'Old people smell' really does exist

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Old people smell, but are not as pongy as middle aged and young people, a new study has found.

In a paper published today in PLoS One, an open access peer-reviewed scientific journal, research has found humans can identify another person's age group on smell alone.

"Signals in body odour can help us identify kin from non-kin, choose a suitable partner and also determine age," said the author of the study, assistant professor Johan Lundstrom, an experimental neuropsychologist at the Monell Chemical Sciences Centre in the United States.

ABC News reported that in the study, scientists gathered data from three age groups; 20 to 30 years, 45 to 55 years, and 75 to 95 years.

The participants slept in t-shirts with pads located under their armpits. After five nights the armpit pads were removed and placed in jars.

Other participants were then asked to rate the scent and group the jars according to age.

Dr Lundstrom said the research found that people were easily, and correctly, able to group the armpit pads according to age categories.

Although people often masked their scent, we pick up an array of messages on an unconscious level from body odour, he said.

Older studies have found that rats could identify ages based on smell and researchers wanted to see if humans also have this ability.

"These results indicate that we are much better at using our noses than we previously thought," Dr Lundstrom said.

He said the study's findings also challenged misconceptions that old people smell bad.

"Elderly people have a discernible underarm odour that younger people consider to be fairly neutral and not very unpleasant," he said.

"This was surprising given the popular conception of old age odour as disagreeable.

"However, it is possible that other sources of body odours, such as skin or breath, may have different qualities."

The results also showed that in the young and middle-age groups, people were able to identify differences between genders.

Overall, middle-aged men were reported to have the strongest and most unpleasant smell.

Associate Professor David O'Carroll, a neuroscientist from the University of Adelaide, said the findings were "very interesting".

"This study shows quite clearly that as we get older we smell better," he said.

Prof O'Carroll said he is keen to discover what other messages are hidden in a person's scent and how this impacts our day to day life.