On their return from visiting a nursing home, my children when we were in kindergarten happily shared with me their impression that the residents “smell.” A nursing home is not the best place to get to know older adults, but the stereotype remains. There are even some fancy scientific theories to explain why this is so. We know that taste and smell diminish with age, but that older people also have a distinct odor is worth exploring.
Visiting Japan, one is immediately faced with the strict culture of washing and bad odor is frowned upon. The Japanese even have a distinct name for the body odor of older people Kareishu. After conducting a poll of 150 men and women, the Japanese Shiseido Group found that odor from older people is the second most offensive scent behind bad breath. We will return to this study later on.
Body odor in humans is determined by various factors, including genetic background, physiological conditions, behavioral patterns, food ingestion, and disease types, but most often there is a stereotype that it relates to getting old. The theory is that older people smell because of their aging biology. One theory suggests that aging causes hormonal imbalances resulting in more lipid acid in our skin. And as skin matures, its natural antioxidant protection decreases, resulting in greater oxidation of this lipid acid resulting in Nonenal. The smell of this chemical compound is similar to oil that goes rancid when left out. This chemical is more common among people over 40 years of age. Another biological theory is that the major contributor is the bacterial activity in skin gland secretions. Numerous skin bacteria help produce smelly substances and as we get older this bacteria seems to be more common.
It could also be related to diet. In 2017 Jun Nishihira with Hokkaido Information University and his colleagues reported that eating a mushroom extract (Champignon) was found to improve body smell, as well as bad breath and smelly poo. The idea that perhaps we can counteract this Kareishu was explored by Dae Youn Hwang with Pusan National University, Republic of Korea, and his colleagues. They found that extracts of Spiraea Japonica—a deciduous, perennial shrub native to Japan—reduced the odor of older adults.
Developing products to counteract Kareishu opens the market to businesses making money off older people’s fears and stereotypes. Shiseido Group at one point developed a perfume "Harmonage Fragrance" specifically formulated to neutralize older people’s body odor. Then there is the line of anti-age-stench soaps by Mirai Clinical that this time uses persimmon extract as a natural deodorizer. The issue is not that body odor changes with age, it does, the issue is whether this smell is bad.
Researchers have shown that the body odors of some animals—including mice, black-tailed deer, otters, owls, and rabbits—change with age and that animals can distinguish their young and old peers by smell. Even people can tell the difference between old and young otters and rabbits by how they smell.
Older people might smell differently from younger people, but this is not always a bad smell. We know for example, that some frail older people experience difficulties in mobility and getting washed, but those that are still functional and maintain good hygiene might be different.
Johan Lundström and his colleagues at the University of Pennsylvania stitched absorbent pads into the armpits of T-shirts and asked volunteers of different ages to sleep in the shirts for five consecutive nights. During the day, the volunteers stored the T-shirts in sealed plastic bags; avoided spicy foods, cigarettes, and alcohol; and showered with odorless shampoo and soap. After the fifth night, blindfolded volunteers rated the pads and found elderly people's odors both less intense and less unpleasant than odors from young and middle-aged people. Middle-aged men had the most unpleasant odor while the odors of middle-aged women were judged to be the most pleasant. Old people's smell was often instantly recognizable and not necessarily in a bad way. The result from this study is different from the earlier study by the Shiseido Group. But then again if I am selling a fragrance I want to create a market of smelly older adults so that they will buy my fragrance. In reality, older adults might smell differently but not in a bad way. The lesson is how easily we accept the negative stereotype of older people smelling.
References
Nishihira, J., Nishimura, M., Tanaka, A., Yamaguchi, A., & Taira, T. (2017). Effects of 4-week continuous ingestion of champignon extract on halitosis and body and fecal odor. Journal of Traditional and Complementary Medicine, 7(1), 110-116.
Kim, J. E., Choi, Y. J., Lee, S. J., Gong, J. E., Seong, J. E., Park, S. H., & Hwang, D. Y. (2022). Evaluation of Deodorizing Effects of Saccharina japonica in 10-Month-Old ICR Mice Using a Novel Odor Marker Associated with Aging. Evidence-Based Complementary and Alternative Medicine, 2022.
https://www.scientificamerican.com/article/old-person-smell/
Mitro, S., Gordon, A. R., Olsson, M. J., & Lundström, J. N. (2012). The smell of age: perception and discrimination of body odors of different ages. PloS one, 7(5), e38110.
https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0038110
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