British Journal of Nutrition

Full Papers

Human and Clinical Nutrition

Identification and assessment of markers of biotin status in healthy adults

Wei Kay Enga1, David Girauda1, Vicki L. Schlegela2, Dong Wanga3, Bo Hyun Leea2 and Janos Zemplenia1 c1

a1 Departments of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, NE 68583-0806, USA

a2 Food Science and Technology, University of Nebraska-Lincoln, Lincoln, NE 68583-0919, USA

a3 Statistics, University of Nebraska-Lincoln, Lincoln, NE 68583-0963, USA

Abstract

Human biotin requirements are unknown and the identification of reliable markers of biotin status is necessary to fill this knowledge gap. Here, we used an outpatient feeding protocol to create states of biotin deficiency, sufficiency and supplementation in sixteen healthy men and women. A total of twenty possible markers of biotin status were assessed, including the abundance of biotinylated carboxylases in lymphocytes, the expression of genes from biotin metabolism and the urinary excretion of biotin and organic acids. Only the abundance of biotinylated 3-methylcrotonyl-CoA carboxylase (holo-MCC) and propionyl-CoA carboxylase (holo-PCC) allowed for distinguishing biotin-deficient and biotin-sufficient individuals. The urinary excretion of biotin reliably identified biotin-supplemented subjects, but did not distinguish between biotin-depleted and biotin-sufficient individuals. The urinary excretion of 3-hydroxyisovaleric acid detected some biotin-deficient subjects, but produced a meaningful number of false-negative results and did not distinguish between biotin-sufficient and biotin-supplemented individuals. None of the other organic acids that were tested were useful markers of biotin status. Likewise, the abundance of mRNA coding for biotin transporters, holocarboxylase synthetase and biotin-dependent carboxylases in lymphocytes were not different among the treatment groups. Generally, datasets were characterised by variations that exceeded those seen in studies in cell cultures. We conclude that holo-MCC and holo-PCC are the most reliable, single markers of biotin status tested in the present study.

(Received July 13 2012)

(Revised October 16 2012)

(Accepted October 16 2012)

(Online publication January 10 2013)

Key Words:

  • Biotin status assessment;
  • Carboxylases;
  • Gene expression;
  • Organic acids

Correspondence

c1 Corresponding author: J. Zempleni, fax +1 402 472 1587, email jzempleni2@unl.edu

Footnotes

  Abbreviations: 3-HIA, 3-hydroxyisovaleric acid; ACC, acetyl-CoA carboxylase; HABA, 2-(4′-hydroxyazobenzene)-benzoic acid; MCC, 3-methylcrotonyl-CoA carboxylase; PCC, propionyl-CoA carboxylase