Vitamin B12 is an essential nutrient that helps the body create DNA, nourishes the brain and nervous system, and assists with the formation of healthy red blood cells. It naturally occurs in meat, fish, and dairy products, and can be created in a laboratory. A lack of Vitamin B12 can lead to specific types of anemia, making one feel weak and tired. It is also linked to depression, age-related macular degeneration (an eye disease that can lead to blindness), and neural tube defects during pregnancy. Vitamin B12 is crucial for brain health, and a deficiency can result in memory loss and dementia. For osteoporosis, Vitamin B12 helps maintain bone density and reduce the risk of fractures.