EFFECTS OF FISH OIL ON TRIGLYCERIDES, CHOLESTEROL, LIPOPROTEIN(A), ATHEROGENIC INDEX AND FIBRINOGEN - INFLUENCE OF DEGREE OF PURIFICATION OF THE OIL

Administration of fish oil is known to have a positive effect on blood lipids, but this effect has varied largely between different investigations, a discrepancy which may be due to a difference in the quality of the fish oil preparations. To study the effect of the degree of purification of the fish oils, 13 volunteers were given 30 ml of a semipurified fish oil concentrate, ESKIMO-3, or placebo daily for 4 weeks. Thirteen other subjects, healthy or with slightly to moderately increased blood lipids, were given 30 ml of a chromatographically highly purified fish oil with a very low anisidine value, or of placebo oil daily for 4 weeks. After a washout period of 2 weeks all groups received the other treatment. Thirty millilitres of each fish oil corresponded to 5.4 g of eicosapentaenoic acid. Compared with placebo, both the semipurified and the highly purified oil had a pronounced effect on plasma phospholipid fatty acids and triglycerides. The quotient between eicosapentaenoic and arachidonic acid increased by 475 and 467% respectively. Interestingly, the semipurified fish oil decreased lipoprotein(a) by 19%. The highly purified oil had a less positive effect on total cholesterol, HDL cholesterol, atherogenic index and lipoprotein(a). Thus highly purified fish oils may not have better effects than semipurified fish oil concentrates, possibly because of loss of active component(s) during the purification procedure.