I recognized her immediately in the grocery store parking lot, although I had not seen her in years. She was quite a bit younger than my mom, but they had been good friends when I was a child. As she was getting into her car, she looked up at me and I walked over. Identifying myself by my maiden name, I greeted her, “I’m Ruth Wright, Olive’s youngest daughter.”

“Well, I’ll be. I thought I recognized you.”

When I reached in to give her a hug, a warm embrace and the strong fragrance of aging enveloped me. I know that you know what I mean. We have all had the experience, even though it is not a frequent topic of conversation.

Some people describe it as “grassy or greasy.” Others have called it a “a sweet stink.” On the animated series “Rugrats,” Lil once described her grandpa’s room as “smelling funny, like cheese.” You may have noticed it at long-term care facilities, the homes of elderly folk, or even when sitting beside an older person at church. Possibly, you associated it with the term “old people smell.”

Most people assume that it is just what happens when you get older, or that this distinctive but not dreadfully offensive odor is related to closed quarters, lack of good hygiene practices, or loss of housekeeping skills.

The Journal of Investigative Dermatology published a study in 2001 in which researchers discovered that the odor is likely due to a chemical compound – 2-nonenal. A natural by-product of the aging process, 2-nonenal is produced when fatty acids produced by the sebaceous glands react to the oxygen in the air. Since nonenal is not water soluble, it can exist in even extremely clean environments. Because it is related to the deterioration of the skin’s antioxidant defenses, both men and women will experience the production of nonenal close to their fortieth birthdays. The production of this chemical will increase – up to three times as much – from middle to old age. The hormonal changes of menopause may exacerbate its production. Research has also shown that stress makes it worse. Nonenal is easily absorbed into clothing and other fabric such as pillows and upholstery, which explains why an older person’s bedroom or entire house can be permeated with the odor. It thrives in enclosed areas.

In an article by Melanie Haiken, Health Journalist, updated in October 2017, physician and clinical gerontologist Eric Shapira is quoted: “There’s absolutely a particular smell we associate with aging, but there isn’t one specific cause. It’s a combination of many different things that are all associated with what happens to the body as we get older.”

Here’s a summary of the main reasons old people and their homes smell according to Haiken: closed quarters (nobody opens windows anymore); inadequate housecleaning (dust, mold, mildew and dander accumulate); laundry limitations (it’s a lot of work to wash clothes and easier to wear soiled ones); sensory decline (older people often do not notice the odor because the sense of smell decreases up to 75 percent in later years); dental problems associated with aging (dry mouth, dentures); dehydration (everything become more concentrated and odors seep through pores); aversion to or fear of taking baths; use of medications (both oral and topical); and being surrounded by old things that give off a musty odor.

Even the experts disagree on the exact cause, but everyone concurs it would be nice to find a remedy. Part 2 looks at ways to eliminate, or at least decrease, that smell.