In our country rape is an oil plant grown on a large scale for food industry. It is the only oil plant giving good crops in our climate and at our soil. There is no doubt now that high-erucic acid rapeseed oil (30—50% of erucic acid) liquid or partly hardened exerts a harmful effect on the organism of many experimental animals (rats, rabbits, chickens, turkeys, guinea pigs, hamsters, mice, miniature pigs, piglets and monkeys). In view of this, in the countries where rape is grown including Poland varieties of rape with low erucic acid content and without erucic acid have been obtained by genetic selection methods. Presently low-erucic acid (1—5%) rape is grown in our country, and rapeseed oil obtained from it is widely used in liquid form and also as fat base for the production of margarines. A review of the world literature shows that high-erucic acid rapeseed oil produced pathological changes in many species of experimental animals. The experiments conducted for over 25 years at the National Institute of Food and Nutrition in Warsaw also demonstrated that administration of high-erucic acid rapeseed oil to experimental animals causes various functional and morphological changes in various organs. The most pronounced pathological lesions were found in the myocardium where after initial transient fatty infiltration focal microcellular infiltrations developed in the form of granulomas followed by fibrosis development. These lesions were particularly evident in young animals. After many experiments it was demonstrated that high-erucic acid rapeseed oil given to experimental animals in amount of 30% or more of the total energy intake stops weight gain in joung animals, while the studies of the authors showed that low-erucic acid oil (1—3%) administered in the same amount has no harmful effect on weight gain. This effect on weight gain in young animals is probably due, to lower consumption of food and poor assimilability and low energy value of this oil. It was found that high-erucic acid rapeseed oil is digested worse than other edible oils, while low-erucic acid rapeseed oil has the digestibility index similar to that of soybean oil or sunflower oil. One may assume, thus, that the degree of digestibility of rapeseed oil depends on its content of erucic acid. In high-erucic acid rapeseed oil erucic acid is situated nearly exclusively in positions 1 and 3 of triglyceride molecule, which probably determines the low digestibility index of this oil. It was shown in many experiments that administration of high-erucic acid rapeseed oil causes rapid and intense accumulation of lipids in the myocardium what is caused by erucic acid. Studies performed by Ziemlanski et al., confirmed by other authors, showed that fatty infiltration appeared in the myocardium already three hours after administration of high-erucic acid rapeseed oil with diet, with maximal infiltration after 3—4 days, which persists until the 7—8th day. With regression of fatty infiltration, that is after 6—7 weeks, microfocal histocytic infiltrations appeared, which with time were transformed into fibrosis. Low-erucic acid rapeseed oil (1—5% erucic acid) caused no fatty infiltration in the myocardium, but after administration of this oil in amount exceeding 20% of the total energy intake it produced microfocal necrosis with histiocytic infiltrations and microfocal fibrosis in the myocardium of some animals. It should be emphasized that the intensity of these lesions and their incidence were much lower than after high-erucic acid rapeseed oil. As yet it has not been explained whether a relationship between myocardial fatty infiltration and the development of microfocal necrosis exists. The recent studies of Ziemlański et al. showed that no-erucic acid rapeseed oil (i.e. double zero) caused practically no myocardial lesions. Besides myocardial changes produced by high-erucic acid rapeseed oil adrenal changes were found. The authors demonstrated changes in the corticosterone content of adrenal plands, plasma and urine in the experimental animals proportional to the content of erucic acid in diet. Low-erucic acid rapeseed oil administered in amount equal even to 50°/o of the energy intake caused no such changes. In the light of these experiments the authors concluded that the content of low-erucic acid rapeseed oil (1—5% erucic acid) in diet should not exceed 10% of the energy value of the daily food ration. The data on the effects of high-erucic acid and low-erucic acid oil on the human organism are rather scant, and are related mainly to the digestibility of rapeseed oil and erucic acid, and to the effect of one dose of this oil on the rate of utilization of fatty acids by the myocardium. The possibility of a cause-and-effect relationship between the consumption of high-erucic acid rapeseed oil by humans and the development of myocardial fatty infiltration and microfocal necrosis has not yet been demonstrated. Nevertheless, the results of many experiments on various animal species indicate a need for caution, particularly with regard to high-erucic acid oil. The studies of Canadian authors on young volunteers have shown that low-erucic acid rapeseed oil was more effective than soybean oil in reducing the blood cholesterol level. Our animal studies confirmed this observation; besides, we demonstrated a strong antiatherosclerotic effect of no-erucic acid rapeseed oil. On the basis of the results of the studies carried out until now it may be assumed that no-erucic acid or low-erucic acid (1—5%) rapeseed oil is not a threat to health. Moreover, the oil contains large amouts of oleinic acid, approaching those found in olive oil, and this plays a beneficial role in human nutrition. The present widely accepted opinion is that no-erucic acid or low-erucic acid (1—5%) acid) are valuble edible oils and may be recommended to adults. Considering its antiatherosclerotic and hypocholesterolaemic effects it may be recommended to subjects with hypercholesterolaemia and in dietetic treatment of various diseases. However, caution is suggested, as yet, in its administration to infants and babies.
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