Odiferous Tinkles

Though we ate asparagus fairly often in my house while I was growing up, and though I noticed that occasionally my urine would smell funny, it wasn’t until I was 20 years old and on Semester At Sea that I finally put the pieces together. I remember the circumstances well: the lunch buffet featured cream of asparagus soup and the bathrooms stank to high heaven. I finally realized that asparagus makes your pee smell funny.

Today, several hours after I had tuna for lunch, I noticed that my urine had a definite tuna aroma. Which led me to wonder two things: how many other foods have an impact on urine odor, and by what means do these foods have this effect?

As I mused on the first question to Aurora, we realized that we couldn’t come up with any other culprits off-hand, though, as the first 20 years of my life go to show, is far from iron clad evidence that others don’t exist. The one observation Aurora did make is that “beets make your poop turn red.”

“Maybe,” I countered, “but they’re a solid food and exert an effect on your solid waste,” which is much less of a stretch of the imagination to figure out than how solid foods impact your urinary composition (though, upon closer reflection, one does realize that every food contains some water, and all foods are broken down into their component molecules via the digestive process), but still, I alleged, “beets don’t turn your pee red.”

Turns out I was wrong. Consulting Harold McGee’s comprehensive guide On Food and Cooking: The Science and Lore of the Kitchen, I came to discover that beets do impact the color of your urine, though usually so minutely as not to be discernible to the naked eye. However, “because the body has a limited ability to metabolize” the betain molecules that give beets their crimson appearance, “a large dose of red beets or prickly pears can give a startling but harmless tinge to the urine.”

Mr. McGee’s only other explanation about food’s impact on the urine comes in relation to our good friend asparagus. Its effect on urine has been noted for centuries; On Food and Cooking quotes Louis Lemery’s Treatise of All Sorts of Foods, which dates to 1702, “‘[Asparagus] cause a filthy and disagreeable smell in urine, as everybody knows.” Except it turns out that not everybody does know it: there is a small portion of the population in whom asparagus doesn’t have this effect, and a somewhat larger number of persons who are unable to smell the asparagus pee stench.

Those of us who do both experience the effect and are able to smell it shouldn’t be surprised that it is caused by “a chemical relative of the essence of skunk smell called methanethiol,” which results when “apparently the body metabolizes a sulfur-containing substance, asparagusic acid.” Fascinating! An acid apparently limited or closely enough related to asparagus that its name is derived from the vegetable. I wanted to know more, but Mr. McGee wasn’t revealing anything further.

Fortunately, there’s some chap out there who writes under the name of Bandolier who wonders about these issues, too, and has examined asaparagus and beets and their effect on urine. It turns out that, though asparagus is the main source of asparagusic acid, it is also “found in a few other food plants, though some non-food plants like tropical mangrove also contain it.” Evolutionarily, it “kills parasitic nematodes, and protects the asparagus plant against them.” Perhaps Bandolier’s most noteworthy observation, though, is “that despite appearing in historical works for about 2,500 years, it was only in the 1700s that it was associated with malodorous urine. This coincided with the use of sulphur-rich fertilizers to improve the flavour of asparagus and onions and garlic.” I can’t recall a urine odor that corresponds to the other two vegetables, but that may be because I haven’t paid attention.

Then again, a quick internet search for information about foods that cause smelly urine turned up a lot of discussion about asparagus and not much else, though I did find a reference that provides more evidence for my ongoing disapproval of low-carb diets: “I noticed recently that I developed an ammonia smell in my urine after going on a low carb diet, the kind of diets which are known for putting bodies in a state of acidosis. The ammonia smell went away when I went off the diet and started eating more carbs, and presumably increased the alkalinity of my body in the process.” Our bodies need complex carbohydrates as its main source of energy; a smart nutritional plan will put emphasis on these foods whilst de-emphasizing heavily processed foods including sugars and simple carbs. But that’s another post altogether.

There was no mention anywhere of tuna causing a distinctive odor in urine. So, now I’m wondering, what other food-related urine odors are going underreported? Please, try to keep one nostril open as you tinkle and let me know what you find out.

42 Responses to “Odiferous Tinkles”

  1. Lydia Says:

    I don’t know about the cause of the asparagus odor, but I can’t imagine giving up eating asparagus because of it.

  2. Mom Says:

    I don’t know about odor but beets definitely give urine a red color, especially if you eat a lot of them.

  3. June Says:

    Surely you saw Cecil Adam’s column on smelly asparagus pee as you trawled the Web?
    http://www.straightdope.com/classics/a2_383.html

    I have an extremely sensitive schnoz and can detect odors at lower concentrations than anyone else I know (with the possible exception of my mom). Anyway, I can, er, smell something in my pee after I drink coffee. I wondered whether it was caffeine, but it turns out that regular and decaf coffee will break down to whatever molecule it is that I smell. (The reason I noticed it at all - I have a long commute and drink a tall coffee before I start driving. By the time I get to work 1:15 later, I’m busting to go - and that’s when I’ll smell it. OK, sorry, maybe that was too much information!)

  4. Johanna Says:

    I have also notice the coffee smell - but it usually happens when I’m working on a big campaign at work and I drink coffee all day long to keep me moving, and then I never get around to peeing until the end of the night. At that point what I usually smell is just coffee. I assume it’s because I’m not keeping my poor body hydrated enough.

  5. anon Says:

    It is not just urine that has an odor as a result of the food you eat. I have noticed that certain , um …, “female scents” are more fishy after consuming seafood.

  6. Kristy Says:

    I just started to search the internet because I myself went on a daily tuna diet and just started to notice that my pee smells just like the tuna. I wanted to research this to make sure that by eating so much tuna that I wasn’t harming my kidneys or anything else. So far this is the first thing I found that actually referenced the tuna pee auroma, so at least I know that its not just me. Its been great for the diet but being a woman not exactly the smell I would like to smell like.

  7. Giles Austin Says:

    As an “Anglo-Saxon” culture, that is we English speakers, we are not given to the examination of our foecal matter and urine, which we find distastefull and such phenomena as you describe go unnoticed or deliberately ignored. We put a high value on regularity but not quality! This was not the case in much of Europe, some their porcelain was designed to aid inspection before flushing.
    I would suppose that aspargus and almost anything else you put into your digestive tract has some effect. One eighteenth century pharmacologist did observe with surprise that the several hundred wood-lice he consumed in the interests of science had no discernable effect. This struck him as a great peculiarity,- you may care to re-try this simple experiment.

    Breast feeding mothers can find their milk changed by the seemingly most innocuous of foods - strawberries to name one. Onions, garlic and a lot of spices, especially asefoetida, which some hold smells similar to onion when cooked, are observable in the perspiration. I find globe artichokes, which in season I eat in great quantity, also noticeably taint the urine whilst aspargus also acts a diuretic, (unexpectedly, I observe that so does ox tongue).

    The strangest instance of the transmission of flavours/smells I have seen cited is the flavouring of semen by the ingestion of large quantities of Jaffa Cakes. I lack the curiosity to confirm the truth of this assertion.

    It could be that our opinions in this general area are coloured by a century of the marketting of relatively simple but effective synthetic drugs. Whilst synthetics were in their infancy it was in the interests of their purveyors to persuade us that all else was hocus pocus. (Just as the supermarkets have persuaded us to eat “fresh” beef, and to eschew mutton, greatly to their advantage in every way- except when many stopped buying their dreary tasteless products). I still know nothing in my chemist shop as effective, or as distaseful, for a painful stomach as Fernet Branca.
    The pharmaceutical interest in recent works on the early herbals has surprised me, I am guessing that now that it is commercially feasible to analyse and synthesise much more complex organic compounds we will see more and more drugs derived in emulation of nature.

    Diet is an intrinsic element in maintaining and boosting health. The early dietaries which used the Galenic classifications had millenia of experience and observation behind them. The codification by the humors, which now seems quite absurd, does not have to discredit the whole system. We try to “scientifically” explain an attribute, the humoralic system was the explanation given by Natural Philosophy - observation remains unaltered.

    There are plenty of illogical dietary credos current today, amongst those who have the luxury of choosing what they eat, with not even the authority of long-term observation.
    Anyone interested in seeing just how much our ancestors were quite well aware of, which is now presented to us as the fruit of modern research, might refer to Thomas Moffet, the Elizabethan doctor and entomologist famed for his daughter’s arachnophobia.

  8. Sheila Says:

    I am so glad I ran across this. I mentioned to my sister and my husband just yesterday about tuna making my pee smell funny and they both looked at me like I was crazy. Coffee and asparagus do this to me too, but apparently none of these have any effect on my sister. I was starting to wonder if something were wrong with my kidneys. Thanks folks, I am so glad I’m not alone with strange urine odors.

  9. david Says:

    I’ve got to say I don’t recall any smell of aparagus in the urine , but the tuna smell I have experienced . I have however noticed a new smell in the urine . Last night I had some beef stew , and in a little less than an hour after I ate I had to ” tinkle ” . With little surprise , a strong beef stew smell was present . So whats next ?

  10. Corduroy Orange » Blog Archive » More About Asparagus Pee Says:

    [...] Ever since I put up my original smelly urine post, Aurora has been insisting that asparagus doesn’t affect her urine.  Turns out, though that she’s just one of the folks who can’t smell it even though the odor is there.  Weird…. [...]

  11. Corey Says:

    I also notice a tuna odor in my urine after eating it. I am glad to know I’m not the only one! My brother and his wife thought I was crazy too.

  12. Mary Says:

    It baffles me that besides asparagus urine, the topic of odorous urine isn’t more casually spoke of in social gatherings. After waking up this morning from eating a late night hot dog at an Independence day gathering, I noticed my urine smelled exactly like a hot dog. My doctor, a personal friend who attended the gathering as well, said she made sure to drink 2 cups of water before going to bed. This infact will help prevent odorous urine.
    The water helps dilute the concentration of particular elements of food that can cause odor, such as vitamins, acid, food dye, and artifical food flavorings.
    If the smell of your urine is accompanied by any pain or a cloudy, murky color, then a doctor should be contacted.
    But the smell of urine - I think people just do not bring up this common yet unspoken event.

  13. Kevin Says:

    I can vouch for the tuna smell that many have described. Just happened to me today. I do not usually eat tuna, but today all I had for lunch was a full can of tuna and some water. When I urinated this evening, I was a bit disconcerted about the strange, powerful smell. Then it hit me that it smelled exactly like the tuna I had eaten for lunch. very strange.

  14. ksich Says:

    I got on the internet to research why my pee may smell funny the past couple days. I dont have any other urinary tract infection type symptoms, so I wondered if something else was off balance in my body. Sure enough, to find out that asparagus causes this! I have been eating asparagus for lunch and dinner the past 2 days. (leftovers you know!) Glad to know I’m still healthy as ever.

  15. Canny Says:

    Am I ever happy that I fell across this site. I really thought that I was the only one this was happening to. I also have an extremely sensitive nose when it comes to odors and can detect almost any odor there is to detect!
    The other night I made myself a sea food stir-fry containing shrimp, petoncle and lots of asparagus tips (other veges too) and had two huge plates. A few hours later when I went to the washroom I noticed a strong odor from down there. I was freaking out because well it wasnt very pleasant. The next morning it happened again and I decided to check online for solutions. Im not a very big sea food or asparagus eater so this is the first time I really noticed the difference. I feel much better now knowing that this is the cause and not something else. Thank you!!
    Oh and I agree about the tuna too, when I eat it that happens to me as well. Bye!! =)

  16. Wombat Says:

    I found a really good recipe for a shrimp and asparagus fettucine. I’ve noticed a strong odor in my pee after I’ve eaten this dish—I was thinking it was from the shrimp. The recipe calls to cook up raw shrimp. I found this article interesting about the asparagus. It’s a very tasty dish. So it sounds like it’s the asparagus is the culprit for the strong odor.

  17. Mixmaster Mike Says:

    I have been aware of the effect of asparagus on my pee for years (First discovered this thanks to the Austin Powers movies), but I have recently noticed other foods & beverages have similar effects. Even a single cup of coffee can take its toll on the odor of my urine. Lately I have also noticed that chili will alter the smell of my yellow stream.

  18. Bob Says:

    Well I am another one with the tuna smell when urinating, I recently went on a lower carb diet, eating no breads and white rice but not restraining from much else, I also increased my tuna intake by having it on sallads, and yes i smell tuna very strong, but this will stay in effect for a few days, however i am now not to worried, thanks.

  19. chrissy Says:

    i too get the “tuna odor” after eating tuna, but i’m not sure if it’s urine i’m smelling, because sometimes i can smell it even before i’ve tinkled. i am female - perhaps there is something else at play here other than just urine?

  20. Kenny Says:

    I am like June. I too have an extremely heightened sense of smell and taste. I have been treated to the obvious asparagus odor and recently noticed the tuna smell, particularly because I ate tuna jerky.

    Another food that does it to me: bacon.

  21. Amanda Says:

    I am so glad I read this! I went to the beach this weekend and went out to eat at the seafood buffet last night. I wake up this morning and go to the bathroom and my urine has a strong fishy odor. The more I think about it this happened last time I ate seafood. I wonder what causes it???

  22. Alysn Says:

    Same here on tuna as well as canned chicken and occasionally other foods, though I cannot recall which. It’s very interesting to find this page as I thought perhaps there might be something wrong, but I now see I am just one of a larger group of people who have noted this in their lives. I’ve only recently noticed the more obscure smells, but it does appear to correlate with my drinking less liquids in an attempt to cut back on sugary drinks. I expect this new ability would decrease if I was properly hydrated.

  23. carmella Says:

    hi;
    i dont have kidneystone but my urine is so smelly
    that is so embarrassing to to the bathroom at family hosr or friend because the smell any adivece? i do drink a lot of water and cranberrie juice

  24. Jiggy Says:

    Surfed into CO.com for your knife skills articles–thanks for those!

    Supplementing vitamin B-12 will turn it neon green, and men’s one-a-day multivitamin adds what strikes me as a fruity, maybe pineapple scent. Someone knowlegeable told me once that the coffee smell is actually a product from digesting the coffee (and not the coffee itself flushing through, I guess), and that this trait is not genetically present in everyone. I, for one, welcome our air-freshening genes.

  25. mslion42 Says:

    I am glad I ran across this article for the last 5 years whenever I eat any kind of seafood, I smell it in my urine, my family thought I was crazy, but I ran across an article today talking about the Methyl marcarbin (probably not spelling this word right) and aspargine and the way the body breaks down these acids, it is also in onions and garlic too. It was saying some bodies breaks down differently from others thats why some folks smell and some don’t when they eat these foods So for all of you out there you are NOT CRAZY OR ALONE, I have learned if you keep drinking plenty water during and after eating these foods the smell goes away faster, I guess the more you urine the less you smell.

  26. Kitty Says:

    I’ve had this happen for years, it always happens with meats with me, tuna/chicken/turkey/fish/etc. I’ve got a very sensitive nose, and it always seems that I start smelling like my food.

    Pineapple is great for flushing the system to restore a sweeter smell. For girls and guys it helps change not only the smell of urine, but other bodily fluids as well. Anyone who eats a diet high in spices & herbs can easily tell you that what you eat will change every bodily fluid smell that you have.

    Most people who say they don’t have those scent reactions to food often just can’t smell the difference, though others with more sensitive noses still can. I can always tell when the people in my life have changed their diet by either scent or taste (if I’m dating them).

  27. Rose Says:

    Glad to have found this site. I have also noticed an odor after eating turkey, fish and some other foods. Beets also make the urine red and also can smell coffee. I am in my 40’s and wondered if this was an age thing or is it how our poultry/fish is massed produced or farmed? I don’t remember that happening when I was young.

    Thanks Kitty I love pineapple.

  28. Raul Says:

    Wow until now I thought something was wrong with me. I smell tuna fish in my urine and I been asking people if this happens to them when they eat tuna, they laugh and think I’m crazy.

  29. cereal Says:

    when i was a kid my mom bought us that sugar puff cereal and everytime i would eat it my urine would smell like it.

  30. Dave Says:

    Today had a reminder of my previous meal. I had beef roast for lunch and smell it by evening. I have been wondering if others have this condition.
    My mother told me I have had this since I was born. She would feed me and could smell it in my diaper shortly after.
    I also have problems with purple dyes.
    I know tuna, beef, garlic, asparagus and some others create urine odor for me.
    I am a type A positive blood type.
    I have read “Eat Right for Your Type” referring to blood type. It would say that a type O blood would digest protein better.
    Is anyone type O experiencing this?
    Maybe I will try the books suggestion if this is the case.

  31. Colleen Says:

    I too can smell a fish smell in my urine, later in the day or the next day after consuming most types of fish, glad to know I am not alone! I do not eat asparagus often so I have not noticed a smell with that. I have noticed a smell with certain breakfast cereals and coffee.
    I also have A+ blood type.
    I consider myself in excellent health so I am not concerned, just interested on why this happens to me and no-one else in my family.

  32. O+ Says:

    I happen to be O+. After I eat tuna or drink more coffee than usual I can smell the change in my urine… Incidentally, I’ve never smelled the asparagus, although I tend to eat a lot in the spring. Hopefully I’m not unintentionally grossing out my polite housemates!

    As for digesting protein better, I couldn’t vouch for that. However, I do need to eat red meat at least once a week, or I don’t function properly.

    Speaking of bodily quirks, have any of you noticed that you smell things differently? For example, to me BO smells like onions, and often chedder cheese smells like vomit.

    Ps. Sorry Carmella, I haven’t got an answer for you… Have you asked a doctor or PA?

  33. dbug Says:

    I swear my sweat and whole body smells like onions when i eat them. Yes, my friends and family think i’m crazy. I also have the asparagus stinky urine syndrome.
    I’m not going to lie, originally started searching on the tuna smell down south. Was worried about what my husband could be doing in his spare time. You always here that a fishy smell is a sign for bad vaginal health. I’ve never heard mention [until now] that eating tuna daily could cause fishy smelling bodily fluids. Ewwww what about sexual encounters? Can men smell or have any evidence of these odors in semen? Any smells/tastes during sex?

  34. ana Says:

    I have eaten too much asparagus one time and got so worried the day after because of a weird smell when i urinated. Searched for it and found out that eating asparagus makes the urine smell different. It was also verified by a co-worker, probably basing from experience. I am kinda puzzled again, been fascinated with nutella for maybe a month now and i’m into my second jar. I’ve noticed a changed in my urine’s odor, been drinking cranberry juice and some other juices to hopefully get rid of the smell. Of course i’m still devouring the hazelnut based spread. Just wondering if it is making the urine smell odd… Anyone fond of nutella here that noticed the same?

  35. Catherine Says:

    Lately I have noticed a fishy odor in my urine after eating halibut. (This doesn’t seem to affect my husband. Or he isn’t paying attention.) I believe this may also have something to do with how fresh the fish is. We are a military family and move around a lot. When we lived in the Seattle area, and could get really fresh fish, malodorous urine was not an issue. Now, living in Missouri we can’t get fresh fish and there is definitely a fishy smell in my urine

  36. Christy, expert dog urine smell remover Says:

    Jiggy - interesting about the B12 vitamins, I’d never heard that! Thanks for sharing.

    Could the smells have anything to do with ammonia? I know that in dog urine, ammonia is the culprit of the smell, not necessarily the dog’s diet. But I may have to watch how much tuna she gets now… ;)

  37. fjord83 Says:

    My urine usually smells of tuna, however, I never touch ANY seafood. Why am I smelling it?

  38. mimi Says:

    fjord83, have you been checked for STI’s? sorry to ask but you may have one.

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