How can hay fever affect your sense of taste?
One in five of us struggle to experience flavour – a condition that can be caused by anything from hay fever and viruses to head injuries and biology. Why is our sense of taste so susceptible to damage and is there a way to still enjoy food when we lose it? There are lots of tactics for boosting flavour in cooking: using pungent ingredients, cooking low and slow, pairing tastes that complement each other and making the most of seasonings, for instance. But what happens when these efforts become fruitless and every bite of your favourite dish tastes of, well, nothing? With the start of the hay fever season upon us, people with allergies to pollen may experience just this. Loss of smell (and so taste more on that later) is a common symptom. What causes loss of smell and taste? Prof Carl Philpott, an academic surgeon and professor of rhinology and olfactology at the University of East Anglia, has conducted extensive research into the loss of these senses and explains there are many reasons why people lose their sense of smell. “The most common reason for loss of smell is chronic sinus disease which causes swelling of the nose and sinuses,” says Philpott. This swelling impacts receptors at the top of the nose, responsible for picking up scents. Usually, these receptors send signals to a nerve structure in the brain called the olfactory bulb, which results in us experiencing a smell. But those receptors are blocked by the swelling in the nasal passage, stopping smells from reaching the brain. This swelling can also be caused by allergies – such as hay fever and viruses (which are the second most common culprits of anosmia) like common colds and flu. “The third most common cause of anosmia is head injuries,” says Philpott. “Trauma to any spot between the nose and the brain can damage the pathways between the two. Neurological conditions can also impact smell: Parkinson’s and Alzheimer’s are notable ones. When people are diagnosed with Parkinson’s, the majority will have no sense of smell.” He estimates that loss or reduction of smell affects up to 20% of the population, which might seem high until we consider how susceptible this sense is to damage. “In some ways, the sense of smell is quite resilient given it’s the only bit of the central nervous system that is dangling into the outside world in the nose. It is the latter feature that makes it vulnerable – for example when a virus or environmental pollutants get in the nose.” Related stories Can you grow out of a food allergy?Why are food allergies on the rise?Have hay fever? Look out for allergies to these foods Can you grow out of a food allergy? Why are food allergies on the rise? Have hay fever? Look out for allergies to these foods The relationship between smell, taste and flavour While many people talk about loss of taste, for the majority it’s actually a loss of smell that is impacting their ability to experience flavours. “For every 100 referrals to my smell and taste disorder clinic, 99 will be due to smell and just one will be due to taste,” says Philpott. When there is food in our mouth, we breathe its aroma through our nose, which helps us experience flavour – it’s called retro nasal olfaction. Taste, on the other hand, is what we do with our tongue, which gives us sensations like salty, sweet, sour, bitter and umami. “Because those two things occur in parallel, most people struggle to separate them. Colloquially, we talk about taste as enjoying the flavour of food but, medically speaking, taste is very specifically the taste receptors (buds) on the tongue. So if, for example, you suddenly couldn’t taste the difference between sage and marjoram, that would be down to smell, whereas if you can’t experience bitterness or sourness, that’s taste. When you take your sense of smell away, those basic tastes are all you’re left with.” If you can taste these bitter dishes you’re experiencing a loss of smell rather than taste Radicchio, chestnut and blue cheese saladGrapefruit chicken stew with dumplingsCoffee and chocolate custard pots Radicchio, chestnut and blue cheese salad Grapefruit chicken stew with dumplings Coffee and chocolate custard pots How to enjoy food when you can’t taste it Many people who lose their sense of smell struggle to come to terms with it – it can alter their experience of eating and drinking forever. Losing your smell can have a massive impact on your enjoyment of food and, in turn, your health, says Philpott. “People tend to go one of three ways. They lose weight because they lose interest in food; they gain weight because they try to eat everything they can and tend to eat lots of takeaways with the hope it gives them some sort of enjoyment; and then about a third of people manage to keep the weight steady.” Focusing on texture is key, alongside using ingredients that stimulate those core tastes (sweet, sour, bitter, salty and umami). These crunchy dishes also come with core tastes HoneycombSpiced crispy pitta chips and chickpeasKale crisps Honeycomb Spiced crispy pitta chips and chickpeas Kale crisps Recovery from anosmia is unpredictable and the treatments available are very limited. That said, smell training – which essentially involves purposeful exposure to certain scents – has been shown by studies to aid recovery in some people. As yet, there’s no treatment for those who lose their sense of smell due to head injuries. Originally published October 2023. Updated April 2024