From the Research
Asparagus and Urinary Odor
- Asparagus consumption has been associated with the production of a pungent urinary odor, which is due to a combination of up to six sulphur-containing alkyl compounds, including methanethiol, dimethyl sulphide, and dimethyl disulphide 1.
- The possible precursors of these odorous substances are S-methylmethionine and asparagusic acid, which are related to the known chemistry of the vegetable 1.
- Individual differences exist in both the production of the odorants and the perception of the asparagus odor in urine, with some people unable to produce the metabolite in detectable quantities or smell the odor 2.
Mechanism of Urinary Odor Production
- The derivatives of 1,2-dithiolane, including asparagusic acid, may be responsible for the distinctive urine odor produced after consuming asparagus 3.
- The urinary excretion of odorous substances after eating asparagus is not an inborn error of metabolism, but rather a specific smell hypersensitivity 4.
- Thresholds for detecting the odor appear to be bimodal in distribution, suggesting a genetically determined specific hypersensitivity 4.
Kinetics of Urinary Odor Production
- The elimination half-life of the asparagus effect on malodorous urine has been estimated to be 7.2 hours, with an absorption process half-life of 25 minutes 5.
- Interindividual variability in urinary odor kinetics has been characterized using a kinetic-pharmacodynamic model, which included data from crowdsourced studies 5.