Ascorbic acid, or vitamin C, is needed to make collagen. Collagen is the most abundant protein in your body, serving a variety of structural functions. It is a major component of your skin, cartilage, blood vessels and eyes. Collagen is also rich in the amino acids proline and lysine. In the case of ascorbic acid deficiency, collagen fibers cannot be linked, greatly decreasing their tensile strength. The result is often a tendency to bruise.
A typical collagen molecule is a long, rigid structure in which three protein chains are wound around each other in a triple-helix. More than 20 types of collagen are found in your body, according to the November 2003 issue of "Advanced Drug Delivery Reviews." The structure and function of collagen is determined by the amino acid sequences. In some tissues, collagen may be dispersed as a gel. In tissues such as tendons, collagen is bundled into tight fibers to provide strength. Collagen helps maintain the health of your skin, bones and internal organs such as the liver and lungs.
Collagen is rich in the amino acid proline, which helps to maintain the helical formation. Specifically, collagen consists of repeated sequences of three amino acids, one of which is usually proline. Proline may be found in a modified form known as hydroxyproline. Glucose and galactose, two types of sugars, are often attached to proline before collagen winds into its characteristic helical formation. Proline is an amino acid present in virtually every type of food that has protein. Your body can synthesize proline from another amino acid, so it is nonessential in your diet. Proline may also help reduce hypertension and lower your risk of heart disease, according to a study in the February 2014 issue of "Amino Acids."
Lysine is an amino acid found in large quantities in all types of collagen. Specifically, lysine is hydroxylated in a chemical reaction that adds oxygen and hydrogen to the molecule before it becomes part of collagen. Hydroxylysine helps to stabilize the collagen molecule and provide tensile strength. Lysine is an essential amino acid that must be obtained in the diet. The best sources of lysine include dairy products such as yogurt, cheese and milk. Seafood is also high in lysine. Lysine helps treat herpes infection and cold sores, boosts absorption of calcium and may help improve anxiety, according to Drugs.com.
Ascorbic acid, or vitamin C, does not form part of the collagen molecule. Rather, it is required for the reactions that form hydroxylysine and hydroxyproline and serve to stabilize the collagen molecule. Without adequate dietary ascorbic acid, collagen fibers cannot be cross-linked, greatly decreasing their tensile strength. Deficiencies can manifest as bleeding gums, a condition known as scurvy. Bruises are the result of capillary fragility that allows blood to leak from vessels. Ascorbic acid also helps protect against heart disease, high blood pressure, cancer, osteoarthritis, asthma, macular degeneration and reduces the length of the common cold, according to the University of Maryland Medical Center. The recommended intakes of vitamin C are 75 milligrams per day for women and 90 milligrams per day for men -- a requirement that can be met by 1/2 cup of sweet red peppers. Strawberries are another excellent source of vitamin C.