Which food protein should you have every day?

The role of proteins in nutrition: how much protein is healthy?

Proteins as the basic building blocks of life

The scientific name protein means something like “the first” or “the most important”. Proteins perform a variety of functions in the human body. They are building blocks of tissue (e.g. tendons, skin, muscles). In addition, proteins form almost all enzymes, as well as some hormones. The antibodies of the immune system also consist to a large extent of proteins. In addition, proteins also serve as transport proteins for fats (lipoproteins) or for oxygen (hemoglobin).

Amino acids - building blocks of proteins

Proteins and peptides are made up of amino acids. Most proteins are made up of a limited number of up to 20 different amino acids. Some amino acids have to be taken in with food (essential amino acids), while the body can synthesize some itself (non-essential amino acids).

Essential amino acids

The body cannot completely synthesize the eight essential, i.e. indispensable, amino acids. These must be supplied to the body through food. The essential amino acids in humans include:

  • Isoleucine
  • Leucine
  • Lysine
  • Methionine
  • Phenylalanine
  • Threonine
  • Tryptophan
  • Valine

Non-essential amino acids

The body can synthesize the non-essential, i.e. dispensable, amino acids itself in sufficient quantities to cover its needs. The non-essential amino acids include:

  • Alanine
  • Asparagine
  • Aspartic acid
  • Glutamic acid
  • Glycine
  • Proline

Semi-essential amino acids

A third form of amino acids are the partially dispensable or semi-essential amino acids. Under certain conditions, the body cannot synthesize these itself, or not to a sufficient extent (e.g. during growth phases or in the event of metabolic stress). The semi-essential amino acids include:

  • Arginine (newborns, serious illnesses)
  • Cysteine ​​(newborns, liver disease)
  • Glutamine
  • Histidine (newborns, chronic kidney disease)
  • Tyrosine (newborns, phenylketonuria)
  • Serine (if kidney function is impaired)

Which foods provide proteins?

There are vegetable and animal protein. Animal protein is usually the higher-quality protein source; the body can use them to produce its own protein more efficiently.

Typical animal protein sources

  • flesh
  • fish
  • Eie
  • Dairy products

Typical vegetable protein sources

  • legumes
  • soy
  • lenses
  • Beans
  • Lupins
  • Grain
  • nuts
  • Seeds

Assess the quality of protein

Foods differ in their amino acid composition. Since the amino acid profile of food proteins is never identical to the amino acid profile of body proteins, it is said that these are of "lower quality". The amount of amino acids contained in dietary protein is not limiting for protein synthesis. The limiting factor is the concentration of the amino acid that has the greatest deficit in relation to the requirement. This is called limiting amino acid designated.

If a limiting amino acid is used up, the body cannot produce any more endogenous proteins. Similar to a puzzle, it then lacks the right building block. Basically, we don't have a protein requirement, but an amino acid requirement.

Several methods such as the biological value, the amino acid score or the PDCAA score have been developed to evaluate proteins. The "biological value" is the most common and practicable method today.

Proteins and amino acids are not just building materials

In the energy metabolism, carbohydrates and fats are preferred. Amino acids are only oxidized to an increased extent in the event of long-term stress, in starvation metabolism or when there is a large supply of protein from food. The body uses proteins from the muscle tissue as energy reserves during hunger metabolism (in catabolic phases). He does not use excess protein to build muscle, but as a source of energy.

Therefore, a balanced energy balance should always be achieved. Because building "mass" while the body is starving is virtually impossible.

"Nutrient Timing"

After the workout, the body is in one for about 3 hours "Anabolic time window". In this phase it is particularly good at building up and regenerating new structures. Carbohydrates and proteins should be consumed during this phase. Muscle protein synthesis should be maximally stimulated through the availability of amino acids and the simultaneously stimulated release of insulin through the carbohydrates.

We recommend 45-75 g of carbohydrates and around 15-25 g of protein. A side effect is that the glycogen stores are then also replenished more quickly.

How much protein do we need?

The DGE recommends a daily protein intake with the usual mixed diet for adults with light physical work 0.8 grams of protein per kilogram of body weight.

However, this recommendation is increasingly being criticized. It must be taken into account that the actual protein intake in Germany is already significantly higher on average (approx. 1.2 - 1.4 g / kg body weight). Healthy people can usually tolerate a high-protein, low-carbohydrate diet without any problems. A low-protein diet, on the other hand, often results in a high-carbohydrate diet. A diet with a high concentration of carbohydrates is believed to be partly responsible for the obesity epidemic (mainly due to refined carbohydrates such as sugar).

The protein requirement of the organism ultimately depends on various factors such as higher energy requirements or structural loads (athletes or non-athletes), special circumstances (e.g. illness, injury or pregnancy) or growth phases (children, adolescents, strength athletes). In the best case scenario, the increased protein requirement can be covered by a balanced diet. Otherwise it is possible to cover the increased protein requirement with protein supplements.

Protein requirements of athletes

According to the literature, there are sometimes very different intake recommendations for athletes. For endurance athletes, the recommendations for protein amount to about 1.2 - 1.4 g / kg body weight and with strength athletes 1.6-1.7 g / kg body weight. Some sources recommend even higher values.

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