Elderly people aged 60 and over lose the ability to differentiate between odours, putting them at greater risk from dangerous chemicals and poor nutrition, according to scientists. The scientists studying how the sense of smell changes as people age found that olfactory sensory neurons in those 60 and over showed an unexpected response to odour that made it more difficult to distinguish specific smells. "We found clear changes in olfactory sensory neuron responses to odours for those 60 and up," said Professor Diego Restrepo, Ph.D., director of the Centre for NeuroScience at the University of Colorado School of Medicine who led the researchers. "When we presented two different odours to the olfactory sensory neurons of younger people they responded to one or the other. The sensory neurons from the elderly responded to both. This would make it harder for the elderly to differentiate between them," he explained. According to the study, those losing their sense of smell are at a higher risk of malnutrition since taste and smell are closely related, they may also be unable to detect spoiled food, leaking gas or toxic vapours. The study suggested that changes in nose and the brain contribute to smell loss in the elderly, Restrepo said.