Vitamin B12 serves several primary functions, including red blood cell formation, DNA synthesis, and neuronal health. It is crucial for maintaining a healthy nervous system and plays a vital role in metabolism by aiding in the conversion of food into energy. Adequate levels of B12 can help prevent anemia and contribute to improved mood and mental clarity. Deficiency in vitamin B12 can lead to serious health issues, such as neuropathy and cognitive decline, making its intake essential, especially in vegetarian or vegan diets.