Old people, do they smell different ?

  Do old people smell different?

Well, it's not just you. Old and young people do give off distinctive odours, according to a study just published online in the journal PLoS ONE.

Researchers from the Monell Chemical Senses Center in Philadelphia and Sweden's Karolinska Institute found that people can reliably distinguish the body odor of elderly people from a whiff of the young or middle-aged.

But contrary to the stereotype, the characteristic odour of the elderly is actually pretty neutral. And it's a lot more pleasant than the body odour coming from younger folks — especially the guys.

To collect youthful, middle-aged and elderly body odours, researchers had people in each age group bathe with odourless soap before bed and wear special t-shirts with absorbent underarm pads while they slept. The scientists were after the oily secretions of the apocrine glands, which are found anywhere on the body where there's hair.

The old body odours stick out.

- Johan Lundstroum

"We're trying to identify what signals are hidden within the body odor," study author Johan Lundstrom tells Shots. Previous research has shown that people can identify family members, and even sick people, from body odor alone. They wanted to see if the same was true for age.

Another group of volunteers had the unenviable task of sniffing the different odors, rating their intensity and unpleasantness, and trying to sort them by age group. "We could see that the body odors from the old people were grouped together quite consistently," Lundstrom says. "The old body odors stick out." Young and middle-aged odors, however, were much harder to tell apart.

They also smelled a lot worse — particularly the men's. Women's odors were perceived to have about the same neutral smell and mild intensity throughout all three stages of life, while young and middle-aged men's odors were rated more intense and worse-smelling. But elderly men's odors were perceived to be quite similar to those of elderly women: mild and neutral.

"If you look at the guys, they're getting stinky and even more stinky from young to middle age," Lundstrom says. "As we get older, guys are turning more gender-neutral."

What exactly is causing the shift in elderly odors, or what explains our ability to detect the difference, isn't clear. Lundstrom says there could be an evolutionary benefit, as a means of identifying people with good genes that have let them survive into later life. Or it could just be a side effect of aging.

As for the conventional wisdom that old people tend to smell bad, Lundstrom says context is to blame. He says it's easy to associate advanced age with the smells of disease or poor hygiene, which can be a result of physical disabilities. "You only experience it if you go to a retirement home, or some old guy's home," Lundstrom says. But he says that doesn't mean it's how healthy elderly people, like those in his study, smell.

At least, it's not how their bodies smell.

Grandma might still insist on dousing herself in perfume.