Is Smelling Asparagus Pee Genetic
Edward R. Forte
November 24, 2021
As it turns out, not everyone is lucky enough to experience the phenomenon dubbed “asparagus pee.” New research reveals that only those of us with variations in the genes responsible for detecting smell can get a whiff of the strange scent.Share on Pinterest Recent research has identified the genetic origin of the ability to smell the odor in human urine produced after consuming asparagus. .
Genetics of Asparagus Smell in Urine
There are two distinctive traits in this phenomenon, including the excretion of sulfur compounds in urine after eating asparagus and the ability to smell those compounds.While some people secrete sulfur compounds through their urine following the consumption of asparagus but cannot smell them, others can smell the compounds in their urine without the ability to secrete the same compounds.Some people have the ability to smell “asparagus urine” while others do not.Some people are incapable of producing the compounds that are believed to cause the “asparagus pee” smell in detectable quantities.A small percentage of people cannot smell the odor in “asparagus urine.” The inability to smell odors is called anosmia, and those unable to smell asparagus metabolites in their own urine as well as in others’ urine are said to be asparagus anosmic.Asparagus anosmia is associated with variations in the DNA sequence called SNPs that determine our sense of smell.Humans perceive a wide variety of chemicals as having distinct odors.The production of odorants varies in each individual; therefore people with undetectable odor in urine may still produce the odorous compounds in their urine but at a lower concentration.Besides genetics, how frequently a person eats asparagus also has an effect on their ability to detect the smell of sulfur compounds.Therefore, the real reason for this inability to distinguish a foul odor after consuming asparagus could be that women are less likely to notice an unusual odor because of their position during urination.Recent and ongoing research illuminates the fact that both genetics, as well as metabolism, plays a vital role in the smell of asparagus in the urine. .
Genes for Smelling Asparagus Metabolites Determine Urine Luck
Hey, when I said that postasparagus urine smells like hell, I meant it literally.But does a compound reek if nobody is there to sniff it?Their findings can be found in a paper entitled “Sniffing Out Significant ‘Pee Values’: Genome Wide Association Study of Asparagus Anosmia.” Asparagus anosmia refers to the inability “to smell the metabolites of asparagus in urine,” the authors helpfully explain.They then recruited almost 7,000 people in those studies to rank the rankness of their postasparagus urine.“It is possible that women are less likely than men to notice an unusual odor in their urine,” the scientists say, “because their position during urination might reduce their exposure to volatile odorants.” In this case, men must face the facts. .
Why Your Pee Smells Funny After Eating Asparagus
Depending on which study you read, between 22% and 50% of the population report having pungent pee after eating asparagus.And because those components are "volatile," meaning airborne, the odor wafts upward as the urine leaves the body and can be detected as soon as 15 minutes after you eat this spring delicacy.So the issue isn't whether or not your pee is smelly; it's whether you're able to smell it. .
Why does asparagus make our urine smell?
Back in 1731 the Scottish mathematician and doctor, John Arbuthnot wrote that asparagus gives urine “a foetid smell”.Not everyone dislikes the smell, though: Marcel Proust said it had the effect of transforming his “humble chamber pot into a bower of aromatic perfume”.A quick straw poll over dinner (assuming you feel it’s the right time to raise this kind of subject), typically reveals your guests fall in to certain camps.Then someone else may complicate matters by revealing they’ve smelt it after their partner has been in the bathroom, but can’t detect it in their own urine.In 1956, a team of British researchers demonstrated that fewer than half of people produce the odour in their urine, which was assumed to be down to the influence of a single gene. .
Why Does Asparagus Make Your Pee Smell? – Cleveland Clinic
Although asparagus pee might not be a top priority for scientific research, it’s been observed and wondered about for long enough that it has warranted some investigation.In this article, nephrologist Shane Bobart, MD, explains why the asparagus pee phenomenon happens, who it affects and if there’s anything you can really do to prevent it.When you pee, the sulfur byproducts evaporate almost immediately, causing you to smell that unpleasant scent.It’s worth noting that asparagus isn’t the only thing that can change the smell of your pee.Brussels sprouts, onions and garlic have also been linked to odd smelling pee in some people.So before you start wondering if something is wrong with you, rest assured asparagus pee is a totally normal bodily reaction.Just because your pee might stink after eating asparagus doesn’t mean you should ditch the stalky vegetable. .
Why Does Asparagus Make Your Pee Smell?
This article explains why eating asparagus makes pee smell, and why only some people can smell it.What’s asparagusic acid?Summary Asparagusic acid is a nontoxic, sulfur-containing compound that may cause your pee to have a distinct odor after eating asparagus.One study in 87 people who ate 3–9 spears of asparagus found that the half-life of the asparagus smell was 4–5 hours ( 3 ).Summary When your body metabolizes asparagusic acid, it produces numerous smelly, sulfur-based compounds that give your pee a rotten-like smell that can last 8–14 hours.It doesn’t happen to everyone The effect of asparagus on urine scent is not universal, and a number of hypotheses try to explain this phenomenon. .
Why Asparagus Makes Your Urine Smell
Scientists tell us that the asparagus-urine link all comes down to one chemical: asparagusic acid.Of course, the whole asparagus-urine scent issue is complicated by an entire separate issue: Some people simply don’t smell anything different when urinate after they eat asparagus.Overall, scientists now conclude that most of the difference is in perception—that is, if your urine doesn’t seem to smell any differently after you eat asparagus, it’s likely that you simply can’t perceive the sulfurous compounds’ foul odor, but there’s a small chance it’s because your body digests asparagus in a way that reduces the concentration of these chemicals in your urine.In 2010, the genetic sequencing company 23andMe conducted a study in which they asked nearly 10,000 customers if they noticed any scent in their urine after eating asparagus, and looked for genetic similarities among those who couldn’t. .
Why Asparagus Makes Pee Smell
Dr. Daniel Whitehead, an associate professor of chemistry at Clemson University, describes asparagus pee as "the typical sort of putrid smell that we encounter in our labs.He’s something of an expert in objectionable odors: One of his lab’s main projects is creating nanoparticles that can capture and remove odor-causing molecules from the water and air surrounding offensively foul-smelling areas, like rendering facilities that cook down the "leftovers" from slaughterhouses into pet food and fertilizer.Sulfur-based molecules are the key to why skunk spray smells bad, why cutting onions makes your eyes tear up, and why deadly mustard gas killed thousands of soldiers during World War I.It’s found in some stinky cheeses, bad breath, and farts, but you most likely know it as the molecule you're smelling when the stove burner doesn’t light or there's a gas leak.(Natural gas on its own has no odor, but the highly smelly methanethiol, or sometimes its cousin ethanethiol, is added in tiny quantities so people can detect when there’s a leak.).You tender souls whose post-asparagus bathroom trips have never seemed out of the ordinary are most likely blessed with a genetic condition called asparagus anosmia.A similar study run by public health researchers at Harvard in 2016 that used a stricter definition of being able to smell the odor found that slightly more than half of people don’t detect the aroma of asparagus pee.(That study also looked at statistical associations between genes and people’s answers to a wide variety of questions, and I’m only mentioning it here because it has the wonderfully nerdy stats-joke title of "Sniffing out significant ‘Pee-values’".).A few of the other more unusual genetic associations 23andMe has found include the photic sneeze reflex ("some people sneeze when they look at bright light—it’s a similar thing to asparagus pee where you either know it, or it doesn’t make any sense," Lehman says), as well as individual genes associated with misophonia (a strong emotional reaction to the sound of people chewing), your sweet-or-salty preference, and even your favorite ice cream flavor. .