Excretion and intake of B vitamins in newborn infants.

The present work was undertaken in an attempt to throw more light on the metabolism of vitamin B in the newborn infant, and, in particular, by means of balance experiments, to seek evidence of the biosynthesis of B vitamins in the intestinal tract during the first week after birth. The investigations were confined to aneurin, riboflavin, and nicotinic acid and its metabolites. Very little work has been done on this subject in the past and balance studies have not been attempted. Neuweiler (1943) estimated the urinary excretion of aneurin by infants one to ten days old and observed that the values were low, but higher during the first four or five days than later. Coulson and Stewart (1946) studied the ability of infants to methylate nicotinamide and, in the course of this work, estimated the normal urinary output of N-methylnicotinamide on the first day after birth. They reported an average urinary output of 3 2 mg. of N-methylnicotinamide per 24 hours. Hamil, Coryell, Roderuck, Kaucher, Moyer, Harris, and Williams (1947) examined the concentrations of aneurin, riboflavin, nicotinic acid, N-methylnicotinamide, pantothenic acid, and biotin in the urine of infants during the first week after birth. In the main their results are confirwd by the present findings in so far as the urinary concentrations of aneurin, riboflavin, and nicotinic acid and its metabolites are concerned, but they did not study the faecal concentration and output or attempt to relate the total output to the intake. Their values for the maximum concentration of aneurin in the urine were lower than those found by Neuweiler (1943) and in the present investigation; they also found somewhat lower concentrations of N-methylnicotinamide than are now reported. Their work came to our attention after our experiments had been completed.