What are carbohydrates

What are they

Included in the category of macronutrients along with proteins and fats, carbohydrates (or carbohydrates) are the main source of energy for the body.

They are mainly contained in foods of plant origin and, although table sugar (or sucrose) is the best known exponent, the food group that can provide the greatest quantities is that of cereals.

They are classified according to their chemical structure. Theycan be simple when they consist of a sugar molecule (monosaccharides) or a few of them (disaccharides, trisaccharides, oligosaccharides) or complex, when they take the form of long chains of sugars (equal or different) linked together (polysaccharides).

Simple sugars are glucose, fructose, galactose (fundamental substances from a nutritional point of view) but also maltose and lactose. Complex carbohydrates are starch (rice, wheat, seeds, corn, potato, etc.) and cellulose.

The latter, used as a structural molecule for the construction of plant cell walls, is an exception because it is not digested or assimilated by the human organism that does not draw nourishment from it, but expels it as waste. It is one of the components of dietary fiber, a material consisting of substances resistant to the action of digestive juices but essential in a healthy and balanced diet.

The term “carbohydrate” refers to the basic elements of each sugar molecule, namely carbon atoms and water molecules (or rather, to be more precise, hydroxyl groups).

Food sources

Simple and/or complex sugars, although in a very variable percentage from case to case, are present in almost all foods.

Here you can find them in the form of:

• sugars, contained in fruits, vegetables, milk and dairy products;
• starches, present in cereals, potatoes and legumes;
• fibers, naturally present in fruits, vegetables, whole grains and legumes and unusable from an energy point of view, but essential for the absorption of nutrients.

Let’s see which foods are particularly rich in complex carbohydrates or simple sugars in the table below.

Absorption

Carbohydrates are the most easily digestible and best assimilated compounds by the body.

Monosaccharides, , and and glucose in particular, , can be absorbed and used directly by the cells without requiring further metabolic transformations , because they enter the bloodstream immediately after passing through the intestinal wall.

The longer and more complex ones , on the other hand, must first be split and converted into glucose or fructose in the liver , in order to be re-introduced into the circulation for energy purposes.

The digestion of carbohydrates already begins inside the the mouth : during chewing, thanks to the action of the amylases (enzymes) present in the saliva and proceeds in the first section of the intestine (duodenum), where further amylases are poured, more efficient than the first ones produced by the pancreas.

Effects

Even while the food is still in the stomach, a series of hormonal reactions stimulates the pancreas to .

This means that when the glucose is absorbed from the intestine and reaches the blood, it finds sufficient insulin to receive it and convey it to the cells and tissues of the body which will use it to produce energy.

When insulin is lacking or insufficient , as occurs in Type 1 Diabetes , or when the body fails to use it adequately (conditions of insulin resistance and Type 2 Diabetes ) , the blood glucose concentration after a meal is ( and remains for a long time) very high, but the cells literally starve to death .

Glucose that is not used immediately for energy is stored in the liver and muscles in the form of long chains of glycogen , which represent a “stock” that can be used gradually to keep blood Sugar constant during periods of fasting between meals.

metabolic to fatty acids to form

Shortage

A certain amount of simple and/or complex carbohydrates must be taken every day, even in the context of low-calorie diets , because some organs and tissues can obtain vital energy only from glucose.

In particular , the brain and red blood cells need glucose, because they are unable to metabolize lipids .

The daily requirement of the brain is approximately 140 grams of glucose, while that of red blood cells is approximately 40 grams.

When these nutrients are lacking and glycogen stores are depleted, the body must begin breaking down amino acids and lipids to extract it, using a metabolic pathway known as gluconeogenesis.

These phenomena have unfavorable and “toxic” consequences: in the first case, the demolition of part of the muscle proteins, with a decrease in lean body mass and an increase in nitrogenous waste compounds (ammonia and urea); in the second, the induction of acetone.

Recommended doses

Since carbohydrates represent the main nutrients of our diet (at least in terms of energy), they should constitute the predominant share of the daily caloric intake: ideally around 55-65%; of these, 80% should be complex types .

Precautions

Simple sugars are a precious source to give a ready-to-use energy boost during particularly intense and/or prolonged physical or intellectual effort, but they must not be abused .

Excessive consumption, in addition to promoting weight gain and dental pathologies, predisposes to the development of insulin resistance, antechamber of type 2 diabetes, and hormonal alterations of different types (for example those at the basis of hirsutism in women).

Furthermore, there are scientific indications according to which an excessive consumption of refined sugars and sweet foods can increase the risk of developing certain tumors (in particular, that of the colon and rectum).

Bread, a Bread, a source of carbohydrates par excellence, can contain dangerous mycotoxins. This is how farmers defend themselves…

For these reasons, it is important to consume portions of carbohydrates appropriate to your body and lifestyle, without eliminating them completely from your diet.