Hiding In Plain Sight: Olfactory Loss In The Elderly

Smell loss, since the arrival of the Covid-19 pandemic, is in the news. While the problems of anosmia and associated smell disorders have been known about for a long time, there has been a resurgence of interest in how sensory disorders affect the eating habits and well-being of sufferers.

Gradual smell loss is an anticipated aspect of ageing. In the same way that we need reading glasses or hearing aids with time, diminution of the sense of smell is quite common. This is something that is important, because good sensory function is an important part of neurological function. A study published in 2018 described how the use of hearing aids improves “brain function and working memory”. A healthy sense of smell can also be linked with good brain health. In a piece of research done in 2017, a simple intervention known as “smell training” was demonstrated to be helpful with cognitive function. In this research, two groups of elderly people were investigated. One group was assigned smell training twice daily for a specified time period, and the other group was assigned Sudoku. The goal of the exercise was to see whether smell training had the capacity to improve sense of smell, as well as to observe any other neurological changes. An objective smell test known as the Sniffin’ Sticks test was given before and after the test period. Not only did the smell training group improve their sense of smell, but they also improved their verbal function and reported an improvement in well-being.

In addition, loss of smell is a biomarker for neurodegenerative dis- ease, and loss of interest in food may be the first indication of this. Olfactory deficits have been reliably linked to loss of appetite, depression, and feelings of isolation. These are also attributed to simply getting older. Is it possible that some of these quality of life changes can be mitigated through rehabilitation of smell?

While objective smell tests like the Sniffin Sticks test and the University of Pennsylvania Smell Test (UPSIT) do exist, and are used in the investigation of smell disorders in some cases, testing is not something available freely. Therefore it is important to be aware of certain signs in elderly populations, especially in care settings, because simple interventions may be able to mitigate some of the effects of smell loss, particularly when it comes to food.

So how can the care sector respond in light of this? The most obvious gateway to sense of smell for people living in care settings is food. Where people (clients/customers/residents) are of an age where they may be at risk of smell loss, care should be taken to provide meals that are aromatic and well seasoned. Our experience of food is not just based on smell. What the human brain appreciates as flavour is a combination of three things: olfaction (smell), gustation, or “true taste” (salty, sweet, sour, bitter, and umami, or savoury taste) and chemesthesis (tingling, cooling, hot sensations such as mint, ginger, and chili). Our appreciation of food is also enhanced by mouthfeel, texture and temperature. As texture requirements change in care settings, for instance food is needed that can be easily chewed, important sensory input involving mouth feel is lost. All the more reason then to add fresh herbs where possible, a squeeze of lemon to enhance gustation, Worcestershire sauce for umami, and other flavourings that might add depth to food appreciation.

In addition, simple interventions around mealtime such as the introduction of sensory stimulation can also establish a “smell training” component of meal times. This might be a drop of essential oil on each paper serviette to sniff before or after the meal, or washcloth/flannel, again with a drop of essential oil, that has been microwaved to be warm for wiping the face before/after the meal. This and other tips for work- ing in care settings were covered in a recent symposium at the Institute Paul Bocuse. As a panelist at this symposium, I contributed on this very subject.

Top tips:

• Any loss of appetite should be considered in light of the person/client/customer/resident’s overall health. Loss of smell is important and should be taken seriously. A recent study found that smell loss is associated with a greater mortality than healthy controls.

• Smell training can be helpful for the elderly. Regular exposure twice daily to aromatic substances can improve mood, verbal task completion, and also olfactory test scores. Inexpensive to administer and utilise, smell training can be incorporated into meal times twice daily with the introduction of essential oils on paper serviettes or moistened flannels. For further information abscent.org

• Loss of interest in the outside world, isolation, depression – these may not “just” be signs of ageing but also signs of smell loss