Freshwater fish diet affects lipid composition, deformability and aggregation properties of erythrocytes.

The effect of a 12-week diet of freshwater fish on fatty acid composition of the erythrocyte membrane, RBC deformability and artificial aggregation behavior of erythrocytes was studied in 20 healthy subjects. A different quantity of meals containing fish per week (control group, 1.5 and 3.8 fish meals per week) resulted in an increased content of n - 3 polyunsaturated fatty acids. The whole cell deformability of single erythrocytes characterized by a modified micropipette technique (capillary-rigidometer) was significantly increased dependent on fish intake. The parameter of entry time for cell deformability had a negative correlation with the n - 3/n - 6 ratio of fatty acids. No change was observed in MCV and MCHC of erythrocytes after the diet. The artificial aggregation behavior of washed erythrocytes in a suspension medium of low ionic strength and reduced pH was decreased depending on the number of fish meals eaten. The present results suggest that a relatively small shift in the profile of the polyunsaturated fatty acids causes changes in the viscoelastic properties of the erythrocyte membrane and in the artificially-induced aggregation of erythrocytes.