Effects of dietary selenium and vitamin E on plasma lipoprotein cholesterol levels in male rats.

Male Fischer-344 rats fed a diet deficient in both vitamin E and selenium (Se) for 20 weeks had higher levels of low-density lipoprotein cholesterol than age-matched rats fed an identical diet but supplemented with these micronutrients. The rats supplemented with both vitamin E and Se were switched to a diet deficient in both these micronutrients at week 20. These rats eventually developed elevated levels of low-density lipoprotein cholesterol compared to age-matched rats either continuously maintained on the diet supplemented with vitamin E and Se or rats switched (at week 20) from the vitamin E-and Se-deficient diet to a diet supplemented with both these micronutrients. In a second experiment, we found that Se deficiency alone was sufficient to significantly elevate low-density lipoprotein cholesterol. The basal diet used in these experiments had a very low cholesterol content and the observed alterations in lipoprotein cholesterol levels are likely to reflect alterations in the metabolism of endogenously synthesized cholesterol.