Protein is one of the three basic macronutrients. It has a lot of important functions in our body. However, not everyone knows which protein sources are wholesome and which are not. It is also worth knowing how to determine the need for this nutrient.
Protein – what is it, how it is built and what roles it has in the body?
Protein (proteins), alongside carbohydrates and fats, is one of the three basic nutrients of the diet and has three functions
It is a source of energy. Of burning 1 g of protein, 4 kcal are made.
It is building material. It is used to build and rebuild muscle tissue (myosin, actin), is a building component of bones and teeth (collagen) and skin, hair and nails (keratin).
It regulates metabolic changes in the body creating hormones, enzymes, antibodies and transporting various elements along with blood.
Proteins are organic compounds composed of carbon, oxygen, hydrogen, nitrogen and sulfur. They are made of amino acids that the body needs to function properly. The endogenous amino acids man can produce alone. We obtain exogenous amino acids only from food. These include lysine, methionine, leucine, isoleucine, valine, threonine, phenylalanine and tryptophan.
Sources of wholesome and defective proteins in the diet
Due to the content of exogenous amino acids, when assessing the nutritional value of proteins, we can divide them into wholesome and defective ones.
The source of wholesome proteins, and therefore having a set of 8 essential amino acids, are
Products of animal origin, eggs, milk and dairy products, fish, meat.
Products of vegetable origin quinoa seeds, soy products
The other sources of protein in the diet are defective – this means that the content of exogenous amino acids is insufficient, less than 8 or the proportions between these amino acids are not optimal. This group includes plant products such as
The nutritional value of defective proteins can be increased by combining them with wholesome protein products. An example can be eating oatmeal with milk or pasta with feta cheese or meat.
In conclusion, the best protein in terms of nutritional value is protein of animal origin and quinoa and soy products. However, it should be remembered that plant products, in addition to protein, contain lots of vitamins, minerals and fiber, and should also appear regularly in our diet.
The need for protein
The need for a protein varies depending on body weight, level of physical activity and gender. Due to the variety of functions that it performs in our body, it is worth taking care of its proper supply. It is assumed that the amount of 0.8 gram of protein per 1 kg of body weight is already sufficient for the body to function efficiently. With regard to dietary intake, the protein should provide 10 to 30% of the total energy from the diet. This participation should be greater in the diet of physically active people and those who are on a reduction diet or “on mass” diet – increased amount of protein helps to rebuild heavier working muscles. When calculating your protein requirement, especially if you are on a mass diet, it should be noted that the amount of 2 g per 1 kg of body weight is the maximum,which our body is able to metabolize without overloading the kidneys and liver. For the same reasons, the amount of protein in one meal should not exceed 30 g. This is eg 140 g chicken breast, 180 g pork ham, 120 g tuna, 160 g trout or 5 eggs. It’s easy to see that these are not large quantities.
Protein supplement – supplementing the source of protein in the diet
An additional source of protein in the diet may be a protein supplement.
They can be divided into three types
whey protein, with high nutritional content and very quick absorbability, used immediately after training. These include whey protein concentrate, whey protein isolate and whey protein hydrolyzate
egg protein (albumin) and casein protein, with medium nutritional value and free absorbency, used before bedtime
mixed proteins, i.e. compositions of whey, egg and casein proteins, with high nutritional value and medium absorption rate. The most popular and universal protein supplements that can be used both directly after training and during the day between meals or at bedtime.
Protein supplements should, however, be used in the diet of a physically active person, only as a supplement to the diet and can not be the only source of protein in the diet.