Facts and Food Sources of Proline


Proline with symbol Pro or P, is a proteinogenic amino acid which is used in protein biosynthesis. It incorporates an α-carboxylic acid group (deprotonated −COO− form under biological conditions), an α-amino group (protonated NH2+ form under biological conditions), and a side chain pyrrolidine which classifies it as a nonpolar (at physiological pH), aliphatic amino acid. In humans, it is non-essential which means body could synthesize it from non-essential amino acid L-glutamate. It is also encoded by all codons starting CC (CCU, CCA, CCC, and CCG). It is the only proteinogenic amino acid having secondary amine in that alpha-amino group which is attached directly to main chain making α carbon a direct substituent of the side chain.

It is one of 20 amino acids which is used in living organisms as building blocks of protein. Sometimes, proline is called imino acid though IUPAC definition of imine demands a carbon nitrogen double bond. It is a non-essential amino acid which is synthesized from glutamic acid. It is a crucial component of collagen and is vital for proper functioning of joints or tendons. Proline is a derivative of amino acid L-glutamate in which glutamate-5-semialdehyde is first formed by glutamate-5-semialdehyde dehydrogenase and glutamate 5-kinase.

Dietary sources

Food name Weight (g) Proline (g)
Turkey 863 12
Swiss cheese 132 4
Soybeans 186 4
Monterey cheese 132 3
Soybeans 172 3
Kielbasa 370 3
Spelt 174 2
Durum wheat 192 2
Spirulina 112 2
Lupins 180 2
Mozzarella cheese 112 2
Natto 175 2
Hyacinth beans 210 2
Couscous 173 2
Semolina 167 2
Feta cheese 150 2
Yardlong beans 167 1
Millet 200 1
Adzuki beans 197 1
Tempeh 166 1


Health Benefits of Proline

Listed below are the health benefits of Proline:

  1. Repair wounds

Proline helps to repair damage to skin such as incision, wounds and burns. It is involved in wound healing cascade as it stimulates cellular migration and subsidizes new tissue development. Proline support collagen synthesis or formation of new collagen which is a part of wound healing as it provides structure and strength to skin. Study shows that collagen supplement containing proline could promote skin barrier function, enhance synthesis of hyaluronic acid and uphold fibroblast growth and migration. As people ages, body produces less collagen which shows on appearance of skin. Intake of more amino acids which form collagen keeps the skin look younger. It also helps to prevent and treat cellulite. It tones, firm and tighten skin.

  1. Assist digestion

Collagen protein is the best supplement to improve gut health, treat leaky syndrome and support overall immune system function. Amino acids available in collagen could strengthen tissues which line GI tract and is beneficial for nutrient absorption and prevent autoimmune responses. Study shows that  proline and other amino acids found in collagen supports intestine and gut related lymphoid tissue by improving immune defense of the body and able to  protect against pathogens and foreign antigens. Each of amino acid helps to maintain integrity, function and growth of intestines, improve T-lymphocyte numbers, normalizing inflammatory cytokine secretion and regulate secretion of IgA cells.

  1. Prevent joint pain

Aging is related with increment of joint pain because the ability of the body to produce collagen becomes lower. Collagen is essential for overall physical and mental health, it assist body to hold together and is required for maintaining strength and flexibility of connective tissue. The loss of collagen could be accelerated due to unhealthy lifestyles, diet and habits because it results high level of inflammation, hormonal imbalance, oxidative stress and nutrient deficiencies.

More amino acids which form collagen including proline helps to mitigate these effects by encouraging formation of new cartilage, aiding muscle maintenance or growth and improving bone  density. Other amino acids and proline helps to strengthen cartilage by stimulating chrodrocytes. Study on animals shows that proline supports growth and performance of tissues. It assist functions of immune system and promote antioxidant status which means it is beneficial for lowering inflammation and oxidative stress that could damage joints and connective tissue.

  1. Cardiovascular health

Proline protects heart as well as arterial walls by preventing fat from accumulating in bloodstream and controlling blood pressure. Amino acids are required for forming tissue which constructs arteries and blood vessels. More amino acids help to form collagen that is beneficial for lowering risk of arteriosclerosis.

  1. Combat inflammation

Proline has a role in metabolic functions or synthesis of other compounds. It signalizes molecule and sensor of cellular energy status. It modulates mitochondrial functions, trigger specific gene expression, influence cell proliferation or cell death, these are the reasons which shows its necessity to recover from environmental stress. Proline is also beneficial for energy production or maintain overall health including increment in metabolism, muscle mass and helping with energy output during physical activity, facilitate process of constructing healthy cells from DNA and RNA, improve use of antioxidants, support central nervous system and support phase II liver detoxification.

Possible Side Effects of L-Proline

It might cause side effects such as bloating, flushing, abnormal heart rhythm, blurred vision, liver inflammation and toxic impaired or dim vision. People with kidney or liver disease should not use Proline supplement without consulting medical specialist.


The recommended dose is between 500 milligrams and 1,000 milligrams each day in combination with vitamin C.







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