Vitamin B12 is a vital nutrient due to its effects on major functions of the body, and its ability to restore your energy. A deficiency of vitamin B12 can result in multiple health problems and cause a lack of energy in general. We will look at vitamin B12 benefits and functions, as well as symptoms of deficiency, absorption, and drug interactions. Benefits and Functions of Vitamin B12 Blood Cell Production Vitamin B12 is necessary for proper formation of red blood cells. When formed correctly, red blood cells are small and round, but a lack of vitamin B12 causes them to be larger and more oval and causes anemia. Bone Health People who have a vitamin B12 deficiency tend to have a lower than normal bone mineral density, making bones more fragile and delicate. Osteoporosis can happen as a result. Mood and Brain Health Vitamin B12 is important for synthesis and metabolism of serotonin, a chemical produced by your body to regulate mood. A B12 deficiency can lead to lo