Collagen is the most abundant protein in our body. Is the primary building block of skin, connective tissue, bones, cartilage and blood vessels. So far, 29 different types of collagens have been identified. They all consist of a characteristic repeating sequence of amino acids in the form of a triple helix. They differ in the primary structure, tissue distribution, lenght of the triple helical domain, molecular weight and variations in the post-translation modifications.
Collagen biosynthesis and degradation occur simultaneously in the body. While these two processes are in dynamic balance in youth, collagen production starts to decrease with age. Decreased collagen production is visible on the skin – reduced skin elasticity, wrinkles, and in physical function – decreased muscle mass and reduced mobility. Therefore collagen is often used as an ingredient in anti-age cosmetic products and food supplements for healthy skin, muscles, bones, joints, and cartilage.
Collagen food supplements can be found in pharmacies, grocery stores, drugstores and online. We have collected and reviewed 48 different collagen food supplements available in Slovenian (online) pharmacies. We have also reviewed 24 clinical studies that studied the effect of collagen on skin, bone, muscle, and joints. The review of these studies showed that collagen is safe to consume at daily doses up to 20 g. Only minor side effects, such as nausea, vomiting, and bad breath, have occurred. A review of the scientific literature has shown that specific sources of collagen can cause allergic reactions. For example, it is reported that almost 3 % of the population is allergic to bovine collagen. Furthermore, a case of anaphylactic shock due to the ingestion of hydrolyzed fish collagen has been reported.
Collagen food supplements often contain other ingredients, usually vitamins and minerals. Vitamin C was the most commonly found in the products (83 %). It is also involved in the biosynthesis of collagen. Hyaluronic acid, which, like collagen is a component of the skin's intercellular matrix, is found in 60 %. of products. Other ingredients that we found were zinc (31 %), biotin (23 %), silicon (19 %), niacin (16 %), and selenium (15 %). Based on literature and nutritional guidelines, we characterized each ingredient and defined its role in the product. We checked the daily intake of vitamins and minerals and compared these values
with the recommended daily intakes. Many products have been found to contain higher doses than recommended. In this case, more attention is needed, especially when multiple different food supplements are co-ingested simultaneously due to increased risk of side effects.
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