Why does asparagus make your urine smell

The problem with some studies, such as the Israeli one, is that people were asked to compare asparagus urine with water, rather than with non-asparagus urine, so they could have been detecting other notes in the urine, rather than asparagus in particular.

At the Monell Chemical Senses Center in Philadelphia, physiological psychologist Marcia Pelchat was determined to get to the bottom of the mystery.

One day she had her volunteers drink a bottle of water and eat asparagus which had been roasted for eight minutes in some olive oil with a little salt. Then nature took its course and two hours later the ensuing urine was put into the deep freeze. The next day the same people were given the same-sized bottle of water along with an Italian bread roll containing the same amount of oil and salt as the asparagus.

Then the rest of the procedure was repeated. It is theoretically possible that people may lack an enzyme which prevents them from both producing and detecting a particular odour in urine. The sweet smell of excess - do we have to eat large quantities of asparagus before we can smell it in our urine?

Getty Images. From her results, Pelchat found evidence that the ability to detect the smell was related to a single gene , but she saw no such link for odour production. Or perhaps we all excrete it, but some do so in such tiny quantities that they would need to eat several bunches of asparagus before it was detectable by other humans.

And even if we do find the solution we may never know why Arbuthnot thought the smell is repugnant while some, like Proust, find it so delightful. Disclaimer All content within this column is provided for general information only, and should not be treated as a substitute for the medical advice of your own doctor or any other health care professional.

The BBC is not responsible or liable for any diagnosis made by a user based on the content of this site. Therefore, if the half-life of the asparagus smell was estimated at 4—5 hours, it means that the total effect could last up to 8—10 hours.

Yet, another study in people who also consumed 3—9 asparagus spears reported the half-life of the smell to be 7 hours, meaning that the effect could even last up to 14 hours 7. 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.

The effect of asparagus on urine scent is not universal, and a number of hypotheses try to explain this phenomenon. One hypothesis — called the production hypothesis — suggests that only some individuals are capable of producing the sulfurous compounds responsible for the smell, while others are non-producers. This hypothesis asserts that non-producers lack a key enzyme that helps metabolize asparagusic acid and are thus unable to produce the smelly byproducts 4.

The other hypothesis — called the perception hypothesis — states that everyone produces the smell, but some are unable to detect or perceive it 4. In this case, researchers found a genetic modification that alters one or more of the olfactory receptors that should respond to the asparagus smell, causing what is known as asparagus anosmia, or the inability to smell asparagus pee 8.

The asparagusic acid in asparagus produces many sulfurous byproducts that give your pee a rotten-like smell. The smell can be detected as early as 15 minutes after eating asparagus and may last up to 14 hours. Asparagus is low in calories yet rich in nutrients. The health benefits of asparagus include better digestive health, weight loss, healthy pregnancy…. Asparagus is a delicious and versatile nutritional powerhouse, but you may wonder whether cooking it is necessary.

This article explains whether you…. Here are other symptoms to watch for. Has your urine color changed from its normal hue? Stem cells are nonspecific cells that can develop into any kind of cell in the body. Scientists hope to use them in regenerative medicine. Learn more…. Ability to smell 'asparagus pee' driven by genetic variations.

Written by Hannah Nichols on December 27, Share on Pinterest Recent research has identified the genetic origin of the ability to smell the odor in human urine produced after consuming asparagus. Link between genetic variation, asparagus anosmia explored. More women than men noseblind to asparagus metabolites. Latest news Scientists identify new cause of vascular injury in type 2 diabetes.

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