Proline is one of the twenty DNA-encoded amino acids that makes up protein but is actually known as an ‘imino acid’ as it differs from amino acids. When proline is not consumed in the diet it is made by ornithine and glutamic acid and the kidneys release it into the blood stream. Proline works with vitamin C to promote healthy connective tissue, maintain and heal cartilage and the strengthen joints, tendons and muscles (including the heart muscle).
Proline and collagen
Collagen is the most common protein in the body and comprises approximately 20-30% of all body proteins. It is found in many tissues that serve structural or mechanical functions. Glycine and proline account for about 50% of the amino acids in collagen. Collagen fibres have large amounts of hydroxylysine and hydroxyproline which are important for formation of all types of collagen with their appropriate amount of strength and flexibility.
Proline and the skin
Vitamin C is required to change proline into hydroxyproline (collagen) and lysine into hydroxylysine (collagen) which both help to repair collagen connective tissue damage and promote healthy skin. Because proline plays a vital role in tissue repair and regeneration, it is vital to accelerate the healing of wounds, cuts, burns, and surgical incisions. Along with leucine and glycine, proline can help to reduce fine lines and wrinkles in the skin and delay their onset.
Proline and the bones and joints
Proline also helps support joint health and flexibility, potentially reducing joint pain and the risk of age-related conditions like osteoporosis.
Proline and the heart and veins
Adequate proline intake can help maintain blood vessel elasticity, support healthy blood pressure, and reduce the risk of arteriosclerosis (hardening of the arteries).
Proline and the intestines
Proline supports the strengthening and healing of the gut lining, which can benefit nutrient absorption and support the immune system.
Proline and sports recovery
As a building block of protein, proline plays a role in muscle growth and repair, helping to maintain muscle tissue after intense physical activity and aiding in post-workout recovery.
Proline is involved in metabolic functions and has been shown in studies to have anti-inflammatory effects and can help protect cells from oxidative damage caused by free radicals.
Cofactors of proline
Proline works in conjunction with lysine, vitamin B3 (niacin), vitamin C (ascorbic acid), bioflavonoids, copper and iron
Hyperprolinaemia
Hyperprolinaemia, also referred to as prolinaemia or prolinuria, is a condition which occurs when proline is not broken down properly by the enzymes proline oxidase or pyrroline-5-carboxylate dehydrogense, causing a build-up of proline in the body.
It is difficult to determine the prevalence of hyperprolinaemia type I, as many people with the condition are asymptomatic. People with hyperprolinaemia type I have proline levels in their blood between 3 and 10 times the normal level. Some individuals exhibit seizures, mental retardation or other neurological problems.
Hyperprolinaemia type II results in proline levels in the blood between 10 and 15 times higher than normal, and high levels of a related compound called pyrroline-5-carboxylate. This rare form of the disorder may appear benign at times, but often involves seizures, convulsions, and mental retardation.
Hyperprolinaemia can also occur with other conditions, such as malnutrition or liver disease. In particular, individuals with conditions that cause elevated levels of lactic acid in the blood, such as lactic acidaemia, are likely to have elevated proline levels, because lactic acid inhibits the breakdown of proline.
Natural sources of proline in alphabetical order
- Alfalfa sprouts
- Almonds
- Apples
- Apricots
- Asparagus
- Beans
- Bone broth
- Buckwheat
- Cabbage
- Cashew nuts
- Cheese (unpasteurised)
- Chia seeds
- Chlorella
- Egg whites
- Flax seeds
- Halibut
- Hemp seeds
- Lentils
- Mushrooms
- Organ meats
- Oily fish
- Peanuts
- Pistachio nuts
- Pumpkin seeds
- Quinoa
- Seeds
- Soya beans
- Spirulina
- Sunflower seeds
- Teff
- Whole grains
- Venison
- Yoghurt
Related subjects
- A-Z of nutrients
- Blood and vein disorders
- Bone and joint disorders
- Heart disorders
- Immune system disorders
- Intestinal disorders
- Liver disorders
- Recovery from Injury and surgery
- Skin disorders
- Sports nutrition
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