Ever since the importance of certain vitamins for adequate nutrition became established, the question of their origin has been earnestly considered. The readiness with which evidences of deficiency—the so-called avitaminoses—arise whenever vitamin shortage in the diet intervenes has made it clear that the vitamins are not manufactured de novo in the animal organism. Even in the case of the antirachitic effects of sunshine and other forms of irradiation the potent factor is dependent on extracorporeal contributions to its genesis. The available experimental evidence today indicates that the human organism is dependent on exogenous sources, notably food, for its supply of essential vitamins. There are also indications that storage may be accomplished to some extent.
In the case of the infant the milk furnished from one source or another is the sole natural supply of vitamins. Consequently it has become imperative to learn how the content of vitamins may be maintained
VITAMIN B SYNTHESIS IN THE COW, AND THE QUALITY OF MILK. JAMA. 1928;91(25):1997. doi:10.1001/jama.1928.02700250061019