Muscle building, recovery, performance: Amino acids are basically the engine of our metabolism and are particularly important for athletes. If you have trained hard, amino acids help you build muscle and recover faster. We will explain to you what functions amino acids have in the body and how you can best absorb them.

What are amino acids and what function do they have?

Amino acids are molecules that consist of the chemical elements carbon, hydrogen, oxygen and nitrogen. Amino acids are crucial for the smooth functioning of the human body because they control all metabolic processes in the body and are involved in many biological processes in the body. These include, among other things, muscle building and the repair of muscle tissue.

There are also amino acids that act as precursors of hormones and neurotransmitters that are responsible for the transmission of signals between nerve cells or regulate various physiological processes in the body.

Amino acids are the basic building blocks of proteins in our body. The individual amino acids are linked together to form a long chain and thus create the finished protein. Depending on the composition of the chain, different proteins are then created.

The body cannot produce all of the amino acids it needs itself. Some of them must be consumed through food. Amino acids are therefore divided into essential, semi-essential and non-essential .

If the body lacks these important basic building blocks, it can have an impact on many processes in the body. These include the immune system, performance, fat metabolism, muscle building and muscle regeneration.

The most important functions of amino acids at a glance (1):

1. Muscle Growth and Repair: Amino acids are the building blocks of proteins, which are essential for building and repairing muscle tissue. After exercise, muscle tissue is often damaged. Providing adequate amino acids helps support muscle repair and promote muscle growth.
   
2. Muscle protein synthesis: Amino acids stimulate muscle protein synthesis, which means they promote the formation of new muscle proteins in muscle fibers – a crucial step for muscle building and recovery after training.
   
3. Energy production: Amino acids can serve as fuel for energy production, especially during prolonged or intense exercise when glycogen stores are depleted. Under certain conditions, amino acids can be converted to glucose to meet muscle energy needs.
   
4. Reducing muscle breakdown: Consuming sufficient amino acids can help reduce muscle breakdown and maintain muscle mass.
   
5. Supports hormone synthesis: Some amino acids serve as precursors for the synthesis of hormones. Hormones are chemical messengers that regulate various physiological processes in the body, including metabolism, growth, and mood.
   
6. Production of neurotransmitters: Amino acids are precursors of neurotransmitters - chemical messengers involved in the transmission of signals between nerve cells in the brain and nervous system. Neurotransmitters play a key role in the regulation of mood, memory, sleep, pain sensation and other neurological processes.
   
7. Strengthen immune function: Amino acids are important for the functioning of the immune system. They are involved in the formation of antibodies and immune cells that protect the body from infections and diseases.
   
8. Transport and storage of nutrients: Some amino acids serve as transport molecules for vitamins, minerals and other nutrients in the body. Others can act as storage forms of nitrogen and other important elements.
   
9. Support of healing processes: If there are injuries to the bones or muscles, the body needs amino acids to heal and they also play an essential role in wound healing.

There are over 250 amino acids in total, but only 20 of them are important for the body . These amino acids are therefore also known as proteinogenic (i.e. protein-forming) amino acids. The majority of these amino acids are formed in the cell metabolism itself, others must be supplied through food. Our body therefore does not need complete proteins, but only amino acids from which it takes what it needs in order to be able to produce its own proteins.

The most important information about essential amino acids

Amino acids that the body cannot produce on its own are called essential amino acids (EAAs). They are vital for all bodily functions and must be ingested with food or supplements.

There are a total of eight essential amino acids that you need to remain physically fit and mentally fit. If you do not consume them regularly and in sufficient quantities, you may suffer from serious deficiencies because your body is unable to produce them itself. And your muscles will suffer as a result. We have stores of fats and carbohydrates in our bodies, but not of proteins. The body is therefore forced to break down proteins from our muscles unless we get the proteins that the body needs for daily functioning.

Ideally, you should therefore consume a combination of animal and plant protein sources. In addition, you can also use protein supplements with a high biological value.

Essential Amino Acids and Their Effects at a Glance
All of the essential amino acids mentioned are building blocks for protein synthesis. They contribute to the formation of proteins that are essential for the construction and repair of tissue, enzyme function, the immune response and many other biological processes in the body.

1. Isoleucine : Involved in the maintenance and regeneration of muscle tissue and an important source of energy in strength and endurance sports.
   Contained in: Chicken breast, salmon, egg, peas, walnuts, whole wheat flour
   
2. Leucine: Involved in the building and maintenance of muscle protein, provides energy to muscles and supports healing processes in the body.
   Contains: Chicken breast, peas, salmon, egg, whole wheat flour, walnuts
   
3. Methionine: Plays an essential role in the formation of glutathione. Glutathione protects cells from oxidative stress and damage caused by free radicals.
   Contained in: Brazil nuts, salmon, beef, sesame, egg, broccoli, peas, corn, spinach, millet
4. Tryptophan: Precursor for the synthesis of neurotransmitters in the brain, especially serotonin. Serotonin is known as the feel-good hormone and regulates mood, sleep, appetite and other cognitive functions in the body.
   Contains: Cashews, soybeans, cocoa powder (unsweetened), chicken breast, peas
5. Lysine: Supports the synthesis of collagen, which is important for the strength and elasticity of skin, bones, cartilage and connective tissue. Involved in fat metabolism.
   Contained in: chicken breast, salmon, pumpkin seeds, peas, egg, tofu, buckwheat flour, walnuts
6. Valine : Serves as fuel for the muscles during intense physical activity because it is converted into glucose in the liver. Sends important messengers to the nervous system and has a positive effect on its function.
   Contained in: Peas, Chicken, Whole Wheat Flour, Spirulina, Chlorella Cheese
7. Phenylalanine: Involved in the formation of numerous proteins. Precursor substance for the synthesis of important hormones such as adrenaline, noradrenaline and dopamine (known as the happiness hormone).
   Contained in: pumpkin seeds, peas, soybeans, poultry, walnuts, pork, salmon, egg
8. Threonine: Precursor for the synthesis of glycine, an amino acid that is involved in many important metabolic and tissue functions – and, among other things, ensures that connective tissue and muscles remain strong and elastic.
   Contains: Cashews, peas, soybeans, cocoa powder (unsweetened), chicken breast
   

Note: Some sources speak of nine essential amino acids. Histidine is sometimes classified as an essential amino acid, but often as a semi-essential amino acid. For infants, however, histidine is always considered essential (2).

Importance of semi-essential amino acids

The semi-essential (or conditionally essential) amino acids are in a kind of intermediate position. The body can normally produce them itself, but under special conditions (such as stress, illness, intense physical activity, pregnancy or growth phases) it is not always able to do so sufficiently, which is why they must then be ingested additionally with food.

The distinction between non-essential and semi-essential amino acids is sometimes unclear. However, the following amino acids are generally classified as semi-essential (3):

• Histidine: Histidine is considered an essential amino acid, at least for infants. Its classification for adults is controversial, as the body can store large reserves of it, so that deficiency symptoms only appear very late, even with a histidine-free diet. Our body produces the tissue hormone histamine from histidine - and this plays a central role in the defense of our immune system against foreign substances. Histidine is also essential for wound healing and tissue repair, but is also involved in the formation of iron-containing molecules. Contained in: beef, pork and chicken, as well as turkey and fish.
  
• Arginine: Can make an essential contribution to muscle growth and plays a major role in strength training, as arginine improves blood flow and nutrient supply to the muscles. This should also lead to better regeneration and increased nutrient storage, which is why arginine is often used in pre-workout boosters, among other things.
  Found in: fish, meat, nuts, legumes, shrimp, seeds.
  
• Tyrosine: Not only has an antioxidant effect, but is also a precursor for the synthesis of neurotransmitters such as dopamine, noradrenaline and adrenaline, which regulate mood, responses to stress and attention.
  Found in: meat, salmon, eggs, pumpkin seeds, walnuts, peanuts and unpolished rice.
  
• Cysteine: Starting substance for the formation of non-essential amino acids, is an important source of sulfur for humans, is a component of the body's own antioxidant glutathione and provides the basic structure for the synthesis of glucose. Contained in: mushrooms, fish and seafood, legumes, nuts.

Role of non-essential amino acids
Unlike essential amino acids, the body can produce non-essential amino acids itself if its metabolism is intact, either from other amino acids or molecules. They therefore only need to be taken in through food to a limited extent. Nevertheless, they also play a major role in the body.

The non-essential amino acids include (3):

1. Alanine: Valuable amino acid for strength-intensive training sessions, supports energy metabolism, which is why many athletes also supplement with alanine. Contained in: fish and seafood, eggs and cheeses such as Camembert, Gouda and Tilsiter.
   
2. Asparagine: Of great importance for the metabolism of ammonia and plays a role in the nervous system.
   Found in: soy, peanuts and other legumes, sunflower seeds, eggs and fish.
   
3. Aspartic acid: Produces energy and can be made in the liver from asparagine.
   Found in: soy, peanuts and other legumes, sunflower seeds, eggs and fish.
   
4. Glutamine: Supports the body's energy metabolism. Can serve as an energy source, especially for cells and tissues that have high metabolic activity, such as intestinal cells, immune cells and certain cells in the brain.
   Found in: meat, fish, legumes.
   
5. Glutamic acid: Important for the synthesis of proteins and neurotransmitters. Found in: meat, fish, legumes.
   
6. Glycine: Involved in the formation of collagen, plays a role in the central nervous system. Found in: fish, meat, lentils, soybeans, peanuts, oatmeal.
   
7. Proline: Involved in the formation of collagen and cartilage and ensures healthy joints.
   Found in: beef, pork, chicken, fish, offal, eggs, some cheeses.
   
8. Serine: Involved in the production of nucleotides and supports a healthy immune system.
   Contained in: pumpkin seeds, sesame, linseed, wheat germ, soy milk, legumes, nuts, fish.

BCAA's: Special importance for muscle building

A total of three of the eight essential amino acids that the body cannot produce on its own belong to a special group: isoleucine, leucine and valine . These are called branched-chain amino acids .

You may know them better under the name BCAA (branched chain amino acids). These three amino acids are among the only ones that the body does not process in the liver, but converts into protein and uses directly in the muscles. According to research, they are particularly well suited to:

• to trigger anabolic muscle protein synthesis (4). Leucine is the first amino acid to be used, as this amino acid is said to have the greatest effect on muscle protein synthesis.
• to support muscle building (5).
• lead to faster muscle regeneration (6).
• to actively strengthen the immune system (6) .
• to inhibit muscle breakdown (7).
• Prevent muscle soreness and muscle damage (8).
  

In food, valine, isoleucine and leucine are found primarily in meat and fish, but also in nuts, grains and legumes. When choosing your BCAA sources in food, pay attention to which macronutrients they are made up of. For example, protein-rich foods almost always contain a lot of BCAAs, but sometimes also provide a lot of fat (such as nuts). Depending on what training goals you are currently pursuing, you should therefore take this into account.

To ensure your body is supplied with sufficient amino acids and proteins, you can also take supplements regardless of your diet. Ideally, choose products with high biological value and natural ingredients. Our Athletic Whey Protein (LINK), for example, contains a full amino acid profile, vitamins and minerals with little sugar and all the important ingredients for muscle building, regeneration and digestion. The low-lactose formula also makes it ideal for people with lactose intolerance.

Sources:

1: Wu G. Amino acids: metabolism, functions, and nutrition. Amino acids. 2009 May;37(1):1-17. doi: 10.1007/s00726-009-0269-0. Epub 2009 Mar 20. PMID: 19301095.

2: Hahn A, Ströhle A, Wolters M: Nutrition – Physiological principles, prevention, therapy. Wissenschaftliche Verlagsgesellschaft mbH Stuttgart 2006.

3: Löffler G., Petrides P., Heinrich P.; Biochemistry & Pathobiochemistry, 8th edition, Springer Medizin Verlag Heidelberg 2007 and G. Rehner, H. Daniel. Biochemistry of Nutrition. 2nd revised and expanded edition, Spektrum Akademischer Verlag, Heidelberg, Berlin 2002.

4: Apró W, Blomstrand E. Influence of supplementation with branched-chain amino acids in combination with resistance exercise on p70S6 kinase phosphorylation in resting and exercising human skeletal muscle. Acta Physiol (Oxf). 2010 Nov;200(3):237-48. doi: 10.1111/j.1748-1708.2010.02151.x. PMID: 20528801.

5: Blomstrand E, Eliasson J, Karlsson HK, Köhnke R. Branched-chain amino acids activate key enzymes in protein synthesis after physical exercise. J Nutr. 2006 Jan;136(1 Suppl):269S-73S. doi: 10.1093/jn/136.1.269S. PMID: 16365096.

6: Meeusen R, Watson P. Amino acids and the brain: do they play a role in "central fatigue"? Int J Sport Nutr Exerc Metab. 2007 Aug;17 Suppl:S37-46. doi: 10.1123/ijsnem.17.s1.s37. PMID: 18577773.

7: Holeček M. Branched-chain amino acids in health and disease: metabolism, alterations in blood plasma, and as supplements. Nutr Metab (Lond). 2018 May 3;15:33. doi: 10.1186/s12986-018-0271-1. PMID: 29755574; PMCID: PMC5934885.

8: Greer BK, Woodard JL, White JP, Arguello EM, Haymes EM. Branched-chain amino acid supplementation and indicators of muscle damage after endurance exercise. Int J Sport Nutr Exerc Metab. 2007 Dec;17(6):595-607. doi: 10.1123/ijsnem.17.6.595. PMID: 18156664.