Early Discovery of Polyunsaturated Fatty Acids

Fish oil is an extract of fatty fish fat, rich in long-chain omega-3 polyunsaturated fatty acids (n-3/ω-3 PUFA). The two primary components of fish oil are docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA).

In the late 1970s, researchers earliest found that the low incidence of coronary heart disease in Denmark was associated with the traditional marine diet (lactating animals and fish) of the local population.

Following that, the first research on Greenland Inuit was conducted. Duplicate specimens of diets collected from 50 adults, 25 males and 25 females, were analyzed for water, ash, protein, fat, individual fatty acids, cholesterol, and carbohydrate. The results are compared with those of typical Danish diets. The researchers found that the results are connected to earlier studies of the plasma lipids in Inuit. The rarity of ischemic heart disease in Greenland Inuit may be partially due to the antithrombotic effects of long-chain polyunsaturated fatty acids, particularly EPA, which is prevalent in diets rich in marine oils (table 1).

Early Discovery of Polyunsaturated Fatty Acids — *Table 1 Average content of fatty acids as percentage of total fatty acids in Inuit (Eskimo) food as compared with Danish food*

Inuit diets were higher in polyunsaturated fatty acids, with a saturated fatty acid ratio of 0.84 compared to 0.24 in Danes. The polyunsaturated fatty acids were predominantly of the linolenic class (n-3) in Inuit and the linoleic class (n-6) in Danes (table 2).

*Table 2 Dietary fats in Inuit (Eskimo) and Danish food divided in fat types*

After that, the accumulation of data from the research suggested a correlation between the intake of PUFAs and a reduced risk of cardiovascular diseases. Further studies in vivo and in vitro also indicated that n-3 PUFAs may have multiple physiological functions.

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