People's sense of smell deteriorates as they get older.
This is the main conclusion from research at the Center for NeuroScience at the University of Colorado School of Medicine, which found that elderly people are unable to distinguish between many different odours.
The scientists explained that the olfactory sensory neurons in people over the age of 60 were less sensitive than the corresponding neurons in people under the age of 45.
Doctors believe this could have important implications for the care of elderly people.
Without a keen sense of smell, elderly people can become malnourished as they can no longer detect when food has become spoiled and they are also unlikely to be able to smell chemical vapours or gas leaks, the scientists explained.
Age UK states that in addition to olfactory decline, 50 per cent of elderly people are likely to experience hearing problems and many will have sight impairments due to glaucoma and age-related cataracts.