Ailment-induced odors are far from the domain of obscure problems like maple syrup-urine disease or trimethylaminuriaâa genetic condition that makes sufferers smell like rotten fish. But a study released by scientists at the Karolinska Institute in Sweden found that there are subtle differences in a person’s body, breath, blood, and urine odor that denote illness and possibly threat of contagion.
The finding is not, strictly speaking, a new discovery. Certain diseases have been observed to cause a person’s body odor to change due to how they affect the body’s chemical arrangements. Typhoid fever has been observed to make victims smell like baked bread and diabetes has a trademark odor of rotten apples due to low concentrations of acetone. However, normally it takes a trained nose (or a dog) to notice the difference.
What the Swedish team attempted to do was assess the impact of illness in general on body odor rather than focus on a specific ailment. The theory was that the ability to sniff out infected individuals was an evolution meant to allow for identification and avoidance of the ill.
The study employed eight healthy volunteers who were either injected with a placebo or with a compound called LPS, which is known to trigger immune and inflammatory responses. In this manner, the volunteers who were given LPS began experiencing a form of generic immune response to invading bacteria. Volunteers wore T-shirts that were then collected and presented to a panel of nose-trained judges. The panel of 40 then had the unenviable task of sniffing the shirts and describing the intensity and pleasantness of the smell. The LPS-injected bodies were observed to have a more repellant smell, suggesting that illness affects body odor.
The team undertook additional studies later on that found smelling something unpleasant, whether another person or something like rotting food, was enough to trigger a slight immune reaction. This suggests that the body uses scent as a form of warning light and will attempt to stave off possible infection in response to offensive odors.
Further research is planned to investigate how illness affects the scent of urine and breath, although these elements will prove harder to test. As anyone who has eaten garlic or asparagus can attest, how one’s breath and urine smell is sometimes more a matter of what you’ve eaten rather than whether you are ill.
Sources for Todayâs Article:
Olsson, M. J., et al., “The Scent of Disease: Human Body Odor Contains an Early Chemosensory Cue of Sickness,” Psychological Science 25, no. 3 (January 22, 2014): 817-23.
Senthilingam, M., “How Your Smell Can Reveal If You’re Sick,” CNN web site, January 20, 2016; http://www.cnn.com/2016/01/20/health/the-smell-of-disease/index.html.