Iron deficiency in young rats alters the distribution of vitamin A between plasma and liver and between hepatic retinol and retinyl esters

We assessed whether iron deficiency alters the concentration of vitamin A (VA) in plasma or liver and the chemical distribution between hepatic unesterified and esterified retinol. Weanling male Sprague-Dawley rats (n = 10/group) were allocated to one of four diet groups: low iron (ID3, 3 mg of elemental iron/kg diet), marginal iron (ID15, 15 mg/kg), control diet food-restricted to the ID3 group (FR, 35 mg/kg), and control diet ad libitum consumption (AD, 35 mg/kg), Both ID3 and FR rats grew less than AD and ID15 rats. At the end of 5.5 wk, plasma retinol concentrations of the ID3 and FR rats were reduced >40% compared to ID15 and AD rats [Kruskal-Wallis test (K-W), P < 0.0042)]. Paradoxically, the hepatic VA concentration was greater in FR rats, with accumulation of more retinyl esters and retinol compared to the other dietary groups. Concentrations of hepatic retinyl esters and retinol did not differ among the other groups, but the molar ratio of hepatic retinyl esters to retinol was greater in ID3 rats(20.1 +/- 1.4) compared to ID15 rats (13.8 +/- 1.6, P = 0.02), AD (11.3 +/- 2.1, P < 0.0042) and FR (9.5 +/- 1.1, P < 0.0042). Iron deficiency may cause changes in liver and plasma VA that are refractory to VA intake, and thus a benefit may be derived from combining iron and VA supplements during nutrition interventions.