What Your Earwax Says About You

What Your Earwax Says About You

Published March 2, 2017

What does your earwax have to do with your stinky B.O.?

I’m Anna, and this is Gross Science.

Human earwax has a variety of purposes. It’s used to flush dead skin cells out of the ear, and also to prevent foreign objects, like dust, from getting into the ear. It even contains some antimicrobial properties to potentially keep out bacteria and other pathogens. But not all earwax is created equal.

Human beings actually have two varieties of earwax. Most people of Caucasian or African descent have wet-type earwax, which is sticky and yellow or brownish. (That’s the kind I have.) But most people of East Asian descent have dry-type earwax, which appears light and flaky.

These earwax traits are caused by different variants of the same gene. The wet-type is probably the ancient form, while the dry-type is a variant that arose later, likely in a population of early humans who had migrated to northern and eastern Asia.

The interesting thing is that the type of earwax you have is correlated with how stinky you are. Earwax is secreted in part by modified apocrine glands, which are one of the glands that release sweat. Apocrine sweat is especially delicious to bacteria, who release that gross B.O. scent after they chow down on it. And, some studies have found that people with wet-type earwax also have more body odor.

Earwax itself has a scent, too. Scientists have said that it smells acidic, fecal, and like sweaty feet. But the amount of odor differs between people. In one small study, researchers measured the amount of volatile organic compounds in earwax from people of African, Caucasian, and Asian descent. Turns out, each group had different amounts of these smelly compounds.

This might sound silly, but earwax could one day help researchers learn more about you than just your race or ethnicity. We could potentially use it as a non-invasive way to diagnose disease. We already know that certain conditions, like maple syrup urine disease, can be detected through the smell of earwax earlier they can be identified by other methods.

Earwax might even be able to track where we’ve been—after all, a big part of its job is to trap particles from our environment, which might provide clues to where we’ve spent our time. And it contains a lot of fats, which are great at holding on to certain types of chemicals. But more research needs to be done to determine just how long our earwax might hold on to that material. Especially since many of us clean our ears on a regular basis.

Whales, however, don’t have that luxury. Their earwax builds up for years, and each layer of it corresponds to about six months of a whale’s life. Consequently, it can be used almost like tree rings to glean detailed information about an individual whale. For example, scientists have used a foot-long plug of earwax to determine when a particular blue whale was exposed to different pollutants.

So far, we haven’t been able to do anything similar with human earwax. But it could help us track an ancient human migration. Native Americans also frequently carry the gene for dry earwax, supporting the idea that their ancestors migrated from Siberia.

Who knew we could learn so much from this one bodily secretion?

Ew.

PRODUCTION CREDITS

Host, Writer, Animator, Editor

Anna Rothschild

Camera, Sound

Ana Aceves

Additional Voice Over

Allison Eck

Original Footage

©WGBH Educational Foundation 2017

Rolling Underground

Music Provided by APM

GROSS IMAGES AND FOOTAGE

Fig 1. from Trumble, S. J., et al. (2013). "Blue whale earplug reveals lifetime contaminant exposure and hormone profiles." Proceedings of the National Academy of Sciences 110(42): 16922-16926.

Courtesy Dr. Sascha Usenko and Dr. Stephen J. Trumble, Baylor University

Image of Prokop-Prigge, K. A., Mansfield, C. J., Parker, M. R., Thaler, E., Grice, E. A., Wysocki, C. J., & Preti, G. (2015). ETHNIC/RACIAL AND GENETIC INFLUENCES ON CERUMEN ODOR PROFILES. Journal of Chemical Ecology, 41(1), 67–74.

OhrenSchmalzBrocken

Wikimedia Commons/Freak1972 aka Ulf Hundeiker

Dry Earwax

Wikimedia Commons/Kelvinc

Armpit by David Shankbone

Wikimedia Commons/David Shankbone

GROSS SFX

Cockroaches

Freesound/StateAardvark­
(used with permission from author)

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Freesound/Corsica_S

Wink

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Poof of Smoke

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Male drinking slurping aaaaaaaaaaah small belch

Freesound/Anton

Running Water Bubbles 02

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Gross Science is produced by WGBH for PBS Digital Studios

POSTER IMAGE

Original Illustration

©WGBH Educational Foundation 2017

Want More Info?

Yoshiura, K., et al. (2006). “A SNP in the ABCC11 gene is the determinant of human earwax type.” Nature Genetics, 38, 324 - 330.
http://www.nature.com/ng/journal/v38/n3/full/ng1733.html

Prokop-Prigge, K. A., Thaler, E., Wysocki, C. J., & Preti, G. (2014). Identification of volatile organic compounds in human cerumen. Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences, 0, 48–52.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3987112/

Prokop-Prigge, K. A., Mansfield, C. J., Parker, M. R., Thaler, E., Grice, E. A., Wysocki, C. J., & Preti, G. (2015). ETHNIC/RACIAL AND GENETIC INFLUENCES ON CERUMEN ODOR PROFILES. Journal of Chemical Ecology, 41(1), 67–74. http://doi.org/10.1007/s10886-014-0533-y
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4304888/

Trumble, S. J., et al. (2013). "Blue whale earplug reveals lifetime contaminant exposure and hormone profiles." Proceedings of the National Academy of Sciences 110(42): 16922-16926.
http://www.pnas.org/content/110/42/16922.abstract

(Smithsonian.com) For Scientists, Chunks of Whale Earwax Can Be Biological Treasure Troves
http://bit.ly/2mnlc6G