What Happens When You Lose Your Sense of Smell?
Would you give up your sense of smell to shop on Amazon or watch Netflix?
Apparently, some people would.
In a study of more than 400 people, researchers asked participants what they would give up their sense of smell for. The answers were surprising. Some chose $10,000. Others chose their cellphone. About 7% said they would give up their sense of smell to shop on Amazon, while 6% would give it up to watch Netflix.
So why do we undervalue smell when it affects what we eat, the memories we make, and even our ability to detect danger?
Smells can make ordinary moments memorable—a mother reminiscing about the scent of their newborn, cookies fresh out of the oven, or newly cut grass. A familiar smell can instantly transport you to a favorite memory or feeling.
Your sense of smell also helps keep you safe by alerting you to hazards such as smoke, chemicals, and spoiled food. Because smell works closely with taste, losing your sense of smell can make eating less enjoyable. 55% of people who lost their sense of smell after COVID-19 reported having less appetite.
Despite all this, many people still consider smell the least important of the five senses. The same study found that most participants would give up their sense of smell before any other sense. About a quarter of college students said they would give it up to keep their cellphone, while nearly half of women would give it up to keep their hair.
The study also found that the American Medical Association Guides to the Evaluation of Permanent Impairment assigns loss of smell a value of 1% to 5% of a person's earnings, compared with 85% for loss of vision.
Maybe we don’t give enough credit to one of our most important senses.
Smell disorders can affect people in different ways. Some people can’t smell anything, while others find that familiar scents seem strange or unpleasant. Sometimes, people notice smells that aren’t really there.
Changes in smell are linked to reduced enjoyment of food, changes in eating habits, and a lower quality of life. Loss of smell can sometimes indicate an underlying health problem.
Types of Smell Disorders
Anosmia: loss of sense of smell
Hyposmia: reduced ability to smell
Parosmia: changed smell perception; familiar odors smell unpleasant
Phantosmia: sensation of smelling something that is not actually present
How Common Are Smell Disorders?
Smell disorders are more common than many people realize. Smell disorders are more common than many people realize. Approximately 1 in 8 Americans over age 40 —
about 13.3 million people — have some type of smell disorder. These problems become more likely with age and are more common in men than in women.
About 3% of adults have a weaker sense of smell, or have lost it completely. The COVID-19 pandemic made these problems more noticeable because sudden loss of smell became a common symptom, and many people experienced lasting changes.
What's the Connection Between Smell and Taste?
Smell and taste work together to create flavors we experience when we eat.
Your taste buds can detect five basic tastes: sweet, sour, salty, bitter, and umami, which is a savory, meaty taste. But taste alone doesn’t give you the full flavor of your food. Smell adds many of the details that make foods taste different from each other, playing an important role in how we experience flavor and can influence which foods we find appealing.
When you chew, tiny molecules from the food travel through the back of your throat into your nose. There, they trigger smell receptors. Your brain combines those signals with information from your taste buds to create the flavor you experience.
Imagine eating a slice of lemon meringue pie. Your taste buds notice the sweet meringue and tart lemon filling. Your sense of smell picks up the scents that make the pie taste like lemon meringue. Your brain combines these signals to create the full experience.
This is why food can seem bland when you can’t smell. You can still tell if something is sweet, salty, sour, bitter, or savory, but you miss the subtle flavors and aromas that make food enjoyable.
Also, living with a distorted sense of smell can be very hard; familiar foods may suddenly smell or taste unpleasant. One study found that people with this problem may have an even tougher time than those who have completely lost their sense of smell. Foods you once liked may suddenly smell or taste bad, so you might stop eating them. For example, coffee could start to smell like garbage; certain foods could have an unpleasant, sickly-sweet smell, making eating unpleasant and reducing your appetite.
Research shows that reduced appetite is common in people with smell disorders, affecting about 22% to 48% of those with these problems. Sometimes, these changes lead to eating less, losing weight, or not getting enough nutrients.
Smell Helps Keep Us Safe
Your sense of smell isn’t just for enjoying food. It also warns you about nearby dangers.
Spoiled food: smell helps you notice when food has gone bad to prevent food poisoning
Smoke and fire: the smell of smoke alerts you to a fire in your home or workplace.
Chemicals and gases: their strong smells warn you to leave a dangerous area and get to safety
How Does Smell Work?
Smell starts when you breathe in odor molecules. Things we recognize by smell have many different odor molecules. When these molecules enter your nose, they meet special cells called olfactory receptors. These receptors are high inside your nose and have tiny hair-like structures called cilia.
Different receptors respond to different odor molecules. When they are activated, they send signals to the brain through the olfactory nerve. The signals travel to your brain, where they are processed and understood. Your brain puts these signals together to recognize the mix of molecules as a particular smell, like coffee, freshly cut grass, or a lemon.
Because humans have millions of olfactory receptors that respond to different odor molecules, our brains can tell the difference between many different smells.
What Can Cause Loss of Smell?
Problems anywhere along the pathway from your nose to your brain can affect your sense of smell. Causes can include a stuffy or blocked nose, inflammation, nerve damage, or problems affecting the brain.
Nasal Problems That Can Affect Your Sense of Smell
Conditions that cause swelling, congestion, or irritation in the nose include:
Acute or chronic sinusitis
Common cold
COVID-19
Hay fever
Flu
Smoking
Physical Blockages That Can Affect Smell
Something that blocks the nasal passages can prevent odors from reaching the smell receptors.
Nasal polyps
Tumors
Enlarged tissue inside the nose(turbinates) makes it harder to smell
Nerve and Brain Conditions That Can Affect Smell
Damage to the nerves involved in smell or to parts of the brain that process smells can also cause anosmia.
Aging
Alzheimer's disease
Parkinson's disease
Multiple sclerosis
Huntington's disease
Diabetes
An underactive thyroid (hypothyroidism)
Brain tumors or aneurysms
Traumatic brain injury
Brain or nose surgery
Radiation therapy
Exposure to certain toxic chemicals
Some medications
Poor nutrition, including low levels of zinc or vitamin B12
Certain rare genetic or neurological conditions
When Should You See a Doctor?
It is common to temporarily lose some or all of your sense of smell when the lining of your nose becomes swollen or blocked during a cold or sinus infection. Your sense of smell usually returns as the congestion improves. If it doesn't come back after you recover, see a healthcare provider. A lasting change in your sense of smell can sometimes point to an underlying medical problem.
How Are Smell Disorders Diagnosed?
If you have a persistent change or loss of smell, an ear, nose, and throat specialist (otolaryngologist) can evaluate you. They will ask when you first noticed you could no longer smell and whether it happened gradually or all at once. They will also examine your nose and give you a smell test.
During a smell test, you will be asked to sniff and identify different scents. Your doctor may also see how well you can notice smells as they get weaker by making the scent less strong each time.
Depending on your symptoms and medical history, your provider may recommend imaging tests such as an MRI or CT scan to look for possible causes.
How Are Smell Disorders Treated?
Treatment depends on the cause. For example, antibiotics can treat a sinus infection. If a medicine is causing your loss of smell, your doctor may change it or adjust the dose. If something is blocking your nose, like a polyp or a crooked septum, you may need surgery.
In many cases, treating the underlying problem can improve your sense of smell.
Can Loss of Smell Be Prevented?
Not always. Many possible causes of smell loss exist, and you can't always prevent it.
Protecting yourself from respiratory infections and seeking treatment for persistent nasal or sinus problems may help reduce your risk.
Living With Loss of Smell
Losing your sense of smell can create safety concerns because you may not detect smoke, gas, or spoiled food.
If you have lost your sense of smell, consider taking a few extra precautions:
Make sure your home has working smoke detectors and replace the batteries regularly.
Follow food expiration and storage guidelines rather than relying on smell to determine whether food is safe to eat.
Be aware that you may not be able to detect certain warning odors from gasoline, chemicals, or some potentially harmful gases in your home or workplace.
Conclusion
Your sense of smell may be easy to overlook unless it changes or disappears. It helps you enjoy food, connect with memories, recognize danger, and experience the world around you. When something goes wrong with your sense of smell, the effects can reach far beyond your nose.
If you've noticed a change in your ability to smell, don't just chalk it up to getting older or having a stuffy nose. Pay attention to the change. Some causes are temporary and easy to treat, while persistent or unexplained changes may need medical evaluation. If your ability to smell has changed and hasn't returned, talk with your healthcare provider. Finding out why is the first step toward treating it.
The next morning you're enjoying your first cup of coffee, fragrant honeysuckle on a stroll with your dog, clean laundry fresh out of the dryer, or a scent that connects you to a fond memory; take a moment to savor it. Your sense of smell may be doing far more for you than you realize.
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