Humans evolved a sense of taste not just for good taste

　　Taste is an important way we perceive love and beauty. But the original purpose of humans evolving the sense of taste was not to enjoy delicious food. In ancient times, primitive humans did not have the right to be picky eaters. They could not eat based on experience, and had to keep trying everything that seemed edible. In this process full of danger and death, human beings have evolved the function of judging the nutritional value and harmfulness of food-taste. Our taste buds help determine whether something is edible. Here are five basic tastes and how they help our bodies.
　　The “five original flavors” of taste
　　The colorful world we can see is actually produced by the mixture of red, green and blue, and these three colors that cannot be decomposed are what people call the three primary colors of optics. . So, in the sense of taste, is there something similar to the three primary colors?
　　Studies have shown that humans can distinguish between 4,000 and 10,000 different taste qualities. Although the tastes of these taste qualities vary widely, they are essentially formed by the combination of five basic taste sensations: salty, sour, sweet, bitter, and fresh. The “five original flavors” of taste. 　　Bitterness
, with its strong and often unpleasant taste, is not something humans naturally like, and for good reason.
Bitterness is a strong indicator of toxins or poisons. In nature, most of the bitterness comes from alkaloids in plants, and many types of alkaloids are poisonous.
　　Something that tastes bitter is much more likely to be poisonous than something that doesn’t taste bitter. As a result, we have evolved bitter taste receptors that can quickly recognize which foods may be poisonous and avoid ingesting toxins.
　　However, we can develop a liking for bitter foods, such as coffee and bitter melon. Even cocoa powder is bitter unless sweetened. The same goes for green tea and red wine. Some bitter foods help digestion. When we eat these foods, they increase saliva production, which triggers the secretion of stomach acid and bile—an integral part of the digestion process.
　　salty
　　While salt can make food taste better, that doesn’t mean more is better. Too much is overwhelming – drowning out the natural flavors of the food. Too much salt in your diet can also lead to high blood pressure, stroke and heart disease. However, adding the right amount of salt can improve the taste of food. Seasoning with salt throughout cooking is most effective.
　　Besides bringing out the best flavor in food, making meat juicier and reducing bitterness, there’s another reason we crave salt — our bodies need sodium as an essential nutrient to maintain electrolyte homeostasis. Electrolytes participate in many important functions and metabolic activities in the human body, and supplementing electrolytes is very important for the maintenance of human life activities.
　　Sodium ions and chloride ions are the main inorganic salt ions that maintain the osmotic pressure of intracellular fluid, so we have evolved salty taste receptors that can sense inorganic salt ions.
　　Sour
　　In hot summer, we like to eat slightly sour food to regulate appetite, but for primitive humans, sour taste is a bad sign-it may be a warning sign of immature or spoiled food. To survive better, sour taste receptors have evolved, which may help people avoid eating foods that negatively affect their health.
　　Sourness is mostly associated with citrus fruits, yogurt and other fermented foods such as Swiss cheese and spoiled meats. As we look at the animal world, we find that certain carnivores no longer detect sweetness, umami, or bitterness, but sourness is a taste that is always perceived. Orangutans seem to like sour tastes, which the researchers think may be because acidic foods are associated with vitamin C.
　　Since humans’ ability to naturally produce vitamin C was lost 60 million years ago, eating acidic or sour foods may have a protective effect against scurvy.
　　Sweet
　　All life activities need energy, so those things that can provide sufficient energy are what our ancestors dreamed of, such as carbohydrates. Like all carbohydrates, sugar releases serotonin—one of the reasons people love it. These carbohydrates help us replenish our energy.
　　Since sweets are high in calories, they provided our ancient ancestors with energy and a greater chance of survival. Generally speaking, the sweeter the food, the higher the carbohydrate content, so we have evolved sweet taste receptors to specifically recognize this high-energy food. But the sugary food sources our ancestors ate were fruit, honey and some root vegetables, which couldn’t be consumed in large quantities for regular consumption.
　　Fresh
　　protein is the material basis of life and an important component of all cells and tissues in the human body. The intake of essential nutrients is an essential link to ensure survival. If a food is rich in protein, it will easily release free amino acids and nucleotides, and the evolution of umami receptors that can “detect” these substances can help us find protein-rich foods.
　　Japanese chemist Dr. Kenne Ikeda discovered this taste in 1907 and named it umami. He realized that kombu tasted different from the other four. After figuring out that the source of the taste was the amino acid glutamic acid, he started using glutamic acid to produce seasonings. It was not until 1990 that umami was officially recognized as the “fifth taste”.
　　Spicy is not the sense of
　　taste The “spicy” in the familiar “sour, sweet, bitter, spicy, salty” is not the sense of taste. Spicy is a kind of pain produced by some compounds in plants, such as capsaicin, piperine, gingerol, etc., that stimulate human TRPV-1 receptors (pain receptors). These compounds are originally products used by plants to fight against microorganisms and natural enemies, but they are used as seasonings by humans because of their special aroma and sensory stimulation.
　　Pain receptors are not only distributed in the oral cavity, but also on the surface of the human skin, the intestines and other parts. This is why the hands after washing chili and the intestines after eating spicy hot pot will have a “hot” feeling.
　　Will people’s sense of taste change?
　　From a physiological point of view, the taste quality of different tastes is actually different types of “external stimuli”. For example, the sour taste mainly comes from hydrogen ions, and the salty taste mainly comes from the stimulation of metal ions such as sodium and potassium. , and substances with other tastes such as “sweet”, “bitter” and “umami” will bind to their corresponding G protein-coupled receptors, triggering corresponding neural electrical signals.
　　As the “receivers” of taste, our taste buds are not static. Generally speaking, as we age, the number of taste buds on the surface of the tongue gradually decreases and their function decreases. Clinical studies have found that people over the age of 60 are less sensitive to salt, sucrose and other substances than people aged 20 to 40. The interference of diseases, drugs, smoking and other factors can also lead to dysfunction or even loss of people’s sense of taste.
　　However, for most people, “tasting” is more common in daily life, that is, a temporary change in taste function. For example, local anesthesia can temporarily lose people’s sense of taste, while other substances can affect a certain taste. Or several tastes play a role of inhibition or enhancement.
　　I believe that many friends have had such an experience. After brushing their teeth, eating fruit immediately, the originally sweet and sour fruit will become bitter and astringent… It’s just brushing our teeth. Could it be that we have damaged our tongue?
　　In fact, this is likely to be related to a surfactant called sodium lauryl sulfate in toothpaste. Scientists believe that sodium lauryl sulfate can inhibit sweet taste receptors and activate bitter taste receptors, and the effect can even last for an hour. .
　　In the long process of survival and evolution, humans have evolved a variety of taste receptors to judge the nutritional value of food and avoid ingestion of poisonous substances. The role of taste today is not limited to seeking advantages and avoiding disadvantages in survival. The long-term effects of various factors such as living environment and eating habits make people’s recognition of taste different, and finally form a rich and colorful food culture for human beings.