STUDIES OF NIACIN REQUIREMENT IN MAN. I. EXPERIMENTAL PELLAGRA IN SUBJECTS ON CORN DIETS LOW IN NIACIN AND TRYPTOPHAN 1

Abstract

Five female subjects were maintained on a corn diet containing 4.7 mg. of niacin and 190 mg. of tryptophane for 40-135 days. The 3 subjects so fed for over 50 days developed clinical signs of pellagra. After 50-60 days N1-methylnicotinamide (N1-Me) excretion decreased to 0.5-0.6 mg. and remained at that level. One of 2 other female subjects received the corn diet supplemented with 2 mg. of niacinamide daily for 122 days and the other a wheat diet containing about 5.7 mg. niacin and 230 mg. tryptophane for 95 days, without developing signs of niacin deficiency. In the 1st of these subjects urinary excretion of N1-Me decreased to 0.9 mg. daily after 60 days and remained at that level; in the second it measured 1.1 mg. after 95 days. In all subjects, excretion of the 6-pyridone of N1-Me fell to non-detectable levels after 2 weeks. All subjects remained in N balance. With the corn diet, the minimal niacin requirement was approx. 7 mg. daily.