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Gory Details

The bizarre side of science
Erika Engelhaupt

Gory Details

What your earwax says about your ancestry

ear wax

Dry earwax, typical in East Asians and Native Americans, is light-colored and flaky, while earwax found in Caucasian and African groups is darker, wetter and, a new study shows, smellier.

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If you would describe yourself as white or black, your earwax is probably yellow and sticky. If you are East Asian or Native American, it’s likely to be dry and white.

And for those with the yellow kind, I hate to break it to you, but your earwax stinks.

Don’t take it personally. Smelly earwax is just another of the genetic quirks we inherit as part of one ethnic group or another. In new tests of earwax in Caucasian and East Asian men, yellow earwax from Caucasians gave off stronger odors than the dry, white kind.

“We could obtain information about a person’s ethnicity simply by looking in his ears,” chemist Katharine Prokop-Prigge said. Prokop-Prigge is one of the researchers at the Monell Chemical Senses Center in Philadelphia who measured the earwax smells. The team was inspired to see if ethnic groups have different earwax odors after learning that the same gene controls both a person’s underarm odor and the type of earwax they make.

Ultimately, the researchers hope to mine our ears for whatever health secrets they may hold. Monell chemist George Preti calls earwax “a neglected body secretion.” Other research has shown that you can tell a person’s gender, health status and more from their underarm odors. “We think it possible that earwax may contain similar information,” Preti said on the center’s website.

A giant earwax plug pulled from a blue whale recently revealed a fair bit of its life history, from its testosterone kicking in as it grew up to its times of stress (measured by cortisol levels) and contaminants it picked up from the waters it swam in. So who knows, maybe human earwax is trapping a trove of health information. Already, earwax is known to give a heads-up to two odor-causing diseases before they can be detected in blood or urine. One is called maple syrup urine disease, which makes urine smell delicious but is actually a dangerous and deadly metabolic condition. The other is alkaptonuria, or black urine disease, also plenty frightening.

As for our different ear odors, they came about because of a tiny change, just one little letter in the genetic alphabet that long ago granted an East Asian population a reprieve from both smelly underarms and sticky earwax. This mutation appeared about 2,000 generations ago, according to a study published in 2011, and became more common across Asia over time. Today most East Asians and nearly all Koreans lack a chemical in their armpits that bacteria munch on to make body odor, because they carry this variant of the ABCC11 gene.

About 98 percent of Europeans have the smelly-armpit version of the gene, and along with it comes stickier and smellier earwax.

In the new study, 12 odiferous compounds were common to both groups, but earwax from Caucasian men produced more of 11 out of the 12 compounds, the researchers report February 5 in the Journal of Chromatography B. Some of the biggest differences were in 2-methylbutyric acid and isovaleric acid, which smell of sweaty socks, and hexanoic acid, which is described as smelling like a goat. If you’ve never been around goats, I can assure you that it’s not a good smell.

I’m sure we’ll all be sniffing our Q-tips now when no one is looking. Don’t act like you won’t.

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