Understanding Vitamin A and Retinol to Promote Healthy Skin
Vitamin A is essential for healthy growth and development, good vision, a strong immune system, and a healthy skin barrier. In the 1960s, dermatologists commonly used vitamin A for treating acne until it was later identified as an effective vitamin for the repair of aging skin.1 It is currently one of the most popular ingredients used in skin care formulations for skin revision. However, little information is presented concerning the importance and necessity of retinol binding proteins, which are required for the cells’ ability to utilize retinol.2 This article will focus on identifying the different forms of vitamin A, the metabolism, and the necessity of binding proteins to use retinols. First, it is important to identify the various types of vitamin A.
UNDERSTANDING RETINOLS AND RETINOL BINDING PROTEINS
The retinol form of vitamin A is stored in the liver. In order to travel from the liver to the dermis, it has to be attached to a protein, most commonly referred to as retinol binding protein.2 When retinol or retinoic acid are circulating within the cells, it must be attached to a retinol binding protein. These proteins assist in the recycling process of retinol as it enters and exits the liver several times a day. Because retinoids are insoluble in water, they must bind to retinol binding protein to enter the cell and perform its task. When retinol or retinoic acid are circulating within cells, damaging or miscommunication to cells occurs.2
Another important vitamin A receptor is stimulated by retinoic acid 6 (STRA6). This receptor is a transmembrane cell receptor for retinol binding. It functions specifically as a cytokine signaling transporter.6 The primary responsibility of STRA6 is to transport retinol to the eye. STRA6 is also responsible for homeostasis and metabolism of cell signaling; therefore, this receptor is also necessary for retinol uptake.
Embryos are extremely sensitive to retinol concentration and malformations of the embryo may occur during development. If retinol or retinoic acid are out of balance, early embryo mortality or developmental malformations may occur.5 It is important to recognize that retinol is crucial to the growth of various tissues, most specifically in embryo formation. Subsequently, retinol binding protein binds to retinol and plays a critical role in regulating the transport and metabolism of retinol in embryos.
Vitamin A, in its many forms, is proclaimed to be the superior ingredient for skin revision, especially for the aging market and acne. However, important components to the success of retinols are retinol binding protein and specialized receptors like STRA6. As continuous and increased usage of retinols are available in cosmeceutical products, one must be cognizant of the cells’ ability to utilize them without becoming harmful and detrimental to the skin.
Written by Susan Wade