title: Urinary excretion of vitamin B12 depends on urine volume in Japanese female university students and elderly.
abstract: Recent studies have shown that urinary excretion of water-soluble vitamins reflects their intake in humans. However, some have reported that physical characteristics and urine volume may affect the amount of vitamin compounds found in urine. We hypothesized that physical characteristics and urine volume could affect urinary excretion of B-group vitamins. Twenty-four-hour urine samples were collected from 186 free-living Japanese women aged 19 to 21 years and 104 free-living Japanese subjects aged 70 to 84 years. Correlations between urinary output of each B-group vitamin and body height, body weight, body mass index, body surface area, urine volume, and urinary creatinine were determined. Only urinary vitamin B(12) was strongly correlated to urine volume in young (r = 0.683, P < .001) and elderly (r = 0.523, P < .001) subjects. To confirm this finding, 20 Japanese adults were orally administered 1.5 mg of cyanocobalamin (500-fold higher daily intake); and correlations between urinary vitamin B(12) and urine volume were determined. The load of cyanocobalamin increased vitamin B(12) content in the urine by only 1.3-fold. Urinary vitamin B(12) was strongly correlated with urine volume on the day before taking, the day of taking, and the day after taking cyanocobalamin (r = 0.745, P < .001; r = 0.897, P < .0001; and r = 0.855, P < .0001, respectively). We conclude that urinary excretion of vitamin B(12) is dependent upon urine volume, but not on intake of vitamin B(12). Physical characteristics and urine volume are less important for B-group vitamins except for vitamin B(12) as biomarker.
authors: Department of Food Science and Nutrition, School of Human Cultures, The University of Shiga Prefecture, Hikone, Shiga 522-8533, Japan. fukkie@shc.usp.ac.jp
authors: Tsutomu
authors: T
authors: Fukuwatari
authors: Ema
authors: E
authors: Sugimoto
authors: Tomiko
authors: T
authors: Tsuji
authors: Junko
authors: J
authors: Hirose
authors: Tomiho
authors: T
authors: Fukui
authors: Katsumi
authors: K
authors: Shibata
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000652:urine*; D000886:Anthropometry; D001361:Avitaminosis / Q000652:urine; D015415:Biomarkers / Q000652:urine; D015992:Body Mass Index; D003404:Creatinine / Q000652:urine; D004032:Diet; D005260:Female; D006801:Humans; D007564:Japan; D008297:Male; D009752:Nutritional Status; D014556:Urine; D014805:Vitamin B 12 / Q000008:administration & dosage / Q000652:urine*; D014803:Vitamin B Complex / Q000378:metabolism / Q000652:urine; D055815:Young Adult
chemical_list: D015415:Biomarkers; D014803:Vitamin B Complex; D003404:Creatinine; D014805:Vitamin B 12