There are 6 essential vitamins - A, B, C, D, E and K. Vitamins are classified as either water-soluble or fat-soluble. The document provides information on each vitamin, including their sources, functions in the body, and deficiency diseases. Vitamin A, D, E and K are fat-soluble while vitamins B and C are water-soluble. Each vitamin plays an important role in growth, development, and preventing various diseases.