title: Method for Evaluation of the Requirements of B-group Vitamins Using Tryptophan Metabolites in Human Urine.
abstract: Tryptophan metabolism is directly involved with B-group vitamins such as vitamin B2, niacin, and vitamin B6, and indirectly with vitamin B1 and pantothenic acid. We evaluated the validity of requirements of B-group vitamins set by the Dietary Reference Intakes for the Japanese (DRI-J). We investigated the fate of dietary tryptophan in 10 Japanese adult men who ate the same diet based on DRI-J during a 4-week study. Vitamin mixtures were administered based on the amounts in the basal diet during weeks 2, 3, and 4. Daily urine samples were collected eight times (days 1 and 5 in each week). Administration of vitamin mixtures had no effect on tryptophan metabolites such as anthranilic acid, kynurenic acid, xanthurenic acid, 3-hydroxyanthranilic acid, and quinolinic acid within individuals. Surplus administration of B-group vitamins against DRI-J requirements did not elicit beneficial effects on tryptophan metabolism. Our findings supported the requirements of B-group vitamins set by the DRI-J.
authors.forename: Katsumi
authors.initials: K
authors.lastname: Shibata
authors.forename: Junko
authors.initials: J
authors.lastname: Hirose
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Fukuwatari
keywords: human; quinolinic acid; tryptophan; urine; vitamin