We need vitamin B12 in order to make an appropriate supply of red blood cells. If you have too little of this vitamin, you can become anemic. Anemia is a common cause of fatigue.
A slightly low level of B12 does not usually cause a bad anemia. So if you do not have anemia, it is not very likely that your slightly low B12 level is the cause of your fatigue.
We also need vitamin B12 to keep our nerves in good health. Low vitamin B12 causes problems from poorly functioning nerves, including:
- Numb or tingling feet or hands
- Memory difficulties, balance
- Walking problems
You can have low B12 if you do not eat meat. You can also have it from long-term use of antacids, or from a change in the way your digestion handles B12.
If you are low on vitamin B12, you might need to take a supplement for the rest of your life. You can take this supplement by mouth or injection.