Vitamin B12 is vital to brain health and energy. It is also essential for building new blood cells, DNA, and nerve insulation. Deficiencies lead to brain fog and fatigue. Studies show that it may help with weight loss, chronic fatigue, MS, nerve damage, brain disorders, shingles, and headaches. Since your body doesn't make vitamin B12, you have to get it from animal-based foods or from supplements on a regular basis. While B12 is stored in the liver for up to five years, you