[The effect of dietary fats on the hemolysis resistance of the erythrocyte membrane during alimentary zinc and calcium deficiency in rats].

In an earlier Zn-deficiency experiment (8) pair-fed-control rats surprisingly showed a 100% increased osmotic fragility of erythrocytes against hypotonic sodium chloride solutions. Because coconut fat, which is very low in essential fatty acids, was used, a deficiency of essential fatty acids was assumed. When the experiment was repeated the diet's coconut fat was replaced by sunflower oil (21% oleic acid, 69% linoleic acid). The erythrocytes of the animals with Zn-deficiency showed an increase in osmotic fragility as against the control groups fed ad libitum. The data of the pair-fed control animals was in between those two groups and did not differ from the other two groups. Using sunflower oil instead of coconut fat decreased the osmotic fragility of the pair-fed animal's erythrocytes in opposition to the preceding experiment up to 100%. Additional Ca deficiency increased the osmotic fragility of the erythrocytes significantly in all three groups. When the Zn and Ca deficiency animals were repleted over 5 days on the basic diet the osmotic fragility of the erythrocytes was decreased significantly. The results show that the use of coconut fat in a restrictive diet causes essential fatty-acid deficiency. It ist also shown that the osmotic fragility of the erythrocytes depends partially on the status of Zn in dietary fat as well.