If you have felt drained for weeks, get random "pins and needles" in your hands, or struggle to focus, the cause might be smaller than you think: a vitamin you are not getting enough of. Vitamin B12 deficiency is one of the most common — and most missed — nutritional problems in India, particularly among vegetarians. It is one of several common shortfalls covered in our guide to vitamin and mineral deficiencies.
The good news? Once spotted, it is usually straightforward to fix. This guide covers what B12 does, the warning signs, why deficiency happens, the best foods, and how doctors treat it.
What vitamin B12 is and why your body needs it
Vitamin B12, also called cobalamin, is a water-soluble vitamin your body cannot make on its own — you have to get it from food or supplements. Despite needing only tiny amounts, it helps make healthy red blood cells, keeps your nervous system working, and supports energy production.
When B12 runs low, red blood cells become large and ineffective (megaloblastic anaemia), and nerves slowly lose their protective coating. That combination explains why deficiency makes you feel both exhausted and "tingly." Your liver stores B12, sometimes for a couple of years, so a poor diet takes a long time to cause symptoms — and by the time you feel unwell, the shortfall has often been building for a while.