Healthy Aging

Might You Have (Gasp) Kareishuu?

On the list of “First World problems to worry about,” it’s definitely not number one – but for some kareishuu – it holds a spot near the top. Kareishuu is the Japanese term for — literally “the smell of gaining years.” Most Americans refer to it, sometimes with disgust, anxiety, or a sneer, as “old people smell.”

Is help at hand? I admit it, I googled “soap for old people smell,” got a bunch of hits and was reassured that Amazon could have some solutions on my front porch within days.  Among the options are persimmon soap, a pouch to place around the house (1 per 150 square feet) to soak up those nasty old odors like a sponge and spray on odor eliminator.  Other ”experts” talk about eating right, exercising and drinking green tea to ward off old people smell, but I couldn’t find any studies to back up those suggestions.

So I delved deeper into the science.  Here’s what I found out:

There is age-related body odor, and it does change as we get older. In a published report, researchers long ago said the origin is 2-nonenal, a compound ”with an unpleasant greasy and grassy odor” detected only in older subjects, those 40 and up in the group they tested, who were 26 to 75 years old.

Later on, other research has suggested that one person’s ”disgusting” is another person’s “delightful,” or at least “less than disgusting.” These scientists collected body odor from the armpits of men and women ages 20-30, 45-55 and 75-95. They asked 41 participants, ages 20 to 30 (and not the same ones who contributed their BO to science) to rate the intensity and pleasantness (or unpleasantness) of the samples.  Surprise: Older people’s BO was rated as less intense and less unpleasant than either of the other age groups.

Nonenal Studies

Back to the Japanese, who continue to study 2-nonenal. Shinobu Nakanishi, PhD, a Japanese researcher at a cosmetics company, and his colleagues did an experiment on cultured human keratinocytes, a kind of epidermal cell that is important for skin repair. They found that nonenal decreased viability and promoted cell death in these cells. In a 3-D model that mimicked the skin’s epidermis, they also found the nonenal reduced skin thickness.

The suggestion is that nonenal could be involved in the thinning of the skin that’s well known to occur with age—and make us look older, no matter how we smell. Next, they tested masking odorants in skin care products. “Odorants in those skin care products and perfumes inhibit the nonenal effect,” Nakanishi told us.

The premise is that masking those malodors and tamping down the nonenal could keep skin thicker and more youthful looking.

So, the choice for now looks like it boils down to: have a smell that’s less unpleasant and less intense than younger people or try to reclaim the skin of your youth.

Have you noticed Kareishuu?  What have you been doing about it? Tell us in the comments!


Photo: Shaun Newton

Kathleen Doheny is a Los Angeles-based independent journalist, specializing in health, behavior, fitness and lifestyle stories. Besides writing for Senior Planet, she reports for WebMD, Medscape, Endocrine Web, Practical Pain Management, Spine Universe and other sites.  She is a mom, mother-in-law and proud and happy Mimi who likes to hike, jog and shop.

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5 responses to “Might You Have (Gasp) Kareishuu?

  1. Thanks for the article. I’ve always had the nose of a hound, and I have thinking about this. I think there are two kind of kareishuu: funky household, and funky BO
    Yesterday, I pulled out the steam cleaner I bought to steam clean the kitchen surfaces, last week, I shlepped my blankets and covers to the laundromat, threw away a pillow, I washed my yoga mat yesterday.

    But for the funky BO because of an aging irritable GI…. candles, incense, and sage

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