EFFECT OF THE DIETARY-FAT TYPE ON ARTERIAL THROMBOSIS TENDENCY - SYSTEMATIC STUDIES WITH A RAT MODEL

To study the influence of dietary fatty acids on arterial thrombosis t endency 65 groups of male rats were fed diets containing 50% of their digestible energy as fat from 32 different oils and fats. After 8 week s their arterial thrombosis tendency was assessed by measuring the obs truction time (OT) of a loop-shaped polythene cannula inserted into th e abdominal aorta. Using multiple regression analysis log(10) OT was m odelled as a function of the relative amounts of the various dietary f atty acids and their combinations. The best fit (R-2 = 0.79) was obtai ned for the sums of all monoenoic and (n-6) and (n-3) polyenoic fatty acids, which appeared antithrombotic. The fit for the sum of all satur ated fatty acids, which had a prothrombotic effect, was almost as good (R-2 = 0.76). The ratio between dietary polyunsaturated and saturated fatty acids (P:S ratio) appeared a strong predictor of arterial throm bosis tendency (R-2 = 0.77). Marine oils did not have a more powerful antithrombotic effect than could be expected on the basis of their P:S ratios. Using stepwise regression analysis myristic acid, 14:0, was s hown to be the strongest prothrombotic fatty acid whereas linoleic aci d, 18:2(n-6), was the strongest antithrombotic fatty acid. Since the n umber of marine oils was very limited the effects of the 'fish fatty a cids' eicosapentaenoic acid, 20:5(n-3) and docosahexaenoic acid, 22:6( n-3), on arterial thrombus formation could not be tested reliably. The same appeared true for gamma-linolenic acid, 18:3(n-6), and stearidon ic acid, 18:4(n-3), present in a few vegetable oils only. (C) 1997 Els evier Science ireland Ltd.