Taste is a very complex phenomenon. We do not experience sensation through a single sense (as we would when we see something using our sense of sight, for example). Still, rather it is made up of five senses working together to allow us to appreciate and enjoy food and drink. An initial visual inspection of food indicates if we would consider consuming it. Then, when eating, smell and flavour combine to us to perceive a taste. Meanwhile, the mix of ingredients, texture and temperature can further impact our experience.
What this means actually is that losing of any our senses, particularly smell or taste, can reduce our enjoyment of eating food. Think of when you had a cold or your nose was blocked, and how the food-eating experience is different then. It is likely that the temporary loss of smell changed the way you tasted the food, lowered your appetite, or might even caused you to overconsume as a means of seeking satisfaction and satiation.
A similar phenomenon happens when we get older. The way we perceive taste starts to change by the age of 60-when the sensitivity of our sense of smell also starts to diminish-becoming severe from the age of 70.
Contributing Senses
As mentioned above, when our sense of smell functions less and is not able to detect and discriminate between different smells, it affects our taste perception also. The decline in sensitivity of the sense of smell with age is due to several factors, including a reduction in the number of olfactory receptors-which recognize different odour molecules- in the back of the nasal cavity, as well as a declining rate of regeneration of the receptor cells.
Another reason for impairment of the sense of taste with ageing is due to structural changes in the taste papillae. These bumpy structures host taste buds in the mouth, on the tongue and palate. One type of these papillae, fungiform, which contain a high level of taste buds, decreases in numbers as we age and also changes in shape, becoming more closed. The more open papillae, the easier it is for chemicals in food to come into contact with the receptors to create taste. Closed papillae reduce the contact surface between food compounds and receptors resulting in less perception of food tastes.
Changing Tastes
Poor chewing is another factor that contributes to low detection of tastes. Due to ageing or poor oral health, some people lose their teeth, with many resorting to dentures. But dentures, particularly if ill-fitting, can affect the quality of chewing and breaking down of food compounds. This can then reduce the dissolution of the food compounds in saliva and reduces the contact levels with sensory receptors in taste buds. In addition, saliva secretion can also decline as a result of ageing. This means that there is less fluid to carry food compounds to the taste receptors, and less liquid available to help food compounds to dissolve, so the taste is more poorly received.
General health also plays an important role in our sense of taste at any age. Head injuries, medicinal drugs, respiratory infections/issues, cancer, radiation, and environmental exposure such as smoke and particulates can all contribute to an impaired sense of taste and exposure to many of these factors increase as we get older.
Not everyone’s sense of taste declines in the same way. Changes are known to be diverse among different people and genders, and not everyone shows the same level of impairment as they age. Though some things are inevitable, these are things that we can all due do at least reduce loss of taste. As per the experts keeping a healthy diet, an active lifestyle and ensuring a low to moderate consumption of five tastes-sweet, sour, salt, umami (meaty taste of foods) and bitter- could help to slow down the changes in papillae.
Waiting for your views on this blog.
Anil Malik
Mumbai, India
17th July 2023