VITAMIN A RICH FOODS AND THEIR CHEMICAL PROPERTIES

Vitamin A is a fat-soluble micronutrient essential for vision, immune system function, cell differentiation, and growth. It occurs in two primary forms: preformed vitamin A found in animal products and provitamin A carotenoids found in plant sources. This article analyzes the chemical characteristics of vitamin A and evaluates major food sources rich in this vitamin. Particular attention is given to the molecular structure, chemical properties, and transformation of carotenoids into biologically active retinol in the human body. The study also discusses the nutritional importance of vitamin A-rich foods and their role in preventing vitamin A deficiency.维生素A（Vitamin A）是一种脂溶性微量营养素，对视觉功能、免疫系统正常运作、细胞分化及机体生长均具有关键作用。该营养素主要存在两种形式：一类是存在于动物源食品中的预形成维生素A（preformed vitamin A），另一类是来源于植物的前维生素A类胡萝卜素（provitamin A carotenoids）。本文分析了维生素A的化学特性，并评估了富含该维生素的主要食物来源。本文特别关注了类胡萝卜素的分子结构、化学特性，以及其在人体内转化为具有生物活性的视黄醇（retinol）的过程。本研究还探讨了富含维生素A的食物的营养学价值，以及它们在预防维生素A缺乏症中的作用。