Factors Unrelated to Vitamin A Intake that Influence Plasma Vitamin A Concentration

Abstract

Experiments on young calves showed that dietary factors other than carotene or vitamin A intake affected the level of vitamin A in the blood plasma. When calves were placed on a diet deficient in carotene and vitamin A the level increased temporarily, for 4 to 24 days, and remained above levels that existed when on the adequate diet for 4 to 49 days.In these cases the calves always had body stores of vitamin A and the deficient diet always contained skimmilk and a lower amount of fat than the adequate diet. Certain dietary factors apparently affect the release or utilization of vitamin A stored in the body. The results indicate that on certain dietary regimes plasma vitamin A levels were not a reliable indicator of intake.