期刊名称：Journal of Nutritional Science and Vitaminology
印刷版ISSN：0301-4800
电子版ISSN：1881-7742
出版年度：2014
卷号：60
期号：4
页码：255-260
DOI：10.3177/jnsv.60.255
出版社：Center for Academic Publications Japan
摘要：We have previously reported that dietary supplementation with up to 5.0 g/d of L -tryptophan ( L -Trp) for 21 d has no adverse effects, judging from the levels of general blood variables, in healthy women. We performed a randomized, double-blind, placebo-controlled, crossover intervention study in 17 apparently healthy Japanese women. The subjects were randomly assigned to receive a placebo (0 g/d) or 1.0, 2.0, 3.0, 4.0, or 5.0 g/d of L -Trp for 21 d each with a 5-wk washout period between trials. We examined the 24-h urine profiles on days −1 (1 d before starting L -Trp), 7, 14, and 21 to determine whether administration of L -Trp at doses of up to 5.0 g/d affects time-dependent urinary excretion of L -Trp or its metabolites in healthy women. The urinary excretion of L -Trp, kynurenic acid, 3-hydroxykynurenine, xanthurenic acid, 3-hydroxyanthranilic acid, quinolinic acid, N 1-methylnicotinamide, N 1-methyl-2-pyridone-5-carboxamide, and N 1-methyl-4-pyridone-3-carboxamide increased in an L -Trp dose-dependent manner on day 7. The amount of urinary excretion of these compounds was unchanged on days 14 and 21. The urinary excretion of serotonin, 5-hydroxyindole-3-acetic acid, 2-oxoadipic acid, and nicotinamide was unaffected by L -Trp at any of the doses tested. L -Trp doses had weak effects on the urinary excretion of kynurenine and anthranilic acid. Based on these findings, we conclude that there are no time-dependent effects of L -Trp administration in urinary excretion of L -Trp metabolites. Additionally, L -Trp and its metabolites do not accumulate in the body.
