Urinary excretion of vitamin B12 depends on urine volume in Japanese female university students and elderly

Fukuwatari, Tsutomu; Sugimoto, Ema; Tsuji, Tomiko; Hirose, Junko; Fukui, Tomiho; Shibata, Katsumi

doi:10.1016/j.nutres.2009.10.008

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Volume 29, Issue 12 , Pages 839-845, December 2009

Urinary excretion of vitamin B12 depends on urine volume in Japanese female university students and elderly

Tsutomu Fukuwatari
- Department of Food Science and Nutrition, School of Human Cultures, The University of Shiga Prefecture, Hikone, Shiga 522-8533, Japan
- Corresponding author. Tel.: +81 749 28 8443; fax: +81 749 28 8499.
Ema Sugimoto
- Department of Food Science and Nutrition, School of Human Cultures, The University of Shiga Prefecture, Hikone, Shiga 522-8533, Japan
Tomiko Tsuji
- Department of Food Science and Nutrition, School of Human Cultures, The University of Shiga Prefecture, Hikone, Shiga 522-8533, Japan
- Department of Health and Nutrition, School of Health and Human Life, Nagoya Bunri University, Aichi 492-8520, Japan
Junko Hirose
- Department of Food Science and Nutrition, School of Human Cultures, The University of Shiga Prefecture, Hikone, Shiga 522-8533, Japan
Tomiho Fukui
- Department of Food Science and Nutrition, School of Human Cultures, The University of Shiga Prefecture, Hikone, Shiga 522-8533, Japan
Katsumi Shibata
- Department of Food Science and Nutrition, School of Human Cultures, The University of Shiga Prefecture, Hikone, Shiga 522-8533, Japan

Received 11 September 2009; received in revised form 6 October 2009; accepted 12 October 2009.

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 B₁₂ 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 B₁₂ and urine volume were determined. The load of cyanocobalamin increased vitamin B₁₂ content in the urine by only 1.3-fold. Urinary vitamin B₁₂ 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 B₁₂ is dependent upon urine volume, but not on intake of vitamin B₁₂. Physical characteristics and urine volume are less important for B-group vitamins except for vitamin B₁₂ as biomarker.