We stink, but does it mean anything?

Smell has a direct path to the brain. It plays a role in the taste of food, sexual attraction, and pleasure. It is said that humans have never appreciated the role of the sense of smell, which is just as crucial as other senses, such as taste, vision, hearing, and even disease detection. There is even data to suggest that we all smell at different ages.

Smell is a “time portal” because old and vivid memories can be revived in stark detail. The human brain creates a library of smells from early childhood to adulthood. Those who like the classics might remember that the great French author Proust felt that Madeleines dipped in tea inspired him and brought back fond memories of his past.  This has been called the Proust Effect.

The nose works for everyone, and some scientists say that training the sense of smell in most people could improve their lives. There is a condition called hereditary hyper-osmia (hyper = over, osmia = sense of smell), a rare and fine-tuned ability to smell. It is remarkable and does not exceed an animal's sense of smell, such as a dog. Such talents tend to run in families.  Some people can't smell anything, and these people have something called anosmia.

There is new proof that toddlers smell like flowers and teenagers smell like goats. Anyone with grown children knows the hircine smell of a teen, especially boys who sometimes wreak of body odor if not bathed with regularity.  Emily Anthes wrote about this in the New York Times.  The original article appeared in Communications Chemistry.  Body odor, she says “is a blend of airborne chemicals, many of which are produced by sweat and sebum (an oily substance secreted through the hair follicles and broken down by skin bacteria “ (the microbiome of the skin)

There is also no question that some physicians and nurses have an extensive library of familiar scents. They might have hyper-osmia. One nurse could smell her husband’s neck and clothes and predict the onset of Parkinson’s disease. Subsequently, there were biomarkers in the sebum that researchers could identify. In the case of disease, these compounds are waste products of abnormal metabolism. They were known as volatile organic compounds (VOCs).   I suspect that people with certain conditions have these VOCs in abundance in conditions like cancer or even immune disease.

Some dogs can be trained to smell disease. Dogs have an uncanny capability to smell tumors, blood disorders, and many other things. Dogs have a susceptible nose. By testing, the average hound can smell glabric acid (the substance in green peppers) a few hundred feet away. Dog owners know that a dog can smell its master, most members of the household in which it lives, and which strangers might be friendly.

I recall the great Professor Lewis Thomas using dogs to identify a specific genetic strain of mice in a large room full of cages.  The dogs could distinguish which mice might be of a specific strain or had specific genetic markers.  Both he and I were fascinated by this canine talent.

This is why dogs magically smell cadavers buried in large plots of land or collapsed buildings under tons of concrete and are the staple of drug detection at airports and border crossings. Animals have amazingly accurate smell senses. If you are a fan of truffles, you can recall that pigs can easily find them in the forest through the sense of smell.

Smell does many intimate things. It gives us subliminal clues regarding suitability for mating, just like in other mammals. The likelihood of reproductive success is directed by smell. The smell of male sweat is a subtle aphrodisiac to many females. It is scientifically known that women who live together in sorority houses synchronize menstruation and ovulation over time.  In summary, smell is a powerful means of attraction and has limitless effects on behavior, sexual and otherwise.

These are the so-called “love molecules” that validate relationships and enhance the act of love.  It is probably the “chemistry” of relationships.  We are unaware of these subtle chemical smells powerful enough to change lives and relationships.  I have always wondered what role colognes and perfumes have in masking relationships because they must interfere with pheromones. 

Two examples illustrate the power of pheromones: first, a cow in heat or at a particular time in her estrus cycle that a bull can detect many miles away; second, companies attempting to create a pheromone-laden trap for Japanese Beatles that some gardeners place in their gardens, which attract beetles from miles around. These are two apparent illustrations of how powerful pheromones genuinely are.

As if we have not had enough, there is data to support the idea that smell can improve deficits in memory recall in patients with major depression. Odors are more powerful than words in enhancing memory, and they can reduce depressive symptoms.  (JAMA Network Open 2024)

Let's not take the sense of smell for granted. We know from the ravages of COVID-19 that smell can be decreased for a time after the infection; for example, patients did not enjoy eating or savoring their favorite wine for many weeks or months after COVID-19.

 Yes, we all stink, but we need our sense of smell for relationships, diet, mental well-being, and disease detection.  Praise the nose for its remarkable functions and savor that smelly cheese, the bouquet of your favorite wine, or your teenager’s sweaty underwear.