What happens when you lose your sense of smell?

Freshly baked bread, petrol, cut grass: for many of us, our sense of smell feels like a non-essential sense. In a way, it’s a nice to have. It’s something that complements our other senses. It’s also something that can be very dangerous not to have.

Think about those times you’ve sniffed the mouldy milk before pouring it into your coffee and saved yourself an upset stomach. Or when you’ve smelt gas and realised you left the hob on. Or, if you’re really unlucky, smelled fire and escaped from a burning building.

We’ve all lost our sense of smell at some point. We might have had a heavy cold, which stopped us from being able to smell or taste something, or perhaps a sinus infection managed to wipe out our sense of smell. As well as colds, losing your sense of smell may mask a more serious condition. It can be a symptom of diabetes, Parkinson’s, a side effect of chemotherapy, or Alzheimer's.

Around five per cent of the population experience anosmia (loss of smell), and American researchers found that among elderly people who lose their sense of smell are four times more likely to die in the next five years compared to those who retain a good sense of smell.

But why is a sense of smell still relevant? It’s understandable that having a good sense of smell was important when we were rooting around in the jungle trying to ascertain whether the mushrooms we were about to eat were poisonous or not, but why is one so crucial today?

Studies have shown that a sense of smell can be important for our survival. Depression is connected to smells: when we’re depressed we may actually be able to smell less. Around 80 per cent of what we can taste is also dependent on being able to smell. Another study found that when people who were aged 50 or over exercised their sense of smell practising it in the same way you might practice Sudoku, they were less affected by depression.

Bluntly, having a sense of smell is much more important than we think it is.

Think for a moment how much is lost when you cannot smell any more.

Laura Parks is 84 years old and after having a small stroke, lost her sense of smell. At Christmas she made noises about how delicious the food tasted, but could neither taste nor smell it. “Eating has turned from a pleasure to a chore for me,” she says. “What’s odd is you don’t really realise that the texture of the food is so horrible until you cannot taste it. It’s actually this strange, semi-cold mush in your mouth and it makes me not want to eat.”

It goes without saying that elderly people who don’t want to eat are at risk of losing weight, especially when they live alone. Our taste buds, which are linked to our sense of smell, die as we age.

Something anosmiacs complain about most is not being able to smell someone’s scent during sex, or their pheromones, which can severely reduce intimacy. As well as being (appropriately) concerned that you might not be able to smell yourself if you forgot to shower, there are a myriad of smells we take for granted each day. These include a new baby smell, smells which our body give off to show whether we’re afraid or happy, or to work out if there’s dog poop on our shoes.

When a sense of smell is damaged because of a head injury, it may just be that the receptors are damaged forever. There’s no one way to restore smell loss because if the connection between the olfactory receptors and bulb is broken because of an injury or disease, then smell loss is inevitable.

Unless it’s something that can be removed, like a polyp, or a brain tumour, there’s little experts can do to improve or bring back a sense of smell.

However, developments are happening which may transform the way sense of smell loss changes forever. The Virginia Commonwealth University’s medical director of the VCU Cochlear Implant Center began to think about how implants work in ears, and whether something similar could be used in the nose. In an article on VCU News, Daniel Coelho MD says: “We noted how wonderful it is to be able to offer hearing impaired patients cochlear implants and lamented that there are not great clinical options for people with complete smell loss. Then we started talking about the electrophysiology of how cochlear implants work.”

Read: How and why we should train our sense of smell

The way the implants would work is by perhaps developing a device to replace the way smells are transmitted to the brain. Coelho told the magazine: “There may be a way to use some cochlear implant technology to stimulate highly selective parts of the brain that are not getting input when smell is lost and to see whether or not that could result in return of smell for patients.”

Another way doctors are trying to bring back sense of smell is by using shock therapy. The Massachusetts Eye and Ear hospital have been trying to kickstart the lost sense of smell in humans by using electrodes in the nose which they hope will trigger nerves. This will, in turn, stimulate the olfactory bulb and help patients regain their sense of smell.

This could work when smells the nose has gathered have been sent to deeper parts of the brain Speaking to Science Daily,  Eric Holbrook, MD, chief of rhinology at Mass. Eye and Ear and associate professor of otolaryngology at Harvard Medical School, said: "Our work shows that smell restoration technology is an idea worth studying further.”

When Laura Parks lost her sense of smell, she said that for a time, life “lost meaning”. When she met people, she struggled to connect with them. “I couldn’t smell coffee, I couldn’t smell their perfume or their scent, hugging somebody was a bit like hugging a rag. I think it’s something you don’t appreciate until it has gone, and then you miss it very much. Even the bad smells!”

For Laura, and for many others who have lost their sense of smell, any advance in this arena is exciting.

This is a guest blog and may not represent the views of Virgin.com. Please see virgin.com/terms for more details.Thumbnail from gettyimages.

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