December 21, 2022 – In some relationships, women are the heart, vision and brains. In our marriage, my wife is the nose.
“What happened to the milk in the fridge?” she’d ask.
“I drank it.”
“Didn’t you notice it went bad?”
“You’re eating sardines again, aren’t you?” she would accuse.
“I had lunch 2 days ago!”
“Something died in the house,” she would insist.
Sure enough, behind the couch in the basement, there was a dead mouse.
“Women generally have a better sense of smell than men,” said Dr. Richard Doty, director of the Smell and Taste Center at the Hospital of the University of Pennsylvania. “And the gap between the sexes widens with age.”
The reason is unclear, but it appears to be a cradle-to-grave advantage. “If you put the breast pad [from nursing mothers] Females are often more responsive when babies are observed in a cradle for rooting or orienting behaviors,” he said. They found that women had, on average, 43 percent more olfactory bulb cells than men.
This is just one of many interesting facts about our sense of smell, or sense of smell. The adverse effects of COVID-19 on the sense of smell have attracted public and scientific attention. We see an impetus to develop a quick, simple and affordable odor loss test. (The Monell Chemical Senses Center in Philadelphia offers the 1-minute, $1 SCENTinel Quick Smell Test.)
COVID-19 also causes a unique loss of smell, with less than a third of patients having nasal congestion. We used to think that congestion would cause the smell to go away, but now we know that’s not always the case. Scientists are re-examining how viruses damage the olfactory system, both in the short and long term.
These are exciting times for otolaryngologists who study and treat nasal conditions. Not always. Darwin regarded smell as a fundamental sense, since its use in hunting, detecting danger, and other primitive activities is now far less important. In a 2019 UK survey, 250 adults actually scoffed at smell, ranking it as the least important of our five senses.
But smell is still crucial to our health. We’re learning more and more that our sense of smell is closely linked to our health — and may one day be used to monitor our health and predict disease.
what happens when you smell something
Think about what happens when we detect an odor — we do it thousands of times a day. For something to smell, it must release molecules. We inhale these molecules into the tip of our nose, where 6 million to 10 million specialized receptor cells are waiting. Some molecules contain multiple chemicals so they bind to a family of receptors to create an odor pattern.
Once this happens, the receptor cells send a message to the olfactory bulb at the base of the brain, and the process of recognition and response begins. Sometimes this happens immediately (rotting flesh). Other times, it takes a little time. (“Well, what flavor do you find in Chardonnay?”) Sometimes, there’s nothing. (When you have a cold, mucus keeps the molecules from fighting.)
Dr. Joel Mainland, a neuroscientist and researcher at the Monell Center, estimates that there are 40 billion molecules that make up an odor. Some of these scents may smell the same or be undetectable to humans. It’s impossible to know exactly how many we could detect, but Doty puts it at “tens or even hundreds of thousands.”
Our sense of taste works in a similar way, which is why people often confuse the two senses. Sensory cells that line taste buds on the tongue, back of the mouth, and palate detect chemicals in food molecules and relay that information to the brain. When we chew and swallow, some of these molecules are forced through the nasal cavity and into our old friend smell receptors, where they participate in the process.
To get hold of this, Doty recommends pinching your nose while chewing on a bar of chocolate. Closing the passage between the mouth and nose prevents food molecules from getting through, and you can’t taste anything. The same thing happens when you have a cold.
“Most of what we think of as taste depends on the odor system,” he said. “That’s why a lot of people who come to our clinic complaining of not being able to taste anything actually have a problem with their sense of smell.”
The same receptors found in the nose also appear in the kidneys, heart and lungs. Why this is so is unclear, but Continental thinks it’s because the cells serve multiple functions. Some, for example, arise in the “carotid body,” a small group of cells near the carotid artery in the neck, and “seem to sense how much oxygen and carbon dioxide is present — basically measuring and responding to lactic acid as if that were an odor .
Smells can also trigger memories, such as smelling perfume and reminding you of the person who wore it, or the smell of cooking food reminding you of your grandmother. These “olfactory flashbacks” occur because the brain’s odor-processing centers are connected to its emotional and memory centers. A study at Wheeling Jesuit University in West Virginia found that the smell of cinnamon can improve brain function and working memory, a finding that could help us treat dementia.
What Your Sense of Smell Can Tell You About Your Health
Jayant Pinto, MD, professor of surgery at the University of Chicago School of Medicine, likens anosmia to the canary in a coal mine. “It doesn’t directly cause death,” he said, “but it’s a precursor.”
In a 2014 study, he gave 3,000 people between the ages of 57 and 85 a smell test. Five years later, he had a review. Nearly 40% of those who performed poorly on the initial test have died, compared with 19% who scored moderately and 10% who tested well. He calculated that significant loss of smell was a better predictor of 5-year mortality (the likelihood of dying within the next 5 years) than emphysema, cancer, heart attack, stroke, diabetes or congestive heart failure.
The study has already been replicated, so the association wasn’t a one-time fluke. Other studies have linked olfactory dysfunction to many neurodegenerative (Parkinson’s, Alzheimer’s, epilepsy) and autoimmune (multiple sclerosis, Crohn’s, myasthenia powerless) to connect.
“Smell disturbances can be an early indicator of these problems,” says Doty, so it doesn’t hurt to consult your doctor or arrange to be tested for smell problems if you notice anything unusual.you can use it SCENTinel Rapid Odor Test the aforementioned or the gold standard Penn/Sensonics Odor Recognition Test (about $30). Both are self-administered and involve scratching and sniffing cards with various scents. The results provide a baseline for your sense of smell and may also indicate disease. For example, “approximately 90 percent of people with Parkinson’s disease have significant anosmia early on,” Doty said.
Disease can even be smelled. My wife, “Nose”, is a registered nurse at our local hospital. Years ago, when she was pregnant, she walked into the hospital room and had to turn around right away. “There was a strong smell of decay,” she recalls, “like when you come across a dead animal while hiking.”
The patient in that room had stage IV cancer, and she insisted she could smell it. (Her allergies ended with our baby.)
“At 19day century, the smell of acetone [nail polish remover] in the breath is considered a sign of diabetes,” says Doty. “There’s also a metabolic disorder called maple syrup disease where the urine has a sweet smell. There are many other examples in the medical literature linking skin odor to certain diseases. There’s no reason why the bodily changes caused by certain diseases wouldn’t be able to be discerned by dogs or even humans if they ended up in our saliva or blood. ”
The existence of “super-smellers” – people with a hypersensitive sense of smell – is controversial. But Doty and Mainland agree that the olfactory spectrum varies widely. Just like anything else, some people are better at it than others.
You May Not Be Sick — Just Getting Older
Like hearing and sight, our sense of smell diminishes over time. Doty’s research shows that 75 percent of people over the age of 80 have “some significant defect.” Half the population is between the ages of 65 and 80. Between 5 and 15 percent of people over the age of 65 have no sense of smell at all (a condition called anosmia).
It’s believed that this decline is at least partially caused by the colds we’ve had over the years. “Whenever we have a bad cold, the olfactory endothelium, or the membrane at the top of the nose, accumulates islets of damage called metaplasia,” Doty explained. “So, by the time we’re in our 60s and 70s, something that would otherwise be harmless, like the common cold, can take us over the waterfall.”
A big area of current research is whether age-related loss of smell can be slowed or stopped, and whether our sense of smell can be improved. Not true: Recipient cells can’t be strengthened by exercise, so to speak. And once damaged by viruses, accidents or aging, it cannot be regenerated.
but you can study It smells better. The popular concept of “smell training” is a bit misleading; it’s the brain that can be trained. We can teach ourselves to recognize and recognize new smells. Continental tries to smell new things every day, and even orders unique scents from perfumers to taste. Sommeliers essentially do the same thing, exposing themselves to multiple wines to learn the nuances of their aromas.
The future of odor research
As Darwin pointed out, we no longer spend our time sniffing the ground and tracking prey. But the genes that control these ancient behaviors are still with us, explains neuroscientist Marissa Kamarck, Ph.D. Scientists can not only detect the original or ancestral versions of these genes (so-called non-functional genes or pseudogenes), but also identify their variant or updated versions. In a recent study she co-authored with Mainland, Kamarck found evidence for the theory that our sense of smell as a species may be in decline.
“We found that, most of the time, variants with lower predictive strength [for smells] are newer variants,” she said. “For smell, our genes are mutating faster than other gene families,” Mainland said.
If anything, it will take centuries to unfold. Any ability to smell that we lose may be replaced or compensated by new abilities we gain. (Just like smelling a gas leak, prehistoric humans didn’t need to be aware of or fear the smell.) Like the rest of our bodies, our sense of smell is constantly evolving.
More interesting discoveries are yet to come. Mainland points out that the mapping from chemical structure to olfactory perception is unknown (unlike in vision, where wavelengths are converted to color, and in hearing, where frequency predicts pitch).
“There isn’t a single scientist or perfumer in the world who can observe a new molecular structure and predict how it will smell,” he said. The goal of his research is to develop it.
In fact, a recent global survey by Ericsson ConsumerLab found that the majority of consumers expect to be able to smell movies and even products digitally by 2030 through the “Internet of Senses”.
imagine. If my wife is at work, I can send her a smell sample of milk to see if it is safe to drink.