IX 



RADIATION AND THE VITAMINS 



Charles E. Bills 



Research Laboratory, Mead Johnson and Company, Evansville, Indiana 



The discovery of activation. Physical chemistry of activation. The individual 

 products of irradiation. Origin of vitamin D in nature. References. 



It is well to preface a paper on radiant energy and the vitamins 

 with the remark that the discussion will necessarily center on vitamin D. 

 The formation of the other vitamins does not involve radiant energy 

 except in the indirect relation that green plants require it for their growth, 

 and that vitamins are elaborated in abundance by plants. There is no 

 good evidence that any vitamin except certain forms of vitamin D is 

 directly a photochemical product, and it is by no means certain that all 

 forms of vitamin D require radiant energy for their formation. 



Vitamin A probably never occurs in the vegetable kingdom, Moore 

 (60) demonstrated that animals synthesize it from carotene. It is 

 true that carotene, or provitamin A, is a common pigment of green 

 plants, yet it can also be elaborated by microorganisms in culture (Bau- 

 mann, Steenbock, Ingraham, and Fred, 5). The B vitamins are plentiful 

 in green plants, but even more so in yeasts which grow in the dark. 

 Vitamin C is developed not only in green plants, but in germinating 

 seeds and in the bodies of certain animals. 



It seems that the effect of radiant energy on the vitamins is mainly 

 a destructive one. The investigations on this subject are assembled 

 in the excellent monographs by Browning (18), the Medical Research 

 Council (58), and Laurens (52). Since all vitamins are comparatively 

 unstable substances, they are more or less subject to destruction by radia- 

 tions, particularly by ultra-violet rays and the ozone frequently associated 

 therewith. Inasmuch as most experimental work has been conducted 

 with crude edible products in which the vitamins comprised only a trace 

 of the total, very little indeed can be said regarding the stability of the 

 vitamins per se toward radiant energy. It is, however, a point of prac- 

 tical significance that in the momentary exposure to ultra-violet rays 

 which is required to endow foodstuffs such as milk with vitamin D, no 

 appreciable destruction of the other vitamins is evident. 



The researches of the past decade which culminated in the activation 

 of ergosterol were, in a sense, a bringing together of old observations 

 on the therapeutic value of fish oils and of light. In brief, they have 



323 



