Today we will talk about CARBOHYDRATES. Obviously, the film will not be a didactic lesson but rather informative, which is why it may seem quite GENERIC to the more experienced. On the other hand, for those who do not have a chemical-nutritional knowledge base, I strongly suggest paying attention to fully understand the subject!
Carbohydrates, also called GLUCIDES, GLICIDES, SUGARS and CARBON HYDRATES, are MACRO-NUTRIENTS with a predominantly ENERGETIC function. Each gram of AVAILABLE carbohydrates provides approximately 3.75 kilocalories (kcal), while those NOT AGGREDIBLE by the digestive system are called NON AVAILABLE carbohydrates. We remind you that SUGARS ARE NOT AVAILABLE NOT they are nutritional molecules UNNECESSARY! It is true that they are not absorbed and used for energy purposes by the body, however, they represent a valid support for PHYSIOLOGICAL BACTERIAL FLORA (called PREbiotic function) and help to keep our intestine CLEAN and HEALTHY.
The SUBSTANTIVE difference between available and NOT available carbohydrates (including some FOOD fibers) is the CHEMICAL link between the various monomers. The human digestive system is able to break down only those called ALPHA, while the enzymes of certain HERBIVORIC animals and some MICROORGANISMS are able to digest even the molecules for us totally indigestible.
Carbohydrates can be SIMPLE or COMPLEX. The simple ones, or MONOSACCHARIDES, represent the FUNCTIONAL UNITS (ie the "BRICKS") with which the COMPLEX are built. The most well-known simple ones are: glucose (functional unit of STARCH and GLYCOGEN, as well as the main energy substrate of human cells), fructose (contained in fruit and vegetables) and galactose (which constitutes the lactose of milk).
From their combination, molecules of 2, 3, 10 or HUNDREDS of units are obtained.
Those of 2 units are called DI-saccharides and, despite being "chemically BINDED, therefore complex", their nutritional characteristics ARE MUCH MORE SIMPLE to those of SIMPLE ones. The best known DI-saccharides are SUCROSE (or table sugar, obtained from the processing of beet and sugar cane), MALTOSE (obtained from the "hydrolysis of" starch) and LACTOSE (naturally present in milk).
Generally, up to twenty units (including DI-saccharides), COMPLEX carbohydrates are roughly defined as OLIGOSACCHARIDES. On the contrary, when they reach a considerable size, they take the name of POLYSACCHARIDES.
As anticipated, the most important polysaccharides in human nutrition are: STARCH, which is the complex reserve carbohydrate of plants which is the most important food energy nutrient for humans; and GLYCOGEN, which is the complex reserve glycide of animals that the human body synthesizes independently and STORES in the liver and muscles.
Carbon hydrates are found both in foods of VEGETABLE origin and in those of ANIMAL origin but, in HUMAN NUTRITION, carbohydrates contained in cereals, legumes, tubers, fruit and vegetables certainly prevail.
However, there are ARTIFICIALLY REFINED foods based on CARBOHYDRATES (such as white wheat flour, potato starch, etc.) and even REFINED and ISOLATED CARBOHYDRATES (such as table sucrose, table fructose, malto dextrins in food supplements, starch from cereals, etc.).
The intake of carbohydrates in the diet is often the subject of discussion. Many consider carbohydrates as potentially HARMFUL nutrients and therefore introduce as little as possible. Obviously this is IMPROPER behavior.
Assuming that some tissues of the human body, under normal conditions, ONLY "WORK" with glucose (for example, the nervous tissue, the adrenal medulla and red blood cells), this nutrient CANNOT be PERENNEMENTLY introduced in INSUFFICIENT quantities. The adult body needs about 180g of glucose per day and, thanks to the extraordinary efficiency of NEO-GLUCOGENESIS, if it is NOT supplied with food, the liver is able to produce it using amino acids, glycerol and lactic or pyruvic acid. Unfortunately, this mechanism of "defense" from carbohydrate DEFICIT has a limit of effectiveness; in fact, the lack of carbohydrates in the diet determines: a reduction in mental and physical efficiency due to HYPOGLYCEMIA, and intoxication by KETONIC BODIES, or a kind of WASTE released in energy production in the absence of glucose. Carbohydrates are therefore NOT ESSENTIAL nutrients, but rather NECESSARY (since the body is able to SELF produce them only partially DESPITE their extreme importance)! Ultimately, it is a sort of SEMI-ESSENTIALITY!
Respecting the intake of proteins and lipids, that of carbohydrates could be about 55-65% of the total energy; not that, for example, ONLY 45% can be HARMFUL but (if mathematics is NOT an opinion) this would lead to an excess of proteins or lipids. It should be remembered that, in PHYSIOLOGICAL conditions, the percentage fluctuation of some points does not represent a nutritional risk factor; on the contrary, following an improper diet in case of metabolic, liver or kidney diseases can greatly aggravate the general condition.
In compliance with the recommendations of nutritional research bodies, ONLY a SMALL part of the total energy must come from simple sugars, ie about 10-12%. This recommendation arises from the fact that simple sugars (intended as mono- and disaccharides) come ESPECIALLY from foods sweetened with SUCROSE; this refined sugar, in addition to increasing the risk of dental caries, IF in EXCESS has a rather negative metabolic impact. On the other hand, if the simple sugars were entirely made up of the fructose of vegetables and fruit, their percentage in the diet could be even less severe.
It is important to remember that for ENDURANCE athletes, or those who practice prolonged physical activity, carbohydrates play an irreplaceable energy and reserve role! Their RIGHT contribution to the athlete's diet favors: the maintenance of athletic prowess and the preservation of muscle tissue by reducing the phenomenon of OXIDATION of muscle AMINO ACIDS.
The human body, while digesting and absorbing different monoscaccharides, mostly converts them into the substrate most used by the body, namely GLUCOSE.
Food carbohydrates are NOT ALL the same; they are distinguished by the TYPE of molecule and by any chemical BINDINGS within it or in the polymer. These two characteristics, associated with the GENERAL nutritional composition and the QUANTITY of the entire meal, DEFINE the METABOLIC IMPACT of carbohydrates on the human body.
TODAY, sugars (simple and complex) are mistakenly considered the nutrients most responsible for overweight and obesity. In reality, this is only partially true.
This can occur ONLY if meals are eaten FREQUENTLY:
- with EXCESSIVE QUANTITIES of carbohydrates ...
- with an equally EXCESSIVE GLYCEMIC INDEX.
To QUIETLY consume carbohydrates in meals it is necessary to: CHOOSE the RIGHT PORTIONS (to avoid an EXCESSIVE GLYCEMIC LOAD) and obtain a contained TOTAL GLYCEMIC INDEX. For this last measure, it is sufficient to PREDILIGATE RAW products EXCLUDING REFINED FOODS (such as white flours) and even more REFINED CARBOHYDRATES (such as table sugar). This is justifiable by the fact that the dietary FIBER contained in unprocessed foods (such as cereal bran and fruit pectin) favors the containment of the glycemic index of the meal and increases the sense of satiety!
