Influence of vitamin A form and protein nature on the retinol status in the rat

In comparison with soybean proteins, the acid casein increases the blood and liver concentrations of retinol when the diet contains 1 mg of retinol/kg. The effect of the acid casein is more important when the vitamin A is supplied to rats as retinal: with the alcohol form, the amount of liver retinol is 88.7 micrograms; with the aldehyde form, it reaches 137 micrograms.