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.”

13 Father's Day Gifts for Geeky Dads

Amazon/Otterbox/Toynk
Amazon/Otterbox/Toynk

When in doubt, you play the hits. Watches, flasks, and ties are all tried-and-true Father’s Day gifts—useful items bought en masse every June as the paternal holiday draws near. Here’s a list of goodies that put a geeky spin on those can’t-fail gifts. We’re talking Zelda flasks, wizard-shaped party mugs, and a timepiece inspired by BBC’s greatest sci-fi series, Doctor Who. Light the “dad” signal ‘cause it’s about to get nerdy!

1. Lord of the Rings Geeki Tikis (Set of Three); $76

'Lord of The Rings' themed tiki cups.
Toynk

If your dad’s equally crazy about outdoor shindigs and Tolkien’s Middle-earth, help him throw his own Lothlórien luau with these Tiki-style ceramic mugs shaped like icons from the Lord of the Rings saga. Gollum and Frodo’s drinkware doppelgängers each hold 14 ounces of liquid, while Gandalf the Grey’s holds 18—but a wizard never brags, right? Star Wars editions are also available.

Buy it: Toynk

2. Space Invaders Cufflinks; $9

'Space Invaders' cufflinks on Amazon
Fifty 50/Amazon

Arcade games come and arcade games go, but Space Invaders has withstood the test of time. Now Pops can bring those pixelated aliens to the boardroom—and look darn stylish doing it.

Buy it: Amazon

3. Legend of Zelda Flask; $18

A 'Legend of Zelda' flask
Toynk

Saving princesses is thirsty work. Shaped like an NES cartridge, this Zelda-themed flask boasts an 8-ounce holding capacity and comes with a reusable straw. Plus, it makes a fun little display item for gamer dads with man caves.

Buy it: Toynk

4. AT-AT Family Vacation Bag Tag; $12

An At-At baggage tag
ShopDisney

Widely considered one of the greatest movie sequels ever made, The Empire Strikes Back throws a powerful new threat at Luke Skywalker and the Rebellion: the AT-AT a.k.a. Imperial Walkers. Now your dad can mark his luggage with a personalized tag bearing the war machine’s likeness.

Buy it: ShopDisney

5. Flash Skinny Tie; $17

A skinny Flash-themed tie
Uyoung/Amazon

We’ll let you know if the Justice League starts selling new memberships, but here’s the next best thing. Available in a rainbow of super-heroic colors, this skinny necktie bears the Flash’s lightning bolt logo. Race on over to Amazon and pick one up today.

Buy it: Amazon

6. Captain America Shield Apron; $20

A Captain America themed apron
Toynk

Why let DC fans have all the fun? Daddy-o can channel his inner Steve Rogers when he flips burgers at your family’s Fourth of July BBQ. Measuring 31.5 inches long by 27.5 inches wide, this apron’s guaranteed to keep the cookout Hydra-free.

Buy it: Toynk

7. Doctor Who Vortex Manipulator LCD Leather Wristwatch; $35

A Doctor Who-themed watch
Toynk

At once classy and geeky, this digital timepiece lovingly recreates one of Doctor Who’s signature props. Unlike some of the gadgets worn on the long-running sci-fi series, it won’t require any fancy chronoplasm fuel.

Buy it: Toynk

8. Wonder Woman 3-Piece Grill Set; $21

Wonder Woman three-piece gill set
Toynk

At one point in her decades-long comic book career, this Amazon Princess found herself working at a fast food restaurant called Taco Whiz. Now grill cooks can pay tribute to the heroine with these high-quality, stainless steel utensils. The set’s comprised of wide-tipped tongs, a BBQ fork, and a spatula, with the latter boasting Wonder Woman’s insignia.

Buy it: Toynk

9. Harry Potter Toon Tumbler; $10

Glassware that's Harry Potter themed
Entertainment Earth

You can never have too many pint glasses—and this Father’s Day, dad can knock one back for the boy who lived. This piece of Potter glassware from PopFun has whimsy to spare. Now who’s up for some butterbeer?

Buy it: EntertainmentEarth

10. House Stark Men’s Wallet; $16

A Game of Thrones themed watch
Toynk

Winter’s no longer coming, but the Stark family's propensity for bold fashion choices can never die. Manufactured with both inside and outside pockets, this direwolf-inspired wallet is the perfect place to store your cards, cash, and ID.

Buy it: Toynk

11. Mr. Incredible “Incredible Dad” Mug, $15

An Incredibles themed mug
ShopDisney

Cue the brass music. Grabbing some coffee with a Pixar superhero sounds like an awesome—or dare we say, incredible?—way for your dad to start his day. Mom can join in the fun, too: Disney also sells a Mrs. Incredible version of the mug.

Buy it: ShopDisney

12. Star Wars phone cases from Otterbox; $46-$56

Star Wars phone cases from OtterBox.
Otterbox

If your dad’s looking for a phone case to show off his love of all things Star Wars, head to Otterbox. Whether he’s into the Dark Side with Darth Vader and Kylo Ren, the droids, Chewbacca, or Boba Fett, you’ll be able to find a phone case to fit his preference. The designs are available for both Samsung and Apple products, and you can check them all out here.

Buy it: Otterbox

13. 3D Puzzles; $50

3D Harry Potter puzzle from Amazon.
Wrebbit 3D

Help dad recreate some of his favorite fictional locations with these 3D puzzles from Wrebbit 3D. The real standouts are the 850-piece model of Hogwarts's Great Hall and the 910-piece version of Winterfell from Game of Thrones. If dad's tastes are more in line with public broadcasting, you could also pick him up an 890-piece Downton Abbey puzzle to bring a little upper-crust elegance to the homestead.

Buy it: Hogwarts (Amazon), Winterfell (Amazon), Downton Abbey (Amazon)

At Mental Floss, we only write about the products we love and want to share with our readers, so all products are chosen independently by our editors. Mental Floss has affiliate relationships with certain retailers and may receive a percentage of any sale made from the links on this page. Prices and availability are accurate as of the time of publication.

Tear Gas vs. Pepper Spray: What’s the Difference?

This is probably pepper spray.
This is probably pepper spray.
Siberian Photographer/iStock via Getty Images

Pepper spray and tear gas are both non-lethal irritants that cause extreme burning of the eyes, nose, and throat—but there are a few key differences between the two substances.

For one, they’re created from different chemicals. According to biohazard remediation company Aftermath, the active ingredient in pepper spray is oleoresin capsicum, which comes from the compound that makes hot peppers so hot: capsaicin. If you’ve ever accidentally rubbed your eyes after chopping a chili pepper, you’ve gotten a very tiny taste of what it’s like to be sprayed with pepper spray. Tear gas, on the other hand, contains 0-Chlorobenzylidenemalononitrile (CS), 2-chlorobenzalmalononitrile (CN), or a similar artificial chemical. At room temperature, both of those chemicals are powdery solids, not gases—they’re mixed with liquids or gases so they can be dispersed in the air.

Delivery methods differ, too. Pepper spray often comes in an aerosol can, which shoots it in a stream, a mist, or some other relatively direct path (though it’s also available as a gel or foam). As the Berkeley Science Review explains, tear gas is mainly dispersed with a grenade, which releases the substance over a wide area when it explodes. Since the grenades can cover so much ground, law enforcement officers are more likely to use tear gas to try to break up a crowd, and civilians are more likely to carry pepper spray as a personal safety measure.

The immediate effects of the two substances are similar—burning sensation in mucous membranes, rise in blood pressure, difficulty breathing, runny nose, etc.—but tear gas can also cause nausea and vomiting in higher concentrations.

For more on tear gas, including what to do if you’re exposed to it, head here.

[h/t Aftermath]