Introduction

Anosmia is a disorder that can have quite a significant impact on a person’s quality of life. Usually, on a day-to-day basis, people can take their strong sense of smell for granted, often going unaware of the importance of smell in many areas of their lives. In some cases of those suffering from anosmia, there can be a period before and after the loss of smell, during which a person has to reorient themselves and learn how to function safely and happily again. In long-term cases, concerns can arise surrounding the safety of those close to the affected person, as a sense of smell plays a primary role in maintaining human safety. Additionally, losing the sense of smell can have implications for nutritional intake and pose a risk to human health through nutritional deficiencies or the development of chronic diseases. 

Anosmia

What is Anosmia?

Anosmia is the term used to describe a person’s inability or reduced ability to detect various smells. This usually affects people with advancing age greater than 60 years, with some causes identified in this age group.¹ In younger individuals, and in more recent years, post-infective causes, including post COVID-19, have been discovered in a large majority of this population.² The process of anosmia includes the death of olfactory cells or a blockage or destruction of other parts of the nasal pathway, stopping the flow and identification of certain scents through the nasal cavity. ³ There are many reasons why someone can develop a loss of smell, and it is important to note any other symptoms that may be experienced so that an accurate cause can be determined.

The sense of smell has a crucial role in human function, serving as a vital warning system and influencing emotional well-being. It helps detect dangers like gas leaks or spoiled food, aids in identifying food based on aroma, and even plays a role in social interactions and mate selection through the detection of body odors Furthermore, some studies have shown that woodland smells, as well as other natural scents, can be positive for both mental well-being and physical health, making sense of smell even more critical than it seems on surface level.⁴

Causes of Anosmia

Anosmia, or the loss of smell, is often caused by nasal inflammation or obstruction in 50-70% of cases. These can include common conditions like allergic rhinitis and nasal polyps. Other causes include head trauma, autoimmune diseases, ageing, and exposure to toxins.⁵ COVID-19 is also a significant factor, with many experiencing anosmia as an early symptom. 

Nutritional issues

The process of eating doesn’t solely rely on the intake and chewing of food. It is a multisensory experience, involving sight and smell in addition to taste and touch. Anosmia can significantly impact food intake and lead to health changes, with outcomes varying based on age and gender. While anosmia can lead to reduced enjoyment of food and potential avoidance of certain foods, it's also associated with higher BMI and obesity in some individuals.⁶ 

In individuals with higher BMIs and obesity, there can be a correlation with a preference for highly palatable foods, particularly those high in fat and sugar, potentially leading to a cycle of overeating and further weight gain.⁷ Over time, this can have an impact on overall health, leading to chronic nutrient insufficiencies as well as chronic disease development, including obesity and cardiovascular disease. 

Safety concern

Loss of smell can pose significant safety risks and negatively impact mental well-being. Besides the obvious dangers of not detecting gas leaks or smoke, anosmia can lead to neglecting personal hygiene and health, potentially causing worry, disgust, and social isolation. 

FAQs

What are the common causes of Anosmia?

Anosmia is frequently a symptom observed after infections, notably in COVID-19 cases, where it can be both an acute symptom and a persistent issue. Additionally, anosmia can occur due to nasal obstruction with polyps or inflammation. Other, rarer causes can include nasal and/or facial trauma disrupting the normal nasal pathways.

What are the main safety concerns with Anosmia?

Safety concerns can come in many different ways, some being more obviously dangerous than others. The loss of smell can affect the detection of harmful substances and chemicals in the surrounding area, such as gas leaks. Additionally, losing the ability to smell when food and beverages may be off or when you or another family member is unwell can be quite stressful for the individual, heightening their sense of stress and worry.

Are there any treatments for Anosmia?

Most people who experience anosmia after contracting COVID-19 or other infections will recover their sense of smell within six months, often without any intervention. While many recover without intervention, some benefit from treatments like intranasal steroids and nasal exercises

Who gets Anosmia?

Anosmia can affect anyone; however, outcomes vary based on age and gender, and certain groups are at higher risk. Older adults, particularly those over 60, often experience some decline in smell sensitivity due to the natural process of ageing. People with chronic nasal conditions, autoimmune diseases, or a history of facial trauma are also more vulnerable. Additionally, research has shown a link between anosmia and higher BMI in some individuals, possibly due to altered food preferences and compensatory eating behaviours.

When should someone with Anosmia seek medical attention?

While temporary loss of smell often accompanies colds or infections, medical evaluation is advisable if symptoms persist beyond a few weeks, occur suddenly without an apparent cause, or are accompanied by other symptoms (such as headaches, changes in vision, or facial numbness). A healthcare provider can assess and conduct necessary testing to determine the underlying cause and recommend appropriate treatment.

How does Anosmia impact nutrition and eating habits?

A person's sense of smell plays a huge role in how flavours are perceived and, therefore, in food enjoyment. People with anosmia may find that foods taste bland or unappetising, which can lead to a reduced appetite or avoidance of certain meals, thereby increasing the likelihood of developing nutrient deficiencies. On the other hand, some individuals may gravitate toward foods that provide stronger sensations through texture or spice, often high in sugar or fat, which can potentially lead to weight gain over time. However, tailored meal plans can be introduced that focus on texture and appropriate seasoning, which can help maintain balanced nutrition.

Summary

Anosmia is a symptom that can present itself as a result of many different medical issues, most commonly associated with obstructions or infections that affect the nasal passages or the olfactory nerves. There are significant emotional and well-being implications related to how we experience smells. While the immediate fear of missing danger cues is a well-known aspect, the impact of smells on emotional well-being and memory retrieval is also substantial. Understanding the emotional burden that comes with anosmia can be beneficial to those suffering, providing different areas of support, including family/friends and mental health professionals. Additionally, providing a pre-designed meal plan can play a crucial role in ensuring adequate nutrient and calorie intake, minimising the risk of further health complications.