Vitamin B12 is stored in the liver, where there can be up to three years’ worth of vitamin B12 requirements stored. If you don’t take a B12 supplement, or eat vitamin B12 fortified foods regularly, you will eventually start to run low on vitamin B12.
The standard vitamin B12 blood test can be inaccurate because there are often inactive vitamin B12 analogues in our food (especially plant foods). These can show up in a vitamin B12 blood test, giving false reassurance that our levels are not low. The good news is that if you are healthy there is generally no need to have any blood tests to monitor your levels, as long as you take a regular supplement or eat vitamin B12 fortified foods.
For further information on how to incorporate B12 into your diet please see the Nutrition section.