The Identity of Flavin with the Cataract-Preventive Factor

Abstract

Young rats given a diet deficient in all B vitamins, but supplemented with an extract of rice polish prepared with 80% ethyl alcohol, developed cataract and alopecia. Litter mates receiving the same diet, further supplemented with 30 micrograms, 60 micrograms or 90 micrograms of lactoflavin weekly, did not exhibit cataract. From this it is concluded that flavin is a specific cataract-preventive substance for the rat. Growth was roughly proportional to the amount of flavin fed, and the highest level of feeding promoted good growth. None of the animals receiving the diet, either with or without flavin supplement, developed dermatitis of the extremities. It is obvious that the rice polish extract contained considerable amounts of vitamin B, the antidermatitis factor (vitamin B₆), and any other of the B vitamins required by the rat except flavin. Rats given a diet deficient in all B vitamins, supplemented with crystalline vitamin B only, developed the characteristic inflammation and edema of the extremities termed ‘rat pellagra,’ ‘florid dermatitis’ or ‘rat acrodynia.’ Flavin failed to prevent this syndrome. Thus flavin deficiency, evidenced by alopecia and cataract, can be clearly distinguished from this other symptom-complex.