Some twenty years ago, however, the realisation came that the economy of the animal body calls for the activities of substances with functions apparently akin, in many respects at least, to those of the hormones, which the body itself is nevertheless unable to produce, and therefore must receive them in its food. The indispensable functions of these, like those of the hormones, are adequately fulfilled by extraordinarily small amounts of each one. These food constituents yield therefore no appreciable supply of energy, nor do they serve in any ordinary sense as structural materials. Their presence like that of the hormones is necessary rather for the normal progress of active events. They have dynamic functions. I am alluding, of course, to the vitamins.
British Food Journal – Emerald Publishing
Published: Jun 1, 1935