Vitamin B 1 Metabolism in Man. Excretion of B 1 in Urine and Feces

Goodhart and Jolliffe 1 have emphasized the need for a practical chemical method for studying vitamin B₁ metabolism. The fermentation method recently published by our laboratories^2,3 is, we believe, admirably suited to this purpose.

After, and in conjunction with, considerable work on rat metabolism of vitamin B₁, we have applied our method to a group of human subjects. Five adults and 3 children, all ‘normal’ subjects with the possible exception of Subject E, who was under treatment for nervous breakdown, coöperated with us in this project. The main diet was in all cases normal, i. e., no attempt was made to restrict these individuals to a standard diet. The average daily urinary output of the adults (average of 32 determinations) was 497.7±47 gamma. For the children the urinary average was 333 ± 60 gamma.

Having established the normal urinary output on the average or normal diet, doses of 5 and 10 mg. (5000 and 10,000 gamma) were given once daily per os to the adult subjects. Table I gives the results obtained in this experiment.

The first point to be noted is the non-uniform response to the 5 mg. close. We feel that this variation in response may be related to either the level of body stores or individual rates of absorption.

After sufficient time has elapsed on the 5 mg. level, we find that urinary excretion of the vitamin takes place at a steady rate. This condition we designate as excretion equilibrium. When a subject in excretion equilibrium at 5 mg. per day is placed on the 10 mg. level, we do not obtain a significant rise in urinary output even after 15 days at this level. This phenomenon cannot be explained by body storage and the explanation must be sought elsewhere.