Etiology, Epidemiology, Pathophysiology, Signs and Symptoms, Evaluation, and Treatment of Vitamin A (Retinol) Deficiency.

Vitamin A, also known as retinol, is a non-water-soluble vitamin. Vitamin A is very important for the proper functioning of the human body. Retinol, especially in the form of retinyl ester, can be found in many animal-based products and is essential for the efficient operation of many physiological processes. Fruits and vegetables are also excellent sources of vitamin A; the majority of them include carotenoids, which are precursors to vitamin A. The human body has the ability to convert natural retinols like retinyl ester, retinoic acid, and provitamin A into biologically active forms that interact with a variety of molecular targets like nuclear receptors and retinal opsins. This review article provides knowledge regarding retinol deficiency in humans. It provides brief information about the sources, etiology, epidemiology, pathophysiology, and treatment of vitamin A deficiency.