Why are vitamins called A B C?

Vitamins are labeled with letters like A, B, and C to categorize them based on their distinct chemical structures and functions in the body. The naming convention originated in the early 20th century when scientists discovered these essential nutrients and assigned letters to them sequentially. Each vitamin plays a unique role in maintaining health, with different vitamins involved in processes like vision, metabolism, and immune function. This classification helps simplify the study and understanding of their contributions to nutrition.