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The nutrients - Proteins

Published: 23.07.2017

Let’s try to answer the following question: What do we eat? Of course one can study this topic (as well as any other one) forever. You can research chemical formulas, or go even further – study atomic and subatomic levels and find a great pleasure in such intellectual exercises. But then you do not need to do it all. You can just learn the nutrition rules and follow them rigorously. Many people think that this is enough for improving their health. However, it is not completely true. 

Continuing our metaphor with a car driver, we can say that apart from knowing about different parts of the car and their functions, it is also useful to know many other things: what is the difference between different types of gasoline and oil, which metal is used for which details, what is sulphuric acid… And one can only become a true expert after learning all kinds of different things, some of which seem unnecessary at the first glance. So, let’s examine, at least with a superficial approach, which substances does our food contain and which role do they play in our body. 


It is hard to find a person who has never heard anything about proteins. They are mentioned in all the works dedicated to nutrition, and all dietitians, from nutritionists to naturopaths, talk about proteins in all their speeches. From a chemist’s point of view, proteins are one of the most complex components of food. Their significance is incredibly high, and it was not in vain that Engels defined biological life as “the mode of existence of protein bodies”. Proteins amount to 20% of the total mass of human body cells. 

One of the main functions of proteins is to build new tissues. All cell’s organelles, membranes and extracellular structures are based on proteins. Without proteins there would be no organic life on Earth (at least in the form that we are used to). Specific types of proteins that can act as catalysts are called enzymes. Almost all natural chemical transformations occur with the help of enzymes. Catalyst qualities of proteins are quite specific – almost every (!) reaction needs a special type of enzymes. Without enzymes, the reactions just would not happen, as they make these processes tens and hundreds of million times faster.

 One more function of proteins is transportation of necessary substances and chemical elements. Hemoglobin, for example, transports oxygen, delivering it to the most distant parts of our bodies, and it also transports carbon dioxide. We are capable of moving also because of proteins. All the movements that living organisms are capable of, from plants turning their leaves to animals moving, all of them, without exceptions, are possible because of special contractile proteins. Proteins also fulfill a protective function. When foreign proteins or cells get inside our body, special proteins called antibodies are produced; they neutralize and disinfect foreign substances. 

Finally proteins can also be used as a source of energy. But this type of “fuel” is the least profitable one, as much more energy can be obtained from fat and carbohydrates, for example. All proteins are composed of simpler parts – amino acids. Amino acids are compounds based on carbon and hydrogen, containing oxygen and nitrogen to a smaller extent. About 80 natural amino acids are known, but only 22 of them are normally found in food. These building blocks, combined in different ways, constitute all the variety of protein molecules. According to scientists’ calculations, there are around 1010–1012 types of proteins in nature. 

Apart from natural ones there are also synthetic amino acids. Such artificial amino acids are used for nylon production, for example, which is used to make car tires and clothes (by the way yogis do not recommend using nylon clothes). In nature, amino acids are produced by living organisms. It is known that the human body can synthesize 12 amino acids on its own, so these acids are called nonessential. Other 10 amino acids cannot be normally produced by a human organism that is why they are called essential amino acids. 

It is clear that essential amino acids should be incorporated as we eat. Depending on their presence, all proteins are subdivided into complete (containing amino acids) and incomplete (lacking amino acids). However, you do not really need to think about it a lot. With a more or less varied diet, we usually receive enough different amino acids and there is also the intestinal microflora producing lots of necessary substances. Moreover, in extreme conditions or after a corresponding training the organism itself starts synthesizing them. Because of these reasons some scientists doubt the “essentiality” of amino acids. 

Serious disorders caused by wrong metabolism of an amino acid usually happen only as a result of some diseases or medicine overdose and also because of malnutrition or forced monotonous diet. Almost all natural products contain proteins. In the process of digestion, proteins are broken down into amino acids that are used by the organism for synthesizing proteins on its own or they can be oxidized, i.e. burnt as a fuel. During oxidation, uric acid is produced among other substances which go into the blood and, ideally, should be removed by the kidneys. If the organism is weakened or there is too much uric acids (both problems are usually caused by overeating meat products), they stay in the tissues and can cause gout. 

People often talk about a “norm” of protein consumption. Indeed, during every stage of life an organism needs some amount of proteins. But this need also depends on age, genetics, temperament, workload, climate and many other reasons. That is why you should not be talking about any norms in this matter. 

In early childhood, when we need the most proteins (in the first year of life the weight of a child increases three times), a child receives all the necessary substances with its mother’s milk. One cannot deny that it is an ideal product to ensure such an intensive growth. Meanwhile, just 7.4% of calories contained in breast milk come from proteins. 

With age our protein needs decrease. Tissues grow slower and slower and by the time we are mature, the energetic function of food becomes more important than the structural one. Our organism is focused on the compensation of the energy spent. This tendency becomes clear in adults and even clearer in elderly people. Therefore, the percentage of proteins in general calorie content of our diet should decrease. 

So it turns out that the protein consumption with age increases instead of decreasing! Our organism cannot take more proteins than it needs, the rest becomes poison and those excesses should be burnt. That is how different toxins are formed in our bodies: uric acid, urea, ammonia, creatinine, creatine and others. When there is an excess of toxins, it becomes hard to remove them, they accumulate in your body, hindering all metabolic processes.

Of course the speed of toxin removal depends on various factors: proportion of acquired and spent energy, amount of vitamins, macro- and microelements, physical activity, general health of the organs etc. But anyway, protein is the least profitable fuel. According to A.A. Pokrovsky, its energetic value in the oxidation process is just 70.8% of total heat of the combustion. For fats and digestible carbohydrates it’s 96.3% and 100% respectively. This means that 1 gram of protein in normal combustion produces 5.65 kcal, and in case of oxidation – 4.0 kcal. Where does the rest go? The rest turns into toxins.

If we also keep in mind that an excess of proteins leads to unnecessary intensification of metabolic processes (and this contributes to untimely ageing of tissues), then the conclusion made by Bircher-Benner about protein decreasing the value of food does not seem that paradoxical anymore (according to the data received by K.S. Petrovsky, proteins increase general metabolism by 30-40%, fats by 4-14% and carbohydrates by 4-7%).

Of course some amount of diverse proteins is necessary even for adults. But even “normal” food contains much more proteins than we really need. Sometimes a person’s body might be needing some amino acid, but in this case he instinctively starts eating necessary food, so we do not need to worry about not consuming “enough” proteins and we should not nurture our bodies with them, because that only leads to harmful consequences.

Text: from the book of A Eddar "The treatise of nutrition".


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