This question is almost as old as asparagus itself . . . well, about 15 minutes younger, I’d guess, because that’s how long it takes us to break down the chemical culprit that lies within-namely, asparagusic acid.
This acid, while stable when in asparagus, breaks down quickly in our bodies to various unstable sulfuric compounds, all of which volatilize when we pee-hence, the rotten smell.
But not everyone can smell it, and apparently, not everyone produces the odor. This has set up asparagus’s very own scientific controversy, along the lines of the “Nature versus Nurture” debate-only this one is more like “Production versus Perception.” Do those who do not smell it not produce the foul-smelling stuff, owing to a difference in their digestive tract, or do they just not smell it, owing merely to a difference in their olfactory sense?
As of this writing, this pressing question has not been answered definitively by scientists. It has been established that there are some people who do not produce foul-smelling pee after eating asparagus and there are some who do not perceive the smell even when another person’s foul-smelling pee is introduced to them. (And the DNA mutation responsible for that olfactory deficiency has even been identified.)
What’s the bottom line? You might rue your luck if you can smell it, but take some consolation that you’re in a talented minority. The latest estimate is that only 22 percent of folks have the genetic endowment for this ability. The more important bottom line: Take pride in the fact that you’re in the talented minority of folks who can eat their own homegrown asparagus!