The human body is a complex system that has evolved over thousands of years and has developed ways to interact with nature. Although modern humans have come a long way from their original way of life, our bodies have preserved almost all the tools they used at that time. For example, our eyes can adjust our vision in a way that allows us to easily distinguish delicious fruit in a heap of leaves. This means that we can easily spot objects in our environment, but we may sometimes miss things that are right in front of us, like the car keys on the table. Our ancestors often lived near rivers, so our brains have adapted to ignore constant noise, such as the sound of a waterfall or the flow of a river. We can also ignore other types of noise, like traffic or the hum of a crowd.
Our sense of smell and taste have always worked in tandem—the smell answered, “What is it?” and the taste—”Do I want to eat it?”. These two senses were the only way to test food for suitability for consumption—which is why we are now able to distinguish a huge variety of tastes and smells, even though there are only four flavors. Or at least that’s what the researchers used to think about 120 years ago. Only recently have they added a fifth to the main four tastes.
Now, in addition to sweet, sour, salty, and bitter, you can officially consider the taste of protein-rich food—the taste of umami. Some studies suggest the existence of other tastes, for example, fatty (oleogustus or fatty acid), but officially, scientists name only five; but there may be more than six of them. Umami, which translated from Japanese means “pleasant taste,” was discovered by the Japanese scientist Kikunae Ikade in 1908. The sensation of umami is associated with the amino acid glutamine and is associated with monosodium glutamate, a derivative of this acid commonly found in meaty and mushroomy food.
Umami was added to the list of flavors for a reason. Scientists have discovered a special receptor responsible for its recognition, but the taste of umami is difficult to imagine in its pure form for three reasons. First, our receptors recognize umami with less intensity than saltiness or sourness. Second, it is difficult to synthesize the pure taste of umami, as it’s usually an aftertaste. Thirdly, there is the cultural aspect. A Westerner will have difficulty recognizing this taste, but in Asian culture, everyone is familiar with it from childhood.
Our sense of taste is essential to identifying the nutrients in our food. A sweet taste unsurprisingly indicates the presence of sugar, which is a valuable source of calories. When we consume potatoes, our salivary enzymes break down starch into sugar, which we can taste. Dilicious amino acids are responsible for the umami taste, and they tell us about the presence of proteins in the food. The salty taste receptors help us identify electrolytes. These nutrients are crucial for our well-being; we have learned to find them through taste. However, our sense of taste also helps us differentiate between potentially harmful foods. For instance, many poisonous substances taste bitter, which triggers our subconscious aversion to everything bitter.
It is said that cats, for example, lack a crucial gene that allows them to sense sweetness. As a result, they cannot taste anything sweet and, therefore, show no interest in sugar-rich foods. This is because their ancestors did not consume sugary foods, and so the gene responsible for detecting sweetness was not passed down to domestic cats. Similarly, pandas cannot taste umami, while vampire bats that feed exclusively on blood have no clue what sweet, bitter, or umami flavors taste like.
There is a common misconception regarding the classic concept of the tongue map, which shows that different areas of the tongue detect different tastes. However, this is actually an inaccurate translation of a passage from a German dissertation published in a book by American psychologist Edwin Boring in 1942. Many molecular biologists have shared their thoughts on the issue over the course of the last 20 years. They have provided evidence that each kind of taste triggers a specific receptor protein in taste cells located in the mouth, throat, and tongue. The receptor activated by sweet flavors is the same, while the one activated by bitter foods is entirely different. This means that taste receptors, or “papillae,” on the tongue are distributed unevenly and irregularly, and each one can perceive all five basic tastes at different intensities. This finding further disproves the notion that only specific regions of your tongue can detect particular flavors since these receptors are present in every tastebud.
