New York Times

“During an extended period of travel last year, my husband and I lent our house in the Ozarks to an older couple who were having work done on their own house. We returned after a month away to a spotless house and two hostess gifts. But there was also a distinctive smell in the air: slightly stale and sweet, like the musty first whiff of strawberries in a cardboard box. I wiped countertops and mopped floors. Still, the odor remained. Not terrible but strange and cloyingly human. Late that night I guiltily googled, “Do older adults smell?”

The answer I found was yes. Then no. And maybe …

I mentioned my question to a group of women writers, ranging from 40 to 70, and got drastically different responses. The younger women said yes, there’s an odor associated with aging. But to the older women it sounded like ageism and a few took offense. At 52, I felt a little prickly about it myself, but also in need of information. If there was anything I could do to improve my personal scent, now and in the future, I wanted to know. So I consulted two scientists from a renowned research lab and ran into the very same split.

Johan Lundstrom, a 46-year-old biologist with the Monell Chemical Research Center, says his studies confirm what Japanese researchers found in 2001: An unsaturated aldehyde called 2-nonenal is more concentrated on the skin of older adults, often producing a distinctive grassy, waxy or fatty odor. Dr. Lundstrom’s study affirmed the existence of “older adult smell” but stated that on average participants found it “neutral” and “not unpleasant.” He believes the odor is perceived as negative largely due to context. It’s similar, Dr. Lundstrom says, to the smell of fresh manure: Smelled in a stable, it’s perceived as natural. But in one’s bedroom it becomes disturbing and bad. “In the Japanese study, when researchers did not tell participants what the odor was, they rated it as ‘inoffensive,’” Dr. Lundstrom says. “But when they said it was from an old person, it was rated as ‘nasty.’”

The bias in Japan is clear. They have a name for older person odor — kareishu — and it has a definitively negative association. A Japanese company called Mirai Clinical sells a $16 persimmon soap bar that promises to eliminate the “offensive” smell.

Dr. Preti distrusts the science of the 2001 study. “I was 57 when the original Japanese study came out and I remember being quite offended,” he said. “The group they sampled as being ‘old’ included people in their 40s. That’s insane.” Dr. Lundstrom endorsed the Japanese findings but was leery of the industry around kareishu; he said expensive creams and soaps will not provide a fix. “Smell has a very large subconscious component,” Dr. Lundstrom said, “so masking it will not do any good. Each odor binds to a particular chemical receptor in the nose and this information will travel even through heavy perfume.” Nonenal and its sweeter-smelling cousin, nonanal, are aldehydes that were discovered in the 1920s. They’ve been used in small concentrations by the scent and flavor industries ever since. “It’s possible you find these aldehydes more in Japanese populations than in Americans,” he said. (Dr. Preti also proposed that Japanese subjects might have higher levels of nonenal from eating fish.) “But I’m almost 80 years old and I’ve spent my life in odor research. If someone told me I had a particular smell I wouldn’t take offense, I’d want to do something about it.”