DIETARY LINOLEIC-ACID AT HIGH AND REDUCED DIETARY-FAT LEVEL DECREASESTHE FECAL EXCRETION OF VITAMIN-E IN YOUNG-RATS

Vitamin E is the major lipid-soluble antioxidant in human subjects and is crucial in protecting polyunsaturated fatty acids (PUFA) against l ipid peroxidation. Dietary PUFA have been suggested to inhibit the abs orption of vitamin E. The present study in young male rats was designe d to investigate the effect of increasing concentrations of dietary li noleic acid on the faecal excretion of vitamin E. The fats were fed on semi-synthetic diets containing two concentrations of fat (59 g/kg di et, 15 energy % (en %) or 131 g/kg, 30 en %) for 3 weeks. Triacylglyce rol rich in Linoleic acid was added at the expense of triacylglycerol rich in saturated fatty acids to obtain dietary concentrations of 13, 39 or 66 g linoleic acid/kg diet for the high-fat diet (131 g fat/kg) and 12, 24 or 36 g linoleic acid/kg diet for the reduced-fat diet (59 g fat/kg). The results from the present study demonstrate that the fae cal excretion of vitamin E was significantly lower in rats fed on diet s with high levels of linoleic acid compared with rats fed on lower le vels of linoleic acid irrespective of the dietary fat content. The con centration of vitamin E in liver and plasma was significantly lower in animals fed on the highest concentration of linoleic acid compared wi th those fed on the lowest level. Results from the present study also demonstrate that at the same concentration of Linoleic acid, the faeca l excretion of vitamin E in rats fed on reduced-fat diets was signific antly lower than in rats fed on high-fat diets. Our findings indicate that the apparent absorption of vitamin E is not inhibited by dietary PUFA. Results from the present study also demonstrate that a reduction of dietary fat content from 30 en % to 15 en % does not lower the app arent absorption of vitamin E.