A comprehensive review on the role of Vitamin A on human health and nutrition

Vitamin A is a crucial nutrient that protects the body from oxidative stress caused by free radicals, which are unstable molecules that can damage cellular components. Its antioxidant properties helps maintaining various physiological functions that depend on its presence, including vision, immune function and skin health. The human body can convert natural forms of vitamin A (retinol, retinal and retinoic acid) and provitamin A (β-carotene) into active forms, which interact with specific molecular targets, influencing gene expression, cell differentiation and cellular processes. This comprehensive review provides an in-depth examination of vitamin A, covering its dietary sources, physiological roles and consequences of deficiency. In this research review explored the metabolic pathways of vitamin A, including absorption, transport and storage, as well as its potential applications, offering a thorough understanding of this essential nutrient. Furthermore, we have decreased the latest research on vitamin A's role in, maintaining healthy vision, immune function, and skin health, treating various diseases and conditions, such as retinal disorders, infectious diseases and cancer, mechanisms of action, including gene regulation, cell signaling, and antioxidant activity, relationships with other nutrients and health outcomes, including vitamin D, iron, and zinc, impact of deficiency on human health, including night blindness, impaired immunity, and skin disorders and emerging research on potential benefits and risks, including its role in chronic diseases and interactions with medications. Key words: Nutrition, retinyl ester, Nyctalopia, Rhodopsin, Vitamin A, β-carotene