Protein intake in sport is frequently controversial.Again and again is a sensible intake to the debate regarding muscle growth and performance improvement. But also for endurance athletes, it is a non-negligible issue.
Protein (from the Greek proteios- “senior”, which highlights importance of this nutrient) plays in the human body the vital role almost all life functions and serves as the useful source of nitrogen element (N).
The body consists of about 16% of protein. All body tissues such as muscle, connective tissue, nerve cells or organs contain certain proportions protein. Here proteins perform a variety of functions such as contraction of the muscle fibers, transportation of substances between the cells and the blood stream, as enzymes in the acceleration of substance transformations (digestion and absorption of nutrients), or as components of the immune system (antibodies).
Important for understanding of structure and function of proteins is to know their smallest building blocks, the amino acids. The basic structure of each protein is a chain of amino acids, which may be between 100 and several thousand units long. If they are less than 100 amino acids, it is called peptides. During digestion, large proteins are cleaved from the food in these smaller units, whereby they taken up in the blood and can thus get access to the various body tissues.
Amino acids are stored in the blood, in the liver and in the muscles (70-80%) and can be further processed by the body. Here there is a brisk turnover of protein, which is always in equilibrium. Approximately 75 g muscle protein are up every day and dismantled.
20 different so-called proteinogenic (protein forming) amino acids are known to form all structures of the body in different rows chains. 8 (two more are under discussion) of them are considered to be indispensable (formerly essential), ie. they must be taken with food. The other can be produced by the body itself, which is based the concept of biological value of dietary protein. The higher the content of essential amino acids, the higher is the valence of a protein to the human body. This fact leads to often ulitization of products wich associated with high levels of essential amino acids or combinations of certain acids in powders or liquid form to the market by sports nutrition industry. Consumption of these supplements should be viewed critically, the scientific evidence for the actual effectiveness is still unclear at the moment.
How much protein the body needs?
On average in a day loses 24 g protein. This can be ascertained by the nitrogen excretion in the urine. This loss must be compensated for in order to perform the life functions of the body. The American Society for Nutrition recommends 0.8 grams of protein per kilogram of body weight, where individual differences and the digestibility of proteins are involved. While 15% of daily energy intake are recommended as a rule. With an average intake of 2500 kCalories per day therefore would come approximately to 90 grams of protein. This value is usually easily achieved through a balanced diet.
It should be noted that the value applies for normal healthy adults. Various professional societies (for strength) athletes recommend higher intake of up to 1.7 g per kg body weight. A recording of up to 2 g / kg body weight, which is frequently observed in sport, this is considered safe. However, large amounts of water is should be drunk in order to effectively excrete the end product of protein metabolism, the urea and the urine.
Specially for endurance athletes, there is a recommendation from 1,2-1,4 g per kg on body weight. An increased proportion of dietary protein accelerates this regeneration after stress and has a positive effect on the immune system. a 70 kg adult operates 3 times per week with running training so should therefore take 70 kg = 84 grams of protein a day to be at least 1.2 g *, which are having three meals and 1-2 snacks a day and can well achieved good results with reasonable food choice. For our boot camp participants we recommend a protein intake of 1.5 g per kg of body weight. This high protein content, a sufficient supply of the muscles is ensured the body fat reduction and optimally supported.
Suitable food to meet the protein requirements are dairy products, meat, fish, eggs, and legumes. Nuts, especially walnuts, are also rich in quality protein, but also very high in calories.
Vegans rely on soy and other vegetable proteins, however, should in intensive sport, due to the lower biological value of these pull dietary supplement into consideration when compared to animal protein. One can increase the protein quality of a food by clever selection for example an herbal combination with an animal protein. Examples are potatoes with egg, pasta with fish or cereals and pulses.