title: Urinary excretion of B-group vitamins reflects the nutritional status of B-group vitamins in rats.
abstract: We have reported previously that the urinary excretion of B-group vitamins reflects recent dietary intakes of these vitamins. We also proposed reference values for the urinary levels of B-group vitamins for human subjects, and used these for evaluating human nutritional status. However, the question arises as to whether the urinary excretion of B-group vitamins in animals or human subjects decreases immediately before they become B-group vitamin insufficient or when fed a diet low in vitamins. In the present study, rats were fed a vitamin-free diet for 5 d, and changes in the levels of B-group vitamins in urine and blood were monitored. Urinary excretion of vitamin B1, vitamin B2, 4-pyridoxic acid (a catabolite of vitamin B6), pantothenic acid, folate and biotin steeply decreased, and all of the values reached zero within 1-2 d. With respect to blood, the concentrations of only three of the eight B-group vitamins (vitamin B1, pyridoxal phosphate and biotin) decreased to 15 % (P < 0·0001), 7 % (P < 0·0001) and 2 % (P < 0·0001) on day 5, respectively, compared with the values at the beginning of the experiment. The decrease was more rapid and the changes were greater in the urine samples than in the blood samples. The present data complement our previous proposal that the urinary excretion of B-group vitamins reflects the nutritional status of these vitamins.
authors.affiliation: Department of Food Science and Nutrition , School of Human Cultures, The University of Shiga Prefecture , Hikone, Shiga 522-8533 , Japan.
authors.forename: Katsumi
authors.initials: K
authors.lastname: Shibata
authors.affiliation: Department of Food Science and Nutrition , School of Human Cultures, The University of Shiga Prefecture , Hikone, Shiga 522-8533 , Japan.
authors.forename: Chisa
authors.initials: C
authors.lastname: Sugita
authors.affiliation: Department of Food Science and Nutrition , School of Human Cultures, The University of Shiga Prefecture , Hikone, Shiga 522-8533 , Japan.
authors.forename: Mitsue
authors.initials: M
authors.lastname: Sano
authors.affiliation: Department of Food Science and Nutrition , School of Human Cultures, The University of Shiga Prefecture , Hikone, Shiga 522-8533 , Japan.
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Fukuwatari
keywords: Blood; Deficiency; MW, molecular weight; Rats; Urine; Vitamins