Can everyone smell it or only certain folks?
Winter says: "Beauty is in the eye of the beholder... or, asparagus-urine stench is in the nose of the smeller... AND actually depends on the pee-producer.
"Urine that smells foul after a nice asparagus salad is actually a multifaceted phenomenon. Some people make asparagus-stench urine, but some don't (producers vs. non-producers). What’s even more complicated is that some people can't smell asparagus-stench urine, no matter whether or not the smell is actually there (detectors vsn non-detectors)! We don't know exactly why people differ so much, but it seems to be an inherited/genetic trait you are stuck with.
"The reported rates of 'inability to smell asparagus urine' have ranged from 76% to 90% of people in some studies. We don't know the true rate, but it may vary based on the group you look at.
"Given that most people (myself excluded) don't spend a ton of time talking about urine, you may have a friend or two who actually have no idea this is even a thing. Seriously. Ask around."
Why is it so particular to asparagus?
Winter says: "We think it is because asparagusic acid is only found in asparagus. But to be honest, researchers identified asparagusic acid with a goal of finding a chemical that is only in asparagus... a bit of circular logic."
Can you eat a specific part of it and not get smelly urine? Is it in the stalk? The top part?
Winter says: "The concentration of asparagusic acid is higher in the tips. Seriously though, are you not going to eat that part? That would be like only eating the crust of the pizza."