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Sense of smell facts: 10 Incredible Facts About Your Sense of Smell


10 Incredible Facts About Your Sense of Smell

Olfaction, the sense of smell, might be the Rodney Dangerfield of the five senses: It gets no respect — or at least not as much as it should. From how many different scents the nose can pick up to the link between smell and overall health, there are a lot of things about this sense that may surprise you.

Here are 10 strange but true facts about our sense of smell:

1. People can detect at least one trillion distinct scents. Scientists thought that the human nose could only detect about 10,000 different smells, but that information was based on a study from 1927 and very outdated. This year, researchers from Rockefeller University tested people’s sense of smell by using different mixtures of odor molecules. The results, published in the journal Science, showed that the nose can smell at least one trillion distinct scents.

So how exactly does humans’ sense of smell work? When odors enter the nose, they travel to the top of the nasal cavity to the olfactory cleft where the nerves for smell are located, explains Amber Luong, MD, PhD, assistant professor at the University of Texas Health Science Center at Houston. “There, the odorant is detected by various receptors located on the nerve cells and the combination of activated nerves travel to the brain. The combination of activated nerves generates all the unique smells that we as humans can detect,” says Dr. Luong.

Some of the most pleasant or pleasurable scents include vanilla, some forms of orange scents, cinnamon, crayons, and cookies, according to Luong and Dolores Malaspina, MD, MSPH, professor of clinical psychiatry at Columbia University in New York.

2. Scent cells are renewed every 30 to 60 days. The sense of smell is the only cranial nerve — nerves that emerge from the brain and control bodily functions including eye movement, hearing, taste, and vision — that can regenerate, says Luong.

3. You can smell fear and disgust. You can smell feelings of fear and disgust through sweat, and then you can experience the same emotions, according to a 2012 study published in the journal Psychological Science.

Researchers collected sweat from men as they watched movies that caused these feelings. To remain odor-neutral for the sweat test, the men used scent-free products, and quit smoking and using alcohol. Women participants then completed visual search tests, while unknowingly smelling the sweaty samples. The women’s eye movements and facial expressions were recorded during this time.

The researchers found that women who smelled the “fear sweat” opened their eyes widely in a fearful expression, and women who smelled the “disgust sweat” also displayed facial expressions of disgust.

4. Smell is the oldest sense. Chemodetection — detecting chemicals related to smell or taste — is the most ancient sense, says Malaspina. “Even a single cell animal has ways to detect the chemical composition of the environment,” she adds.

5. Women have a better sense of smell than men. “Women always are better at odor and smell identification than men, and every study finds that,” says Malaspina. She says one of the reasons for this may be that women have a more developed orbital prefrontal region of the brain. It may have also evolved from an ability to discern the best possible mates, or to help women better bond with and understand newborns.

6. Age-related loss of smell is linked to race. African-Americans and Hispanics experience loss of smelling related to age earlier than Caucasians, according to a 2013 study published in the Journal of Gerontology: Medical Sciences. Researchers asked more than 3,000 adults aged 57 to 85 years to identify five common odors.

Although age-related loss of smell is common, this is the first study to examine racial differences.

Results showed non-Caucasian individuals consistently scored 47 percent lower than Caucasians, and were equivalent to being nine years older. Women from all races performed the smell test better than men, and were equivalent to being five years younger.

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The exact cause for this difference is unknown, but researchers believe genetics and environment (such as exposure to nerve-damaging substances) could be factors.

7. Dogs have nearly 44 times more scent cells than humans. “Humans have five to six million odor-detecting cells as compared to dogs that have 220 million cells,” says Luong. ”We have evolved to rely less on our sense of smell, while most animals have retained this sense.”

Another fun fact about canines and smell: Dogs can distinguish non-identical twins but not identical twins based on odors, says Malaspina.

8. Loss of smell may signal future illnesses. “Decreased sense of smell may be an early sign of Alzheimer’s or Parkinson’s disease,” says Luong. Two studies presented at the Alzheimer’s Association International Conference 2014 found that a reduced ability to identify scents was associated with brain cell function loss and advancement to Alzheimer’s disease. A study published in the Annals of Neurology also found that a diminished sense of smell can precede the development of Parkinson’s disease.

9. Each human has their own distinct odor. Like fingerprints, every person has their own distinct odor. The distinct odor you have comes from the same genes that determine tissue type, says Malaspina.

10. Decline in smell may predict death within five years. A recent study published in the journal PLOS ONE found that a decreased ability to identify scents may predict death within five years. The study looked at more than 3,000 Americans aged 57 to 85, and found that people unable to identify scents like rose, orange, and peppermint were more than three times as likely to die in the next five years.

Still, having a diminished sense of smell isn’t necessarily something to panic about. Most of the things that interfere with olfactory senses are allergies and head injuries, and not factors that suggest an increased risk of death.

“We know that new brain cells are produced throughout life in a few different olfactory areas, and the earlier death may relate to the decline of cell regeneration that is occurring in other body regions as well,” says Malaspina.

Six curious facts about smell

Don’t underestimate the power of your nose. It makes our everyday eating experience pleasant and interesting and it warns us of spoiled food, corked wine and the dangers of gas and smoke. It evokes strong emotional reactions, influences sexual attraction and can be used as a sensitive analytical instrument.

1. We taste with our nose

Many people think that we do all of our tasting with our tastebuds, but they can only detect if something is sweet, salty, bitter, sour or umami (for example, the savoury taste of Marmite). The truth is, we also “taste” with our nose, eyes and ears.

The taste or, more correctly, the overall flavour we perceive as we mow our way through our favourite meal, is a combination of the signals that we receive from all our senses. It is the job of the brain to interpret these signals and tell us whether the food is up to scratch, whether the potatoes are burnt, the cabbage is overcooked or the fruit is ripe.

Read more:
The strange science of odour memory

These aromas are detected by receptors at the back of the nose that relay signals to the olfactory bulb where the signals are collated and sorted. The information is then sent to the brain which tells us the quality and intensity of the aromas (or smells) around us and in the food we eat. When we say we can’t taste food, we really mean that we can’t smell it.

2. Not everyone can smell

About 5% of the population is anosmic, which means that they cannot smell. This can be devastating. Imagine that your food just doesn’t taste of anything apart from a bit sweet and a bit salty. You can no longer enjoy your favourite foods and eating out is no longer fun. Also, you can’t smell mouldy bread or sour milk or burning pizza – what if the house caught fire? And one question that haunts anosmics is: do I smell? These anxieties often lead to an insular lifestyle, depression and a decline in mental health.

Imagine not being able to tell if the milk is off?

3. You don’t need an olfactory bulb to smell

Some people are born without an olfactory bulb, the organ that was previously believed to be essential for the perception of smell.

While carrying out brain imaging, a group of researchers realised that one of their normal control subjects had no apparent olfactory bulb, yet they obtained normal scores for standardised smell tests. They discovered that 0.6% of all women can smell perfectly well without an olfactory bulb. This rises to 4.3% in left-handed women. But if you are a man without an olfactory bulb, the evidence so far suggests that you are destined to a lifetime of tasteless food.

4. Viral infections can rewire your sense of smell

The common cold is a well-known thief of our sense of smell, albeit usually temporarily. Yet for some people, their sense of smell doesn’t return after a viral infection such as the common cold, a sinus infection or upper respiratory tract infection. Recovery can take several years and is not even guaranteed.

Most people develop parosmia (an inability of the brain to properly identify a smell) during the early stages of recovery, when a few everyday smells return but with a badly distorted and usually repulsive character. These new smells are incredibly hard to define but attempts to describe these sensations often include words like burnt, foul, rotten or sewage.

Coffee, chocolate and meat seem to be repeat offenders. Researchers believe that as the damaged olfactory neurons are slowly regenerated or repaired, the distortions are a result of cross-wiring in the olfactory bulb. Exactly how this happens, though, remains a mystery.

Read more:
Phantosmia: when you smell smells that aren’t there

5. Smell training is better than sudoku

An exercise that helps anosmics to regain their sense of smell is “smell training”. Researchers believe that systematically exercising the olfactory neurons stimulates growth and repair, much in the same way that physiotherapy promotes injury healing. The technique was pioneered in Germany and involves actively sniffing (and concentrating) on different smells at least twice a day for several months.

In a recent study of older people, smell training was shown not just to improve their olfactory function but also their verbal function and overall wellbeing, demonstrating that smell training is a good way to improve the quality of life in older people. What is remarkable is the fact that the control group was given sudoku puzzles to complete twice a day during the experiment, suggesting that smell training is more effective than sudoku on these measures.

6. Humans can track scents like a dog

Have you ever been amazed at the ability of dogs to follow scent trails and wondered why we can’t? Research in 2017 showed that, in fact, we can. We don’t have the advantage of the optimised airflow through a dog’s nose, but if we practice a bit – and get down to the level of a dog’s nose – we can effectively track a trail of chocolate aroma laid across a field.

Ten Fun Facts About Sense of Smell

To celebrate National Sense of Smell Day on April 27, Cintas Corporation announced 10 fun facts about humans’ sense of smell. Sponsored by Sense of Smell Institute, National Sense of Smell Day aims to educate and raise awareness about the power of scents. Odor control specialists highlighted facts to help organizations understand the powerful role that scent plays within their facilities and how it impacts the lives of building occupants each and every day.

“Since our sense of smell is highly linked to memory and perception, businesses should implement programs that work to tackle malodors in restrooms and other key areas of the facility,” said Dave Mesko, Senior Director of Marketing and Strategy, Cintas Corporation. “Through cleaning programs and odor-control products, businesses can ensure customers are constantly greeted with a fresh scent and positive first impression.”

Ten fun facts about sense of smell:

1. Everyone has a unique odor identity similar to a fingerprint — no two people smell the same way except identical twins.

2. The human brain can process roughly 10,000 different smells in an area the size of a postage stamp.

3. A woman’s sense of smell is much stronger than a man’s.

4. A person’s sense of smell is weakest in the morning and the ability to perceive odor increases throughout the day.

5. Approximately 80 percent of what we taste is actually qualified by our sense of smell. This is why our taste is diminished during a cold or flu.

6. Prolonged exposure to unpleasant smells can actually impair your ability to smell. Wearing a mask over the nose and mouth can help lessen the effects of malodors.

7. Smell has a very powerful link to memory and links to the emotional regions of the brain more directly than other senses.

8. Our sense of smell is strongest in the spring and summer because of the added moisture in the air. It is also stronger after exercising because of the additional moisture in the nasal cavity.

9. Scent works in the opposite direction of other senses. With sight, sound and taste, we identify the information first and then react emotionally. With scents, we have an emotional reaction first and then identify the scent shortly thereafter.

10. People can remember smells with 65 percent accuracy after a year, while visual recall is about 50 percent after three months.

“A pleasant scent can signal powerful memories that bring us back to a great experience—while a disagreeable odor can be offensive,” added Mesko. “The facts about scent help businesses understand how critical this sense is for customers and how it impacts overall perception of a facility.”

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Making Sense of Scents: Smell and the Brain

With every whiff you take as you walk by a bakery, a cloud of chemicals comes swirling up your nose. Identifying the smell as freshly baked bread is a complicated process. But, compared to the other senses, the sense of smell is often underappreciated. Scientists studying olfaction have shed light on how our sense of smell works and provided compelling evidence that it’s more sophisticated than previously thought.

In a survey of 7,000 young people around the world, about half of those between the age of 16 and 30 said that they would rather lose their sense of smell than give up access to technology like laptops or cell phones.

“We’re not that acutely aware of our use of olfaction in daily living,” explains Noam Sobel, a scientist who studies smell at the Weizmann Institute of Science. But 5 percent of our DNA is devoted to olfaction, a fact that emphasizes how important our sense of smell is, he said.

The Nose Knows

Smell begins at the back of nose, where millions of sensory neurons lie in a strip of tissue called the olfactory epithelium. The tips of these cells contain proteins called receptors that bind odor molecules. The receptors are like locks and the keys to open these locks are the odor molecules that float past, explains Leslie Vosshall, a scientist who studies olfaction at Rockefeller University. 

People have about 450 different types of olfactory receptors. (For comparison, dogs have about two times as many.) Each receptor can be activated by many different odor molecules, and each odor molecule can activate several different types of receptors. However, the forces that bind receptors and odor molecules can vary greatly in strength, so that some interactions are better “fits” than others. 

“Think of a lock that can be opened by 10 different keys. Two of the keys are a perfect fit and open the door easily. The other eight don’t fit as well, and it takes more jiggling to get the door open,” explains Vosshall.

The complexity of receptors and their interactions with odor molecules are what allow us to detect a wide variety of smells. And what we think of as a single smell is actually a combination of many odor molecules acting on a variety of receptors, creating an intricate neural code that we can identify as the scent of a rose or freshly-cut grass.

Odors in the Brain

This neural code begins with the nose’s sensory neurons. Once an odor molecule binds to a receptor, it initiates an electrical signal that travels from the sensory neurons to the olfactory bulb, a structure at the base of the forebrain that relays the signal to other brain areas for additional processing.

One of these areas is the piriform cortex, a collection of neurons located just behind the olfactory bulb that works to identify the smell. Smell information also goes to the thalamus, a structure that serves as a relay station for all of the sensory information coming into the brain. The thalamus transmits some of this smell information to the orbitofrontal cortex, where it can then be integrated with taste information. What we often attribute to the sense of taste is actually the result of this sensory integration. 

“The olfactory system is critical when we’re appreciating the foods and beverages we consume,” says Monell Chemical Senses Center scientist Charles Wysocki. This coupling of smell and taste explains why foods seem lackluster with a head cold.  

You’ve probably experienced that a scent can also conjure up emotions and even specific memories, like when a whiff of cologne at a department store reminds you of your favorite uncle who wears the same scent. This happens because the thalamus sends smell information to the hippocampus and amygdala, key brain regions involved in learning and memory. 

A Better Smeller

Although scientists used to think that the human nose could identify about 10,000 different smells, Vosshall and her colleagues have recently shown that people can identify far more scents. Starting with 128 different odor molecules, they made random mixtures of 10, 20, and 30 odor molecules, so many that the smell produced was unrecognizable to participants. The researchers then presented people with three vials, two of which contained identical mixtures while the third contained a different concoction, and asked them to pick out the smell that didn’t belong. 

Predictably, the more overlap there was between two types of mixtures, the harder they were to tell apart. After calculating how many of the mixtures the majority of people could tell apart, the researchers were able to predict how people would fare if presented with every possible mixture that could be created from the 128 different odor molecules. They used this data to estimate that the average person can detect at least one trillion different smells, a far cry from the previous estimate of 10,000. 

The one trillion is probably an underestimation of the true number of smells we can detect, said Vosshall, because there are far more than 128 different types of odor molecules in the world. 

No longer should humans be considered poor smellers. In fact, new research suggests that your nose can outperform your eyes and ears, which can discriminate between several million colors and about half a million tones. “It’s time to give our sense of smell the recognition it deserves,” said Vosshall.


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Facts | Taste and Smell

Thank you for your interest in the Taste and Smell Center. You are one of about 2 million adult Americans affected by taste or smell disorders. Unfortunately, very little is known about these problems, which is why our Clinic was established in 1981 with funds from the National Institutes of Health. We evaluate patients with taste and smell problems at weekly clinics, as well as conduct taste and smell research programs here at UConn Health. Treatment is offered when appropriate, although less than a third of patients evaluated here will be determined to have a treatable taste or smell problem.

If you wish to be evaluated here, call 860-679-2804.

What Are the Chemical Senses?

The chemical senses include taste and smell. The perception of a smell occurs when substances in the air pass through the nose and stimulate the olfactory (smell) nerve. The experience of taste, or gustation, occurs when the taste buds in your mouth respond to substances dissolved in saliva. The four basic tastes are salty, sweet, sour and bitter.

 What Are Some of the Disorders of Taste and Smell?

  • Anosmia – total loss of smell
  • Hyposmia – partial loss of smell
  • Parosmia – perceiving a smell when no odor is present or perceiving familiar odors as smelling strange
  • Hypogeusia – a diminished sense of taste
  • Dysgeusia – a persistent taste, usually unpleasant

What Are the Causes of Taste and Smell Disorders?

Losses or distortions of taste and smell have many causes such as nasal disease, upper respiratory infections, head injury, neurological disorders, or dental problems. There are some people who have had no sense of smell since birth.

Are Taste and Smell Related?

Taste and smell are two separate senses. However, both contribute to the experience of flavor.

What Is Flavor?

Flavor is what people commonly call the “taste” of food. It is actually a combination of smell, taste, spiciness, temperature and texture. Much of the flavor of food comes from smell, so that when you are unable to smell you have lost much of your ability to experience flavor.

What Can Be Done to Improve the Flavor of Food?

Eating can be more enjoyable when the other aspects of flavor, such as texture, temperature, and spiciness are emphasized. Texture can be enhanced by adding crunchy foods (nuts, croutons, water chestnuts) to your meals. Combining cold and hot temperatures in the same dish (sour cream on a baked potato), as well as trying hot and spicy foods may help to make food less bland. Keep in mind that a pleasant atmosphere and attractively prepared meals can also help to make food more enjoyable.

What Other Suggestions Are There for People with a Taste/Smell Loss?

We would strongly recommend that you equip your home with smoke detectors. Those individuals potentially exposed to gas leaks should consider purchasing a gas detector. Your gas company should be able to supply you with information regarding gas detectors. If not, the Taste and Smell Center can be contacted for this information. In order to guard against eating food you suspect may be spoiled, ask someone else to smell it. If that is impossible, pay particular attention to the dates stamped on most perishable foods and do not consume them after that date.

The Sense of Smell in Humans is More Powerful Than We Think

Imagine walking into a meeting room. You shake hands with colleagues, then everyone sits down. Within seconds they all start sniffing their palms, picking up clues about you from the chemical traces left over from the handshakes.

Sniffing palms after a handshake, usually within 30 seconds of the interaction, would likely help people learn about someone’s health and genetic compatibility, according to a 2015 study by researchers in Israel. Sniffing can also offer information on people’s emotional state, such as if they are happy, sad or fearful. The smeller gleans these emotions subconsciously, of course.

For decades, scientists believed humans were not very good at detecting and identifying odors. Our animal ancestors used their noses way more than we do in modern society, says Jessica Freiherr, a neuroscientist at RWTH Aachen University, in Germany, and the author of several studies on the human sense of smell. “We are disconnected from our noses,” she says. “We need them much less in everyday life. And our vision overrides the sense of smell in a lot of situations.”

(Credit: corbac40/Shutterstock)

But that doesn’t mean we don’t have powerful smell potential. A 2014 study showed that we can distinguish at least 1 trillion different odors — up from previous estimates of a mere 10,000.

Awareness of our innate smelling abilities, however, is complicated because the human language doesn’t have words for a trillion smells, and much of smelling happens under the radar of our consciousness. Unlike our other senses, the olfactory nerves do not proceed directly to the brain’s thalamus, the gateway to consciousness. Instead, information feeds from the nose to cortical areas to arouse emotions and memories without our awareness. When it comes to smells, people can be influenced and not realize it.

Who Passes the Smell Test?

An animal schnoz is obviously superior to our own mediocre noses, right?

Not so fast. Matthias Laska, a biologist at Linköping University in Sweden, has been comparing senses of smell across species — including humans — for more than two decades. “The more data I collected on different species over the years, the more interesting the picture became,” Laska says.

But sizing up how sensitive the snout of, say, a seal is compared with a bat or human isn’t straightforward. People can tell you when a certain scent is no longer detectable. But each animal has to learn to associate a particular odor with a reward and then do something, like press a button, to let researchers know when they smell it.

The odors compared between species also have to be the same. That sounds obvious, but while humans have sniffed around 3,300 different scents for science — out of the trillions possible — the highest number for animals is 81, by spider monkeys. Laska only found solid enough data to compare humans with 17 species, all mammals.

(Credit: Alison Mackey/Discover)

However, human noses held their own. Humans tested as generally more sensitive sniffers than monkeys and rats on a limited range of odors. In fact, humans detected certain scents at lower concentrations than the notoriously top-notch nostrils of mice and pigs.

Humans even beat the indomitable dog for at least a handful of scents. These include aromas produced by plants, a logical evolutionary advantage for our ancestors seeking fruits. The majority of the odors in which dogs bested us were the fatty acids, compounds associated with their own meaty prey. “Odors that are not relevant for you, you are usually not good at [smelling],” Laska says.

Bottom line: Humans, Laska says, “are not as hopeless as the classical wisdom will tell us, and dogs are not the super nose of the universe for everything.” — Ashley Braun

A Scented Fingerprint

If you were assaulted by a stranger you didn’t get a good look at, could you identify the person by smell in a police lineup? Would the perpetrator’s body odor be enough? It very well could be, according to a 2015 study by scientists in Portugal and Sweden.

Researchers collected body odor samples from 20 male university students. Other students then watched a video of an actual assault by a man on a woman (to stir them emotionally), while sniffing a scent they were told was that of the suspect. In reality, it was the scent of one of the 20 male students. Afterward, the sniffers were given a “lineup” of five odor samples and asked to identify the person whom they had smelled — presumably not a very enjoyable task. Results were quite impressive, though. The “witnesses” were able to pinpoint the would-be suspect 75 percent of the time.

(Credit: Alison Mackey/Discover)

Every person has a unique scent. “It’s like a fingerprint,” says Johan Lundström, a neuroscientist at the Karolinska Institute in Sweden. “There is a large genetic component to body odor. Even trained sniffer dogs have a hard time distinguishing between identical twins, unless the twins are on different diets.”

Scientists still don’t know how human body odor can act like a scented fingerprint. It could be from the apocrine sweat glands in the armpits, which produce odorless substances made smelly by skin bacteria. In 2015, scientists from the University of Düsseldorf identified unsaturated, or hydroxylated, branched fatty acids as the “olfactorily most dominant,” or stinkiest.

Human scent affects our brain differently than other scents. When we catch a whiff, the areas of the brain responsible for social processing light up, according to a study that used positron emission tomography (PET) to measure brain function. “There is much more information in body odor than we can extract from normal odors,” says Lundström, the study’s lead author.

Smelling Emotions

Another reason you might be able to identify a criminal, or at least someone feeling agitated, is that he or she may simply smell dangerous. In one of Freiherr’s experiments published in 2015 in the journal Chemical Senses, researchers obtained sweat from 16 men. The men took a timed math test and were falsely told they had performed below average. Disgruntled, they then participated in a workout where sweat was collected. As a control, the men took the math test again under no time constraint and were told they got an average score. Again, they followed up with a sweaty workout.

Volunteers sniffed the men’s sweat samples while taking a test that measures cognitive performance. When sniffing the sweat of the men told they scored below average, the volunteers were distracted and slower to respond during their own test. When sniffing the sweat from the men’s second workout, the volunteers scored in a manner indicating emotional neutrality.

A hefty pile of evidence suggests that emotions have a scent. What’s more, such smelled emotions may be contagious. Say you go out to meet a friend who had been watching funny videos on her mobile phone, making her feel happy. As you approach her, you catch a whiff of her scent and automatically smile. But had your friend just watched a scary movie, her body odor would have likely made you feel apprehensive.

An fMRI brain scan of a volunteer sniffing the sweat of a parachute jumper shows high activity, in yellow, in the left amygdala. (Credit: Mujica-Parodi et al. 2009 PLoS ONE)

Using electrodes, European researchers in 2015 measured the facial movements of volunteers who sniffed sweat samples of people who had watched either pleasant or scary videos — happy-go-lucky scenes from Disney’s The Jungle Book versus hair-raising clips from Stanley Kubrick’s The Shining. After inhaling the scent of The Jungle Book watchers, participants “assumed a genuine happy facial expression,” says Jasper de Groot, a psychologist from Utrecht University in the Netherlands. “It was subtle, yet significant.”

Meanwhile, smelling the body odor of stressed-out people ups our vigilance, while the odor of people who had just watched something disgusting makes our faces twist in disgust. In fMRI scans, people sniffing the sweat from first-time parachute jumpers lit up the brain’s left amygdala, where basic emotions are processed, suggesting fear is contagious, too.

“These chemosignals ring an alarm bell in your brain to attract your attention,” Freiherr says. “Maybe you can smell a dangerous place because somebody was there five minutes ago feeling scared.”

Scent of a Lover

Inhaling body odor can offer more information about people than their emotional state. The health and biological compatibility of the opposite sex might also be gleaned, all the better to help pick the perfect mate.

In an experiment published in 2014 in the journal Psychological Science, people could tell who showed signs of sickness by their body odor (the researchers injected the sweat donors with a toxin that prompted an immune reaction). From an evolutionary standpoint, smelling sickness or disease has advantages. Choosing an unhealthy partner is not the best way to pass on your genes.

Yet of maybe even greater gene-spreading significance is the ability to tell differences in MHC — the major histocompatibility complex, a gene family linked to the immune system and body scent. Scientists have long known that animals such as mice and rats can tell how genetically related they are to others of their species by smelling one another’s urine. Studies show humans are masters of this skill, too — and thankfully, no urine smelling is necessary. When scientists from the University of Chicago asked a group of women to sniff T-shirts worn for two consecutive nights by different men, the women pinpointed their closest genetic matches — even though there could be millions of unique combinations of MHC genotypes.

(Credit: Dean Drobot/Shutterstock)

A study by researchers from McGill University in Canada involving neuroimaging, which creates pictures of the brain’s structure and neural activity, showed that smelling the body odor of someone closely related activates the dorsomedial prefrontal cortex, a part of the brain responsible for recognizing family.

“Biologically, it makes sense. We want to protect our own gene pool,” Lundström says. But “it’s not so much picking the best partner, it’s deselecting bad partners.” Research shows that people — and women in particular — prefer potential partners who are somewhat genetically related, but not too related. Having children with someone with an MHC genotype that is too similar, studies show, can lead to spontaneous abortion or low birth weight. Conversely, pursuing someone with a close (or semi-close) genetic makeup means preserving adaptations to an environment — think regional people having immunity to local strains of pathogens.

Meanwhile, some scents can make us appear more attractive to potential partners. Take the aroma of grapefruit. In a study that involved guessing the age of women shown in photos, participants knocked off 12 years from actual ages if they smelled, and enjoyed the smell of, grapefruit. If the participants smelled spicy and floral notes, the women appeared four pounds slimmer.

And it’s much safer to buy cologne for people within your family rather than outside it. Genetic kinship seems to influence smell preference. In one study, people with similar genotypes chose similar perfume ingredients.

That New-Baby Smell

If you’ve ever thought there is something special about the smell of babies, you’re right. In 2013, scientists from Germany, Canada and Sweden took fMRI scans of 30 women while they sniffed the cotton undershirts of newborns. The new moms’ thalamus lit up more than that of women without kids, suggesting the mothers’ increased attention. All the women showed activity in the brain’s neostriate areas, where the reward system lies.

The fresh scent of newborns activates the same biological mechanism in women as a baby’s “very round eyes, the round face, the cute voice,” says Lundström, who was involved in the study. It is nature’s way of bonding mother and child. Although only women were tested in that particular study, Lundström suspects that similar results would be found in men.

For now, researchers haven’t managed to pinpoint the molecules responsible for that new-baby smell. Lundström and his colleagues have some chemicals under the microscope (figuratively and literally), and are even researching whether the newborn smell could be used to treat depression. The team is also investigating whether women who suffer postpartum depression lack receptors for newborn scent molecules or don’t receive the reward signals from the baby smell.

Similar to our ability to winnow out incompatible mates by scent, new moms can distinguish their biological babies by sniffing them. In one classic study, mothers identified the smell of their child from two other newborns six hours after birth, even though mother and child were separated for most of that time. Sixty-one percent of mothers guessed right. (Chance would be 33 percent.)

(Credit: Sickova Tatyana/Shutterstock)

This works the other way, too. Newborns know the scent of Mom by the second day of life. In a 2015 study, breast-fed babies turned their heads toward scent pads of their mothers for nearly twice as long as the pads of lactating strangers. “Mother’s body odor might be learned to some degree, as this odor is related to the chemosensory signature of the amniotic fluid, which the unborn senses,” says Katrin T. Lübke, an olfaction researcher at the University of Düsseldorf in Germany who was not part of the study.

Yet simple exposure is not enough for parents to identify the smell of their nonbiological children. In one study, mothers were able to pick the scents of their biological kids in 90 percent of cases, but with stepchildren, they were only 28 percent accurate. Among families in Wales interviewed for a government-funded study on failed adoptions, several parents mentioned that the distinctive body odor of their child had a negative impact on the relationship. One mom said her adopted daughter “didn’t smell right.”

Although our noses can sometimes lead us astray, in general they send us important messages about other people. Be careful, a dangerous person was here and may be lurking nearby. Be cautious, a person is sick and may be contagious. Be alert, your newborn needs your care. Be flirtatious, this person is a potential partner. Being more open to our sense of smell has payoffs, even in modern times.

“Listen to your inner voice, because your inner voice might be your nose telling you what to do,” Lundström says.

Psychology and Smell – Fifth Sense


As shown in the How Smell Works section of the site, upon detecting a smell the olfactory neurones in the upper part of the nose generate an impulse which is passed to the brain along the olfactory nerve. The part of the brain this arrives at first is called the olfactory bulb, which processes the signal and then passes information about the smell to other areas closely connected to it, collectively known as the limbic system.

The limbic system comprises a set of structures within the brain that are regarded by scientists as playing a major role in controlling mood, memory, behaviour and emotion. It is often regarded as being the old, or primitive, part of the brain, because these same structures were present within the brains of the very first mammals. Knowing this helps us to understand why smell plays such an important role in memory, mood and emotion.

Smell and Memory

The sense of smell is closely linked with memory, probably more so than any of our other senses.  Those with full olfactory function may be able to think of smells that evoke particular memories; the scent of an orchard in blossom conjuring up recollections of a childhood picnic, for example.  This can often happen spontaneously, with a smell acting as a trigger in recalling a long-forgotten event or experience.  Marcel Proust, in his ‘Remembrance of all Things Past’, wrote that a bite of a madeleine vividly recalled childhood memories of his aunt giving him the very same cake before going to mass on a Sunday.

Smell and Emotion

In addition to being the sense most closely linked to memory, smell is also highly emotive.  The perfume industry is built around this connection, with perfumers developing fragrances that seek to convey a vast array of emotions and feelings; from desire to power, vitality to relaxation.

On a more personal level, smell is extremely important when it comes to attraction between two people.  Research has shown that our body odour, produced by the genes which make up our immune system, can help us subconsciously choose our partners – read more here.  Kissing is thought by some scientists to have developed from sniffing; that first kiss being essentially a primal behaviour during which we smell and taste our partner to decide if they are a match.

It is likely that much of our emotional response to smell is governed by association, something which is borne out by the fact that different people can have completely different perceptions of the same smell. Take perfume for example; one person may find a particular brand ‘powerful’, ‘aromatic’ and ‘heady’, with another describing it as ‘overpowering’, ‘sickly’ and ‘nauseating’. Despite this, however, there are certain smells that all humans find repugnant, largely because they warn us of danger; the smell of smoke, for example, or of rotten food.  This is explored in more detail on the Danger! page.

The Psychological Impact of Smell Loss

Given that our sense of smell clearly plays an important part in our psychological make-up, in addition to it being one of the five ways in which we connect with the world around us, its absence can have a profound impact.  Anosmia sufferers often talk of feeling isolated and cut-off from the world around them, and experiencing a ‘blunting’ of the emotions.  Smell loss can affect one’s ability to form and maintain close personal relationships and can lead to depression.  An important issue here is the fact that smell loss is invisible to all but the patient; how would you know that you had met an anosmia sufferer unless they themselves told you?  This is one of the reasons, alongside the general lack of understanding of the impact that smell has on our lives, why anosmia has never received much attention – you really do not know what you have got until it is gone.

Going back to the points made about the strong connection between smell and memory, it can be seen that losing one’s sense of smell can result in the loss of an important sentimental pathway to memories.

Research has shown that loss of olfactory function can be an indicator of something far more serious. Smell loss occurs with both Parkinson’s disease and Alzheimers, and studies have indicated that a diminishing sense of smell can be an early sign of the onset of both conditions, occurring several years before motor skill problems develop.

90,000 Sniff your health. Five Fun Facts About Your Smell

Appreciate the ability to smell and take care of your nose.

Associate Professor at the Department of Aromatic Chemistry, University of Reading Jane Parker reminds that the sense of smell makes our life not only pleasant, but also warns of dangers. The ability to smell smells causes strong emotional reactions, affects sexual desire, and therefore procreation.

These 5 facts will help you love your nose even more:

1. We taste with our nose. The taste of food is a combination of signals that we receive from all of our senses. When we say we can’t taste food, we don’t actually smell it.

2. Not everyone knows how to smell. About 5% of the population cannot smell. This is a real disaster! An obsession that haunts anosmics: what do I smell like? These anxieties lead to a secluded lifestyle, depression.

3. Viral infections can alter the sense of smell. The common cold is a famous stealer of our sense of smell. Often, the sense of smell disappears completely after a common viral infection. The inability of the brain to correctly recognize the smell develops.

4. Nose – the brain’s helper . Exercise helps to regain the sense of smell, which includes actively sniffing various smells at least twice a day for several months.Smell training has been shown to improve verbal function and overall well-being in older adults more effectively than doing crossword puzzles.

5. Humans are able to track odors. Studies have shown that after proper training, humans can follow scent trails as well as dogs.

As Kubanskie Novosti reported earlier, a chronic runny nose can be a sign of nasal cancer.

Interesting facts about the sense of smell

The article was prepared by neurologist Izhboldina Olga Petrovna

What is Smell?

Smell is the ability to perceive and detect the smells of substances dispersed in the air.By its nature, the olfactory system is a very complex chemical analyzer, which has no equal in sensitivity and selectivity.

How does the olfactory process take place?

When inhaling, air enters the nasal cavity with the molecules of the odorous substance in it. Then the receptor cells catch these molecules – a nerve impulse arises, which then passes through the olfactory tract to the cortical representation of the olfactory analyzer, namely to the temporal lobe, and here the decoding of the received signals is obtained.

The structure of the olfactory analyzer is unique and each person has receptors for any smell that is available in the world. Even to those that have not yet been discovered. The fact is that each cell is capable of capturing molecules of different odorous substances.

How does our smell change in life?

Elderly people have their own peculiar smell. Things and apartments smell a certain way and it may seem that these are our general impressions. In fact, the smell of an elderly person has a certain chemical called 2-nonenal.

This chemical was discovered by scientists only in 2000 and it is only formed by the breakdown of omega-7 fatty acids that are found in human skin. The fact is that with age, the epithelium sloughs off more and more, and with the breakdown of these fatty acids, a large amount of this very substance is released – 2-nonenal.

A similar smell is also due to the fact that this chemical is very well absorbed into furniture, things, books that surround an elderly person.

How do we breathe?

Our nostrils breathe alternately. When you are sick and you have a stuffy nose, you probably noticed that first the right, then the left nostril breathes. In fact, even in a healthy person, the breathing process occurs alternately.

Since in general we do not control the breathing process, we do not notice it. This fact has a name – the nasal or nasal cycle.

What facts do you know?


90,000 10 Interesting Facts About Smell

Smell, it would seem, is a much less important sensation than sight, hearing or touch.However, it is precisely this – the most ancient feeling, without which we could not perceive either the taste of food, or learn about the danger in the world around us.

1. According to a study published in the journal Science in 2014, a person’s nose can perceive at least 1 trillion distinct odors.

2. Some of the most pleasant smells people consider the aroma of vanilla, some smells of citrus, cinnamon, cookies and … colored pencils.The author of this study is Dolores Malaspina, professor of clinical psychiatry at Columbia University in New York.

3. According to Professor Malaspina, the sense of smell is the most ancient sense. Even unicellular organisms have ways of perceiving the chemical composition of the environment.

4. There are a number of anomalies in the sense of smell. Among them are anosmia (complete or partial loss of smell perception), dysosmia (impaired sense of smell, when instead of one smell another is perceived), hyperosmia (excessive perception of smell).

5. A group of scientists from Tel Aviv University are developing a new way to identify a person – using the smell of his sweat. According to their theory, sweat is a person’s chemical fingerprints, unique to everyone.

6. Smell is responsible for 75-95% of taste perception. Without inhaling the smell of a product, we perceive its taste much worse and cannot distinguish one type of food from another only by its texture.

7. Loss of smell may indicate the development of Alzheimer’s disease. A decrease in the ability to perceive odors is associated with a loss of brain cell functionality.

8. Smell perception can be one of the ways to diagnose autism. According to some studies, children with autism do not distinguish between pleasant and unpleasant odors and inhale them in the same way, without trying to inhale a deeper “tasty” scent or breathe shallowly if the smell is bad.During experiments, this “breath test” showed 81 percent accuracy in making a diagnosis in children aged 7 years.

9. The nose determines the sound of the voice. What we hear when people speak or sing depends a lot on resonating structures in the throat and nose. The sound itself is produced by the vocal cords, but its richness is determined by how it is “processed” above the vocal cords. The characteristic “nasal” voice in nasal congestion is due to a lack of nasal resonance.

10 . Rhinoplasty, or nose job, is the second most common cosmetic surgery. According to the American Society of Plastic Surgeons, more than 250,000 nose reshaping surgeries were performed in the United States in 2010 (breast augmentation ranks first in terms of prevalence). At the same time, it is one of the most complex plastic surgery procedures in terms of functionality. Indeed, sometimes we are talking about millimeters that separate a successful operation from an unsuccessful one.

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90,000 40 facts about smell and smell on Aromo.Ru

Imagine what would happen if you stopped smelling the flowers in the garden, the many smells that you unconsciously smell in everyday life, or, for example, the smell of food on your plate. Dishes will lose half of their appeal, and life will become monotonous, monotonous and boring. Smells and aromas bring versatility and brightness to our lives.Without them, the kaleidoscope of emotions and memories will lose its flavor and significance. There are many more scents in the world than meets the eye. Open yourself up to new facts and random little things about smells, perfumes, smell and everything that surrounds the unique world of fragrances.

About smell

1. In fact, we perceive smells with our brain, not with our nose, as one might suppose.

2. Each person has their own unique perception of smells.There are no two people in the world who smell exactly the same. This is because each of us has aromatic numbness zones, which include those smells that we cannot recognize. The same perfume smells of violets for you, but for a friend of herbs? You both might be right.

3. Smells can bring up memories, but most aromatic memories are formed in the first decade of life, as opposed to, say, visual or other sensory types of memory.The deepest childhood memories are associated with the smell of just sharpened pencils!

4. Our nose contains 10 million olfactory receptors, which are capable of distinguishing 10 trillion different scents.

5. Feelings of fear and disgust are transmitted through sweat. When you hear this smell, you can automatically pick up this emotion. You can also calculate happiness and sexual arousal by smell, and this happens as long as the person you are sniffing is a close romantic partner.

6. People who do not have a sense of smell (suffering from anosmia) are more prone to depression than those who are not without this feeling. Another disorder – dysosmia – involves confusion of smell, that is, when things smell the wrong way. Hyperosmia (a painfully heightened sense of smell) is another disorder often encountered by pregnant women.

7. The human nose is almost as sensitive as the noses of many animals, including dogs.

eight.The olfactory receptor cells are renewed every 28 days. Yes, every four weeks we get a “new nose”, but the very sharpness of the sense of smell fades with age.

9. Nice smells make us happier. Breathing in a scent that we find pleasant has a positive effect on the brain. So if you love musk, rose or citrus, keep a small bottle of essential oil on your desk to help you cheer yourself up when you need it.

10. Smell is a mysterious and elusive process. All the smells of the world can be divided into several groups – some researchers distinguish only seven categories of smells: musky, putrid, pungent, camphor (like the smell of naphthalene), ethereal (like a liquid for dry cleaning), floral and mint.

11. Contrary to popular belief, blind people are not endowed with an increased sense of smell.

12. Perfumers do their job so brilliantly, not because they have better noses, but because they have perfected the art of perceiving fragrances and learned to classify them.

13. Humans have 350 functional olfactory receptor genes. In mice, there are 1300 of them.

14. Our nose can get oversaturated when we listen to many different scents in a row. It is important to give your nose a break. How? Burrow your nose into your own clothing and inhale its scent. Clothing may not have a strong odor, but this technique will clear the nasal passages to help the body perceive other odors. In addition, inhaling the aroma of the coffee beans helps to “format” the olfactory palette.

15. Men smell female ovulation. Both sexes hear major histocompatibility complex smells (genetic codes important to the immune system) that are different from their own. This is interesting because offspring from parents with different codes have a stronger immune system.

16. Perverted gustatory habits of pregnant women can be caused by a heightened sense of smell: the nose becomes hypersensitive, which leads to the development of an abnormal sense of taste.Probably, this explains the ability of pregnant women to combine salty and sweet, sour and spicy in one dish.

About perfume

17. The first perfume was developed by the ancient Egyptians and was used in religious rituals.

18. The first famous perfumer in the world was Taputti, a chemist from Mesopotamia.

19. Recent excavations have unearthed the first perfume factories over 4,000 years old.

20. Cleopatra used liters of aromatic oils to seduce Julius Caesar.

21. The ancient Romans sprinkled the walls with various oils to create a pleasant aroma in the house.

22. The ancient Greeks created various aromatic compositions for different parts of the body.

23. Napoleon Bonaparte asked his beloved Josephine not to wash before he returned home. That was how he loved her natural scent.

24. The first spirits also served as drinks. Perfume “Hungary Water”, created in 1370, is considered the progenitor of modern perfumes, as it contained alcohol (brandy). For a more pronounced effect, in addition to being applied directly to the skin, it was suggested to drink this perfume. Given the cost of perfume, it would be unreasonably expensive to do this internally at this time.

Some more interesting facts and curious details

25.On average, a modern woman has five different perfume bottles in her arsenal at the same time.

26. The favorite scent of men is the aroma of fresh breakfast; the favorite scent of women is the smell of a newborn baby.

27. 88% of women wear perfume to please themselves exclusively, without looking back at the opinion of others about perfume.

28.55% of women use perfume to lift their spirits.

29. A third of all men’s fragrances are bought and worn by women.

30. The most expensive perfume in the world is Imperial Majesty by Clive Christian – for 500 ml of a unique composition you will have to pay $ 215,000. The fragrance is enclosed in a crystal Baccarat bottle, and its neck is adorned with 18-carat gold and inlaid with a 5-carat diamond.

31. Ambergris is one of the most valuable raw materials in perfumery. The smell of this ingredient is described as watery and sweetish, and it originates in the gastrointestinal tract of sperm whales.Currently, the use of natural amber is prohibited, and the rare ingredient is being replaced with synthetic analogues.

32. The process of creating a perfume involves two different approaches, each of which requires the extraction of fragrances from flowers or other herbs. The first method uses a fat-saturated wax that absorbs the aroma of the mixed ingredients for three months. Subsequently, alcohol is used to remove the odor from the wax. Another approach requires placing flowers in water until they have tripled their own weight.Then this water is brought to a boil, and the resulting condensate is accumulated and cooled. Before use, all fragrances are passed through filters to remove excess impurities.

33. Today in the world there are about 1000 real “noses”, of which about 400 are included in the cohort of top-class perfumers. These four hundred are the elite responsible for all modern perfumes in the world.

34. It takes many years to train the nose.

35.One of the tests that aspiring perfumers must go through is the ability to recognize each note in a composition of 250 ingredients.

36. The creation of one perfume can take several months or even years.

37. There is a reason why men use cologne and women don’t (although some women do prefer masculine fragrances more). The acidity levels of eau de toilette and eau de parfum vary greatly.Men’s skin has a higher pH level than women’s, which means that men’s fragrances are designed to regulate this level. The level of acidity of the skin of each person is different, add here the individual hormonal background, diet, skin condition, and you will understand that the same perfume smells differently on each person. The release of a scent on a particular person depends solely on the chemical properties of his skin.

38. If you put perfume on your wrists and immediately begin to intensively rub them against each other, you thereby destroy the molecular bond of the ingredients and break the pyramid of scent.The perfume needs to breathe as well as your skin.

39. The scent of your favorite perfume will envelop you more if you apply it to your hair, but be careful with alcohol – it can damage your hair.

40. Before applying any fragrance in any concentration, be it a light cologne or a rich elixir, thoroughly moisturize your skin. The brightest bouquet of perfume will be revealed precisely on well-moisturized skin. To do this, it is advisable to apply a cream of the same aroma or a product without any extraneous fragrance at all.

Let’s hope you were pleased and at least somewhat surprised by our list of facts about smell and smell, and finally: remember that the best place to store a scent is in the refrigerator!

Artist: Shoshina Olga

12 interesting facts about the sense of smell that you might not know


July 10, 2019

text: Masha Medvedeva

Smell is a gift given to us from above. Like many other things received for free, the sense of smell is perceived by us as commonplace.But if you study its nature more deeply, it becomes clear how complex and pervasive this phenomenon is. Without smell, all our senses would be different. And our life too.

Evaporation is to blame for everything

Have you ever thought about the nature of odors? But they exist only due to evaporation. It is this process that leads to the separation of light molecules from the source and their subsequent penetration into the nasal cavity. Thus, the smell is a kind of signal that a certain substance emits.If we associate the ability to evaporate with the fragility of a substance, with the presence of life, emotions, with the desire to call for help, then the reason for the appearance of odors acquires a deeper meaning. Stones, iron do not smell. Perhaps they simply have nothing to say to the outside world?

Diagnostics of diseases

A striking fact: it turns out that you can diagnose diseases by smell. Many diseases have their own unique aromatic markings. Dogs are able to catch the onset of the disease in the owner long before diagnosis.However, a person is also able to distinguish diseases by smell. There are already examples of how some types of cancer are diagnosed in this way. And the ability of one Scottish woman to accurately feel Parkinson’s disease in dozens of patients is quite incredible.

Olfactory receptors on the body

Smell is not all that smells. The fact is that the receptors responsible for the sense of smell can be located in other parts of the human body, for example, on the skin. In this case, the process of signal perception does not go through the brain, but is produced at the local level.Scientists have recently discovered this phenomenon. Its further results threaten to change our understanding of the role of odors.

Undervalued sense

The sense of smell is critical to the body. Of the five senses that a person possesses, it is customary to distinguish sight and hearing. However, sense of smell and taste is something that is directly related to a person’s ability to choose and consume food. The loss of these feelings threatens to imbalance the body and can be fatal.

Thousands of receptors

Man is much more selective in smell than in touch.This is a consequence of our structure. Over a thousand receptors are responsible for recognizing aromas in the human body, and only four for vision.

Hardening, training

We are endowed with the ability to distinguish smells, but, as a rule, we cannot distinguish their components. This is not always related to physical abilities. Often we just don’t need to decompose the smells into separate fragments. For example, wine tasters or perfumers have a much wider range of olfactory possibilities than the average layman.The reason lies in regular practice and fitness.

Under the pressure of the brain

A person does not use the full range of olfactory possibilities due to his ability to think critically. The intellect completes for us what we physically do not want or cannot achieve. To defeat the lion, we do not need to be stronger than him in fact. We are able to simply drive him into a cage with the power of our intellect. Compared to humans, dogs, for example, have many more olfactory receptors.Due to the lack of intelligence, she cannot afford such a luxury – not even partially use what nature has given her for survival.

Complete picture of the world

When a person smells, he remembers. Without smells, the picture of the world would be incomplete. It is no coincidence that, having felt a familiar aroma, we are able to transport ourselves even to the distant past. However, the detail of the picture reproduced in the brain can be surprisingly accurate.

We are artists

The ability to discern aromas makes us a bit of an artist.We are not always able to classify the source of a particular smell; we internally tie it to an event, thing or place. This develops the associativity of thinking in us. The smell of a burning candle will quickly evoke memories of a warm family evening from childhood than sorting out the names of chemical elements in your memory.

Direct contact

Smell is much faster than other senses such as taste or touch. The signal enters the brain instantly. It is believed that the sense of smell is the most vulnerable of the senses of our nervous system, because through the sense of smell we are directly exposed to the environment.

Activity 24/7

Smell is the only senses active in sleep. Scientists say that even in a coma, a person can smell.


Fragrances are emotions. Every step we take is associated with smells that we remember and which are capable of suddenly appearing out of nowhere, exciting our imagination. The bitterness of loss, memories from a carefree childhood, the hardships of everyday routine, the touch of a loved one – all these events swirl like autumn leaves in our subconscious.Only the scent is able to remind us of past, but indelible emotions, whether it be a barely noticeable trail of branches and dust, the joyful crunch of the first snow, or the weary inevitability of the arrival of a new, albeit belated spring.

Photo: @amorburakova

14 facts about smells and smell that you did not know- Pink.ua

Fragrances are the easiest way to go back in time. As soon as you hear the smell of fried potatoes, you immediately remember your grandmother, and when you smell the perfume that you had at the age of 18, you immediately return to the student disco.We tried to figure out why we react this way to smells, and found many interesting facts.

1. It turns out that not only people have their favorite scents, but also animals. For example, cats like the smells of valerian and mint, while camels like tobacco smoke.

2. We perceive smells with our brains, but our nose simply transmit them. That is why when we feel a scent, we immediately go deep into memories.

3. People living in megalopolises do not notice 70% of odors.But those who live in the wilderness can even catch the scent of a friend who passed along the road.

4. The influence of fragrances on men has been known for a very, very long time. According to one of the legends, Hera seduced her husband Zeus with a fragrant belt that Aphrodite lent her to her. Modern perfumers suggest that the composition of the aphrodisiac included several aromas: ylang-ylang, nutmeg, pink vanilla, jasmine and cloves. We take on arms!

5. Favorite smells of many people – freshly cut grass, bread and coffee.

6. Lavender is one of the most powerful antidepressants. It takes a few minutes to inhale the scent of flowers and the bad mood will immediately disappear.

7. Have you noticed that when “meeting” the dogs … sniff each other under the tail? It turns out that they have a special gland there, which is responsible for the individual smell. And when they are happy with a new friend, they wag their tails to spread their scent as much as possible.

8. Japanese scientists believe that the smell of lemon has a positive effect on people working at computers.Tea for everyone.

9. In fact, the smell of coins is not the smell of metal. It is formed from the connection with organic substances. For example, with human sweat. Moreover, for this smell to appear, a minimum of contacts is enough.

10. The olfactory cells are renewed every 28 days. But with age, these feelings become dulled.

11. Smells we like make us happy. So an aroma diffuser in the house will definitely not be superfluous.

12. A person is capable of being oversaturated with odors. To reboot, just inhale the aroma of the coffee beans. That is why you can see jars of coffee in perfume shops.

13. Perfumers go through a very difficult test before getting a job. They need to recognize every note of a perfume, which can be composed of up to 250 ingredients.

14. Perfume is best stored in a dark cabinet to avoid exposure to sunlight.They can trigger chemical reactions in a perfume that can ruin the quality of the perfume.

Article author: Pink.ua

90,000 Interesting facts in the world of medicine!

What threatens the deterioration of the sense of smell? Pain relievers increase the risk of cardiac arrest.

What threatens the deterioration of the sense of smell?

Smell is one of the five basic human senses. Dr. Kara Hoover from Durham University, compared how the Neanderthal and Denisovan ancestors perceived odors, and compared their sense of smell with the sense of smell of living people. It turned out that we perceive smells in about the same way as the Neanderthals did, but the Denisovans had a worse sense of smell. However, modern people are now gradually approaching Denisovans – because simple and strong smells of a polluted environment “interrupt” the smells of nature, and the ability to perceive the nuances of various aromas is deteriorating.Kara Hoover said that this negatively affects people’s health.

According to a specialist, a deterioration in the sense of smell can lead to a number of consequences. First of all, the lack of perception of smells affects the taste. People whose sense of smell does not work well are more prone to obesity, as they choose foods with a stronger smell – and these foods often contain much higher fat and sugar. Previous research has shown that people who smell good have a lower body mass index on average.Another danger that can accompany a poor sense of smell is anxiety disorders, as well as depression. A person may be very worried that, for example, they do not smell their own body and therefore cannot determine if they are smelling bad or not. Another possible cause for concern is the gas stove. Such anxiety can increase the risk of developing more serious mental disorders.

A study was conducted in the United States, and an article was published in the journal Scientific Reports.In 2005-2006, a survey was conducted among 3005 people aged 57 to 85 years, during which specialists from the Monell Research Institute (Monell Center) were interested in, among other things, the social life of respondents and tested them for their susceptibility to odors. Neurologist Johan Lundström, one of the authors of the article, said that among the US population, more than 20% of older people (over 50) have a reduced sense of smell compared to normal. The doctor explained that in the course of the study, he and his colleagues were looking at how the perception of smells can influence social life.

It turned out that there is a direct relationship between the perception of smells and the number of social contacts, and it was characteristic only of women. The better the women felt the smells, the more often they “went out” – they met with friends, communicated with their family. In men, this dependence was not traced – their social contacts did not depend on the sense of smell. Scientists led by Johan Lundström said in a survey that for women over the age of 50, training in smell recognition can be extremely useful, as it will help them communicate more often with other people, which means it will improve their quality of life.

Another article was published in the Journal of the American Geriatrics Society. Its senior author, Dr. Jonas Olofsson, said that he and his colleagues observed 1,774 people between the ages of 40 and 90 for 10 years and found that loss of smell increased the risk of early death. People with a reduced sense of smell were 19% more likely to die prematurely than people with normal odors. Each smell correctly recognized by the study participants reduced this probability by 8%.

Scientists have proposed to change the standard procedures for diagnosing heart disease

Previously, it was believed that soft atherosclerotic plaques pose a greater threat to health than hard ones, as they are more prone to rupture, damaging components of the cardiovascular system. Now scientists are reconsidering this point of view. At the Intermountain Medical Center Heart Institute, researchers conducted a study in collaboration with the Johns Hopkins School of Medicine and the National Institutes of Health.They followed 224 patients with diabetes but no symptoms of cardiovascular disease at the time of the start of work.

Scientists monitored the health of patients for an average of seven years, including analyzing the composition of cholesterol plaques in their vessels, in order to understand whether this composition can predict the risk of developing heart or vascular problems. Specialists were especially interested in such consequences as unstable angina pectoris, myocardial infarction or death. It turned out that the more hard plaques are in the patient’s vessels, the greater the likelihood of developing these cardiovascular diseases.The presence of soft plaques did not affect health as much. Study co-author Professor Brent Muhlestein said that more research is needed to validate the results of this scientific work, but in itself it could mean a paradigm shift is needed. Perhaps, the specialist added, many people could do without statin therapy, even if they have high cholesterol levels.

In the described study, coronary angiography was used as a diagnostic method – catheters with a radiopaque contrast solution were placed in the arteries in the participants, with the help of which they looked for possible places of vascular obstruction.King’s College London suggested replacing this invasive procedure with magnetic resonance imaging when examining patients, claiming that it is just as informative. Scientists diagnosed 918 patients with stable angina pectoris, dividing them randomly into two groups. One group underwent standard coronary angiography and the other underwent MRI. All participants were followed up for a year, and cardiovascular-related health problems were reported, such as myocardial infarction, vascular repair, and of course death.It turned out that only 3.9% in the group undergoing coronary angiography and 3.3% in the MRI group had healthy vessels. Thus, in identifying people at risk, magnetic resonance imaging was almost as effective as coronary angiography, but at the same time, MRI did not have such disadvantages as invasiveness and the need to receive, albeit small doses, but still radiation. In addition, significantly fewer cases of vascular plasty were recorded in the MRI group.

Another study was devoted to vascular stenosis.One way to know if blood is flowing normally through a vessel is through fractional blood flow reserve (FFR). It is also an invasive procedure that uses powerful drugs. The consequences of the procedure can be different: pain, low blood pressure, breathing problems. The new technique, according to experts from Imperial College London, does not have such serious side effects. The technique is called iFR – instant wave-free ratio. The study involved 2492 patients with a diagnosis of acute coronary syndrome or those who complained of chest pain.They were randomly divided into two groups, examining one group with PRK and the other with iFR. Based on the examination, a decision was made on vascular stenting. It turned out that the effectiveness of both techniques is comparable, despite the fact that after iFR side effects were observed 10 times less often (3% versus 31%).

Painkillers increase the risk of cardiac arrest

Danish scientists have discovered a link between the use of non-steroidal pain relievers – primarily ibuprofen – and cardiac arrest.It turned out that patients who died of a heart attack often took non-steroidal anti-inflammatory drugs for a month before death. True, the study speaks of very extensive courses of therapy, when patients took ibuprofen or diclofenac for weeks. This does not seem to apply to occasional pain relievers.

The use of ibuprofen and other popular pain relievers is associated with an increased risk of cardiac arrest. This is evidenced by the results of a study published in the European Heart Journal – Cardiovascular Pharmacotherapy.The authors of the paper say that these drugs should be used with caution, and people with heart problems are generally better off avoiding them.

Non-steroidal anti-inflammatory drugs are one of the most popular drugs in the world. Some of them are sold over the counter, and experts fear that people consider them safe and free of side effects.

A Danish study only looked at prescription anti-inflammatory drugs in Denmark, including ibuprofen and naproxen.The team of researchers examined prescriptions filled in Danish pharmacies since 1995, as well as medical records of about 30 thousand people who suffered cardiac arrest between 2001 and 2010.

It turned out that 3,376 people who suffered from cardiac arrest had taken NSAIDs for some time in the past 30 days.

At the same time, diclofenac increased the risk of cardiac arrest by 50%, and ibuprofen – by 31%. The drugs naproxen, celecoxib and rofecoxib have not been shown to be associated with cardiac arrest, but the study authors say this is likely because they are not prescribed very often in Denmark and are not well represented in the work.

The average duration of treatment with a non-steroidal anti-inflammatory drug was 13-29 days. The Russian instructions for the use of ibuprofen indicate that “the duration of use of the drug without consulting a doctor is not more than 5 days.” Side effects from the cardiovascular system include heart failure, tachycardia, and increased blood pressure.

Research results indicate that these drugs are not harmless. “Non-steroidal anti-inflammatory drugs should be used with caution and for reasonable indications,” the author of the study is quoted by the study leader Dr. Gunnar Gislason, professor of cardiology at Copenhagen University Hospital.“They should probably be avoided by patients with cardiovascular disease,” he says.

Gislason also noted that he would not advise taking more than 1,200 milligrams of ibuprofen per day. The same maximum dose is called the Russian instruction for the use of this drug.

Danish scientists have discovered a link between the use of non-steroidal pain relievers – primarily ibuprofen – and cardiac arrest. It turned out that patients who died of a heart attack often took non-steroidal anti-inflammatory drugs for a month before death.True, the study speaks of very extensive courses of therapy, when patients took ibuprofen or diclofenac for weeks. This does not seem to apply to occasional pain relievers.

The use of ibuprofen and other popular pain relievers is associated with an increased risk of cardiac arrest. This is evidenced by the results of a study published in the European Heart Journal – Cardiovascular Pharmacotherapy. The authors of the paper say that these drugs should be used with caution, and people with heart problems are generally better off avoiding them.

Non-steroidal anti-inflammatory drugs are one of the most popular drugs in the world. Some of them are sold over the counter, and experts fear that people consider them safe and free of side effects.

A Danish study only looked at prescription anti-inflammatory drugs in Denmark, including ibuprofen and naproxen. The team of researchers examined prescriptions filled in Danish pharmacies since 1995, as well as medical records of about 30 thousand people who suffered cardiac arrest between 2001 and 2010.

It turned out that 3,376 people who suffered from cardiac arrest had taken NSAIDs for some time in the past 30 days.

At the same time, diclofenac increased the risk of cardiac arrest by 50%, and ibuprofen – by 31%. The drugs naproxen, celecoxib and rofecoxib have not been shown to be associated with cardiac arrest, but the study authors say this is likely because they are not prescribed very often in Denmark and are not well represented in the work.

The average duration of treatment with a non-steroidal anti-inflammatory drug was 13-29 days. The Russian instructions for the use of ibuprofen indicate that “the duration of use of the drug without consulting a doctor is not more than 5 days.” Side effects from the cardiovascular system include heart failure, tachycardia, and increased blood pressure.

Research results indicate that these drugs are not harmless. “Non-steroidal anti-inflammatory drugs should be used with caution and for reasonable indications,” the author of the study is quoted by the study leader Dr. Gunnar Gislason, professor of cardiology at Copenhagen University Hospital.“They should probably be avoided by patients with cardiovascular disease,” he says.

Gislason also noted that he would not advise taking more than 1,200 milligrams of ibuprofen per day. The same maximum dose is called the Russian instruction for the use of this drug.

Biomechanical stimulation can replace sports

An entertaining study published in the journal Endocrinology compares the benefits of biomechanical stimulation with regular exercise, a passive muscle training procedure using mechanical waves of a specific wavelength and frequency.Preliminary research results suggest this groundbreaking invention could combat obesity and prevent diabetes.

Obesity is becoming a serious problem. As the American Center for Disease Control puts it, “obesity is common, serious and costly.” Diabetes is just one of the negative health effects of obesity. One of the best ways to deal with this ailment is physical activity, but many people, for one reason or another, fail to regularly devote time to physical activity.

A team of scientists from the University of Augusta, Georgia, decided to study a potential alternative to sports – biomechanical stimulation (BMS). During the procedure, the patient stands, sits or lies on the apparatus with a vibrating platform. The mechanism vibrates and transfers energy through the body, and the muscles contract and relax. Incidentally, the European Space Agency is studying the potential of BMS to support the muscle mass of astronauts during long flights.

Scientists from Georgia studied the effect of the procedure on mice.The study involved five week old mice. 50% were normal and the rest were genetically insensitive to leptin. Leptin is a satiety hormone; animals without a reaction to leptin are prone to overeating, and therefore to obesity with diabetes.

The mice were divided into three groups: in one mice they underwent the BMS procedure, the participants in the second group ran daily in the wheel, and the representatives of the third did not do any exercises at all. The study lasted three months.The animals were weighed every week.

At the end of the experiment, the genetically obese mice progressed from both exercise and BMS. The mice still weighed more than normal mice, but gained less weight as a result of sports and biomechanical stimulation. Both increased muscle mass and insulin sensitivity.

BMS is not intended to replace sports entirely, but it can play an important role for patients who either cannot or do not exercise enough.However, study leader Megan McGee-Lawrence says the results should be interpreted with caution because the procedure has yet to be seriously tested in humans.

A new test will help to find out if the graft is taking root

In the USA, about 30 thousand organ transplants are performed every year. 20-50% of such operations fail within five years – and in many cases this happens because the human immune system does not identify the donor organ as its own.As a result, the graft is rejected. Researchers at the Perelman School of Medicine, University of Pennsylvania have discovered a way to see if the body is rejecting or not. The new technique has two main advantages – firstly, it can be used to detect that the process is already underway, at an earlier date, and secondly, it is not as painful as a biopsy; a blood sample is sufficient for analysis.

If further research confirms the effectiveness of the new method, people who undergo organ transplant surgery will feel better and their new organs will work longer.The new biomarker will enable doctors to better control the condition of patients and respond in time to the onset of rejection. The lead author of the study, Prashanth Vallabhajosyula, explained that such a biomarker, which will be active all the time from organ transplant onwards, is now critically needed. In addition, if the biomarker correctly reflects the patient’s condition, then, perhaps, in some cases, when there is no active rejection, it will be necessary to prescribe smaller doses of immunosuppressive drugs.In turn, this will help avoid the side effects of such medications, including cancer, high blood pressure, and kidney damage.

The new method is to analyze the concentration and composition of exosomes. Many cells secrete small capsules that contain proteins and other molecules from the mother’s cells. Such capsules are called exosomes. Scientists do not have accurate information about why they are needed, but it is known that they can affect the cells around. On the surface of exosomes there are protein markers – MHC antigens (major histocompatibility complex).For these antigens, the immune system distinguishes “its” cells from “foreign” ones. The MHC antigens of the donor and recipient are different, and this is what the technique is based on – the less donor exosomes are contained in the recipient’s blood, the more likely the rejection process is in an active phase.

Scientists have transplanted groups of cells from the human pancreas into mice in the laboratory. Experts were able to identify and count human exosomes in the blood of animals, and when, during the experiment, they provoked the rejection of donor cells, the number of corresponding exosomes dropped sharply.Human studies were also successful – researchers analyzed blood plasma samples from five transplant recipients and found donor exosomes in these samples. Moreover, having discovered a sharp decrease in the number of exosomes in the blood of one of the patients, scientists announced that the body does not accept a new organ, six and a half months before the failure of the latter.

Further work showed that exosomes contain insulin and other hormones, and this “load” changed during the rejection of the transplanted organ.