When someone arrives in a foreign country, he or she loses appetite, vomits and has diarrhea, and is weak, which is often said to be a discomfort. Some old people even bring a packet of soil from their hometown when they leave home, saying that drinking it can prevent “discomfort”. Why does “discomfort” occur? Modern medical research has proved that the so-called “discomfort” is in fact a disorder of intestinal flora. It has been observed that when the fetus is conceived in the amniotic fluid in the uterus, the gastrointestinal mucosa begins to learn and recognize the memory. After birth, breast milk and various feeding foods initiate the selective growth and settlement of gastrointestinal microorganisms, which constantly accept the substances that people eat and induce the corresponding dominant symbiotic flora accordingly. By adulthood, the number of symbiotic bacteria in the human gastrointestinal tract can reach 1000 trillion, with 500-1000 species and up to 1.5 kg in weight. If all cells in the human body are counted, the number of cells in the human body itself is only about 10%, while the number of cells of symbiotic bacteria accounts for nearly 90%. The gastrointestinal tract symbiotic bacteria not only have a large number, but also carry more genetic groups than human beings, and learn, recognize, and remember through contact with ingested food throughout their lives, influencing people’s food preferences and absorption and tolerance, as the saying goes, “Live to learn, learn to grow old”, and thus form a family with similar eating habits and body shape. In fact, why some people “drink cold water to grow meat”, while some people can maintain a thin body no matter how to eat, the root does not necessarily lie in the genes of human cells, but in the gastrointestinal tract symbiotic bacteria can be screened to identify food for human absorption and use. This also explains the reason why people always miss their childhood food when they leave home as adults, but children born in foreign countries prefer local food and are no longer accustomed to their ancestral food.
It can be said that it is the symbiotic bacteria in the gastrointestinal tract that determine the absorption and utilization of the food people consume, and also determine the state of people’s nutrient metabolism. Further, it is these symbiotic bacteria that constantly identify and learn to remember the various substances that enter the human intestine, including various external disease-causing microorganisms, parasites, plant and animal antigens …… constitute an important part of the largest body cavity immune barrier between the human body and the outside world. When people go to a foreign country, the environment has changed greatly, especially the type of diet has changed, the gastrointestinal tract symbiotic bacteria for a while is not yet adapted to this change, it will occur flora disorders. The normal flora in the organism in terms of species, quantity, virulence, etc. will change, some of the usual symbiotic bacteria with the organism, immediately become friends to enemies, making people sick. At the same time, those normal for the body to provide nutrients, help or promote the digestion and absorption of food bacteria will also be inhibited and reduced, this series of internal maladaptive changes, in fact, is the intestinal flora dysbiosis, people will have a loss of appetite, vomiting and diarrhea, weakness and other symptoms. When the symbiotic bacteria in the gastrointestinal tract have adapted to the new changes and formed a new dynamic balance of flora, the above symptoms will disappear. People will then say that it is adapted to the water and soil of the new place.