They have an extremely broad and multifaceted nutritional value, therefore, their dietary estimation and application is frequently the subject of debate among nutrition professionals.
[N]) containing a carbonaceous skeleton linked to a carboxylic group (-COOH), to an amino group (-NH2) and to a radical (-R) which distinguishes them.Ordinary amino acids can be classified in different ways, for example on the basis of their essentiality; an amino acid is defined as essential if the organism is unable to synthesize it. The quantity and number of essential amino acids within a peptide or a protein determine its biological value, also improperly called protein "quality" . The metabolic functions of proteins are:
- Plastic and structural (myofibrils, collagen, elastin, etc.)
- Bio-regulator (hormones and neurotransmitters)
- Catalytic (enzymes)
- Immune (immunoglobulins, coagulation factors, etc.)
- Carrier (albumin, hemoglobin etc.)
- Membrane and receptor channel
- Energy - 4kcal / g.
Compared to carbohydrates and lipids, proteins require a greater digestive and metabolic commitment, and a consequent superior Specific Dynamic action (ADS); this is the fundamental principle on which high-protein weight loss regimens are based.
and he would have to convert all the nitrogenous groups into urea and then expel them in the urine.Furthermore, low-carbohydrate and high-lipid medium-protein diets can be ketogenic. Ketones are acid molecules which, if produced in excess, reduce the blood pH, causing even serious symptoms and disorders. Furthermore, ketones have a high osmotic power and during filtration, in order to be expelled with the urine, they require large quantities of water; this phenomenon can lead to dehydration. In short, the excessive use of amino acids for neo-glucogenic purposes increases proportionally the hepatic and renal burden.
It should be noted that some studies directly correlate diets with a high content of animal proteins to the worsening of the metabolic balance of calcium [Ca], which as we know is very important in subjects at risk of osteoporosis. On the other hand, this theory has been disproved, at least in healthy subjects. Moreover, thanks to the increased intestinal absorption of the mineral and the stimulation on the synthesis of osteo-anabolic hormones, high-protein diets do not seem to increase the risk of osteoporosis.
In summary, food therapies based on neoglucogenesis can facilitate weight loss but, in addition to the reduction of adipose fat:
- they determine a greater commitment of the liver and kidneys
- engage the buffer system
- promote dehydration - especially in the presence of ketoacidosis
- the muscle and liver reserves of glycogen waste away.
Some technicians, but above all many laymen, attribute miraculous characteristics to food proteins; one of the most recent claims concerns "improvement of muscle trophism" and "optimization of body composition" regardless of the level of physical activity. This half-truth can be highly misleading and the study from which these conclusions were drawn should be read in full. - especially the characteristics of the research sample and the evaluation method.
. Rather, it is very likely that protein malnutrition (therefore deficient in essential amino acids) negatively affects the trophism of the muscles and especially in subjects who have a low or almost zero level of physical activity (LAF). In this case, the increase of the alimentary protein portion can determine an improvement of the muscular trophism, therefore of the body composition.
it is very common in old age and especially among geriatric patients who are not totally self-sufficient. Depressive symptoms, senile dementia and economic difficulties often contribute to worsening eating habits; in many cases, the elderly eat monotonously and prefer foods that are easy to prepare, such as soup in broth.
In the long term, a similar diet determines a "protein insufficiency which is reflected in muscle depletion, worsening the body composition. In these cases, the" increase in "protein dietary intake would undoubtedly improve the muscle trophism of the subjects, but the same concept is not applicable to a healthy and eunnourished subject.
Proteins do not make you fat or lose weight, they are essential nutrients for human nutrition that must be introduced in the right quantities.
