Individuals identified from earwax

Earwax. We get rid of it, like many of the wastes manufactured by our bodies, without a second thought. However, what seems to be simply a smelly secretion actually contains important identifying information about the individual from which it was produced.

“Scientists from the Monell Center have used analytical chemistry to identify the presence of odor-producing chemical compounds in human earwax,” the press release from the Monell Chemical Senses Center said. “The findings suggest that human earwax, an easily obtained bodily secretion, could be an overlooked source of personal information.”

Cerumen, the scientific name for earwax, is a hodgepodge of secretions from a variety of sweat and sebaceous glands. It manifests as either wet and yellow or dry and white.

Researchers at the Monell Center have undertaken investigations on other frequently disregarded bodily by-products prior to their experiment on earwax. “Our previous research has shown that underarm odors can convey a great deal of information about an individual, including personal identity, gender, sexual orientation, and health status,” George Preti, an organic chemist at Monell and the senior author of the study, said in the press release. “We think it is possible that earwax may contain similar information.”

The results of the earwax study indicate that the amounts of odor-producing chemical compounds in human cerumen differ between Caucasian individuals and individuals of East Asian origin. “Individuals of East Asian descent have a form of the ABCC11 gene that codes for dry-type earwax and also for a reduction in axillary body odor relative to individuals of other ethnicities, who typically produce a wet-type ear wax. In essence, we could obtain information about a person’s ethnicity simply by looking in his ears. While the types of odorants were similar, the amounts were very different,” Katharine Prokop-Prigge, a Monell chemist and lead author of the study, said in the press release.

In the study, researchers swabbed earwax from 16 healthy males. Half of the men were of East Asian descent, and the other half were of Caucasian descent. The earwax samples were mildly heated in order to release odorous volatile organic compounds (VOCs). After initial collection and preparation, the earwax samples were subjected to chemical analysis.

The results of such techniques demonstrate notable differences in the earwax of Caucasian and East Asian individuals. Twelve VOCs were present in the the earwax of all the men, but the total amount varied with the subject’s ethnicity: Caucasians have more VOCs than East Asians.

The ability to detect, isolate and analyze VOCs in earwax is attributed to the chemical composition of the substance. The research group hypothesizes that the composition of earwax makes it prone to solvating fatty odorants as picked up from the environment.

Earwax could potentially function as a powerful diagnostic tool for a plethora of diseases. Specifically, chemical analysis of earwax could serve as an effective method for early detection of certain metabolic disorders. “Prokop-Prigge points out that at least two odor-producing metabolic diseases can be identified in earwax before they can be diagnosed using traditional techniques such as blood and urine analysis,” the press release said.

Chemical analysis of earwax is not limited to application in hospitals, clinics and laboratories. Earwax can serve as an activity tracker for any individual, almost akin to a food diary or a GPS. “Earwax odors may be able to tell us what a person has eaten and where they have been,” Preti said in the press release.

Future studies will explore the possibilities of earwax, a neglected body secretion, as a treasure trove of valuable information situated on the frontier of uncharted scientific territory.