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Are you able to smell asparagus metabolites in urine? [from General Topics]

I had assumed that nearly everyone was able to detect the odor of asparagus in the urine of someone who had just eaten asparagus, but I've now discovered that some people lack the ability to do so.

Are you someone who can smell the odor or someone who can't?

How about your first-degree relatives (parents, siblings, children -- not spouses)? Are they the same as you (also have -- or lack -- the ability to detect the odor)?

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  1. I've been wondering about this for a long time but didn't have the cojones to ask. Yes, I am one. Mr. RNR is not. Not sure about our child, he's still a baby and can't tell us yet :)

    1. My father, who will be 87 this spring, recalls listening to some radio broadcast of a dinner where Babe Ruth was a featured celebrity. He apparently was stationed very near the microphones, because when a waitress offered him asparagus, he could be heard very audibly to decline because asparagus made his urine smell....

      1. Yes I can (as can my spouse). I'm not about to ask my family. It's just inviting a whole 'nother set of bodily function jokes. Not gonna do it!!! Got too many f@rt references as it is!

        Not certain if it's related but I'm a super-taster as well. And please don't ask if I can taste the metabolites in urine......don't even.....not funny.....did I mention I have enough bodily function jokes from my family as it is??

        1 Reply
        1. re: Dee S

          Sure glad to know my family isn't the only one like this. lol

          Yes, I can smell it within a very short period after ingesting. I love to eat asparagus but really don't like that smell!

        2. I think it is about 50/50, it's a genetic thing.

          1. yes and immediately, like if I need to 'go' within 10 minutes. We call it 'asparagus wee wee smell' in my family (sorry for the tmi).

            1 Reply
            1. re: smartie

              Yes, it amazes me that the asparagus makes it to my bladder within minutes . . .

            2. There's seems to be some confusion in the responses, so I'll ask for some clarification: did you discover that the urine of some people smells after eating asparagus, or that only some people can detect that smell?

              It seems like you are saying that it's the latter, in which case, I'm a detector, as is my husband, but my sister and her husband are not (we had all always assumed it was about the urine, but I think I'm learning here that it's about the brain/nose).

              5 Replies
              1. re: Cachetes

                I have the same question as you did. Does everyone produce urine with a distinctive odor after eating asparagus and only some can detect the odor? Or, do some people not produce the odor in their urine?

                Since nobody provided an answer for you, and since it is asparagus season, I think you need to follow your sister, her husband, or both into the bathroom and find out if they produce urine with the distinctive odor after eating asparagus.

                1. re: John E.

                  Not everyone produces the asparagus odor in their urine, and not everyone can perceive it.
                  While it's unknown what makes an individual produce the metabolites, the ability to perceive the odor is due to a specific set of genes. If you have the set of genes, you can smell it. If you don't, you won't.

                  Research here:

                  1. re: maria lorraine

                    Thanks. I got the same information from a link earlier in the day somewhere on this thread. It does seem a bit complicated. For the record, I both produce and detect the frangrance ; ) It is just a curiosity for me. I don't understand why people would let this change their eating habits.

                    1. re: John E.

                      At the risk of being....off color.....and in an attempt to be delicate....I know of people who avoid certain foods, including asparagus, for a time prior to dates or intimate encounters so as to not *offend* the senses of a partner. Personally, I'm a huge fan of asparagus and other foods that linger so I tend to lean toward your line of thinking - if you enjoy it, why change your habits? If your partner can't handle it, perhaps that's something that needs to be examined on another level so a compromise can be reached.

                      1. re: Mutch2Do

                        Your delicacy is appreciated -- and your meaning as well. Some people seek out food/beverages in the time-frame you mention so as to enhance the experience.

                1. i can smell it. as could my mom.

                  1. I can (within about 20 minutes), my wife can, my daughter can, but my son wonders what we're talking about...I don't know if his pee doesn't stink, or if he can't smell it. I'm not going to volunteer to smell his pee to find out, tho.

                    1 Reply
                    1. re: ricepad

                      Twenty minutes! One of the things that seems so amazing about this phenomenon is how rapidly the odor is evident after eating!

                    2. I definitely smell it after eating asparagus, as does my SO.

                      1. There appear to be two different phenomena at work, as several posters have indicated: whether you are an excretor (someone whose urine contains the chemicals that produce the odors, whether you can smell them or not) and whether you are a perceiver (someone who is able to smell the odors, whether your own urine contains the chemicals or not).

                        Reading about this has introduced me to a new term "graveolent."

                        It's unclear just what percentages of people are perceivers.
                        As far as I can tell, there have only been a few studies that have examined this phenomenon, and they have varied in methods used and populations studied (ie populations in different countries, different continents).

                        Some people seem to be much more sensitive in their ability to detect the odors; these superperceivers can identify the odors in urine that has been so diluted with water that other individuals (who were able to identify the odors in undiluted urine) can no longer smell them. So I imagine a study that had participants smelling less-concentrated urine might tend to label a higher percentage of participants non-perceivers than a study using more-concentrated urine.

                        Another factor seems to be the asparagus itself.
                        One observer writing 300 years ago noted that eating young white asparagus is more prone to producing the odors than eating older asparagus.
                        An author of a more recent article even suggests that whether the asparagus was grown in soil with fertilizer bearing a high sulfur content probably also contributes to the odor, since the intensity of the characteristic flavors of onion and garlic are affected by the sulfur content of the soil in which they are grown.

                        Although the specific gene or genes that convey a perceiver ability haven't been identified yet, investigators believe they have narrowed down the region of the genome where the gene(s) seems to lie.

                        "Food Idiosyncrasies: Beetroot and Asparagus" SC Mitchell, Drug Metabolism & Disposition 2001

                        "Web-Based, Participant-Driven Studies Yield Novel Genetic Associations for Common Traits"
                        N Ericksson et al, PLoS Genet 2010

                        "Excretion and perception of a characteristic odor in urine after asparagus ingestion: a psychophysical and genetic study" ML Pelchat et al, Chem Senses 2011

                        1. Why is it relevant to chowhound?

                          I'd say it's just one more example of how fundamentally our senses of taste and smell can differ at a biological level, as with cilantro or hot peppers or sweets or alcohol. In the case of being unable to smell these asparagus-related odors, the evidence seems pretty compelling that the differences are genetic.

                          It really makes you re-think how to approach taking recommendations about food from people whose tastes you aren't very familiar with.
                          Recipes might look good online or in a cookbook, but yield disastrous dishes in your hands -- not because the instructions were faulty or you failed to follow them correctly, but simply because your taste might be so different from the author's. Same with reading reviews of dishes and restaurants.

                          3 Replies
                          1. re: racer x

                            "It really makes you re-think how to approach taking recommendations about food from people whose tastes you aren't very familiar with."

                            So, what, you're going to ask people how their urine smells before taking a restaurant recommendation or a recipe?

                            Count me in the group that doesn't want to read about waste products on a food website.

                            1. re: im_nomad

                              You're overly focused on the fact that this discussion involves urine.

                              The urinary aspect really isn't the point (although I've no doubt that it does make for a fun discussion with 8-year-olds).
                              The important point is that this phenomenon shows that people can normally (ie, not just as a result of disease) differ profoundly in their sense of smell, and thus in their sense of taste.

                              It happens that this aspargus example involves smells associated with urine, but that's just incidental. I wouldn't be surprised at all if it is eventually found that people differ in their sense of smell for many (thousands of) other odors, none of which were previously investigated because it has always been assumed that everyone perceives them equally.

                              “Thresholds are highly variable both within and across individuals. Some individuals with an otherwise normal sense of smell are unable to detect some families of similar smelling compounds.... Common specific anosmias include an insensitivity to the following compounds of potential importance in foods: androstenonoe, a component of boar taint; cineole, a common terpene component in many herbs; several small branched-chain fatty acids important in dairy flavors; diacetyl, a lactic bacteria by-product; trimethyl amine, a fish spoilage taint; isobutyraldehyde, responsible for malty flavors; and carvone, a terpene in mint and other herbs.”

                              from “Sensory Evaluation of Food: Principles and Practices” 2nd ed, HT Lawless and H Heymann 2010

                              ^ those are just from a handful of odorants that have been studied -- this is an area that has been relatively untouched by the scientific community.

                              1. re: im_nomad

                                "So, what, you're going to ask people how their urine smells before taking a restaurant recommendation or a recipe?"

                                Of course not.
                                But this information helps explain from a biological standpoint why it pays to try to become familiar with the tastes of someone whose recommendations or recipes you are considering using.

                            2. Neither I, my husband, or our family have ever noticed anything unusual re: our urine after eating asparagus - & we're all asparagus lovers. Thus I never understood all the stories about it.

                              1. what about beet excretors? Some people's urine turns red after eating beet(root), others not.

                                21 Replies
                                1. re: smartie

                                  Now THAT would certainly be a shock. Fortunately, I don't seem to react to either beets or asparagus.

                                  1. re: Tripeler

                                    It's always a bit of a shock until you remember, "oh yeah, i had beets."

                                      1. re: ScubaSteve

                                        Ditto. Scared the bejesus out of me the first time. Had only consed minimal quantity before. Had to check the interweb for causes. Realized the culprit after a few searches.

                                        Both SO and I can smell the asparagus though.

                                  2. re: smartie

                                    Oh yes, I think this one is even more disturbing than the asparagus. And it's not just the urine that changes color...

                                    1. re: Cachetes

                                      I am both a victim of asparagus and beets. Thank god I know about "the beet thing" because if not, I would worry!

                                      1. re: Alica

                                        I'm blessed with the holy trinity:

                                        Asparagus pee
                                        The next morning beet whateveryouwanttocallit
                                        Butternut squash cracked and dried skin (after peeling and cubing)

                                    2. re: smartie

                                      Yes, that topic is discussed in the article I cited above -- "Food Idiosyncrasies: Beetroot and Asparagus."

                                      A hypothesis is that beetroot pigment is mainly metabolized by stomach acid, so people whose stomach secretions are not as acidic as others and/or whose stomachs empty faster than others might be more likely to produce reddened urine after eating beets. The article mentions an example of someone who wasn't a betanin (red pigment in beets) excretor until he started taking medicine that reduced his stomach's acidity.

                                      1. re: smartie

                                        Just for fun, last year I pickled some beets and asparagus together for the riotous sights and smells!

                                        1. re: ricepad

                                          "Just for fun, last year I pickled some beets and asparagus together for the riotous sights and smells!"


                                            1. re: ricepad

                                              Was it delicious? It doesn't sound that appealing, but I'm open to surprises!

                                              1. re: Mawrter

                                                Oh, yes! I don't remember what went into the pickling liquid, but I'm sure I included mustard seed and possibly coriander and black peppercorns. I don't remember what else. I seem to recall I also sliced a yellow onion to be pickled along with the beets and asparagus.

                                            2. re: smartie

                                              what, that doesn't happen to everyone?? really? i really had no idea.... being totally serious here.

                                              ETA: HOWEVER... i don't think it happens with canned, only fresh (fresh and then roasted or steamed) ..... i just happened to have canned beets Sun. night, and .... nothing.

                                              1. re: smartie

                                                Others in their feces as well. Both cause many unnecessary emergency room visits.

                                                  1. re: Fru

                                                    which would you prefer -- to read about it here where you're the only one in the room, or to hear about it from an intern barely able to suppress the giggling when he tells you that the reason you're in the ER is because you ate beets? (don't forget the copays and medical bills attached to it)

                                                    1. re: sunshine842

                                                      Giggle. That could have happened to me but upon reflecting on what I had eaten there was no need. The pee is a pretty pink color though...

                                              2. we are in my family, and my father refuses to eat asparagus because of it :) happens to me with broccoli, spinach, brussels sprouts & shiitake mushrooms as well, which makes me think glutathione metabolism is involved.

                                                coffee also has an impact, though the odor is completely different.

                                                2 Replies
                                                1. re: goodhealthgourmet

                                                  yes, I've noticed coffee has a similar effect too...

                                                  1. re: gembellina

                                                    Yes on all: beets..., asparagus pee, coffee pee, and...artichoke pee!

                                                2. Everyone in my family can smell it. Just to clarify, though, a small study (it was small for obvious reasons) showed that everyone in the study produced the odor, but not everyone could detect it.

                                                  My daughter will sometimes avoid a dish containing asparagus if she decides she doesn't want to deal with the odor.

                                                  1. Self -yes
                                                    Spouse - yes
                                                    Child - yes

                                                    Never had the guts to ask my parents about their bathroom experiences. I remember reading somewhere that it is genetic and it's 2 separate abilities - the ability to produce the smell and the ability to detect it. Isn't it great being special?

                                                    1 Reply
                                                    1. 2 out of 2 in my household can smell it. Doesn't stop me from binging on my favorite spring green!

                                                      1. My husband and I can both smell it, and almost immediately. Blech.

                                                        1. I can smell it and feel it. Asparagus is great for minor to substantial swelling relief. At least for me it is.

                                                          1 Reply
                                                          1. We totally reek and smell it almost immediately in our house.

                                                            1. It seems that the pungency varies depending on when or where the asparagus is grown. I've noticed that it is consistent when I get Peruvian asparagus, but in season in the US, it's more random.
                                                              It's kind of like skunk smell - either you love it or you hate it.

                                                              9 Replies
                                                              1. re: jmcarthur8

                                                                There are people who LIKE the smell? Seriously?

                                                                1. re: Isolda

                                                                  Back in the day , in my fraternity house after a dinner with asparagus, all would gather in the communal shower and pee, amazingly l do like the small. Ah the joys of an Ivy League education.

                                                                  1. re: Delucacheesemonger

                                                                    No offense, but I couldn't think of a better reason not to join a fraternity!

                                                                    1. re: ricepad

                                                                      We were thrown off campus later that year, nothing to do with asparagus but hazing.

                                                                  2. re: Isolda

                                                                    It's inoffensive and (to me) amusing -- not like the men's room of a bus station or similar.

                                                                  3. re: jmcarthur8

                                                                    "It's kind of like skunk smell - either you love it or you hate it."


                                                                    1. re: ttoommyy

                                                                      I adore the smell of skunk, but it prolly has way more to do with the region i was raised in, known as the "emerald triangle." Skunk was all over, but not from the animal itself, and I actually find it hard to differentiate. (Unless I'm on an urban city street and smell skunk, in which case it's definitely not the animal.)
                                                                      Yep, I can smell asparagus pee, as can my family entire. When my son was around five, I told him that sparrowgrass was on the dinner menu, and he said, "but it makes your pee green." And I realized that he was referencing not the color, but the smell.

                                                                      1. re: mamachef

                                                                        I agree that the "badness" of skunk spray smell is hugely overstated - it's burning and acrid if sprayed directly onto mucous membranes but not that unpleasant otherwise. Nowhere near as bad as, say, a wood pulp mill or a row of portapotties at the end of a long hot day.

                                                                        But then, I really love skunks.

                                                                      2. re: ttoommyy

                                                                        Anyone that loves weed would love the smell of skunk too.. I always am like "hooooooooo boy that's some stinky weed someones got" anytime I drive through a skunky area

                                                                    2. We (4) are all asparagas weer's here.

                                                                      1. Another interesting little tidbit I've come across while reading about this.

                                                                        It seems that at least for some odors, it is may be possible to be converted from being a non-perceiver on first exposure to a perceiver after several exposures (although some never seem to acquire the ability to perceive the odor).

                                                                              1. Back in the '80s, when Julia Child taught us to peel the bottom half of asparagus stalks prior to cooking, my (late) father asked me, "Will my pee still smell?" It did, and I think we were all relieved.

                                                                                1. My father can smell it, but I cannot. I don't think my mother could smell it either.

                                                                                  1. I seriously wonder if it has something to do with the asparagus you eat rather than your sense of smell. Here's why: I have heard about "asparagus pee" but have never noticed the smell from my own pee OR my family's (and we are all asparagus fans). But recently I bought a bunch of late-season asparagus at a local market...it was dirt cheap and I figured it might be my last chance for awhile to find good, fresh asparagus that didn't cost a fortune. DH was out of town all week, so I decided to roast it and ate the whole bunch myself with a couple of runny fried eggs. Yummy dinner. But I noticed soon afterwards that my bathroom smelled funny....sure enough, it was the pee. And it lingered long after the toilet was flushed. And it wasn't pleasant.

                                                                                    So why did I notice it after all those years of eating asparagus? Was it the variety of asparagus? The fact that it was late in the season and some chemical was somehow concentrated due to the longer growing season? The cooking method? My imagination? )I don't think my sense of smell suddenly improved; it is after all the peak of allergy season here and my nose is constantly stuffy.) ...Inquiring chowminds want to know.....

                                                                                    1 Reply
                                                                                    1. re: janetofreno

                                                                                      I think it's a little of all three -- you have to have the gene to produce the aroma at all -- you have to have the gene to detect it -- and, yes, the chemistry of the asparagus can producing varying degrees of aroma. I love asparagus, and so accept the bad with the good, but yes, there are varying levels of intensity.

                                                                                    2. I cant smeill it in my pee- and to be perfectly honest, I have never smellled the pee of anyone in my family!!! Though one of my little nephews told me asparagus made his pee smell when he was only about 6!

                                                                                      1. Yes, I can smell the odor.

                                                                                        But it varies, and I cannot figure out the rhyme or reason.

                                                                                        Big spears or thin spears. Early season or late season.

                                                                                        Sometimes a bunch barely produces an odor. The next bunch produces an odor that lasts for a few hours.

                                                                                        1. I can detect the odor after just eating a couple of spears!

                                                                                          1. sometimes i forget that i ate asparagus and then the smell will remind me

                                                                                                1. DH and I both can. Urine also has a distinct odor from imbibing coffee, at least to me.

                                                                                                  1. Everyone that I know of on both sides of my & my dh's family can smell it, as can our chowpup. Probably this means we are all savages, but we find it amusing. I mean, I'm even amused (not revolted) when I notice the distinctive asparagus pee smell in the women's room, to the extent that I'll think,"Gosh, maybe I should have ordered the asparagus!". It's nothing at all like the nasty smell of stale pee, it's more like a variation of the smell of steamed asparagus.

                                                                                                    1. Oh, yes. In mine. But I have no experience in smelling others.