Many people believe that diabetes is caused by eating too much sugar, and many people believe that diabetes is caused by genetics, so there are many people who do not like to eat sugar and whose parents do not have diabetes, why do they still have diabetes? This shows that the above views do not explain the cause of diabetes. What kind of disease is diabetes? Sun Hui, Department of Endocrinology, Wuhan Union Medical College Hospital
In traditional Chinese medicine, diabetes is called “thirst disease” and was described in the Yellow Emperor’s Classic of Internal Medicine about 2,400 years ago and in the Jin Kui Yao of the Han Dynasty. In Yan Liyan’s “Ancient and Modern Recipes” (written around 600 AD) of the Sui Dynasty, it was already recorded that the urine of people suffering from thirst was sweet like bran flakes. It was not until the 17th century that an English doctor called it “diabetes” based on the patient’s urine being “as sweet as honey”, and it has been used ever since.
Diabetes mellitus is a group of diseases characterized by elevated blood sugar and various metabolic disorders, followed by multi-organ damage. How does it happen? First of all, we need to know what blood sugar and insulin are. Blood glucose is short for the glucose contained in the blood. Blood glucose is to the body what a car needs for fuel, and many vital organs such as the brain, heart, and muscles need it for energy when they are active. Under normal circumstances, blood sugar in the body maintains a dynamic balance and fluctuates within a certain range. The most important source of blood sugar is carbohydrates in food, followed by sugar produced by the liver. How to maintain the stability of blood sugar requires an important hormone: insulin.
There is an important organ in the human body called the pancreas, which is located behind the stomach and surrounded by the duodenum, and contains tens of thousands of cell clusters composed of multiple cells, which are spread out like “islets” called islets. Insulin” is a hormone that is released into the bloodstream and transported to other tissues to carry out its physiological effects. Insulin has a wide range of functions in the body, but its main function is to lower blood glucose, so if it is deficient or does not function properly, blood glucose will rise and diabetes will occur. When blood sugar increases, excess glucose enters the urine, so glucose can be detected in the urine and the urine is “sweet as honey”.
How does insulin lower blood sugar? The sugary foods (i.e. carbohydrates) we eat are digested by the stomach and intestines and turned into individual glucose. Glucose is absorbed into the blood through the intestine and raises blood glucose; the body passes the “signal” of elevated blood glucose to the pancreatic ß-cells, which then produce insulin and release it into the blood; insulin is like a “key”, and there are many small structures on the surface of the cells that specifically receive insulin. Insulin is like a “key”, and there are many small structures on the surface of the cells, called receptors, which are like a “lock”, and when the two are combined, the “door” for glucose to enter the cells is opened. The glucose in the blood enters the cell and lowers the blood sugar; the glucose that enters the cell undergoes a complex biochemical reaction and produces “energy”. Some of it is used directly to supply energy for various cellular activities. The main tissues in the body that store energy are the liver, muscles and fat cells.
In a normal person, glucose levels in the blood and insulin secretion are properly matched so that blood sugar remains stable and does not become too high or too low. However, diabetes occurs when glucose in the blood cannot enter the cells and accumulates more and more in the blood in the following situations: 1. This includes two possibilities, one is that insulin and the receptor cannot bind, just like the mismatch between the “key” and the “lock”, and the door for glucose to enter the cell cannot be opened. One is that the number of receptors for insulin is reduced and cannot meet the need for glucose to enter the cell. These two phenomena are known as insulin insensitivity or insulin resistance in medical science.
How does diabetes actually arise? The mechanism is not well understood. Type 1 diabetes is mainly caused by the interaction of genetic and environmental factors (such as viral infections) that cause disorders in the immune function of the body, which attacks and destroys its own pancreatic ß-cells, so it must rely on exogenous insulin to maintain life. For type 2 diabetes, it is mainly caused by the genetic background and environmental factors such as overnutrition and low physical activity, which lead to decreased insulin sensitivity (so-called insulin resistance) and gradual failure of ß-cell function, which is also the reason why type 2 diabetes tends to be familial and has a high incidence in modern and developed countries. In addition, abnormalities in lipid metabolism, etc. are also responsible for the predisposition to type 2 diabetes. It is important to note that diabetes is not directly inherited from the disease itself, but rather from the risk of inherited diabetes. Diabetes can develop only when people maintain a lifestyle of “eating more and moving less” for a long time against the background of genetic factors.