Lots of People Are Missing Out on the Smell of Asparagus Pee

Adriaen Coorte via Wikimedia Commons // Public Domain
Adriaen Coorte via Wikimedia Commons // Public Domain

Scientists have uncovered some staggering news: Many people have never smelled asparagus pee—and never will. The experts, writing in the British Medical Journal, say more than half of participants in a large survey reported an inability to pick up the scent.

People have been remarking on the odor of asparagus pee for just about as long as we’ve been eating asparagus. A bemused Benjamin Franklin noted the “disagreeable odour” the vegetable produced in his urine. Marcel Proust waxed lyrical on the subject, writing that asparagus spears “…played…at transforming my humble chamber into a bower of aromatic perfume.”

The precise cause of that perfume remains to be seen. Scientists’ current best guess is a natural compound called asparagusic acid, which is found only in—you guessed it—asparagus. On its own the acid smells fine; it’s after being processed through your body and coming out the other side that it acquires its signature scent.

Or at least it does for some people. Previous studies have suggested that the ability to smell asparagus pee is not as universal as we once thought. To find out, researchers at the Harvard T.H. Chan School of Public Health pulled data from two long-term projects on American health: the Nurses’ Health Study and the Health Professionals Follow-Up Study. Both studies had, remarkably, asked respondents about their ability to smell their own asparagus pee. All 6909 of the respondents had also submitted samples of genetic material.

The results were kind of astonishing. A full 58 percent of men and 61.5 percent of women said they’d noticed no unusual aroma in their pee after eating asparagus. That’s well over half of everyone in the study. All of the survey respondents, including the ones who could detect the scent, were of European descent, which means these results can’t be considered representative of everyone everywhere.

The researchers then looked at the DNA of smellers and non-smellers to see if they could find any differences. They could. The 4161 people with this asparagus anosmia collectively had hundreds of genetic variants, all located in the region of the chromosome associated with our sense of smell.

"Outstanding questions on this topic remain," senior author and epidemiologist Lorelei Mucci said in a statement. "First and foremost perhaps is: Why such a delicious delicacy as asparagus results in such a pernicious odor, and what are the selective pressures driving genetic variations that lead to asparagus anosmia?"

Pernicious or no, the aroma is one that Mucci and her co-authors imply is an olfactory experience millions are missing out on. They note that “future replication studies are necessary” but suggest a future of “targeted therapies to help anosmic people discover what they are missing.”

Tonight, the Lyrid Meteor Shower Peaks on Earth Day

iStock/dmoralesf
iStock/dmoralesf

Tonight, look up and you might see shooting stars streaking across the sky. On the night of Monday, April 22—Earth Day—and the morning of Tuesday, April 23, the Lyrid meteor shower will peak over the Northern Hemisphere. Make some time for the celestial show and you'll probably see meteors zooming across the heavens every few minutes. Here is everything you need to know about this meteor shower.

What is the Lyrid meteor shower?

Every 415.5 years, the comet Thatcher circles the Sun in a highly eccentric orbit shaped almost like a cat's eye. At its farthest from the Sun, it's billions of miles from Pluto; at its nearest, it swings between the Earth and Mars. (The last time it was near the Earth was in 1861, and it won't be that close again until 2280.) That's quite a journey, and more pressingly, quite a variation in temperature. The closer it gets to the Sun, the more debris it sheds. That debris is what you're seeing when you see a meteor shower: dust-sized particles slamming into the Earth's atmosphere at tens of thousands of miles per hour. In a competition between the two, the Earth is going to win, and "shooting stars" are the result of energy released as the particles are vaporized.

The comet was spotted on April 4, 1861 by A.E. Thatcher, an amateur skywatcher in New York City, earning him kudos from the noted astronomer Sir John Herschel. Clues to the comet's discovery are in its astronomical designation, C/1861 G1. The "C" means it's a long-period comet with an orbit of more than 200 years; "G" stands for the first half of April, and the "1" indicates it was the first comet discovered in that timeframe.

Sightings of the Lyrid meteor shower—named after Lyra, the constellation it appears to originate from—are much older; the first record dates to 7th-century BCE China.

How to See the Lyrid Meteor Shower

Monday night marks a waning gibbous Moon (just after the full Moon), which will reflect a significant amount of light. You're going to need to get away from local light pollution and find truly dark skies, and to completely avoid smartphones, flashlights, car headlights, or dome lights. The goal is to let your eyes adjust totally to the darkness: Find your viewing area, lay out your blanket, lay down, look up, and wait. In an hour, you'll be able to see the night sky with great—and if you've never done this before, surprising—clarity. Don't touch the smartphone or you'll undo all your hard ocular work.

Where is the nearest dark sky to where you live? You can find out on the Dark Site Finder map. And because the shower peaks on a Monday night—when you can expect to see 20 meteors per hour—your local astronomy club is very likely going to have an event to celebrate the Lyrid meteor shower. Looking for a local club? Sky & Telescope has you covered.

Other Visible Bodies During the Lyrid meteor shower

You don't need a telescope to see a meteor shower, but if you bring one, aim it south to find Jupiter. It's the bright, unblinking spot in the sky. With a telescope, you should be able to make out its stripes. Those five stars surrounding it are the constellation Libra. You'll notice also four tiny points of light nearby. Those are the Galilean moons: Io, Europa, Ganymede, and Callisto. When Galileo discovered those moons in 1610, he was able to prove the Copernican model of heliocentricity: that the Earth goes around the Sun.

What to Do if There's Bad Weather During the Lyrid Meteor Shower

First: Don't panic. The shower peaks on the early morning of April 23. But it doesn't end that day. You can try again on April 24 and 25, though the numbers of meteors will likely diminish. The Lyrid meteor shower will be back next year, and the year after, and so on. But if you are eager for another show, on May 5, the Eta Aquarids will be at their strongest. The night sky always delivers.

Does the Full Moon Really Make People Act Crazy?

iStock.com/voraorn
iStock.com/voraorn

Along with Mercury in retrograde, the full moon is a pretty popular scapegoat for bad luck and bizarre behavior. Encounter someone acting strangely? Blame it on the lunar phases! It's said that crime rates increase and emergency rooms are much busier during the full moon (though a 2004 study debunked this claim). Plus, there's that whole werewolf thing. Why would this be? The reasoning is that the Moon, which affects the ocean's tides, probably exerts a similar effect on us, because the human body is made mostly of water.

This belief that the Moon influences behavior is so widely held—reportedly, even 80 percent of nurses and 64 percent of doctors think it's true, according to a 1987 paper published in the Journal of Emergency Medicine [PDF]—that in 2012 a team of researchers at Université Laval's School of Psychology in Canada decided to find out if mental illness and the phases of the Moon are linked [PDF].

To test the theory, the researchers evaluated 771 patients who visited emergency rooms at two hospitals in Montreal between March 2005 and April 2008. The patients chosen complained of chest pains, which doctors could not determine a medical cause for the pains. Many of the patients suffered from panic attacks, anxiety and mood disorders, or suicidal thoughts.

When the researchers compared the time of the visits to the phases of the Moon, they found that there was no link between the incidence of psychological problems and the four lunar phases, with one exception—in the last lunar quarter, anxiety disorders were 32 percent less frequent. "This may be coincidental or due to factors we did not take into account," Dr. Geneviève Belleville, who directed the team of researchers, said. "But one thing is certain: we observed no full-moon or new-moon effect on psychological problems."

So rest easy (or maybe not): If people seem to act crazy during the full Moon, their behavior is likely pretty similar during the rest of the lunar cycle as well.

This story was updated in 2019.

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