Proteins

What is protein?

Protein is one of the three macronutrients that make up our diet. In the body, protein - or more precisely the amino acids that make up each protein - serves as a building block for different types of tissue in the body, including the internal organs and muscle tissue, as well as for countless enzymes and other components of the human body. Without a sufficient protein intake, it is not possible to build muscle mass and an insufficient protein intake can even lead to a breakdown of existing muscle substance.

Proteins (Greek protos = the first, the most important) are among the most important basic building blocks of all animal and plant cells. Without them, life would not be possible, as only protein can build cells and repair tissue. As enzymes and hormones, they regulate the entire metabolism, and as contractile elements (muscle fibers) they enable movement processes. The antibodies of the immune system and certain transport proteins in the blood also consist of proteins. Under normal conditions, proteins do not play a significant role in energy metabolism, but they are all the more important in building metabolism. Proteins are the main building material of muscles. The actin and myosin filaments (myofibrils) of the muscles consist of protein complexes.

Muscles consist of 20 % protein and over 70 % water. After all, around 20 % of body weight is protein. Of the more than 200 known amino acids, however, humans can only form all the proteins they need from 22 amino acids. A distinction is made between essential and non-essential amino acids. The essential amino acids cannot be produced by the body itself and must therefore be taken in daily with food. Semi-essential amino acids, on the other hand, cannot be produced in sufficient quantities by the body under certain metabolic conditions. The remaining non-essential amino acids can be synthesized by the body from the other (essential) amino acids.

Similar to carbohydrates, proteins are also divided into oligopeptides (2-9 AS = amino acids), polypeptides (10-100 AS) and proteins (more than 100 AS), depending on the number of amino acids. Due to the unimaginably large number of 10130 linkage possibilities, the various proteins can be constructed. In addition to the amino acid sequence (primary structure), the specificity of the proteins is determined by the different spatial structure of the peptide chain (secondary and tertiary structure: folded sheet structure and a -helix structure). The quaternary structure describes the assembly and arrangement of several spatially ordered peptide chains to form a biologically active unit. The spatial arrangement and the amino acid sequence are decisive for the biological functions of proteins.

How much protein do you need and when do you need more protein?

A daily protein intake of around 0.8-1g/kg body weight is recommended, which corresponds to a protein proportion of the daily nutrient quantity of around 12-15%. Pregnant women and breastfeeding mothers need more protein, and top athletes even consume protein amounts of up to 2.5g/kg body weight. Children and adolescents also have an increased protein requirement (1-1.2g/kg body weight), although the requirement decreases steadily from infancy onwards. From the age of 25, the human body increasingly loses tissue substance and therefore also protein, so that the protein stock is reduced by around 20% by the age of 60.

The daily protein requirement depends primarily on the level and type of physical activity. The basic requirement established by various health organizations for:

• Physically inactive people is 0.8 grams of protein per kilogram of body weight.
• Physically hard-working people and athletes have a significantly higher protein requirement, with strength athletes needing the most protein at 1.5 to 2.5 grams of protein per kilogram of body weight, as additional protein is needed for regeneration and building muscle mass.

During a diet with a severely restricted calorie intake, an even higher daily protein intake may be necessary to prevent diet-induced muscle loss.

The importance of protein for athletes

Proteinlevels are subject to constant build-up, breakdown and conversion. Under normal circumstances, there is a dynamic balance between the build-up (anabolism) and breakdown (catabolism) of protein structures in the organism. "Due to the constant build-up and breakdown of proteins, there is an amino acid reserve of 600-700 g in the intermediate metabolism, which is known as the amino acid pool. This is the organism's only, albeit quite dynamic, protein reserve that is constantly available."

Since, unlike carbohydrates and fats, the body has no direct energy store of proteins, it must constantly absorb them with food so that no muscle proteins are broken down during catabolic processes. During physical exertion in sport, especially in weight training, proteins are initially broken down in the body.

It is therefore particularly important for athletes that sufficient amino acids are always made available to the body through protein in the diet. It should be borne in mind that proteins are not stored in the body for long and that the body can only utilize up to 40 g of protein at a time. "The correct interval between protein-containing food (concentrate or low-fat meal) and training should be around 1 to 1 ½ hours."

The recommended daily intake of protein for an adult is around 1 g per kg of body weight. Athletes' protein requirements are generally set higher and can vary depending on the sport. Recent studies have shown that protein can account for 5-15% of energy consumption during prolonged exercise. Another reason for the increased protein requirement in sport is that there should be a sufficient supply of free amino acids in the amino acid pool so that the amino acids from the skeletal muscles do not have to be used to generate energy.

The branched-chain essential amino acids play a special role in the context of performance enhancement, which is discussed in detail in the topic "Performance enhancement through amino acids". An athlete's requirement is also increased because - particularly during high-intensity endurance exercise - there is wear and tear on muscle fibers, structural changes to the cell membranes and mitochondria and inactivation of enzymes and hormones.

Reasons for an athlete's increased protein requirement:

• Additional requirement for new muscle formation (build-up training)
• Increased maintenance requirement for greater muscle mass (wear and tear rate)
• Increased wear and tear on functional proteins and other nitrogen compounds
• Possible stimulation effect on protein synthesis
• The pool of free amino acids in the tissue is an additional energy store and protection against the breakdown of body protein

What are the benefits of protein in powder form?

It can be particularly difficult for people with a high protein requirement to cover their daily protein needs with whole foods. This is all the more true the less time there is to cook and prepare food. This is where protein shakes can be a practical and convenient alternative that can be quickly prepared and quickly consumed. Furthermore, by choosing your protein powder, you can select the protein sources that are best suited to your current situation. As the shaker fits easily into any sports bag, whey protein powder, for example, is ideal for supplying the body with protein immediately after training.

The advantages that protein concentrates offer the athlete are obvious: athletes can easily increase the protein content in their diet without adding fat, cholesterol or purines, which would be difficult to do with conventional protein sources such as meat, fish, eggs and dairy products. In addition, a ready-made protein drink can be taken anywhere, so that athletes can easily maintain their protein-rich diet even when away from home. It is also cheaper to cover your protein requirements with protein supplements. Another advantage that a continuous protein intake offers the athlete is a constant blood sugar level, which prevents hunger pangs, which is particularly helpful when dieting. It is advisable to distribute the protein intake sensibly throughout the day. Protein should be consumed especially before going to bed and early in the morning to counteract the nocturnal, catabolic phase.

What different types of protein supplements are available and which protein is best suited to which situation?

In our store you can find a variety of different types of protein powder supplements with different compositions for different applications. The most commonly used protein supplements are so-called fast-digesting protein sources, which include, among others

• Whey protein,
• Whey protein isolate,
• Whey protein hydrolyzate,
• egg protein and
• soy protein.

These types of protein are digested very quickly by the body and quickly provide the muscles with large amounts of amino acids required for regeneration and muscle building. Fast-digesting protein supplements are particularly suitable for use before and after training, but are also an ideal source of protein for any other time of day.

In addition, there are slower digesting protein supplements, such as

• Casein Protein,
• beef protein,
• pea protein or
• a mixture of different protein sources (so-called multi-component protein powders).

These protein products supply the body with amino acids over a longer period of time. These protein powders are best suited as a snack between meals and before going to bed.

Protein supplements that contain proteins from plant sources are becoming increasingly popular, such as

• Rice Protein,
• hemp protein,
• pea protein and
• soy protein.

These products are particularly suitable for vegetarians and vegans, although more and more non-vegetarians are also turning to these products as they are free from lactose and some other ingredients that can cause intolerances.

Summarized biological functions of proteins

• Building blocks of the musculature and serve to build up vision, ligaments, nerve and connective tissue
• Regeneration and recovery in the event of tissue injuries and micro-injuries to the muscles after training
• as antibodies: antibodies ward off invading pathogens
• as enzymes: involved in metabolism
• as hormones: messenger substances that cause a certain reaction at a specific site of action
• Transport functions: in particular the blood proteins.

The chromoprotein haemoglobin is responsible for gas transport (O2 transport). Furthermore, foreign substances (active ingredients from medication) are also attached to proteins and transported in this way.

• Protective and supporting functions: form sheaths around cells (protective colloids), the fiber protein collagen gives bones and tissue tensile strength
• are part of the biological membranes
• Energy supplier for energy metabolism, can form new carbohydrates; have an increasing effect on energy metabolism
• Transmits genetic information: the genetic information carrier DNA (deoxyribonucleic acid) is a protein nucleotide

Function in the body

Proteins are found in the human organism as a component of

• Hormones (peptide or proteohormones)
• enzymes
• Membrane proteins of the cell wall (e.g. receptors or transport proteins)
• Support and scaffold proteins (e.g. collagen, keratin or elastin)
• Contractile proteins (e.g. actin and myosin filaments as contractile elements of the muscle)
• Transport proteins (e.g. haemoglobin, myoglobin and certain plasma proteins)
• blood coagulation factors
• antibodies
• Only reserve function in energy supply

Proteins are not as energy-rich as fats. Their energy density is 17.2 kJ/g (= 4.1 kcal/g). The proteins ingested with food are broken down into their building blocks in the intestine, the amino acids are absorbed and then used as material for building the body's own proteins. The body only uses protein as an energy source when it has used up its carbohydrate and fat stores. This happens during longer periods of starvation. In a complicated chemical process, glucose can be produced in the liver from some amino acids as a source of energy. Other amino acids, similar to fatty acids, can be broken down into so-called ketone bodies, which are metabolized by the organs as an alternative to glucose in times of deficiency.

Protein deficiency

Protein has a large number of functions in our body. A deficiency would have serious consequences:

• Hair loss (97-100% of hair consists of proteins - keratin)
• Lack of drive
• In the worst case, protein deficiency disease kwashiorkor occurs. People (mostly children) who suffer from kwashiorkor can be recognized by their fat bellies. The body tries to cover the protein deficiency with water, so that the water is deposited in the body after a while (edema).

Other symptoms are

• Muscle weakness
• growth disorders
• fatty liver
• oedema

Biological value (BW)

The biological value of dietary proteins indicates how many grams of body protein can be built up by 100 g of the dietary protein in question. It also indicates how valuable the protein of a particular food or protein concentrate is for building muscle and other endogenous proteins (e.g. enzymes, hormones). The whole egg protein serves as a reference value, as it has been given a biological value of 100. All other proteins are compared to it. The higher the biological value of a dietary protein, the less of it the human body needs to maintain its protein balance. In principle, animal protein can be considered to be of higher quality than vegetable protein. However, a suitable mixture of animal and vegetable protein sources can achieve much higher biological values than animal protein alone, as the proteins in different foods can complement and enhance each other in their amino acid spectrum. The suitability of a dietary protein for the biosynthesis of body protein depends above all on the content of essential amino acids and the availability of amino acids. When selecting foods, however, you should not only pay attention to their biological value, but also bear in mind that a large amount of undesirable accompanying substances, namely purines, cholesterol and fats, are ingested with animal protein. Purines in meat produce uric acid as a metabolic end product, which can be deposited in the kidneys, joints and tendons, leading to kidney stones, gout and increased susceptibility to injury. In contrast, eggs, milk and dairy products are purine-free. In view of these facts, you should limit your intake of animal proteins and also include plant-based foods in your diet. The following table shows how the combination of animal and vegetable protein sources can even enhance the biological value of protein.

Buying protein: Separating the wheat from the chaff

There are sometimes big differences in the quality of protein powders. As with "normal" foods, care should be taken to ensure that the list of ingredients is relatively short. Artificial colorings or preservatives are often included. High-quality products do not contain these.

Of course, the origin of the raw materials is decisive for the quality of the product. If the raw materials come from Germany, for example, this speaks for high-quality raw materials due to strict guidelines and hygiene regulations in German production facilities. If a supplement manufacturer does not shy away from the cost of these high-quality raw materials, it will usually advertise this fact.

Finally, the protein content in the protein powder itself is also a sign of quality. A protein content of at least 75g per 100g of protein powder is considered a high-quality product. For example, the 100% Dairy Whey Protein from GN Laboratories has a protein content of 80g per 100g.

Which protein to buy?

There are many different types of protein powder, so it's easy for a layperson to lose track. The different protein sources have individual properties and can therefore be used and combined in a variety of ways. The amino acid profile of a product should be examined closely, as each protein source has a different one. A balanced amino acid profile is generally recommended. A deficiency can be ruled out by combining different protein sources. Apart from the amino acid profile, different protein sources also have different digestive properties.

*Avoid sodium caseinate

References

1. LemonPW (1996) Is increased dietary protein necessary or beneficial for individuals with a physically active lifestyle? Nutr Rev 54(4 Pt 2): 169-75
2. Arndt K. (HG.) (2001) Handbuch Nahrungsergänzungen-Bedeutung und Anwendung leistungssteigernder Substanzen für Bodybuilding und Kraftsport. Pages: 210-212
3. GEISS/HAMM, Handbook of sports nutrition (1992)
4. KONOPKA, Sports nutrition (1996)
5. BREITENSTEIN/HAMM, Bodybuilding, natural, healthy, successful