What is protein and why is it necessary for the human body?

Protein is one of the three main macronutrients (the other two are carbohydrates and fats) and is the most important nutrient for the human body. It consists of 20 amino acids and contains 1 calories per 4 gram.

The human body is able to synthesize only 20 of the 11 amino acids independently. The remaining 9 amino acids are derived from the protein present in the diet. These 9 amino acids are classified as irreplaceable, and the remaining 11 are said to be interchangeable because the body can synthesize them independently.

The importance of protein

Protein is a life-building substance. Its main function is to build, maintain and regenerate all muscles and tissues. It is involved in every tissue in the body and is involved in many functions in the body: digestion, blood clotting, immunity and hormone production (thyroid, insulin and estrogen etc.) and the protein our hair, is a key component in our skin and nails.

Another reason why protein is important is that it helps in satiety. Protein-rich foods keep you full longer because protein digestion takes longer than carbohydrates.

If you feel lazy or constantly hungry, it means you are not getting enough protein from your food source.

The predominance of protein

As mentioned above, protein is a macronutrient that is essential for the survival of the human body. In addition to its vital features, let us also list its advantages:

• Helps the body regenerate cells and create new ones;

• Maintains normal growth and development in children, adolescents, and pregnant women;

• Strengthens and restores immune function;

• It acts as a building block on bones, muscles, joints, skin, blood, enzymes, hormones;

• Easily increases muscle mass (in high calorie), loses fat (in calorie deficit), and increases strength;

• Reduces the feeling of hunger, calorie intake, fat formation, osteoporosis and increased blood pressure, the recovery period after injury;

• Increases brain function, sleep quality, bone density and joint strength.

Complete or incomplete proteins

Depending on the nutritional value of the amino acid composition of proteins, they are divided into complete or incomplete types. Complete proteins contain all 9 essential amino acids. Accordingly, defective proteins do not form a complete set of essential amino acids.

Examples of complete proteins:

• Animal protein: meat, fish, poultry, eggs, dairy products;

• Plant proteins: soy (tofu, tempe, soy milk), buckwheat, chia seeds.

Examples of defective proteins:

• Plant proteins: beans, nuts, seeds, cereals (oats, rice, wheat) and in small amounts, some vegetables and fruits.

The highest biological value in terms of amino acid content is chicken egg protein. It contains a complete set of all amino acids in optimal proportions for the body.

Fast and slow protein

Protein differs in the rate of absorption in the gastrointestinal tract. Fast (whey) protein is the most rapidly digestible, especially if it is not a concentrate, whey protein isolate or hydrolyzate. It is recommended to take fast protein 1-1,5 hours before or after exercise, in the morning on an empty stomach if the body needs amino acids.

Traditional slow proteins are casein and shadow proteins, and their absorption process is slow and gradual. Slow proteins are taken in the evening before bed and in the morning, when food is not consumed for a long time.

Protein compounds

Protein shakes have the same effect on muscle as protein in food. It saturates muscle tissue with amino acids - as a raw material for "building" new muscle fibers.

The difference between protein mixtures and simple organic products rich in protein is in the speed of their absorption into the body. Protein shakes are ready-made proteins that do not require long digestion and breakdown processes.

There is another important aspect of protein: one serving of a fast-digesting protein cocktail contains a high amount of protein, which is present in a large piece of meat.

Recommended amount of protein intake

The recommended amount of protein intake takes into account the purpose of physical activity, body weight, and physical fitness.

The U.S. Centers for Disease Control and Prevention recommends that women between the ages of 19 and 70 consume 46 grams of protein per day, and men of this age 56 grams. This is a basic recommendation for inactive people.

According to the study, "the daily requirement of dietary protein, as a minimum, is determined by zeroing the net balance of the whole body." If you are an active person who wants to increase muscle mass, your daily protein requirement may be 1,5–2,2 grams of protein per kilogram of body weight. Those who want to minimize body fat while maintaining muscle mass can consume protein at a rate of 2,3-3,1 grams per kilogram of body weight per day.

Protein supplements and natural nutrient sources of protein

Both protein supplements and natural nutrients contain a source of high quality amino acids that provide the human body with the proteins it needs not only to survive but also to develop. Almost all protein supplements are designed to provide a complete and moderate amino acid profile, while at the same time, the protein source in a natural diet consists of complete or incomplete natural amino acids.

Protein supplements, especially protein powders, may not satisfy the feeling of satiety when consuming real foods like chicken or steak. This is partly due to the effect on the level of the hunger hormone - ghrelin. Consuming protein supplements lowers hormone levels and gives you a feeling of less satiety than if you ate a natural meal.

In addition, because protein supplements are processed to provide high bioavailability, they are assimilated faster than real nutritional protein. This protein supplement can be consumed before, during, or after exercise, and it does not disrupt gastrointestinal function.

As a rule, there is a significant difference between the time it takes to prepare a protein supplement and a real meal. It is sufficient to add the protein powder to the liquid and stir or shake. Real food usually requires some form of processing, such as boiling, roasting, or microwave cooking. Such processing, unlike protein supplementation, requires time, energy, and resources. However, it is important to remember that a protein supplement is only a supplement to a natural meal.

The richest product in protein is meat. White meat of chicken or turkey is preferred, which contains 100-21 grams of protein per 22 grams of product. In beef - 19–20 g, in mutton - no more than 16,5 grams.

Post-meat protein-rich products: soy, hard cheese and seafood (mussels, squid, shrimp), as well as salmon (trout, trout, gorbusha) and mackerel, 100 grams of product contains 18-20 grams of protein. Nuts, beans, cottage cheese contain 1-2 grams less. Chicken eggs (100 grams) contain 12-13 grams of protein. 100 grams of milk or kefir contains 2,8-3,4 grams of pure protein.

Of course, protein can be replaced with nutritious protein sources. However, this requires eating large amounts of food. The process of assimilation of proteins slows down - the athlete may not have time to meet the most basic needs of the body.

Protein assimilation and digestion

Digestion of food is a process that begins in the oral cavity and lasts until all the substances are absorbed in the intestines.

A number of enzymes are involved in the digestive process, which break down or gysrolyze the protein, from the oligopeptide, or the basic monomer unit of a protein, to the short-chain protein structure known as amino acids.

Two linked amino acids are called "dipeptides", several amino acids in a peptide chain are called "oligopeptides", and their long chains are known as "polypeptides".

Monomeric amino acids are absorbed during active transport in the presence of sodium and enter the blood through cell membranes. Di and oligopeptides can also be absorbed in the form of short chains, which are broken down into free amino acids when they are not in the intestinal cavity but in its cells.

Thus, there are two systems that are not related to each other for the absorption of proteins (and carbohydrates) and because they are independent, they allow better assimilation of protein and maximize o by using both methods together. can be achieved. If you combine nutrition, both processes are naturally optimized through digestion. In addition, “peptide” supplement formulas that use proteins from a variety of sources have advantages because some peptides are fully digested into amino acids before being absorbed, and some remain as peptides.

Side effects and applicable cases

When consuming protein, people with kidney disease are advised not to increase the amount. The kidneys cleanse the bloodstream of slag, excess nutrients, and fluids and expel them from the body. Consumption of large amounts of protein puts a heavy burden on the kidneys, forcing it to work with extra force.

In addition, too much protein that the body cannot process can lead to disorders of the gastrointestinal tract (both diarrhea and constipation), skin rashes (irritation, inflammation), and bad breath. may come.

It is not recommended to take it in cases of allergy to this or that component of the protein (for example, lactose) or individual hypersensitivity to the components.