Vitamin B12 is a water-soluble vitamin that plays a crucial role in the formation of red blood cells and the maintenance of the nervous system. It is essential for DNA synthesis and helps in the metabolism of fatty acids and amino acids. This vitamin is primarily found in animal products, such as meat, fish, eggs, and dairy. A deficiency in vitamin B12 can lead to anemia, fatigue, and neurological issues. Vegetarians and vegans may be at higher risk of deficiency since they do not consume animal products. Supplements and fortified foods can help individuals meet their vitamin B12 needs.