At one time “fish oils” were low-cost industrial materials for the paint and linoleum industries. After World War II (WWII), these industries switched to chemicals and plastics, and therefore, much information in older books became obsolete by 1960.

Because of one of the earliest media-stimulated public health panics in the late 1970s, that of the erucic acid (22:1) of rapeseed and mustard oils, alleged to damage hearts, food use of partially hydrogenated fish oils in that form petered out.

In a positive turn of fate, by 1980, the excellent cardiac health of the Eskimo population of Greenland, who had a high intake of dietary omega-3 (n-3) fatty acids from seal and fish fats, were also noted in the media. In 1985, another positive media bombshell exploded when a long-term study in Zutphen in the Netherlands showed that a large male population group had reduced their cardiovascular mortality rate by eating fish regularly.

By 1994, the United Kingdom had followed up on such reports and released an official government medical report recommending that people eat fish at least twice a week, one meal being of fatty fish. Belatedly the American Heart Association released a “Scientific Statement” in 2002, with a similar recommendation.

In this review, only fish “oils” can be considered. The fat in edible parts of fish ranges from about 16% down to 0.7%, the latter being almost exclusively the basic muscle phospholipids. These lipids are an excellent source of the highly unsaturated C20 and C22 omega-3 fatty acids of medical interest, and the content of omega-3 fatty acids is stable at roughly 0.5-g/100-g muscle. However, it is the muscle triacylglycerols that are variable for quantity and quality.