The access to the necessities of life is what drives a person’s ability to make something of themselves – money, food, and shelter. Money is the commodity that promises to multiply upon investment, shelter is for one’s safety and food is comfort for many people. Other than being a highly influential social element, the consumption of nutrients in food is a biological necessity. These nutrients drive the functions of the body by acting as a fuel.
Before the development of civilization, people depended on raw vegetables and meat to sustain their bodies. However, once humans started cooking their food, digestion becomes easier and something different was observed – humans felt the presence of taste. Since then, in the life of a regular person, the taste of food is an essential factor in planning meals – most people tend to dislike bland food. The taste from food defines the lives of many – chefs and hoteliers have made their livelihoods by making food more delicious, by adding more flavors and elements, all to enhance the taste of the food. Can one imagine if we were to be unable to taste this food?
We can taste food because of TASTE BUDS. Since the mouth is the first organ involved in digestion, the taste buds are present on the TONGUE. The “bumps” observed on a tongue are called the PAPILLAE and it harbors the taste buds inside it. An average person has 2000-10000 taste buds, which vary with age and other habits such as smoking. A structure called MICROVILLI, appearing like thin microscopic hair-like extensions, and the SENSORY CELLS are present in the taste buds. The microvilli are actively involved in transmitting the signals associated with the flavor to the brain. The papillae increase the surface area of the tongue to enhance the absorption of flavors to ensure that the microvilli transmit the exact signal to the brain.
It was widely accepted that specific regions of the tongue respond to a taste – i.e., the sweetness can be detected by a specific region and saltiness by another. For this theory to be true, it would require a special type of selective taste bud at these different regions on the tongue to ensure only one taste is picked up. The one limitation of this theory that was risen was about the migration of a specific component migrating to the corresponding region on the tongue. However, such selectivity of a taste bud was not proved and hence, this hypothesis was rejected. The new mechanism for the distribution of taste buds assumes uniformity in the spread – thus, each taste bud can recognize each taste.
The taste buds and the microvilli breakdown the food and its specific components are tasted – for instance, while drinking sugarcane juice, the taste buds detect the sucrose present in it and send a signal to the brain that the food is sweet. However, the brain is unable to recognize the exact substance with just the taste buds – which means that the brain cannot guess that one is drinking sugarcane juice solely based on the presence of sucrose, as transmitted by the taste buds.
Thus, the concept of taste has another contributor – the NOSE and OLFACTORY SENSES. The olfactory senses transmit the smell of the food to the brain, which further lets us taste our food. Before consumption, the smell of the food is caught by the nose and the breakdown of food by the saliva triggers the olfactory senses, both of which carry the smell to the brain to accurately be able to taste it.
So, the sugarcane juice is first smelled by the nose, followed by the action of the taste buds and the signal transmitted by the olfactory senses. The working of these three in tandem provides the brain with the signal that the substance being consumed is sugarcane juice. It has been postulated that if onion and potato are consumed without the effect of smell, their taste would be alike or the same. One knows the drastic difference in the taste of an onion and a potato – and it can all be attributed to their distinct smell!
Another evidence pointing to the importance of smell in tasting food is seen during a common cold. When one suffers from cold, their nose is congested, and the olfactory senses are low – so food seems bland. Only the basic taste buds work, which helps in identifying whether the food is sweet, sour, salty, or bitter. Since the complimentary smell is not sent to the brain, we are unable to taste every flavor in the food.
The number and function of taste buds are genetic and depends on the genetic predisposition of their sensitivity. Some people have fewer taste buds, while others have more – “supertasters” are people who possess 25% more papillae on average, which makes them highly sensitive to certain foods, leading to them being a picky eater. Taste buds usually die out as the person ages and due to excessive smoking.
Why do we need taste buds?
Other animals do not possess taste buds as sensitive to humans. Humans developed an evolutionary advantage over the other animals, in the form of taste buds and olfactory senses. The taste of the food determined the type of substance in the food and even indicated any dangers. If the food were to taste sour or bitter, it would indicate a poison and the humans would steer away from that kind of food. Although the whole tongue can recognize each of the tastes, the back of the tongue is especially sensitive to bitter tastes. If the poison is consumed, the back of the tongue would trigger the gag reflex to spit out the poison.
Although fruits made up a big part of the diet for ancient humans, their fruits did not resemble the ones sold in the modern world. Sweetness in food was rare and so humans developed a craving for sweet foods. This evolutionary trait is still prevalent and is manifested as having a SWEET TOOTH. Thus, many of the food habits humans possess have evolutionary reasoning behind them.
Although taste buds and the olfactory senses developed to impart evolutionary advantage, they have now become a factor that can unite people. Regional cuisines have spread globally and are enabling people to taste foods from countries they have never visited. Foods are often observed to break down communal and communication barriers as food are the basic common factor between everyone. Only humans are capable of such a feat – the conversion of a biological requirement into a factor of social and societal importance.