Asparagus and Pee

[zut]

I was browsing through Cecil’s classic columns and came across one entitled “Why does asparagus make your pee smell funny?” In this column, Cecil notes

According to Allison and McWhirter (1956), the ability to produce the odor is controlled by a single autosomal (i.e., non-sex-related) dominant gene. In a sample of 115 persons, 46 were rendered fragrant by asparagus and 63 were not. (bolding mine)

However, that’s not the way I learned it. I understood that the ability to perceive the odor is genetically controlled, and that everyone produces the odor. A little searching turned up this site, which says

Early investigators thought genetics had divided the world into stinkers and nonstinkers. That was until 1980, when three researchers had the presence of mind to wave pee from the nonstinkers under the noses of the stinkers. Lo and behold, the problem proved to be one not of producing the stinky pee but of being able to sniff it out.

and also this site, which agrees that

From 1956 until 1980, it was thought that the excretion of odorous methyl mercaptan after eating asparagus was a dominant genetic trait; if you had the particular gene, you were a ‘stinker.’ But a recent study found that all asparagus eaters excrete methyl mercaptan; it is the ability to detect its odor that varies from person to person.

However, this second site also admits that “scientists remain divided” on the issue. OK then, what’s the real Straight Dope?

I also note that Cecil promised, in the aforementioned column,

I can’t exactly say that research is continuing, but if anything develops I’ll let you know.

C’mon, Cecil! Let me know!

[dougie_monty]

According to an article in Sports Illustrated, Babe Ruth was at a high-toned banquet and was offered asparagus. He refused it, saying it “makes my urine smell.”

[BobT]

I’ve polled my family on this question. About half can detect the asparagus smell and half can’t. My father says he can’t. My mother has passed away and failed to leave instructions about this important matter in her will. I have three older brothers. Two of us can smell the asparagus and two can’t. I can only assume that my mother could smell the asparagus pee.

[zut]

*Originally posted by BobT *
I’ve polled my family on this question. About half can detect the asparagus smell and half can’t.

Yeah, but have you tried smelling each other’s pee? I’m convinced genetics and asparagus-pee-smelling are linked, but I wanna know for sure whether genetics controls the ability to produce asparagus-scented pee or the ability to perceive asparagus-scented pee.

C’mon Bob! Go that next step in the name of science!

[Arnold_Winkelried]

*Originally posted by zut *
Yeah, but have you tried smelling each other’s pee?

All I can say is :eek:! BobT, if the answer to this question is yes, perhaps you should answer privately via e-mail, otherwise you’ll never live it down.

[BobT]

My brother and his wife ate asparagus and gave some to their daughter. They didn’t detect anything in her diaper. She didn’t say anything one way or the other. However, she’s not quite two years old yet.

[Duck_Duck_Goose]

Life’s too short to go around eating asparagus and then smelling the resultant pee.

Unless, of course, you can get a government grant to do so.

Must be nice.

[samclem]

Here’s my take on this:

But a recent study found that all asparagus eaters excrete methyl mercaptan; it is the ability to detect its odor that varies from person to person.However, this second site also admits that “scientists remain divided” on the issue.

and

only about half of us have a gene that enables us to smell the specific compounds formed in the digestion of asparagus.

from the second site.

You can’t have it both ways. If the research was done well, how can scientist remain divided? How hard can it be to design a simple experiment? 20 people, chosen at random, passing hot steaming urine under their noses, urine which was collected from some glutton who just ate 3 pounds of asparagus in the last half hour. Approximately 10 people should be able to detect the smell and 10 shouldn’t. That is, if that is a correct number.

Personally, I love asparagus. I can urinate within a short time after eating and be overwhelmed with the smell of the mercaptans(or whatever it is). Now I have to ask my family. Thanks a bunch!

[zut]

*Originally posted by samclem *
20 people, chosen at random, passing hot steaming urine under their noses, urine which was collected from some glutton who just ate 3 pounds of asparagus in the last half hour. Approximately 10 people should be able to detect the smell and 10 shouldn’t.

Sterling proposal, samclem. So…out of the 10,000+ members of this board, do you think we can get twenty “volunteers”?

Actually, you bring up a good point: just how can scientists be divided on an issue (and an important one at that) that seems to be easily resolved? I was hoping that a urologist would post to this thread with up-to-date data, but it looks like I’ll remain disappointed.