Tissue vitamin E status is compromised by dietary protein insufficiency in young growing rats.

Abstract

In vitro erythrocyte hemolysis previously has been found to be significantly elevated in rats fed a low protein diet. To investigate the effects of dietary protein insufficiency on tissue vitamin E status, four groups of male weanling Long-Evans rats were given free access to either an 8% (wt/wt) lactalbumin diet containing 50 (L50) or 500 (L500) mg/kg diet of all-rac-alpha-tocopheryl acetate, or a 20% (wt/wt) lactalbumin diet containing 50 (N50) or 500 (N500) mg/kg of all-rac-alpha-tocopheryl acetate for 6 wk. A fifth group (P50) was pair-fed to the L50 group with the N50 diet. The L50 and L500 groups showed signs of protein malnutrition such as growth retardation as well as lower hematocrit and plasma protein and albumin concentrations. The alpha-tocopherol concentrations of plasma, heart, lung, kidney and muscle were significantly lower in the L50 group compared with the N50 group. The L500 group showed significantly less alpha-tocopherol in heart, kidney, muscle, brain and adipose tissue compared with the N500 group. The alpha-tocopherol concentrations in liver, testis, spleen and adrenal gland did not significantly differ either between the L50 and N50 groups or between the L500 and N500 groups. Supplementation with 500 mg/kg diet of all-rac-alpha-tocopheryl acetate resulted in significantly higher tissue alpha-tocopherol concentration in all tissues except muscle. The tissue alpha-tocopherol concentrations of the P50 group were not significantly different from those of the N50 group. The results indicated that protein insufficiency resulted in significantly lower alpha-tocopherol concentrations in most tissues in young growing rats.