Vitamin B12 may be vital for health, but when it comes to supplements, more isn’t always better. Credit: Shutterstock We’ve all heard the advice: eat your fruit and vegetables, get your vitamins, and stay healthy. For the most part, that guidance holds up. But some nutrients have a more complicated story, and vitamin B12 is a fascinating example. Also known as cobalamin , B12 is essential for life. It helps the body produce red blood cells, keeps the nervous system functioning, and plays a