As we age, our ability to absorb B12 from food declines, and often so does our consumption of foods rich in this vitamin. A B12 deficiency can creep up without warning and cause a host of confusing symptoms that are likely to be misdiagnosed or ascribed to aging. B12 is an essential vitamin with roles throughout the body. It is needed for the development and maintenance of a healthy nervous system, the production of DNA and formation of red blood cells.
Full story at The New York Times