A Study of Nicotinic Acid Restriction in Man

Abstract

Two subjects, each of whom previously had been a pellagra patient, restricted themselves to a diet low in trigonelline and providing only about 3 mg. of nicotinic acid daily, one for a period of 9 weeks and the other for 42 weeks. Each had minimal lesions of nicotinic acid deficiency at the start, but in neither was there any significant development in the direction of pellagra. The nicotinic acid excretion of one remained low throughout the study; the other remained at a normal level. The trigonelline output in each case dropped to a low level within 3 weeks, but showed no tendency to fall to a lower level with prolonged restriction. Niacin tolerance tests in each case were interpreted to indicate a mild state of deficiency. Tests for the fluorescent substance F₂ were zero at the start as well as at the close of the periods of restriction. It is suggested that the failure in the development of pellagra may have been due possibly to intestinal biosynthesis of nicotinic acid, and possibly to the fact that the diet contained little corn. Apparently, under the conditions of our study, the 3 mg. daily of the diet provided an intake somewhere near the minimal niacin requirement.