to intake of n-6 polyunsaturated fatty acids, may have beneficia leffects in the prevention of cardiovascular, autoimmune and other chronical diseases. In agreement with that, medical organizations recommended lowering n-6/n-3 ratio in daily nutrition.
Ključne riječi
lipids; polyunsaturated fatty acids; omega-6 fatty acids; omega-3 fatty acids
Hrčak ID:
21310
URI
Datum izdavanja:
15.6.2007.
Posjeta: 7.593 *