Lipids are organic molecules containing many carbon atoms in a variety of chain or ring conformations. There are five major classes of lipids: fatty acids, triglycerides, phospholipids, sterols and sphingolipids.
Fatty acids are carboxylic acids with long-chain hydrocarbon side groups. Fish lipids are very high in polyunsaturated fatty acids, up to 40% of long chain highly unsaturated fatty acids, containing 5-6 double bonds.
Fresh water fish are slightly lower in polyunsaturated fatty acids. The high level of unsaturated fatty acids in fish provides flexibility to cells and other tissues because these fatty acids are fluid even at cold temperatures.
The fatty acids of fish oil vary according to fish species. The fatty acids in fish oils include eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), both of which are omega-3 fatty acids.
Cold water fish have extra amounts of fat for insulation against cold; contain more omega-3 acids than leaner, warm-water fish. Cold-water fish include albacore tune, salmon and mackerel while leaner warm water fish include cod, catfish, halibut, sole and snapper.
Fatty acids in fish
