What is the importance of sugar to human health? Is eating too much polysaccharide good for your health? How does sugar get into body tissues?

Sugar is a carbohydrate, which is divided into monosaccharides (such as glucose, fructose, galactose, etc. ), disaccharides (such as sucrose, maltose, lactose, etc. ) and polysaccharide (such as starch, most food crops belong to polysaccharide) are divided according to molecular structure; Monosaccharide can be directly absorbed into blood in vivo, while polysaccharide and disaccharide must be decomposed into monosaccharide under the action of glucosidase (a digestive enzyme) and absorbed into blood. Sugar is the most economical and main energy source for human body to obtain heat energy. It participates in various metabolic activities of human cells and is an important substance that constitutes body tissues. Sugar mainly exists in the form of glucose or glycogen in the body. When the body needs enough oxygen to supply tissues, it can be oxidized and decomposed to release all energy, and its final metabolites are carbon dioxide and water. Carbon dioxide is exhaled from the lungs and water is excreted from the kidneys. When oxygen supply to tissues is insufficient, some energy is released to produce lactic acid. It is best not to exceed 40 grams a day. The concept of "sugar" has broad sense and narrow sense. Sugar in a broad sense refers to various digestible carbohydrates, including sweet sugar and starch without sweetness; Sugar in a narrow sense refers to refined white sugar and syrup commonly used in food and beverage processing. The harm of sugar to human body is mainly the latter. Almost all sweets contain a lot of sweeteners made of white sugar or syrup. Therefore, it is very common for some children and young women who like to eat desserts, biscuits, snacks and drinks to consume more than100g of sugar every day. However, the total amount of sugar recommended by nutritionists is about 30-40 grams per day, that is, it should not exceed 10% of the total daily carbohydrate intake. What is the concept of 30-40 grams of sugar? Among the sweets that people often eat, the sugar content of a spoonful of jam is about 15g, that of 1 can of cola is about 37g, that of three small pieces of chocolate is about 9g, that of 1 can of ice cream is about 10g, and that of several biscuits is about10g. Eating too much sugar will lead to a very high purity of refined white sugar after crushing, which can reach over 99%, that is to say, it contains almost no other nutrients and only a lot of energy. If you eat too much sweets, you will feel full, because too much energy will affect the intake of other foods rich in protein, vitamins, minerals and dietary fiber. In the long run, it will lead to diseases such as nutritional deficiency, developmental disorder and obesity. On the other hand, the metabolism of sugar in the body needs to consume a variety of vitamins and minerals. Therefore, eating sugar often will cause nutritional problems such as vitamin deficiency, calcium deficiency and potassium deficiency. Japanese nutritionists believe that children eating too much sweets is an important reason for the increase in fracture rate; American nutritionists also pointed out that children who love sweets have a higher fracture rate. Nutrition survey also found that although eating sugar may not directly lead to diabetes, long-term consumption of sweets will lead to excessive insulin secretion, disorder of carbohydrate and fat metabolism, resulting in imbalance of human internal environment, which will further promote the occurrence of various chronic diseases, such as cardiovascular and cerebrovascular diseases, diabetes, obesity, senile cataracts, dental caries, myopia, rickets and so on. Eating more sweets will also make human blood tend to be acidic, which is not conducive to blood circulation and weakens the defense function of the immune system. Sweetness has the same physiological reaction as drug abuse, and craving for sweets may also cause physical and psychological dependence. According to research, sweetness is the first taste accepted and pursued by human beings after birth, and liking sweets is an instinctive reaction of human beings. Medical experiments have proved that, in a sense, candy containing a lot of white sugar has the same effect on the brain as drugs. If animals habitually eat sweets, it will stimulate the brain to produce opioids and make them feel happy. Once the supply of candy is stopped, they will feel pain and fidgety, and the chemicals in their brains will be out of balance. This phenomenon is very similar to the reaction of drug addiction.