The results of a study conducted by Johan Lundström and several of his colleagues at the Monell Chemical Senses centre indicate the "old person smell" is, in fact, a distinct and distinctly identifiable odor.
To carry out the study, the researchers divided 44 volunteers into three groups: eight women and eight men between the ages of 20 and 30 (the young); eight men and eight women between 45 and 55 (middle-aged); and six women and six men between 75 and 95 (elderly). For five consecutive nights, all volunteers slept in t-shirts into the armpits of which absorbant nursing pads had been sewn. During the day, the sleep shirts were stored in sealed plastic bags.
They were instructed to avoid spicy foods, cigarettes, and alcohol, and to use unscented shampoo and soap -- all to keep outside odours at a minimum, preserving their natural human aroma.
In preparation for a smell test, after the fifth night, Lundström and his colleagues cut the sweaty nursing pads into quarters and placed four pieces from each of the age groups in individual glass jars.
A group of 41 new young men and women volunteers was selected for the second phase, the smell test. Blindfolded, they were asked to take in a big whiff of the air at the top of each jar, then rate it for intensity and pleasantness of odor. Some were asked also to indiciate which of two odours they believed came from the older volunteer; others were instructed to label the jars "young," middle-age," and "old-age."
Based on blind ratings, the scent of the eldest volunteer group was found to be both less intense and less unpleasant than that of the young and middle-aged volunteers. Least pleasant and most intense-smelling was the scent of the middle-aged men, middle-aged women were deemed most pleasant-smelling and old men the least intense.
Moreover, smell-test volunteers had the least trouble identifying old-person odor: labelling the jars by age was difficult when it came to distinguishing between young- and middle-aged and much easier when it came to the old-age sweat jar. Old-age smell was instantly recognisable, for many.
What this means
"Old person smell," while recognised to be distinct among the age groups, is no more offensive than the smell of any other, younger people––and in some cases, it's more pleasant.
In other words
Grandma does smell, but not bad. Generally.
"It might be a way to distinguish the sick from the healthy-not overt sickness, but underlying cell decay," Lundström says. "The older we get, the more natural decay we have." [ScientificAmerican via TheAtlantic - Image via Glenda M. Powers/Shutterstock]