tethered to it; indeed, it has been reported that asparagusic acid can substitute for lipoic acid in α-keto-acid oxidation systems such as the citric acid cycle. The (R)-(+)-enantiomer of α-lipoic acid is a cofactor in the pyruvate dehydrogenase complex and is essential for aerobic metabolism. The degradation pathway of lipoic acid has been well studied and includes evidence of reduction of the disulfide bridge, S-methylation, and oxidation to produce sulfoxides. Similar transformations of asparagusic acid would lead to metabolites like this detected in asparagus urine. Synthetic work has confirmed the relative ease of oxidation of asparagusic acid to yield S-oxides of the dithiolane ring. The rate of degradation appears highly variably between subjects; the typical half-life for odour disappearance is around 4 h with a between subject variability of 43.4%. In the small minority of people who do not produce these metabolites after consuming asparagus, the reason may be as simple as asparagusic acid not being taken into the body from the digestive tract or that these individuals metabolise it in such a way as to minimise the release of volatile sulfur-containing products. References External links Asparagus Carboxylic acids Organic disulfides Dithiolanes