If numbers impress you, the nose has some fascinating ones. The human nose can recognise at least one trillion different scents. It has around 400 scent receptors that detect molecular components of an odour. However, the bad news is that pollution, chemical exposure, infections and certain new factors have affected the nose’s news point.
A new study points out that the sense of smell in humans has deteriorated in the last few years. Sijia Wang of the Chinese Academy of Sciences, Beijing, and Joel Mainland of the Monell Chemical Senses Center, Pennsylvania, US, researched the genomes of 1,000 Han Chinese people.
They found that there are changes in the set of genes that are responsible for our smell receptors. Due to this, our ability to smell has started diminishing gradually. The study was published in the February edition of the journal PLOS Genetics.
“Pollution, exposure to harmful chemicals, hormonal imbalances and certain drugs cause a reduction in sensitivity,” explains Dr Ravinder Gera, Director and Head of Department of ENT, Max Hospital, Gurugram. “Studies show that the pandemic has played a role in people losing their sense of smell, both temporary or permanent,” says Dr Kalpana Nagpal, ENT Specialist at Apollo Hospital, Delhi.
“It has been observed that the sense of smell in humans in this century is not the same as before. People have a reduced sense of smell following nasal allergies or sinus infections and viral disorders. Even nasal polyposis is a common cause for hyposmia, reduced ability to smell and detect odours. Nasal polyps are soft, painless growth on the lining of nasal passages.
Environmental hazards are also equally responsible for the mutation of scent receptors,” adds Nagpal. Even a severe blow to the head and injuries to the nose are also major factors for diminishing smell, Gera explains. Experts believe that due to too much exposure to dangerous gases, chemicals, pollutants, many people have now developed mutations of scent receptors and their fragrances seem weaker.
Says Dr EV Raman, an ENT Consultant at Manipal Hospital, Old Airport Road, Bengaluru, “It has been observed that over the years primal capability of the nose to detect food and predators has become less and less important as humans evolved with better intelligence and understanding of environmental dangers and accessibility to food.”
Lesser use of any organ will eventually lead to progressive loss of function. Raman also emphasises that rapid urbanisation resulting in higher levels of air pollutants is another important factor for a decreased sense of smell.
Better Your Sense of Smell
✥ Reduce exposure to pollution and chemicals
✥ Undergo an olfactory training programme to regenerate the neural pathways. As part of this, patients expose themselves to four different odours, twice daily for at least 24 weeks.
✥ Pairing smell training with Pranayama is a proven olfactory recovery method