People without perception of smell is known to be devoid of life as mentioned in Charak Indriyasthana 4/21. Does it indicate death or it is merely taken for inability to enjoy life? The Hindu, 24th March 2021 highlighted a case of chef who lost her sense of smell 30 years before, but still enjoying her life. Rare cases of congenital anosmia are also reported in Kallmann syndrome and Bardet-Biedl syndrome (BBS). Life-expectancy is not affected in Kallmann syndrome, whereas 25% people of BBS die before 44 years as noted by O’dea et al. (1996). Miyamoto and others (2010) revealed the olfactory dysfunction (including anosmia) in idiopathic rapid eye movement sleep behavior disorder.
Olfactory dysfunction is connected to hindrance of odorants reaching to olfactory receptors in olfactory epithelium. Other causes include sensoneural disorders or malfunctioning of olfactory neurons or disturbances in olfactory pathway. A review article by Ellen and others published in International Journal of Developmental Neuroscience on 29th June 2022 refer to the role of imbalanced release of melatonin by the pineal gland in anosmia associated with COVID-19. Rodella et al. (2013) have shown the restoring capacity of melatonin in endothelial dysfunction related to normalization of lipids and blood pressure. It also increases NO bioavailability. In older people, olfaction problem is linked to physiological declines.
Olfactory dysfunction is noted as sign of various neurological disorders including Alzheimer’s disease, Parkinson’s disease, dementia etc. in older people. Pinto and others (2014) exposed the olfactory dysfunction as strong predictor of 5-year mortality in older adults. Regemorter et al. (2020) have pointed out that olfactory impairment declines the brain plasticity and lowers the physiological repair capacity, an indication of brain aging. Hence, it can be said that the Charak Indriyasthana 4/21 revelation is true in affiliation with older adults only and it cannot be generalized for everyone.