Human life without protein (or protein) is simply impossible. This complex compound of an organic nature is the building material for cells and tissues, as well as the synthesis of hormones, enzymes and the formation of muscle fibers. A person can get protein from food of plant origin or animal. Only in this way and nothing else.
Once in the digestive tract from foods containing protein, proteins are exposed to enzymes. As a result, they change not only physically, but also chemically; then they decompose into simpler compounds; then they are absorbed into the intestines. That is, the body assimilates them. And it happens quite easily and quickly.
Therefore, protein-containing food must be included in the daily diet of any person. The same can be said about products containing protein, fat and carbohydrates. This is especially true for people who, by the nature of their professional activity, are associated with heavy loads; as well as children and adolescents whose organisms intensively develop and grow.
What are proteins
Proteins are an essential component of living cells. Proteins are made up of different types of monomers (i.e., constituents) called amino acids. They, in turn, combined with each other by peptide bonds, form chains that are interconnected by transverse bonds. With food, a person receives about 20 different types of amino acids.
Note: if you change one amino acid to another in a protein molecule, you’ll get a completely different protein. That is, it turns out that it is precisely a certain sequence of certain amino acids that determines the function and structure of the protein molecule.
Most of the proteins are in the muscles, about 20% are concentrated in the bones and tendons, and a very small fraction is present in the cells. But it is these proteins that control brain activity, the activity of the endocrine glands, oxidative reactions and muscle activity.
The composition of the protein molecule includes such chemical elements as carbon, oxygen, hydrogen, nitrogen, iron and sulfur. Some protein molecules have phosphorus.
Duration of existence
The lifespan of different proteins of the same individual is completely different. For example, the duration of plasma proteins is about 10 days; intestines - 4-6 days; and muscle protein - about 6 months. What can we say about some peptide hormones that generally exist in just a few minutes.
Note: when the body's own proteins break down into free amino acids, the human body can again synthesize other proteins from the latter. Here is a cycle of proteins in the body. Naturally, about 35% of free amino acids do not participate in such a process as the synthesis of new proteins. This unused portion will be used for completely different purposes (for example, for the formation of urea or glucose). Therefore, in order for the amino acid balance to be fully restored, it is necessary to take the next portion of food containing protein.
A bit of history
The first scientific article on protein, authored by the Italian scientist Beccari, was published back in 1747. In subsequent years, protein substances were isolated in an absolutely independent class of biological molecules. This huge work was carried out by the French chemists Macke, Fourcroix and others.
In 1836, the Dutch chemist Mulder first introduced a model of the structure of proteins. Two years later, the Swedish chemist Berzelius proposed calling protein compounds proteins (from the Greek language translates as "primary, primary," that is, "ranking first"). Mulder liked the idea, and he voiced it to the general public. However, subsequently studies have shown that such radicals do not exist. But the term, used as a synonym for proteins, has already successfully taken root and has even reached our days.
Only in 1926 was the theory officially voiced by the American chemist Sumner (subsequently awarded the Nobel Prize) about the dominant role of proteins in the human body.
Role in the body
The functions of the protein in the life of the human body are very significant:
- Transport. Protein is actively involved in transporting with the help of blood, primarily oxygen, as well as certain minerals, lipids, carbohydrates, hormones, vitamins and other substances. This fact can serve as a strong argument in favor of products containing protein.
- Protective. Albumins are proteins that act as “overseers” for substances of a foreign nature. If albumin accompanies the “foreigner”, the immune system diagnoses it as “their own” and passes it freely into the cell of the body. If a foreign substance tries to “break through” into the cell without being accompanied by an “overseer”, then protective reactions of the immune system are activated. Another argument in favor of products containing proteins.
- Structural (i.e. construction, plastic). Without protein, cell and tissue renewal processes would simply not be possible. Now you understand why you can not do without the use of foods containing protein.
- Energy. Of course, fats and carbohydrates are the main sources of energy. But with their shortage or with an excess of amino acids, proteins do an excellent job with the energy function (when they are broken down, the energy necessary for normal life processes is released). This fact leaves no doubt about the benefits of products containing proteins.
- Enzymatic (or catalytic). Protein enzymes (proteases, amylases and lipases) are catalysts of all biochemical processes that occur in the body.
- Regulatory. Reception of a sufficient amount of products containing protein, improves the function of the cerebral cortex and the central nervous system; accelerates the production of reflexes; regulates metabolism (for example, growth hormone or insulin - these are all proteins) and other physiological processes.
- Hormonal It is amino acids that form the basis of almost all enzymes and a huge amount of hormones.
- Contractile. Thanks to proteins such as actin and myosin, human skeletal muscles can contract.
Lack of protein in the body
As a result of life, protein is constantly consumed. Their stocks must be constantly replenished using products containing protein (a list of them is presented below). If this is not done, then the following unpleasant things can happen:
- Anemia (i.e., anemia).
- Significant decrease in immunity.
- Stunted growth and development.
- Decrease in calcium and phosphorus in bones.
- Lack of digestive enzymes.
- Dystrophy. Inadequate intake of foods containing proteins (everyone should know their list) can lead to a decrease in muscle mass.
- Decreased emotional tone.
- Diarrhea that is in no way associated with an intestinal infection.
- Decreased barrier function of the liver.
Excess protein in the body
Unlike carbohydrates and fats, protein is not able to accumulate in the body. Therefore, do not lean on foods rich in protein in order to create its reserves in the body. This is not a good idea. Moreover, the excessive absorption of products containing protein (the list of which is very extensive) can lead to the following unpleasant phenomena:
- Osteoporosis. The fact is that the body will have to start the process of processing undigested protein. For these purposes, calcium is needed. If it is not enough, the body will begin to "pull" it out of the bones. This state of affairs is possible if a person drinks little water and eats foods containing a large amount of protein.
- The formation of body fat.
- The development of urolithiasis and gout.
- Extra strain on the kidneys. Avoid eating large amounts of protein-containing foods.
- The risk of developing cardiovascular disease. This is possible if the source of protein is dairy products or especially fatty meat.
Vegetable Protein Food
What foods contain vegetable proteins? First of all, these are cereals (rice, barley or oats), as well as legumes (peas, soy or lentils), seeds, nuts, fruits and vegetables.
All plants receive chemical elements from the soil, which are then synthesized into amino acids, producing starch, carbohydrates and sugar. It all happens solely under the influence of the sun.
Knowing what foods contain vegetable proteins, you can make your diet in such a way that it contains a relatively complete set of essential proteins.
Important! Plant protein is extremely important, but do not completely abandon the use of animal protein. Be prudent.
Animal Protein Food
What foods contain animal protein? Most of it in rabbit meat, beef and chicken. A lot of protein is found in offal (for example, in the tongue, kidneys or liver). In addition to protein, they contain many minerals (for example, iron), as well as vitamins A, group B and C.
Which protein is better and faster absorbed by the body? Do not believe it, but this is the protein of a chicken egg. But remember: this product is high in calories.
Protein in fish
Regarding fish, the following can be stated: the protein of this product is absorbed almost completely (that is, this indicator is about 94-98%). Tuna has the most protein. Therefore, the fish must be present on your table.
Complete and Defective Proteins
From a scientific point of view, all proteins are divided into two types:
- Full-fledged. That is what animal proteins are called.
- Inferior. This name is accepted for vegetable proteins due to the fact that in such foods as fruits, vegetables, grains, seeds and nuts, some of the essential amino acids are missing. But not all scientists agree with such statements. Yes, and recent studies confirm that the proteins that are contained in plant products are absorbed faster, easier and they are as complete as animals.
Grocery list
Standard tables of products containing proteins are usually compiled according to their names and types. This is not very convenient for the user (especially when compiling a diet for various diets). We offer lists of products, divided into groups depending on a certain amount of protein. This is more convenient and logical.
Protein-containing foods:
- The list of products in which the protein content per 100 g of the product ranges from 0.4 to 4 g (inclusive): grapes, margarine (creamy), a variety of apples, cranberries (forest), watermelon, cherry, blackcurrant, apricots, oranges , cucumbers, tomatoes, eggplant (or blue), radishes, carrots, sweet peppers (Bulgarian), onions (green and onions), turnips, beets, cabbage (white and kohlrabi), potatoes, dill, parsley, raisins, bananas, oil (creamy), kefir, sour cream, cream, mayonnaise, milk (cow), ice cream and white mushrooms (fresh).
- Protein content in the range from 4 to 9 g (inclusive): cod liver fish, green peas, garlic, chocolate, a variety of pastries with cream filling, bread (black and wheat), rice, condensed milk (with sugar) and cream cheese .
- The amount of protein is in the range of 10 to 13 g (inclusive): flour, cereals (barley, corn, buckwheat and oat), millet, pasta, chicken eggs, yeast, sausage (Doctor's) and cocoa powder.
- The protein content ranges from 14 to 16 g (inclusive): coffee (in grains), pork, lung and heart (beef), cod, carp, canned sardines in oil and lamb.
- Products containing a large amount of protein per 100 g of product (between 16-24 g): nuts (hazelnuts), cooked sausage, liver and kidneys (beef), squid, horse mackerel, tuna, chicken, beef, rabbit meat and peas.
Protein intake
An adult is recommended to eat about 90-120 g of protein (to be more precise, 1.5-2.5 g per kilogram of weight) during the day.
On a note! For women - no more than 1.5 g per kilogram of weight, for men - about 2 g, and for older people - no more than 1 g.
For adolescents and children, the norm should be increased by approximately 2-3 times. Moreover, the ratio between vegetable and animal protein should be in a ratio of 1: 2.
Important! Do not be too zealous for products containing large amounts of protein so as not to overload the kidneys. Remember: only a balanced diet has a beneficial effect on the body.
But there is no consensus on this issue. Some scientists, after conducting research, concluded that the daily dose of protein may be limited to 25 g. Others insist on 60 g. And the famous academician N. M. Amosov has his own version: to saturate the body with the necessary amino acids, it is enough to use a small portion of meat every day (about 50 g) and a glass of milk.
What is the best combination of protein-containing foods
Which combinations are undesirable:
- Proteins plus proteins. This combination is not welcomed due to the fact that the digestion of various proteins requires the release of gastric juice of different acidity. Therefore, as a result of the use of such products, one of the components will be digested much longer than usual and very poor quality. On this basis, do not combine milk with nuts, meat - with eggs or cheese.
- Proteins plus carbohydrates. A completely incompatible combination. The digestion time of each component is different. Used together, they interfere with each other's normal absorption: for the digestion of proteins, an acidic environment is needed, and for carbohydrates - an alkaline one. As a result of the intake of such products (for example, meat and bread) in the stomach, the fermentation process begins.
- Proteins plus fats. Any fatty food inhibits the secretion of gastric juice. It is a fact. That is, in this case, it turns out that the absorption of proteins is shifted by more than 2-3 hours. It is not good. But there is a way out: the abundance of greens consumed with proteins and fats will significantly reduce the ability of the latter to inhibit secretion.
- Protein plus sugar. Bad again, since sugar (as in the case of fats) inhibits the production of gastric juice. Consequently, the process of protein digestion is also slowed down. Therefore, it will be in the stomach for a long time, causing the process of decay.
- Proteins plus acid. An unsuccessful combination due to the fact that pepsin and hydrochloric acid are needed to absorb protein. But acidic foods contribute to less pepsin, thereby delaying the absorption of protein foods.
A legitimate question arises: why then use protein-containing foods? Vegetables such as onions, zucchini, cabbage, celery, spinach and many others that do not contain starch are best combined with proteins.
Important! With proteins, you should not eat vegetables such as potatoes, beets, turnips, carrots and pumpkins. Beans and peas are also better to eat with others, and not with protein-containing foods. And a few more recommendations: milk is better to use as an independent dish; good absorption of proteins contribute to products that have not undergone heat treatment; do not use several varieties of protein-containing foods at the same time.
Finally
From the foregoing, it becomes clear that you need to regularly eat more protein-containing foods. This must be done so that pathological changes do not occur in the body. Want to be healthy - listen to our recommendations. Tables of protein-containing foods will help you make the right, healthy diet.