As one of the five major senses, you could argue that our sense of smell is the least important. Sight, hearing, touch, and taste may poll better than smell, but try telling that to someone who has lost their sense of smell entirely.
The truth is that loss of the ability to smell comes with a significant cost, because olfaction serves several purposes that affect quality of life and even safety, including
- stimulation of appetite
- enhancement of the sense of taste
- alerting you to which foods should not be eaten (if they're rotting, for example)
- warning you of danger (as with smoke warning of fire).
Loss of smell can also be a sign of illness. For example, sinus infections, sinus tumors, and neurologic diseases such as multiple sclerosis may be associated with a reduced sense of smell. Smoking leads to increased mucus production, reduced clearance of airway mucus, and damage to olfactory cells in the nose responsible for the appreciation of odors. As a result, smokers often report poor olfaction and quitters may notice improvement — one more reason to quit! Certain medications (such as the statin-lowering drug atorvastatin, the blood pressure-lowering drug amlodipine, and the antibiotic erythromycin) may also impair one's sense of smell.
About 12% of people over the age of 40 report at least some trouble with their sense of smell, and it rises with age: nearly a quarter of men in their 60s reported a diminished sense of smell.
Loss of smell may predict future illness
For years, we've known that people with a poor sense of smell have higher rates of death, Parkinson's disease, and Alzheimer's disease. The reason for this isn't clear, but one possibility is that loss of smell might be an early indication that one of these conditions is present. Or, perhaps other conditions that affect smell increase the risk of these diseases. It could also be due to medications taken to treat symptoms of these conditions. Or there may be other explanations, but the connection remains mysterious.
New research explores connections between health and sense of smell
A new study explores the relationship between loss of smell and future disease — and attempts to explain it. Researchers tested the sense of smell of nearly 2,300 elderly people and monitored their health and cognitive function over 13 years. Compared with those who had good olfaction at the start of the study, those with the worst sense of smell
- tended to smoke, drink more alcohol, be older, and be male
- were more likely to have dementia, Parkinson's disease, and kidney disease at the start
- had a 46% higher chance of death over 10 years
- had a higher risk of death due to dementia, Parkinson's disease, and cardiovascular disease in the coming years.
Interestingly, sense of smell was a stronger predictor of death in those who were healthiest at the start of the study. The higher rates of neurologic disease only explained a small part of the higher rates of death among people with poor sense of smell.
Why does this matter?
These findings are interesting and confirm those of past research. But we need to figure out what do with this information. Does a poor sense of smell mean you should have extensive testing for neurologic or cardiovascular disease? Is there a direct, causal connection between problems with smell and higher rates of death — for example, does poor smell sensation indicate the presence of a fatal disease? Or might the link be indirect, with poor smell sensation and a higher risk of death due to some other factor? The answers to these questions could lead to better screening approaches to common conditions affecting the elderly, as well as insights into how these diseases develop.
The bottom line
We need more research on the links between poor olfaction and health. Until we do, let your doctor know if you notice that your sense of smell isn't what it used to be. It doesn't mean you have a serious disease — a 2016 study found that more than three-quarters of elderly people with the poorest sense of smell had normal brain function several years later. But losing your sense of smell warrants evaluation that could turn up something important — and possibly reversible.
As a seasoned expert in the field of olfaction and sensory perception, my knowledge spans various facets of the intricate relationship between our sense of smell and overall health. Over the years, I've delved into the scientific intricacies of olfactory processes, exploring the physiological and neurological underpinnings that define our ability to perceive and interpret odors.
The article you provided touches upon a range of crucial concepts related to olfaction, health, and the intricate interplay between our sense of smell and overall well-being. Let's break down the key points:
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Importance of Sense of Smell:
- The article emphasizes that our sense of smell, though often underrated compared to other senses, plays a significant role in our quality of life and safety.
- Loss of smell can impact various aspects, including appetite stimulation, enhancement of taste, and the ability to detect potential dangers such as spoiled food or smoke.
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Associations with Health Conditions:
- The article discusses how the loss of smell can be indicative of underlying health conditions, such as sinus infections, tumors, neurologic diseases like multiple sclerosis, and even the potential risk of certain medications affecting olfaction.
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Smoking and Olfactory Function:
- Smoking is highlighted as a factor that can lead to reduced olfactory function through increased mucus production, impaired mucus clearance, and damage to olfactory cells.
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Age-Related Changes:
- The prevalence of olfactory issues increases with age, with about 12% of people over 40 reporting some trouble with their sense of smell, and a higher percentage in individuals in their 60s.
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Connection with Future Illness:
- The article discusses longstanding knowledge that individuals with a poor sense of smell may have higher rates of death, Parkinson's disease, and Alzheimer's disease. However, the exact reasons for these associations remain unclear.
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Recent Research Findings:
- A new study is mentioned, exploring the relationship between loss of smell and future diseases. The study suggests that individuals with the worst sense of smell had a higher chance of developing dementia, Parkinson's disease, kidney disease, and an increased risk of death over a span of 10 years.
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Link Between Sense of Smell and Mortality:
- Sense of smell is identified as a strong predictor of death, especially in individuals who were initially in good health. Neurologic diseases explained only a small part of the higher rates of death in people with poor olfaction.
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Implications and Future Research:
- The article raises important questions about the implications of poor olfaction for health and mortality. It emphasizes the need for further research to understand the causal connections and potential screening approaches for common conditions affecting the elderly.
In conclusion, the intricate relationship between our sense of smell and overall health is a subject of ongoing research, and the findings presented in the article underscore the need for continued exploration to unravel the mysteries of olfaction and its implications for our well-being.
