Summary: Olfactory dysfunction can have both physical and social consequences, in addition to influencing food intake and weight. Researchers say foods that stimulate other chemical senses when consumed, such as chili or menthol, can improve life quality for those with olfactory dysfunction.
Source: Aarhus University
Smell plays a key role in our ability to enjoy food. However, many people suffer from a lost, impaired or distorted sense of smell, and this can affect both their health and quality of life, says a new study from Aarhus University.
Losing your sense of smell or having it distorted affects more than your cooking and eating habits, says Alexander Wieck Fjældstad, associate professor, MD. He was part of establishing Denmark’s first clinic for smell and taste, and is the author of the study recently published in the scientific journal ‘Foods’.
“Reduced enjoyment when eating and the social consequences of it are very important to patients and often have serious consequences for their quality of life,” says Alexander Wieck Fjældstad.
The study also shows that 39 percent of patients with severe smell disorders have a significantly increased incidence of weight loss, which can negatively impact their health.
Getting cooking over with as fast as possible
A total of 692 people answered a questionnaire about cooking, smell, weight changes and sensory awareness for the study. 271 had lost or had a reduced sense of smell (olfactory dysfunction), 251 had a distorted sense of smell (parosmia) and 166 were part of a control group.
The study shows that patients with a distorted sense of smell differ from the control group both with regard to food preferences and the ability and desire to cook.
“The patients expressed a wish to get through cooking as quickly as possible. They don’t find cooking to be as enjoyable an activity as previously, they are less interested in cooking for others, and have lost the desire to try new foods. And less variation in food habits can affect health,” says Alexander Wieck Fjældstad.
Previous studies have also shown that the loss or distortion of the sense of smell can have consequences ranging from social insecurity and an increased risk of depressive symptoms to an increased risk of household accidents.
How to rediscover a sense of enjoyment
Fortunately, the recently published study explains how foods with different basic tastes, textures and mouthfeel can increase a patient’s enjoyment. When a food smell released in the oral cavity is not intercepted by the smell receptors in the nose, it is possible to compensate by focusing on other sensory inputs.
In other words, the other senses can enhance the experience of eating so the patient gains greater food satisfaction, a better multisensory food experience and an improved quality of life.
“The patients find cooking challenging, but the study can help because it clarifies which ingredients are unpleasant or pleasant when your sense of smell is distorted,” says Alexander Wieck Fjældstad.
He mentions dried fruits, chilli, menthol and rapeseed oil as good food options for patients who have a distorted sense of smell and taste. When eating these foods, the mouthfeel helps provide sensory stimuli when the sense of smell fails.
Patients with a distorted sense of smell in particular should avoid coffee, mushrooms, butter, ginger, black pepper and toasted bread, as these foods generally provide significantly less pleasure. This is due to a combination of a higher incidence of distorted smell detection and the fact that some of these foods strongly stimulate the other chemical senses, which becomes unpleasant when aroma is not present.
The consequences of a distorted sense of smell on cooking and which foods actually work for patients have not previously been focused on.
A common problem
Taste is a multi-sensory process where each sense contributes with different notes that together result in a complex symphony that makes us able to identify what we are eating, assess its freshness and edibility, and in the end, provides us with a sense of enjoyment. Few people realise how important a sense of smell is until they lose it.
However, in the wake of the Covid-19 pandemic, we have become even more aware of the importance of smell. Around 65% of the more than 300 million Covid-19 patients worldwide have experienced losing their sense of smell. For more than half of those patients, the loss or distortion may be long term.
“In connection with Covid-19, many people experienced losing their sense of smell or having it distorted, but actually it has always been a common problem,” says Alexander Wieck Fjældstad.
Fifteen percent of the population has a reduced sense of smell. The problem increases with age, and is often related to many well-known diseases such as diabetes, kidney disease and several neurodegenerative diseases. About two percent of Danes suffer from a complete loss of sense of smell.
The Effects of Olfactory Loss and Parosmia on Food and Cooking Habits, Sensory Awareness, and Quality of Life—A Possible Avenue for Regaining Enjoyment of Food
Olfactory dysfunction often has severe consequences on patients’ quality of life. The most common complaint in these patients is their reduced enjoyment of food in both patients with olfactory loss and parosmia.
How the different types of olfactory dysfunction differ in relation to food and cooking habits, sensory awareness, and food-related quality of life has not yet received much attention.
By applying questionnaires on cooking, food, olfactory function, weight changes, sensory awareness, and food-related quality of life, we investigated how various aspects of eating differ between participants with olfactory loss (n = 271), parosmia (n = 251), and normosmic controls (n = 166).
Cooking habits in olfactory dysfunction revealed pronounced differences as compared with normosmic controls. Cooking with olfactory dysfunction was associated with, e.g., a lack of comfort and inspiration for cooking and an inability to make new foods successfully. Significant differences in cooking were also found between olfactory loss and parosmia.
Food items were less familiar in participants with olfactory loss and parosmia, while the ratings of liking food items differed between olfactory loss and parosmia, indicating the importance of adapting ingredients in meals separately for olfactory loss and parosmia.
Parosmia was associated with a higher incidence of weight loss, but we found no difference in food-related quality of life between participants with olfactory loss and parosmia.
While olfactory loss and parosmia have wide-ranging consequences on patients’ cooking and food habits, adapting meals to include ‘safer food items’ and integrating multisensory stimulation may be a possible avenue for improving the enjoyment of food.