It often happens that we hear about “protein metabolism”, but are we sure we really know what it is?
So here's how our body digests proteins and how it affects our health and fitness.
What are proteins and what are they used for?
The proteins – or proteins – include a large group of organic compounds and are macromolecules formed by amino acids, joined together by peptide bonds.
The main functions of proteins are:
- supply the amino acids necessary for tissue renewal processes (plastic function);
- transport various substances present in the blood (hemoglobin, hormones, etc.);
- allow the muscle contraction;
- ensure the immune defense of the organism.
In addition to the above-mentioned fundamental functions, proteins can also have energy function, when branched-chain amino acids (leucine, isoleucine, valine) are degraded for energy purposes or during prolonged and/or very intense physical activity.
Protein metabolism: the digestion of proteins
Proteins make up only 10-12% of total calories consumed through the diet, but their digestion requires a rather complex process.
Protein metabolism begins in the stomach, through the action of pepsin, and is completed in thesmall intestine by the action of the enzymes of the pancreatic and intestinal juice.
The absorbed amino acids (or amino acids) then reach the liver (hepatic protein metabolism) and all other organs.
Only when there are no other burnable calories are amino acids used for energy; this process is called "oxidation" and—if incomplete—involves the elimination of the remaining amino acid portion via urea.
Analysis of the level of proteins (and therefore nitrogen) present in urea can be very useful for calculating the nitrogen balance, which may result in:
- in tie, in the case in which the quantity of proteins ingested with the diet is equal to the amount excreted;
- in negative, when the excreted amount exceeds the intake amount;
- in positive, if the amount ingested is greater than the amount excreted. In this case, the difference has been used by the body to build new structures (increased muscle mass, repair processes, or recovery from debilitating diseases).
What is the function of transamination or transaminase in liver protein metabolism?
Transamination is the chemical reaction in which the α-amino group of an amino acid is transferred to an α-keto acid, thus giving rise to a new amino acid.
In fact, when the amino acids reach the liver – which plays an absolutely fundamental role in protein metabolism – is responsible for synthesizing them, using specific enzymes, such as transaminases.
Transamination is the main step in protein metabolism.
Protein metabolism and hormones
There are several factors that can stimulate or alter metabolism protein, some hormones I am definitely one of them.
In fact, they control metabolism and energy balance, influencing, for example, the sense of hunger and satiety, energy expenditure and substrate metabolism.
The hypothalamus first and foremost, but the entire nervous system and the emotional sphere therefore play a fundamental role in the hormonal regulation of metabolism.
Here are some examples of how hormones can interact with protein metabolism…
THE'growth hormone (growth hormone), coordinated byinsulin, activates glycolysis, thus providing energy (ATP).
The androgen hormones (testosterone) stimulate lean mass growth and inhibit fat accumulation.
There thyroxine increases the rate of protein synthesis by exploiting the oxidation of sugars and lipids.
What happens instead with glucocorticoid hormones?
The glucocorticoid hormones, like cortisol, interact with protein metabolism with the “opposite” effect, stimulating the protein or muscle catabolism, caused by a negative energy balance.
Protein metabolism and diet
A protein diet is recommended for both those who want to lose weight without losing muscle mass and for the elderly.
Protein intake in the elderly It is in fact very useful for preventing the reduction of muscle mass and for counteracting anabolic resistance to proteins (less active muscle protein synthesis).
A protein diet helps prevent the onset of sarcopenia and the loss of muscle mass, typical of old age.
Protein deficiency can lead to gradual general wasting, which is why protein metabolism is so important for both athletes and the elderly.
In case your protein metabolism is experiencing problems or you want to increase functionality for the above purposes, it may be useful to take specific food supplements such as Nutragen by Nutrifarma.
Protein supplements for muscle renewal and maintenance
Protein supplements based on branched-chain amino acids, with the addition of vitamin B6, leucine, isoleucine and valine, can counteract muscle trophism, for example.
For optimal and complete recovery in endurance sports, a food supplement such as STRATO plus: based on glucogenic amino acids, in addition to simple and complex carbohydrates, mineral salts, vitamin C and magnesium, useful in reducing tiredness and fatigue.
In other cases, however, the food supplements for protein metabolism may contain:
- amino acids and collagen, for the maintenance of normal muscle function;
- pure concentrated amino acids, for the maintenance of muscle mass and normal bone trophism;
- amino acids and lipoic acid, in addition to N-acetylcysteine and vitamins (Thiamine, Vitamin B6 and B12), in the case of low-calorie diets.
Taking care of your body is essential at any age, regardless of sport or aesthetic taste.
Proteins are essential for human life: For this reason, it is important to consume the right amount through diet, drawing on animal or vegetable sources, and possibly adding food supplements.
