
The bond between dogs and humans goes back thousands of years. Anyone who has ever owned a dog will know how much pleasure they bring to life. Their love and devotion are just two of the reasons humans are such dogged partisans, but, in truth, canines are more than just a cute, four-legged companion.
Dogs have a miraculous sense of smell. They have an astonishing 300 million smell receptors compared to the meagre 5 million humans possess. They can be trained to sniff out drugs and explosives, but their extraordinary noses can also detect bacteria, viruses and signs of disease.
Some dogs are already trained to alert their diabetic owners to drops in blood sugar levels, while others help those with severe allergies to prevent contact with allergens.
A study by Medical Detection Dogs, a charity that works with NHS trusts and universities, revealed that dogs can detect prostate cancer in urine in 93% of cases. Another study revealed that dogs can smell cancer in blood samples with 97% accuracy. Researchers from BioScentDx – developers of cancer scent screening – carried out the study and hope the findings will lead to new approaches for cancer-screening.
Other health conditions dogs can detect include the following.
Narcolepsy – a brain condition that causes a person to suddenly fall asleep at inappropriate times. Dogs detect a scent moments before an attack comes on, but, due to differing scent perceptions between humans and dogs, what that scent is has yet to be identified.
Migraines – a moderate or severe headache felt as a throbbing pain on one side of the head. A recent study showed that 54% of the 1,027 participants involved indicated they had noticed changes in the behaviour of their pets during or preceding migraines, with almost 60% noting that their dog had alerted them to the onset of a migraine.
Fear and stress – as controversial as it may sound, this age-old notion is an accurate one. Dogs smell the surge of hormones a human releases when responding to a stressful situation, including adrenalin. This could help prevent panic attacks.
Can dogs detect cancer better than technology?
Lung cancer is one of the most common and serious types of cancer, but how effectively can dogs accurately detect lung cancer using their superior sense of smell?
A research team from Lake Erie College of Osteopathic Medicine in Erie, PA, trained three beagles – scent hounds that are traditionally bred to hunt – to detect non-small cell lung cancer in plasma (blood) samples by using the power of scent.
After initial training, the three beagles were tasked with correctly distinguishing between blood samples collected from individuals with lung cancer and a set of blood samples obtained from individuals without.
The researchers placed all the samples in one room and the beagles were trained to sit when they could smell cancer or to move on if they couldn’t. A distinction between the two types of samples was successful.
The dogs managed to identify the presence of cancer with 97.5% precision, providing a strong argument for dogs having a better, more cost-effective ability to screen for cancer than our most advanced technology.
Other animals that have a strong sense of smell
Dogs aren’t alone. There are many animals that outperform humans when it comes to smelling ability, including the following ones.
African giant pouched rat – a cat-size rodent native to central Africa that can detect TNT better than dogs and is rewarded with the unfortunate job of sniffing out landmines.
Bears – a grizzly can smell food from a mile away, from rotting carcasses to vulnerable prey.
Great white sharks – the largest predatory fish in the world, able to detect a drop of blood in 25 gallons of water using an organ called the olfactory bulb.
What about humans? We experience smells in different ways
Every person has about 400 different types of olfactory receptors in their nose. One smell can activate several different receptors and these receptors can be activated by several different smells.
A study by researchers from the Monell Chemical Senses Center found that small changes in just one olfactory receptor gene can affect how strong or pleasant an odour is for one person. Interestingly, not only do we each smell odours differently, but some people smell odours that simply aren't there. These olfactory hallucinations are called phantosmia.
Parosmia is a similar smell disorder, where you perceive a smell as something totally different to what it is. For example, a pleasant smell will suddenly smell foul or a familiar scent will suddenly smell like something else entirely. Imagine eating an orange that smells like a durian.
Call off the dogs: hyperosmia and humans
A heightened sense of smell can also affect humans. The medical definition of hyperosmia is ‘an extreme acuteness of the sense of smell’. As with most things, it can be good and bad.
Joy Milne, a former nurse, is proof of the former. She uses her heightened sense of smell to detect Parkinson’s disease after her husband was diagnosed with it aged just 45. She discovered her ability after going to a Parkinson’s support group with her husband, Les, where she realised the other sufferers had the same musky odour as him.
One clinical test later and scientists now believe that changes in the skin of people with Parkinson’s produces a particular odour linked to the condition, long before developing the usual symptoms such as tremors and changes in speech.
With early detection vitally important, and with Joy’s story reaching a worldwide audience, more people with highly specialised senses of smell have been identified in the United States.
The downside of hyperosmia
A superior sense of smell isn’t always a good thing. Ask anyone who is or has ever been pregnant. So much so, a heightened sense of smell can actually be an early indicator of pregnancy. The scent of something you adore – like pulled pork, deodorant, even your partner – could quickly have you retching. Even the thought of your once-favourite curry could make you feel nauseous.
It’s been argued that this heightened sense is a protective measure against products such as cigarettes and alcohol, as if the body is keeping the baby as safe from harm as it can. It makes sense, but some women only notice a slight change in their sense of smell, while others, especially those who suffer from severe morning sickness, will find that hyperosmia is one of the worst parts of being pregnant.
But what if you lost your sense of smell or you were born without it?
Anosmia – what if you can’t stop to smell the roses?
Anosmia is the partial or complete loss of the sense of smell. It can be caused by many things – from infections and injury to neurological diseases such as Alzheimer’s. It can even be a side effect of certain types of medication.
What are your favourite smells? Perhaps you enjoy the smell of cut grass, freshly baked bread or the warm spices of mulled wine at Christmas. No matter where you go, brands are taking a functional approach to scent marketing. The use of a pleasant background fragrance can mask malodour or enhance mood, emotions and wellbeing, and improve the experience.
Research from Premium Scenting has found that 74% of consumers have been attracted to a store because of an inviting smell. Food-based outlets are obviously the most noticeable – research shows that bakeries commonly scent footfall areas with the smell of freshly baked products to entice customers.
But what if the ability to smell these scents were taken away from you? A new study from the University of East Anglia in the UK has revealed an array of emotional and practical impacts caused by a loss of smell – and it’s pretty extensive.
The study was carried out in collaboration with Fifth Sense; a charity for people affected by smell and taste disorders, and involved 71 participants aged 31–80 years old. Results revealed that almost every aspect of life is disrupted, including:
a loss of flavour perception affecting appetite
a feeling of isolation
a lack of hazard perception – not being able to smell rotten food or even gas or smoke
an absence of personal hygiene because participants couldn’t smell themselves
an inability to tell when children’s nappies needed changing, leading to feelings of failure
an inability to link smells to happy memories
Our sense of smell is one of the key aspects in forming strong memories. Smells are linked to life experiences that we’ve stored in our memories – and a memory is instantly triggered when a smell is identified.
If smells link us to people, places and emotional experiences, people who have lost their sense of smell will miss out on all those memories that smell can evoke. The scintillating smells of Christmas, restaurants, people and places – all gone.
Appreciating and enjoying the power of scent is important. That goes for dogs too. By choosing a walk that gives your dog more opportunities to use their powerful sense of smell, they will be more stimulated, and – most importantly, perhaps – tire and relax quicker. In fact, a 2019 study published in the Applied Animal Behavior Science Journal goes further by suggesting that ample sniffing opportunities can make your dog feel more optimistic.
So the next time you’re out walking the dog, don’t get frustrated if they’re spending too long sniffing the grass. Allowing your dog to follow its nose while out roaming will provide a much more beneficial experience. That goes for you too, as long as you remember to take stock and appreciate all of the unique scents that bombard your olfactory system daily.
Yorumlar