Vitamins - those tricky little uncertainties- have managed, during the last ten years, to upset more weighty theories and distract more conscientious housewives than any of us care to remember. Therefore, it seems only fair that vitamins should be made to line up their ever-increasing dietetic alphabet and fully explain themselves to those of us who are not quite sure what the big to-do concerning tomato juice and vegetable cooking water is really all about.