Abstract
The adequacy of nicotinic acid nutrition in man is determined at the present time solely on the basis of clinical findings. Several investigators 1 , 2 , 3 have reported that there is little difference in the quantity of nicotinic acid and its derivatives excreted in the urine in a 24 hr period by normal persons and by patients with dietary deficiency. Perlzweig, Sarett and Margolis 2 have recently suggested that the urinary excretion following the administration of 500 mg of nicotinamide may serve as a test of nicotinic acid deficiency.
This report deals with observations made on 6 normal persons, 18 hospital patients without signs of deficiency disease and 10 patients with clinical findings indicating deficiency of one or more members of the B group of vitamins. Of this last group 7 had lesions of pellagra, 5, evidence of ariboflavinosis and one, thiamin deficiency. The quantity of nicotinic acid and its derivatives excreted in the urine in a 24 hr period was determined by the method of Perlzweig, Levy and Sarett 4 with minor modifications. 5 Nicotinic acid is excreted in a number of forms, a small percentage as nicotinamide, coenzyme and nicotinuric acid (acid hydrolyzable derivatives) and a large percentage as trigonelline, which must be determined separately. The method is very satisfactory for the determination of acid hydrolyzable derivatives and is the best available for the estimation of trigonelline, although in our experience only 40 to 50% of this compound added to urine can be recovered.
Since trigonelline is the main excretion product of nicotinic acid and since it is present in many foods, it is essential in studying nicotinic acid metabolism to place subjects on a diet low in trigonelline, which was done in this investigation.
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