Proline is a major amino acid present in cartilage and collagen. It is critical for maintaining skin health, in helping to repair damaged skin muscle and connective tissue, for proper functioning of tendons and joints, and maintaining and strengthening the heart muscle. Proline is a cofactor of lysine (see entry for “Lysine”) in supporting the cardiovascular system.
Decreases in levels of proline are sometimes seen in endurance runners and others who engage in prolonged exercise. Such individuals may want to take a proline supplement, as well as people who are recovering from traumatic injuries. Deficiency is rare in healthy individuals who follow a nutritious diet.
Most dietary sources of proline are found in animal foods, with egg whites and turkey providing healthy levels. A few non-animal sources include wheat germ, savory cabbage, and asparagus, which provide an appreciable amount. To convert proline into hydroxyproline, which is the collagen form, the body requires an adequate amount of vitamin C, so it is also important to get enough of this nutrient.
Although proline is available as a stand-alone supplement, it is most often seen as an ingredient in supplements marketed for bodybuilders and athletes. Consult your healthcare provider before taking this supplement.