Why does urine smell like asparagus?

After eating asparagus, I thought that all eaters simultaneously started to smell, to put the phenomenon of stinky pee in a somewhat polite way. Honestly: I only have to look at an asparagus. But now it turns out that only 45 percent of humanity carries the gene to produce asparagus pee. What? How come? Our neighbors from FavorFlav let's explain it.

Everyone? No, not really. Strangely enough, only about forty-five percent of people can produce asparagus pee. It's a matter of genetics. There are even known cases of asparagus-eating women who never had asparagus pee until they were pregnant. It turned out their child carried the gene and the substances they produced were excreted via the placenta!

Characteristic and penetrating

And then there's something else. Not everyone seems to be able to perceive the smell at all. The writer of this, an asparagus pee-er, can hardly imagine that. That's how it is with our kind of people. The smell is so characteristic and penetrating; how can you miss it?! Enter anosmia: the inability to smell a scent. One study mentions that as many as seventy-five percent of people are unable to smell asparagus pee. (However, another study shows that everyone can smell asparagus pee.)

Rotting

So the smell, which smells like rotting, is not so strange, because asparagus produces the sulfur-containing substance asparagusic acid. When we get that into our bodies, the substance is broken down and converted. Six sulfur compounds, including methanethiol, are the culprits; they are suddenly present in much higher concentrations than usual in our urine after eating asparagus. That explains why people have asparagus pee. But how it exactly works for those who do not have it is still unknown. To be continued!

Source: FavorFlav