What happens to your olfactory sensitivity as you age? Understanding presbyosmia

According to the National Institute on Aging, more than half of people between 65 and 80 experience a noticeable decrease in their sense of smell. This gradual decline, known as presbyosmia, is a normal part of aging, but understanding what happens to your olfactory sensitivity as you age is crucial for maintaining safety, nutrition, and overall well-being.

Quick Summary

Presbyosmia, the age-related loss of smell, results from nerve degeneration, reduced mucus production, and accumulated environmental damage. This gradual process affects taste perception, leading to altered eating habits and nutritional risks. It also diminishes the ability to detect dangers, like gas leaks or spoiled food, highlighting the need for coping strategies and safety adjustments.

Key Points

• Gradual Decline (Presbyosmia): Age-related loss of smell is a normal process called presbyosmia, which becomes more common after age 60 and affects nerve endings and mucus production in the nose.

• Safety Risks: A diminished sense of smell reduces your ability to detect dangers like smoke, gas leaks, and spoiled food, requiring extra precautions like installing and testing smoke detectors.

• Taste Perception: Because smell accounts for 90% of flavor, age-related olfactory decline can significantly impact taste, leading to altered eating habits and nutritional risks like malnutrition or excessive salt intake.

• Link to Neurodegenerative Disease: A decline in the sense of smell is recognized as an early sign of neurodegenerative disorders, such as Alzheimer's and Parkinson's disease.

• Olfactory Training: A therapeutic option involving repetitive smelling of different scents (e.g., rose, clove, lemon, eucalyptus) can help retrain the brain and improve smell function.

• Lifestyle Adjustments: Compensate for reduced enjoyment of food by using herbs, spices, and varied textures instead of excessive salt or sugar to manage health risks associated with altered diets.

• Medical Consultation: Any sudden or significant change in your sense of smell should be evaluated by a doctor to rule out treatable causes, such as infections, nasal polyps, or medication side effects.

What is Presbyosmia? The Aging of the Olfactory System

Presbyosmia is the medical term for the gradual, age-related loss of the sense of smell. While many people associate aging primarily with changes in vision and hearing, the olfactory system is also significantly affected. This change is often underestimated, but it impacts daily life, from food enjoyment to personal safety.

Unlike hearing loss, which is more commonly discussed, the decline in olfactory function often goes unnoticed or is misattributed to a loss of taste, as the two senses are closely linked. The changes are caused by a variety of factors affecting both the peripheral and central olfactory systems, leading to a decreased ability to detect and identify odors.

The Physiological Changes Behind Age-Related Smell Loss

Several key changes occur in the nasal cavity and brain as we age, contributing to presbyosmia:

• Nerve Degeneration: The nerve endings in the nose, responsible for detecting odors, begin to degenerate and decrease in number. The olfactory epithelium, the tissue containing these receptors, thins and is partially replaced by respiratory tissue, which cannot detect smells.
• Reduced Mucus Production: Nasal mucus production naturally slows down with age. This is significant because mucus is essential for capturing odor molecules and holding them in the nasal passages long enough for the nerve endings to detect them.
• Environmental Damage: The cumulative effects of exposure to airborne pollutants, toxins, viruses (including COVID-19), and cigarette smoke over a lifetime take a toll on the olfactory system, reducing its regenerative capacity.
• Changes in the Olfactory Bulb: The olfactory bulb, the part of the brain that processes smell signals, can also decrease in size and show signs of neuronal loss with age.
• Cribriform Plate Ossification: A crucial, non-neural change is the progressive closure of the tiny holes in the cribriform plate—a bone separating the nasal cavity from the brain. As these holes narrow, they can pinch off or sever the axons of the olfactory receptor cells traveling to the brain, further compromising smell function.

Comparison of Olfactory Decline vs. General Sensory Loss

Feature	Olfactory Decline (Presbyosmia)	General Sensory Loss (Sight/Hearing)
Onset	Often gradual and insidious, often unrecognized by the individual.	Typically more noticeable, often prompting an earlier medical evaluation.
Mechanism	Degeneration of olfactory nerves, reduced mucus, and cumulative environmental damage.	Structural changes in the eyes (e.g., lens hardening) or inner ear components.
Primary Impact	Reduces the ability to perceive and identify smells, leading to decreased flavor perception.	Directly impairs vision or hearing, affecting communication and perception of the environment.
Associated Risks	Malnutrition, weight changes, safety hazards (gas, smoke), depression.	Safety hazards (falling, driving), social isolation, and cognitive decline.
Connection to Disease	Considered an early marker for neurodegenerative diseases like Alzheimer's and Parkinson's.	Linked to cognitive impairment and potential isolation.
Treatment Options	Limited, though olfactory training has shown some benefits.	Often involves corrective devices like glasses or hearing aids.

The Health and Lifestyle Impacts of Presbyosmia

The diminished sense of smell associated with aging can have far-reaching consequences beyond simply enjoying food less. It affects several aspects of physical and mental health, making it a condition that should not be overlooked.

• Nutritional Effects: Since 90% of what we perceive as taste is actually smell, a reduced sense of smell can make food seem bland and unappealing. This can lead to a loss of appetite and unintentional weight loss, risking malnutrition. To compensate, some individuals may add excessive salt or sugar to their food, which can exacerbate conditions like high blood pressure or diabetes.
• Safety Hazards: The inability to smell can be extremely dangerous. The sense of smell is our primary alert system for dangers like smoke from a fire, a natural gas leak, or spoiled food. Older adults with presbyosmia are at a higher risk of ingesting spoiled food or failing to detect hazardous situations.
• Psychological Well-being: Smell is deeply connected to memory and emotion. Losing the ability to smell can lead to feelings of isolation, anxiety, and depression. Missing out on evocative smells associated with holidays, people, and places can diminish quality of life and trigger sadness.
• Early Warning Sign for Neurodegenerative Disease: Olfactory dysfunction, especially the inability to correctly identify odors, is now recognized as an early marker for certain neurodegenerative conditions, including Parkinson's disease and Alzheimer's disease. While not every person with a diminished sense of smell will develop these conditions, it can be an important diagnostic signal for doctors.

Coping Strategies and Potential Treatments

While there is no cure for presbyosmia, several strategies can help manage the effects and improve quality of life.

Lifestyle Adjustments and Practical Tips

• Enhance Food Flavor and Texture: Instead of relying on salt or sugar, use a wide variety of herbs and spices to add flavor to food. Focusing on different textures, colors, and temperatures can also make eating more enjoyable.
• Increase Safety Precautions: Install and regularly test smoke and carbon monoxide detectors with both audible and visual alarms. Get into the habit of checking food expiration dates and being vigilant about food safety.
• Olfactory Training: This technique involves regularly smelling a set of specific odors, such as rose, lemon, eucalyptus, and clove. By exposing the olfactory system to these scents over several months, it may help retrain the brain to recognize and process smells more effectively.
• Address Contributing Factors: Discuss any medications with your doctor, as some drugs can affect smell. Quitting smoking and managing conditions like chronic allergies or sinus issues can also have a positive impact.
• Seek Medical Advice: If the loss of smell is sudden or accompanied by other neurological symptoms, it is important to see a doctor to rule out underlying medical conditions. An ENT specialist can perform tests to assess the severity of the loss.

Conclusion

While a decline in olfactory sensitivity is a natural part of the aging process, it is not an insignificant change. Recognizing and understanding presbyosmia allows individuals and their families to take proactive steps to mitigate its impact. By adapting cooking habits, implementing safety measures, and exploring options like olfactory training, it is possible to maintain a good quality of life and address the associated health risks. Most importantly, any significant or sudden change in smell should be evaluated by a medical professional, as it can sometimes be a sign of a more serious underlying health issue.

Visit the National Institute on Aging for more information about sensory changes.

Frequently Asked Questions

Is it normal to lose your sense of smell as you get older?

Yes, it is a normal and common part of the aging process, known as presbyosmia. It is caused by the natural degeneration of nerve endings in the nose and other changes in the olfactory system.

What is the difference between presbyosmia and anosmia?

Anosmia is the total loss of smell, which can be temporary or permanent. Presbyosmia is the gradual, age-related decrease in olfactory sensitivity, typically leading to hyposmia (reduced smell) rather than total loss, though severe cases can progress to anosmia.

Can medications cause a loss of smell?

Yes, certain medications, such as some antibiotics, antihistamines, and blood pressure medications, can affect your sense of smell. You should discuss any concerns with your doctor, but never stop taking a prescribed medication without their guidance.

How can I make food more appealing if my sense of smell is weaker?

You can use a variety of herbs, spices, and different textures to add flavor and interest to your food. You can also focus on enhancing the visual presentation of meals. Experimenting with a wider range of flavors can also help.

Does olfactory training work for age-related smell loss?

Olfactory training, or repeated, deliberate smelling of specific scents, can be beneficial for some individuals with age-related smell loss. By exercising the olfactory system, it can help improve or retrain the brain's ability to process and identify smells.

Is a loss of smell a sign of a serious disease?

While a gradual decline in smell is part of normal aging, it can sometimes be an early symptom of more serious neurodegenerative diseases, such as Parkinson's or Alzheimer's. A sudden or significant loss of smell should always be evaluated by a doctor.

What safety precautions should be taken for age-related smell loss?

To mitigate safety risks, regularly test and maintain smoke and carbon monoxide detectors, check expiration dates on food, and be cautious with household chemicals and gas-powered appliances.