Vitamin B12 is crucial for maintaining healthy nerve cells and supporting the production of DNA and red blood cells. It plays a significant role in brain function and development. A deficiency in vitamin B12 can lead to serious health issues such as anemia, neurological disorders, and cognitive impairments. It is essential for energy production and helps reduce the risk of heart disease by regulating homocysteine levels in the blood. Ensuring an adequate intake of vitamin B12 through diet or supplements is vital, especially for vegetarians, vegans, and older adults, who are at higher risk of deficiency.