Smoking accelerates biotin catabolism in women

Am J Clin Nutr. 2004 Oct;80(4):932-5. doi: 10.1093/ajcn/80.4.932.


Background: Smoking accelerates the degradation of many nutrients, including lipids, antioxidants, and certain B vitamins. Accelerated biotin catabolism is of concern in women because marginal biotin deficiency is teratogenic in mammals.

Objective: The objective was to assess the effect of smoking on the biotin status of women.

Design: A preliminary study of 7 women and 3 men examined the urinary concentrations of biotin and its metabolites biotin sulfoxide and bisnorbiotin in smokers. The interpretation of the results of this study was limited by the lack of a contemporaneous control group; consequently, we conducted a cohort-controlled study. Smoking women (n = 8) and nonsmoking control subjects (n = 15) provided 24-h urine samples; excretion rates of biotin, the biotin metabolites, and 3-hydroxyisovaleric acid were determined. Increased urinary excretion of 3-hydroxyisovaleric acid, which reflects a reduced activity of the biotin-dependent enzyme 3-methylcrotonyl-Co A carboxylase, is a sensitive indicator of biotin depletion at the tissue level.

Results: Compared with control subjects from previous studies, the smoking women in the preliminary study excreted significantly less urinary biotin (P = 0.02). Moreover, the ratio of urinary biotin sulfoxide to biotin increased (P = 0.04) in these women. In the cohort-controlled study, the urinary excretion of biotin decreased by 30% (P = 0.04), and the ratios of urinary bisnorbiotin and biotin sulfoxide to biotin increased significantly, which indicated accelerated catabolism in smokers. Moreover, the urinary excretion of 3-hydroxyisovaleric acid was greater in the smokers than in the control subjects (P = 0.04), which indicated biotin depletion in the smokers at the tissue level.

Conclusion: These data provide evidence of accelerated biotin metabolism in smoking women, which results in marginal biotin deficiency.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Avidin / metabolism
  • Biomarkers / blood
  • Biomarkers / urine
  • Biotin / analogs & derivatives*
  • Biotin / deficiency*
  • Biotin / metabolism*
  • Biotin / urine
  • Carbon-Carbon Ligases / metabolism
  • Case-Control Studies
  • Chromatography, High Pressure Liquid
  • Cohort Studies
  • Creatinine / urine
  • Female
  • Humans
  • Male
  • Middle Aged
  • Sex Factors
  • Smoking / adverse effects*
  • Valerates / urine


  • Biomarkers
  • Valerates
  • Avidin
  • bisnorbiotin
  • beta-hydroxyisovaleric acid
  • Biotin
  • Creatinine
  • Carbon-Carbon Ligases
  • methylcrotonoyl-CoA carboxylase