Smell - Sight and Hearing
Getting old will always dull the eyes and ears but new research suggests that the sense of smell is protected from ageing, as long as you're healthy.
Smokers, people with sinus complaints and those on medication will lose their sharp nasal capabilities quickest, the Queensland study shows.
Scientists enlisted 1,000 volunteers of all ages to sniff odours ranging from roses to fish to work out what damages the nose's so-called olfactory function.
Results showed healthy women have a more sensitive sense of smell than healthy men.
But the gender difference was not apparent in long-term smokers, people on medications or with a history of nasal problems.
"The ageing process alone has only a small detrimental effect on smell," said lead researcher Amy Johnston, from Griffith University's School of Nursing and Midwifery.
"But all the things that go along with getting old will damage it."
Elderly people were most prone to smell impairment because they take more medication, particularly cholesterol and blood pressure-lowering drugs which the study found were most likely to affect the sense.
They were also more likely to suffer from neuro-degenerative illnesses like Alzheimer's and Parkinson's, for which loss of smelling sense is one of the first signs, Dr Johnston said.
Smoking over days, weeks or months had no effect but a decades-long cigarette addiction significantly dulled the sense.
She said smell was more important than many people realise because it is closely tied to taste and the appreciation of food.
"People who lose their sense of smell, particularly the elderly, are at risk of poor appetite and subsequent poor nutrition," Dr Johnston said.
"Smell is also an important warning sense - telling people when food is not fit for consumption."
The research, published in the international journal Chemical Senses, will be used to help identify older people who could be in the very early stages of dementia.
