Effect of soybean and casein on the vitamin A status in the rat

With a well-balanced diet containing 1.3 mg of retinol/kg, a limited quantity of acid casein (10%) provokes a maximal efficiency of retinol. At a rate of 5% or 25% of casein, the retinol efficiency is decreased and identical to that of soybean diets. In casein-soybean mixed diets, the variations of retinol efficiency are only imputable to the casein presence. With diets containing 6.5 mg of retinol/kg, the specific effect of casein disappears.