The nose knows.

A study has found that old people smell different from young folks. Not bad, just different. You may have mistakenly thought that when you have been in a nursing home, the distinct, and usually unpleasant, odor was caused by the body odors from the patients.

A study by researchers at the Monell Chemical Senses Center in Philadelphia found that the body odor of older people is distinct. The smell is different enough for others to pick out. But old-people smell is not necessarily bad, like the odor of most people usually resulting from sweating. The fact is, the study determined that for most of the people involved, the scent of an old person was preferable to the scent coming from people who were from 20 to 50 years of age.

Scientists used 41 subjects, from 20 to 95 years of age. The subjects slept for five consecutive nights while wearing T-shirts that had absorbent nursing pads sewn into the armpits of the shirts. Each morning, the volunteers would put their nightshirt into a plastic bag and seal the top to prevent bacterial growth. Each evening, the participants took a shower using unscented soap and shampoo and washed their bedding in fragrance-free detergent so that no other scents would be absorbed by the pads. Consumption of spicy food was prohibited, so as to keep bodily odors from being affected.

On the sixth morning of the experiment, the pads were removed from the T-shirts and were put in air-tight canisters. Pieces of pads of others from the same age group were put together so the odor of no single person could be determined.

Another group, different from the ones who slept in the T-shirts gave each of the canisters a hearty sniff. These sniffers then rated each canister for the intensity of the odor and how pleasant or unpleasant it seemed to them.

Result: The pads worn by old people produced the most distinctive smell. Volunteers were able to match that odor to the odor of the canister of pads worn by the elderly more than twice as frequently as they could pair up younger or middle-aged scents. For the seniors, the old people smell was not rated poorly. In fact, for the 75- to 95-year-old participants, the scent was rated both less intense and less unpleasant than that of younger participants. The odor of the women in the study was considered more pleasant than that of men. Couldn’t you have guessed it?

The worst smell category for both intensity of the smell and unpleasantness was among men between the ages of 45 and 55. Men's scents actually tended to improve with age, possibly because changing hormone levels cause a drop in testosterone, which may reduce the amount of sweating for those men.

Humans can distinguish more than 10,000 different smells, even when they are dissipated throughout the air, scientists say. Also, research has found that not only can newborn babies pick out their mother, based on her distinct smell, but mothers can identify an article of clothing worn by their own infant as compared to that worn by another infant, solely based on scent. The capabilities of the human nose are really quite amazing.

Everybody knows that most animals have a much higher olfactory sense that we humans do. Dogs, bears, rats, even tiny moths can smell things that we can’t. (I don’t know how researchers found out that about moths.) But expert perfumers can identify hundreds, even thousands, of different odors after rigorous training.

Humans, like other animals, have body odors made up of a wide range of chemical components that transmit various kinds of social data. Odors among animals help in the selection of a mate, identifying individuals, detecting kin, and differentiating sex, according to other studies.

Although some old people have such difficulty bathing, they don’t stay as clean as others. It’s nice to know we seniors as a group aren’t naturally smelly.

The Baseline of Health Foundation provided the elder smell information. The research, however, was done by the Monell Chemical Senses Center in Philadelphia.

Tait Trussell is an old guy and fourth-generation professional journalist who writes extensively about aging issues among a myriad of diverse topics.

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