Olfactory dysfunction is often dismissed as a minor inconvenience, but new research suggests that the symptom may be an early sign of neurological and many other physiological diseases. Scientists have found a link for 139 diagnoses, all of which involve inflammation, according to the University of California, Irvine website.
"The results indicate an important role for the sense of smell in maintaining physical and mental health," they emphasize.
For example, loss of smell often precedes neurodegenerative conditions such as Alzheimer's and Parkinson's disease. The new study also confirmed this connection. If patients and doctors take this symptom into account in future examinations or screenings, it may help identify some patients at an earlier stage of neurodegeneration that does not yet manifest as cognitive decline.
Other common diagnoses associated with olfactory impairment included depression, rhinitis, schizophrenia, multiple sclerosis, and heart disease.
Interestingly, the authors previously found that aromatherapy was beneficial against olfactory decline. In older people, it improved memory by 226%. Other benefits included normalization of neurotransmitter levels, reduction of inflammation and neuronal loss, increase in neuroprotective factors, and suppression of beta-amyloid levels.
The team now aims to continue their research to understand the mechanisms of inflammation that lead to the disease. In the future, they hope to identify specific molecular pathways to target for prevention and treatment.
Previously, other scientists explained why loss of smell accelerates the development of Alzheimer's disease. It turned out that inflammation in the olfactory tract disrupts the functioning of the hippocampus, which controls memory and learning.
