Carbohydrates are organic compounds made up of water and carbon and represent one of the three macronutrients, along with lipids and proteins.
In human nutrition, they are the most important element from a quantitative point of view, providing more than half of the daily caloric requirement (as part of a varied and healthy diet) given their marked energy function. Carbohydrates are present for less than 1% of the total body weight and are essentially represented by free glucose present in the bloodstream and by glycogen, both hepatic and muscular, which acts as a storage and reserve of energy.
Carbohydrates : physiological functions
The 4 kcal released per gram, carbohydrates in the human body are the most easily and quickly accessible source of energy from all body tissues. They are the main fuel for muscle work and brain function.
When the body requires energy, in fact, glucose is readily released and "burned" by the hepatic and muscle glycogen reserves, thus becoming available for use. There is a maximum limit of glycogen formation and storage in our body, after which all excess glucose is converted into fat and makes up adipose tissue. If, on the other hand, the body does not receive adequate amounts of carbohydrates, the liver acts by converting amino acids into glucose. Nerve cells can only derive energy from the latter.
Simple and complex carbohydrates: in which foods are they present?
The most important sources of simple sugars are sweets, carbonated soft drinks, industrial fruit juices, honey, table sugar, and dried and candied fruit. Products containing refined sugars provide the so-called empty calories, since they only give energy in the form of calories, excluding the presence of the other, fundamental, micronutrients. They are therefore to be distinguished from the simple unrefined sugars present in fresh fruit, as these are accompanied by fiber, vitamins, and antioxidants essential for health.
The main sources of complex carbohydrates are cereals and their derivatives (pasta, bread, rice, corn, barley, spelled, buckwheat, rye, flour, etc.), potatoes, legumes, fruit, and vegetables. In particular, the last three food products are the main sources of fiber, so we should strive to consume about three weekly portions of legumes and five daily of fruit and vegetables, both cooked and raw.
Simple and complex carbohydrates: what are the differences?
Monosaccharides and disaccharides belong to simple carbohydrates, water-soluble compounds with a sweet taste, quick absorption and easy digestion. Complex carbohydrates, on the other hand, are tasteless, insoluble, have a high molecular weight and digest very slowly.
Some polysaccharides are not digestible because humans lack the enzymes responsible for their hydrolysis. They have a different action from the energetic one, since they act by improving gastric function and activity: we are talking about dietary fibers, of which cellulose is the most representative. Once in the colon, the dietary fibers undergo fermentation by the autochthonous bacterial flora, thus favoring the development of "good" bacterial strains to the detriment of the "bad" or harmful ones (prebiotic function). They are divided into soluble and insoluble: let's briefly see their functions and the benefits brought to the body.
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