Zempleni J, Mock D M
Department of Pediatrics, University of Arkansas for Medical Sciences, Arkansas Children's Hospital Research Institute, Little Rock, AR 72202-3591, USA.
J Nutr Biochem. 1999 Mar;10(3):128-38. doi: 10.1016/s0955-2863(98)00095-3.
Human biotin turnover and requirements can be estimated on the basis of (1) concentrations of biotin and metabolites in body fluids, (2) activities of biotin-dependent carboxylases, and (3) the urinary excretion of organic acids that are formed at increased rates if carboxylase activities are reduced. Recent studies suggest that the urinary excretions of biotin and its metabolite bisnorbiotin, activities of propionyl-CoA carboxylase and beta-methylcrotonyl-CoA carboxylase in lymphocytes, and urinary excretion of 3-hydroxyisovaleric acid are good indicators of marginal biotin deficiency. On the basis of studies using these indicators of biotin deficiency, an adequate intake of 30 microg (123 nmoles) of biotin per day is currently recommended for adults. The dietary biotin intake in Western populations has been estimated to be 35 to 70 microg/d (143-287 nmol/d). Recent studies suggest that humans absorb biotin nearly completely. Conditions that may increase biotin requirements in humans include pregnancy, lactation, and therapy with anticonvulsants or lipoic acid.
（1）体液中生物素及其代谢物的浓度；（2）生物素依赖性羧化酶的活性；（3）如果羧化酶活性降低，以增加的速率形成的有机酸的尿排泄量。最近的研究表明，生物素及其代谢物双去甲生物素的尿排泄量、淋巴细胞中丙酰辅酶A羧化酶和β-甲基巴豆酰辅酶A羧化酶的活性，以及3-羟基异戊酸的尿排泄量是边缘性生物素缺乏的良好指标。基于使用这些生物素缺乏指标的研究，目前建议成年人每天摄入30微克（123纳摩尔）的生物素。据估计，西方人群的膳食生物素摄入量为35至70微克/天（143-287纳摩尔/天）。最近的研究表明，人体几乎能完全吸收生物素。可能增加人体生物素需求量的情况包括怀孕、哺乳以及使用抗惊厥药或硫辛酸进行治疗。
