Carbohydrates are a class of organic compounds that are in the nature of sugars or close to sugars in structure and chemical properties. Along with proteins and fats, carbohydrates play a vital role in the metabolism and energy in the human and animal body.
Carbohydrates are part of plant, animal and bacterial organisms and make up the vast majority of organic natural compounds. All organic nutrients ultimately come from carbohydrates produced by plants through photosynthesis from carbon dioxide and water.
Carbohydrates are the main component of food for humans and most animals, supplying them with most of the energy needed for life. In the adult body, more than half of the energy comes from carbohydrates. They also play an important role as the main building material of plants, the skeleton of insects, crustaceans and other organisms.
Carbohydrates are divided into monosaccharides, oligosaccharides and polysaccharides. The main source of carbohydrates in human nutrition are plant foods. Carbohydrates account for more than half of the daily calorie intake. The most important dietary carbohydrates are glucose, fructose, sucrose, lactose and starch.
Carbohydrates are easily digested and quickly enter the bloodstream. Excess carbohydrates in the diet contribute to obesity. When carbohydrate metabolism is disturbed, serious diseases occur, such as diabetes, glycogenosis and others. Thus, carbohydrates play a vital role in metabolism, are the main source of energy and an essential component of nutrition. Their metabolism in the body is closely related to the metabolism of proteins and fats.