QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Purchase Article View Shopping Cart Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Jacob, R. A. Articles by Clemens, R. A. Search for Related Content PubMed PubMed Citation Articles by Jacob, R. A. Articles by Clemens, R. A.

Biochemical Markers for Assessment of Niacin Status in Young Men: Urinary and Blood Levels of Niacin Metabolites

Robert A. Jacob, Marian E. Swendseid^*, Ralph W. McKee^*, Casey S. Fu^* and Roger A. Clemens

U.S. Department of Agriculture, Agricultural Research Service, Western Human Nutrition Research Center, Presidio of San Francisco, San Francisco, CA 94129 ^* UCLA School of Public Health, Division of Nutritional Sciences, Los Angeles, CA 90024 Calreco, Inc., Research and Development, Van Nuys, CA 91412

Biochemical markers of niacin status were studied in healthy young men fed 6.1 to 32 niacin equivalents (NE) per day over an 11-wk period while residing in a metabolic unit. Methylated metabolites of niacin, N¹-methylnicotinamide (NMN) and N¹-methyl-2-pyridone-5-carboxamide (2-pyr), in urine and plasma were determined during periods of low (6.1 or 10.1 NE per day), adequate (19 NE per day = 1 RDA) and high (25 or 32 NE per day) niacin intakes and after small test doses of nicotinamide. Urine excretion of < 1.2 mg/d of either NMN or 2-pyr was a reliable indicator of subjects receiving the lowest intake of 6.1 NE/d, but the NMN metabolite was a better marker of subjects ingesting 10.1 NE/d. The ratio of 2-pyr/NMN in urine was not as good a measure of the 6.1 NE/d intake as the individual metabolite excretions and was not responsive to the 10.1 NE/d intake. Plasma niacin metabolites were generally not as reliable as urinary metabolites for identifying subjects receiving low niacin intakes, however, values for plasma 2-pyr dropped quickly and were eventually nondetectable. After a 1 RDA oral dose of nicotinamide, increases in urine and plasma 2-pyr levels above pre-dose baseline values were significantly decreased in subjects receiving low, as compared to adequate, niacin intake. A leucine supplement had no effect on the rate of repletion of niacin-deficient subjects nor on the level of methylated niacin metabolites in urine or plasma.

KEY WORDS: • niacin • niacin status • niacin metabolism • niacin metabolites • N¹-methylnicotinamide • 2-pyridone

Manuscript received 23 September 1988. Revision accepted 9 January 1989.

This article has been cited by other articles:

				P. I. Creeke, F. Dibari, E. Cheung, T. van den Briel, E. Kyroussis, and A. J. Seal Whole Blood NAD and NADP Concentrations Are Not Depressed in Subjects with Clinical Pellagra J. Nutr., September 1, 2007; 137(9): 2013 - 2017. [Abstract] [Full Text] [PDF]