Vitamins A and B

One suspected vitamin was essential to life and found in some fats, it had to be different from the one that cured beri-beri. Initially code named A and B, they were eventually renamed vitamin A and B. Following the same convention, the one for curing scurvy was called C.
 Elmer Verner McCollum United States 1913 Vitamins A and B

One suspected vitamin was essential to life and found in some fats, it had to be different from the one that cured beri-beri. Initially code named A and B, they were eventually renamed vitamin A and B. Following the same convention, the one for curing scurvy was called C.