title: Urinary Branched-Chain 2-Oxo Acids as a Biomarker for Function of B-Group Vitamins in Humans.
abstract: To find a functional biomarker of B-group vitamins, we collected 24-h urine samples from young Japanese women who lived in the community (n=29) to measure branched-chain 2-oxo acids such as 2-oxo-3-methylbutanoic acid, 2-oxo-3-methylpentanoic acid, and 2-oxo-4-methylpentanoic acid because B-group vitamins are involved in the catabolism of branched-chain amino acids. The relationships between each pair of the three urinary 2-oxo acids were very high (2-oxo-3-methylbutanoic acid and 2-oxo-3-methylpentanoic acid, p<0.001; 2-oxo-3-methylbutanoic acid and 2-oxo-4-methylpentanoic acid, p<0.001; 2-oxo-3-methylpentanoic acid and 2-oxo-4-methylpentanoic acid, p<0.001). The participants were divided into three groups using the upper (n=10), middle (n=9), and lower tertiles (n=10) based on the urinary excretion amounts of the sum of the three branched-chain 2-oxo acids. The administration of capsules containing the daily necessary amounts of B-group vitamins led to a decrease in the urinary excretion of the sum of the three types of branched-chain 2-oxo acids in participants belonging to the upper tertile. A similar phenomenon was observed in the middle tertile, but not in the lower tertile. Intakes of B-group vitamins and the urinary excretion amounts of B-group vitamins were not observed to be significantly different among the upper, middle, and lower tertiles. These results indicate that some young Japanese women need much higher levels of B-group vitamins than the Dietary Reference Intakes for Japanese. Thus, urinary branched-chain 2-oxo acids are useful functional biomarkers for B-group vitamins in humans.
authors.affiliation: Department of Nutrition, School of Human Cultures, The University of Shiga Prefecture.
authors.forename: Katsumi
authors.initials: K
authors.lastname: Shibata
authors.forename: Momoka
authors.initials: M
authors.lastname: Sakamoto
mesh_terms: D044466:Asian People; D015415:Biomarkers / Q000652:urine*; D015992:Body Mass Index; D001835:Body Weight; D004040:Dietary Carbohydrates / Q000008:administration & dosage; D004041:Dietary Fats / Q000008:administration & dosage; D004044:Dietary Proteins / Q000008:administration & dosage; D002149:Energy Intake; D005260:Female; D006801:Humans; D007564:Japan; D007651:Keto Acids / Q000652:urine*; D064167:Recommended Dietary Allowances; D014803:Vitamin B Complex / Q000494:pharmacology* / Q000652:urine; D055815:Young Adult
chemical_list: D015415:Biomarkers; D004040:Dietary Carbohydrates; D004041:Dietary Fats; D004044:Dietary Proteins; D007651:Keto Acids; D014803:Vitamin B Complex; C013082:alpha-ketoisocaproic acid