This document discusses vitamins, including their classification, names, sources, functions, and diseases caused by deficiencies. Vitamins are classified as either fat-soluble or water-soluble. Fat-soluble vitamins include A, D, E and K and are stored in liver and fat tissues, while water-soluble vitamins like the B vitamins and C need to be regularly replenished through diet. The document lists the chemical names and sources of each vitamin and their functions, and also mentions diseases that can result from deficiencies in vitamins A, B1, C, D, E and K.