The N-oxidation of trimethylamine in a Jordanian population

Br J Clin Pharmacol. 1995 Feb;39(2):179-81. doi: 10.1111/j.1365-2125.1995.tb04427.x.


The ability to oxidise trimethylamine (TMA) to trimethylamine N-oxide (TMAO) is distributed polymorphically within a British white population with the majority of individuals excreting greater than 90% of total urinary TMA as TMAO. The opposite extreme is characterised by a rare inborn error of TMA N-oxidation known as the fish-odour syndrome. However there is a lack of information regarding inter-individual variability in the N-oxidation of TMA in other ethnic groups. In this study the urinary excretion of TMA and TMAO was determined over a period of 24 h in 82 Jordanian subjects. A frequency distribution histogram of % of total urinary TMA excreted as TMAO revealed that the majority of subjects excreted greater than 80% of the total urinary TMA as TMAO, however eight subjects (9.7%) excreted less than 80% of the total TMA as TMAO. In a previous study of 169 white British subjects only one (0.6%) excreted less than 80% of the total TMA as TMAO. The results suggest that the prevalence of compromised ability to N-oxidise TMA may be higher in a Jordanian population than in a British population.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Ethnicity*
  • Female
  • Humans
  • Jordan
  • Male
  • Metabolism, Inborn Errors / metabolism*
  • Methylamines / metabolism*
  • Methylamines / urine
  • Middle Aged
  • Odorants*
  • Oxidation-Reduction


  • Methylamines
  • trimethyloxamine
  • trimethylamine