Scent is not to be sniffed at
We underestimate the importance of our sense of smell to our wellbeing - as Barbara Lantin discovered when she lost hers
It was when my children sniffed the fish meant for supper and reeled backwards, holding their noses and pretending to vomit, that I knew I had to do something about my missing sense of smell. Until then, I had considered its absence inconvenient and somewhat depressing - mainly because I could not taste anything properly. Suddenly, I realised it could seriously damage my health.
"Smell is the Cinderella sense," says Dr Glenys Scadding, consultant allergist and rhinologist at the Royal National Throat, Nose and Ear Hospital in London. "One per cent of our DNA is devoted to it - a huge amount. Two to three per cent of the population have a reduced sense of smell and these people often get quite depressed, because it is as if all the colour is washed out of life. They are also in danger because they cannot detect fire, gas leaks or rotten food."
According to Prof Tim Jacob, of the School of Biosciences at Cardiff University: "We certainly underestimate the importance of smell to our wellbeing. There are suggestions that it can influence mood, memory, emotions, mate choice, and the immune and endocrine systems. Every experience has a smell associated with it and people with anosmia - a reduced sense of smell - do not have access to that memory link.
"Anosmia can affect people socially, psychologically and physiologically. It can lead to loss of libido - because a lot of human interaction is down to smell - and weight loss or gain, because people with no sense of taste either forget to eat or overcompensate by eating too much."
The most common cause of smell loss is a nasal blockage, usually - as in my case - due to polyps. Damage to the olfactory nerves from a heavy cold, trauma or inhaling certain chemicals has the same effect. Some illnesses, including Parkinson's and schizophrenia, impair the ability to smell, and loss of olfactory sensitivity can be an early indicator of Alzheimer's.
Surgery used to be the only treatment for polyps, but doctors now carry out medical polypectomies using short-term oral and nasal steroids followed by mild steroid drops. This approach worked for me and though I'll never make a wine taster or a parfumeur, I can now tell when the fish is off.
"We all have our own unique smell by which we can be recognised," says Prof Jacob. "Children can distinguish between the smell of their siblings and other children of the same age. Babies recognise their own mother's smell and mothers recognise their own baby's."
Research has shown that emotions, including fear, happiness and sexual arousal, can be communicated through smell. "Recent research has shown that women can discriminate between armpit swabs taken from people watching 'happy' and 'sad' films, though men were less good at this," says Prof Jacob. Women have a more acute sense of smell, particularly during ovulation and pregnancy.
Scent and attraction
The role of smell in sexual attraction is more complex than perfume makers would have us believe. Pheromones, powerful chemicals emitted from the skin, are not smelled consciously, but are thought to be detected by the vomeronasal organ, a receptor in the nose.
"Smell is a very important component in partner choice," says Prof Jacob, "because we are attracted to people with a dissimilar immune system to our own - so that our offspring have increased disease resistance - and your immune system determines your odour type."
But male sweat is not an irresistible turn-on, he says.
"The male pheromone androstenol, the scent produced by fresh male sweat, is attractive to females," says Kate Fox, author of the Social Issues Research Council's Smell Report. "But androstenone, produced by male sweat after exposure to oxygen - in other words, when less fresh - is perceived as highly unpleasant."
Different smells can produce various physiological effects, but it is not known exactly how. Studies show that aromatherapy treatments can reduce stress. Lavender has been shown to improve sleep and rosemary to act as a stimulant. When the air in a Moscow classroom was scented with peppermint, pupils performed better in some tests.
Some experts put these results down to conditioning, but Dr Judy Howie, an aromatherapist and scientist at Thames Valley University, believes that there is more to aromatherapy than mere suggestion.
"Certain components in aromatherapy oils interact with various biochemical receptors in the nervous system to help rebalance the body," she says. "The combination of emotional and physiological effects occurring at the same time can be very powerful."
Smell and memory
"Whole memories, complete with associated emotions, can be prompted by smell and this is entirely unconscious," says Prof Jacob. This key to our sense of smell lies not in the nose but much farther up the nasal passage, in the olfactory epithelium, which contains olfactory receptor cells. These are directly connected to the limbic system, the most ancient and primitive part of the brain, thought to be the seat of emotion - which may explain why odours can trigger deep-seated feelings and memories. Although the sense of smell diminishes as we get older, odour memory remains when other recollections have faded.
© Copyright of Telegraph Group Limited 2005
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