The Aging-Body Odors-Part XIII

We received the following email from one of our viewers of site:

"Can you possibly tell me what the reasons might be for an elderly person to have a particular odor? It's hard to describe...a strong 'old' smell... not typical bad breath or unclean body smell ... it's just different. I've been told that people sometime begin to have an odor when they are elderly. I am concerned about an elderly relative and need advice if you can help me. Should I be alarmed by this?"

(Co-editor Harold Rubin's response) There would appear to be many different odors associated with the elderly or for that matter, humans in general. The primary source of these odors is poor hygiene, the infrequency of washing oneself, allowing malodorous bacteria to flourish. . During the Middle Ages, the Catholic Church discouraged bathing, as it was a "pagan" custom and many times involved communal baths and public nudity. Over the centuries, being clean was associated with catching diseases, as body filth was associated with providing a protective layer against "vapours". Most Europeans at that time bathed only once or twice a year.

Another cause of odor is urinary leakage. Urinary incontinence is a not infrequent problem of the elderly, particularly prevalent among older women. Over 60% of women over 65 years of age are prone to urinary tract infections, with its own particular odor associated with the content of the urine.

Halitosis (bad breath) is not uncommon as people age. An estimated 70% of the elderly do not produce enough body saliva, not only because of aging, but also as a side effect of some of the common medications taken by the elderly. These medications include antidepressants, blood pressure medications, diuretics and sedatives. Saliva plays an important role in dealing with bacteria. With less saliva, malodor bacteria can thrive, causing bad breath. The medical term for reduced saliva is xerostomia. False teeth also allow odorous bacteria to thrive in the mouth. Hence the resulting bad breath.

The natural compounds released by the body also have their own odor. Bacteria are able to decompose a compound that is found in perspiration (sweating) called isovaloric acid. Isovaloric acid (also called Isopentanoic acid ) is a member of the series of fatty acids of colorless liquid with a penetrating aroma. The smell is associated with sweat and/or stinky feet and can be quite odorous. Sweating is the loss of watery fluid. This fluid consists of salt (sodium chloride) and urea, secreted by the sweat glands. Also in sweat are odorants of the methylphenol family. It is these different compounds that give sweat its bad name.

There are different types of sweat glands in the human body. Sweat itself is almost totally odorless. Body odor, more formally called bromhidrosis, is the smell of bacteria growing on the body. Sweat is the medium in which they thrive. Diet, genetics, health, medication, occupation and mood also influence body odor. Apocrine sweat glands produce sweat that contains fatty materials. These glands are mainly present in the armpits and around the genital area and their activity is the main cause of sweat odor, due to the bacteria that break down the organic compounds in the sweat from these glands. Emotional stress increases the production of sweat from the apocrine glands, or more precisely: the sweat already present in the tubule of the gland is squeezed out.

Apocrine sweat glands essentially serve as scent glands. East Asian people typically have markedly fewer of these glands compared to people of other ethnicities, which is why East Asian people generally do not emit such odors. (It is reported that 17th century Japanese described Westerners with the word bata-kusai, which means "stinks of butter".)

Other unique scents released by the body as result of bacteria decomposing sweat include nonenal, indole and skatole. The extent of these malodorous scents are related to changes associated with aging. A researcher at Shiseido Laboratories has traced the problem to a fatty acid known as palmitoleic acid -an unsaturated fatty acid that is a common constituent of the glycerides of human adipose tissue. He has also learned that the body of a person up to about the age of 30 does not secrete a noticeable amount of this substance, but that once a person--whether male or female hits 40, the volume rises sharply. The volume of palmitoleic acid released by the human body is 10 times as great among people in their seventies as in their forties.


Sebaceous glands (classified as holocrine glands), found in the skin, secrete an fatty oily substance called sebum that is made up of lipids (fat) and debris of dead fat-producing cells. The function of sebum is to prevent the skin from getting dry, cracked and brittle and to protect and waterproof the hair and skin. Sebum itself is odorless. It is because of sebum that hair gets "oily" after several days of not being washed. Sebum is also the dry stuff found in the corner of our eye after sleeping as well as part of earwax.

Skatole is a white crystalline organic compound, C9H9N, having a strong fecal odor. It is found naturally in feces, beets, and coal tar. Indole and skatole (IS) arise from bacterial degradation of tryptophan (trp) and can contribute significantly to the oral malodor "bouquet". Skatole is formed in the intestine by the bacterial decomposition of tryptophan and that has a strong fecal odor that can remain in the air for quite a while, similar to the way a skunk scent remains after the skunk has gone. This odor is a problem in fecal incontinent individuals or individuals with gastrointestinal difficulties that result in flatuence.
Lastly, you have a number of metabolic disorders that have their own distinctive odor. This has to be evaluated by a treating physician.
The take home message from this article is that body odor is a part of the human body, probably a vestige from the past when scent was an important defense for survival. Today, after ruling out all the typical reasons for "foul odor", a physician needs to be informed of the smell and investigate the causes of the scent.

Go Back to Article I of Articles on Aging-Mortality risk factors
The Aging Process-Part II-Gender Difference
The Aging Process-Part III-Cellular Senescence
The Aging Process-Part IV-Biological Aging
Go to Article V of Articles on Aging-Arteriosclerosis
The Aging Process-Part VI-Aging in Males
The Aging Process-Part VII-Aging in Women
The Aging Process-Part VIII-Infectious Disease
Process of Aging-Part IX-DHEA
The Aging Process-Part X-Skin, Skeleton and Brain
The Aging Process:-Part XI-Apotosis and the Elderly
The Aging Process-Part XII-Biomarkers for Aging


Harold Rubin, MS, ABD, CRC, Guest Lecturer
posted April 1,2006

Email: or