Do animals taste their food

biology : Acquired a taste

Cats are poor off - at least when it comes to taste. There are only about 400 taste buds available to you. They do not perceive sweets at all and otherwise they taste poorly. Cats can easily get over that, however. Because they are predators with a penchant for fresh meat, there is little risk that they will eat spoiled or poisoned meat. Herbivores, on the other hand, have the most sophisticated sense of taste of all, and some of them are downright gourmets. Horses, for example, are equipped with 35,000 taste buds, which allows them to easily distinguish hundreds of types of grass from one another.

There are still the omnivores. In terms of taste, they're somewhere between herbivores and carnivores. The human being is a typical representative of this group. He is born with 10,000 taste buds, but is unlucky enough to lose a considerable part of them over time.

Until recently, the human sense of taste was considered to be primitive, coarse and usable only for a few. But research over the past few years has shown that its capabilities are in fact astonishingly high. The theory of evolution explains why it does what it does.

Humans can taste sweet, sour, and salty foods because that's how our ancestors found the right food. So what tastes sweet is usually rich in carbohydrates and thus provides a significant amount of energy. There is also a high probability that it is free from substances that are toxic to the human organism. By the way, even the small intestine can taste sweet. Like the tongue, it is also equipped with the T1R3 receptor required for this.

The fact that people are able to taste sour foods, on the other hand, makes sense to warn them about unripe fruit and spoiled food. The American biologist Charles Zuker (University of California at La Jolla) recently discovered that a single protein called PKD2L1 is responsible for the perception of acid. Zuker later found this protein in certain nerve cells in the spinal cord. It may be there to monitor the body's acid balance.

The fact that a meal tastes salty may not be praise for the cook. But the taste tells us that the food contains salt or other minerals. A constant supply of table salt is essential for the human metabolism. Because the body cannot store salt and, moreover, constantly loses it when sweating.

To prevent animals from eating them, a number of plants produce poisons, including cyanogenic glucopyranosides. People can easily identify these substances, which release hydrogen cyanide in the gastrointestinal tract, because they taste bitter. The receptors responsible for bitter substances are 10,000 times more sensitive than those that specialize in sweets. This extreme sensitivity is, among other things, the result of a genetic mutation that occurred sometime in the Paleolithic. This is the conclusion reached some time ago by Wolfgang Meyerhof and Bernd Bufe from the German Institute for Human Nutrition Potsdam-Rehbrücke and other scientists. However, 13.8 percent of Africans lack this gene variant, so that they only taste cyanogenic glucopyranosides in higher concentrations. But that's probably an advantage for them. If they eat cyanogen-containing foods more often, they are more likely to suffer from sickle cell anemia. However, this in turn reduces their risk of contracting malaria.

“Researchers suspect that bitter substances protect against a whole range of diseases. At the same time, epidemiological studies indicate that a high consumption of vegetables can lower the risk of certain cancer or circulatory diseases. However, many people reject certain vegetables because they taste bitter, ”explains Meyerhof. In order to be able to offer supposedly tastier products, the agro-food industry tries to reduce the bitter substances in food. "Whether this can help to increase vegetable consumption remains to be seen."

But sweet, sour, salty and bitter are not enough. In 1908, the Japanese chemist Kikunae Ikeda discovered a fifth basic taste, which he called "umami" (the Japanese word for "tasty" or "delicious"). The evolutionary meaning of the umami taste is not yet fully understood. But apparently it serves primarily to indicate protein-rich food. In any case, it is no less typical for milk, cheese or soy products than it is for highly ripe fruit or fish and meat in general. Umami is nothing more than the taste of glutamate, the most abundant amino acid in food. The glutamate enhances the particular taste of the food.

For a long time it seemed as if evolution had forgotten to equip humans with the useful ability to track down fatty acids in food with the tongue. Because the assumption of nutritional science has been confirmed again and again that pure fat tastes like nothing. But recently the French physiologist Philippe Besnard (Université de Bourgogne in Dijon) succeeded in locating a receptor that apparently specializes in the perception of fats in the oral cavity. This is the glycoprotein CD36. As soon as this receptor is paralyzed in mammals, they lose their appetite for high-fat food.

Occasionally there is speculation about whether the human sense of taste could have even more in its repertoire - fresh water, for example, or alkaline or metal. That is possible, but science has not yet found any evidence of this.

Not only the primary taste qualities of the food, but also its consistency, smell and temperature contribute to the final taste experience. The sensors responsible for temperature measurement and pain sensations have a strange property: They are also active when they come into contact with spicy food. A little mustard or horseradish is enough to activate the cold receptor. The heat receptor, on the other hand, reacts to the capsaicin contained in all kinds of chilli fruits. The capsaicin not only helps to cool the body by increasing the secretion of sweat. It also fights parasites. But humans are the only mammals that do not find the taste of chilli fruits hideous. Therefore, the capsaicin-producing plants rely on birds to spread their seeds. Apparently they like it spicy.

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