What is proline?

Proline is a non-essential proteinogenic amino acid that the body can produce itself. The chemical name for proline is pyrrolidine-2-carboxylic acid. This amino acid occurs naturally as L-proline and is an important component of many proteins in the human body. Although proline is not an essential amino acid, it nevertheless plays an important role in various bodily functions. [1]

Which foods contain L-proline?

The amino acid is found in many protein-rich foods. Particularly high amounts are found in:

• Meat and fish
• dairy products
• eggs
• Legumes
• Nuts and seeds

A varied diet generally ensures a sufficient supply of the amino acid. The body can also produce proline itself from other amino acids such as L-glutamate or L-glutamine. [2]

What effect does L-proline have on humans?

The amino acid L-proline fulfills various important functions in the body and unfolds its effect in different ways:

Collagen formation: L-proline is a major component of collagen, the most abundant protein in the human body. Collagen is essential for healthy connective tissue, skin, bones and joints. [3]

Structure formation of proteins: This important amino acid influences the secondary structure of proteins, in particular the formation of the alpha helix. [4]

Supporting the immune system: L-proline also has an effect on the immune system. It plays a role in the production of antibodies and white blood cells. [5]

Wound healing: Due to its involvement in collagen formation, L-proline has a positive effect on wound healing. [6]

Proline compared to other amino acids

In contrast to essential amino acids such as L-arginine or L-tyrosine, proline does not necessarily have to be ingested through food. It also differs structurally from other amino acids such as L-glycine or L-glutamic acid. While L-carnitine mainly plays a role in energy metabolism, proline is primarily important for the structure formation of proteins.

L-proline: an essential building block for collagen and connective tissue

L-proline is an important amino acid that is particularly necessary for the production of collagen, one of the most important structural proteins in the human body. Collagen is responsible for the strength and elasticity of skin, bones, tendons and ligaments. Through its central role in collagen metabolism, L-proline contributes to the maintenance and repair of connective tissue, making it essential for physical health and well-being. [7]

In addition to its function in connective tissue, L-proline also supports the regeneration and renewal of tissue and skin. This amino acid can be obtained through a balanced diet and is contained in many protein sources. In situations where there is an increased requirement, such as during intensive physical activity or in old age, targeted intake via the diet can be particularly valuable.

Who should take supplements?

L-proline is an important amino acid for the human body, especially for the formation of collagen and healthy connective tissue. The importance of this important building block for our body should therefore not be underestimated. [8] Anyone who does not produce sufficient amounts of the amino acid themselves should therefore consider taking it in the form of a dietary supplement.

Most people produce enough L-proline themselves and therefore do not need to take the amino acid externally in the form of L-proline powder or capsules. A healthy and balanced diet is usually sufficient. For certain people, however, taking it can offer advantages:

Older people: As the body's own production of L-proline decreases over the years, an additional intake may be recommended for older people.

Vegetarians and vegans: L-proline is mainly found in animal products and is hardly present in plant-based foods. Therefore, people who do not consume animal products can benefit from supplementation.

Endurance athletes and people under heavy physical strain: An additional supply of L-proline can be useful during high physical exertion.

People with an increased need for collagen formation: L-proline is important for the formation of collagen, which is important for connective tissue, bones and cartilage.

Sources:

[1] https://pubs.acs.org/doi/10.1021/acs.chemrev.4c00007 
[2] https://pubmed.ncbi.nlm.nih.gov/19030957/
[3] https://pubmed.ncbi.nlm.nih.gov/33818628/
[4] https://pubmed.ncbi.nlm.nih.gov/34525125/
[5] https://pubmed.ncbi.nlm.nih.gov/33871679/
[6] https://pubmed.ncbi.nlm.nih.gov/28978679/ 
[7] https://www.aok.de/pk/magazin/koerper-psyche/haut-und-allergie/kollagen
[8] https://pubchem.ncbi.nlm.nih.gov/compound/Proline