You have likely been told to act your age or look your age, but can you smell your age? According to new research, you can at least smell another person’s age. Apparently, humans can correctly identify a person’s age simply by smelling their body odor.

The group of genes that makes up the olfactory (sense of smell) receptors is the largest gene family in mammals. And, it’s no wonder why humans have evolved to be able to smell millions of odorants in minute concentrations: body odor helps us identify family versus non-family members, choose a mate, and differentiate between genders. Even though all this happens subconsciously, the olfactory sense is critical to our behavioral and social cues and our evolutionary history.

For the current study, researchers asked three groups of people to sleep in shirts with under-arm pads for 5 nights. The pads collected sweat from the three groups: young (20-30 years old), middle-aged (45-55), and old-aged (75-95). Then, they placed the pads in jars and asked 41 individuals to identify the age group of the person’s scent. Almost every participant was easily able to correctly identify the age group of the person whose sweat was in the jar.

The participants reported that old-age odors were more pleasant than younger age groups. Old-age odors were also less intense. In the young and middle-aged groups, participants were able to differentiate between genders. Middle-aged men were rated as having the most intense and most unpleasant odor.

Body odor results from a complex interaction among the skin, secretions from glands, and bacterial activity. Plus, diet and lifestyle habits influence body odor. As humans age, the composition of skin and of the body’s secretions change, along with a myriad of other factors, which likely results in smells identifiable with old age. Though these findings are interesting, the authors report little consequence for our daily lives. Olfaction is associated with memory, relational signals, food decisions, and overall health. But, is the ability to discriminate age or gender based solely on smell going to change the way we go about our daily olfactory activities? It conjures up visions of greeting people like my dog greets people, and that would stink.

References

Hoover KC (2010). Smell with inspiration: the evolutionary significance of olfaction. American journal of physical anthropology, 143 Suppl 51, 63-74 PMID: 21086527

Mitro S, Gordon AR, Olsson MJ, & Lundström JN (2012). The smell of age: perception and discrimination of body odors of different ages. PloS one, 7 (5) PMID: 22666457

Seo HS, Buschhüter D, & Hummel T (2008). Contextual influences on the relationship between familiarity and hedonicity of odors. Journal of food science, 73 (6) PMID: 19241571

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