B12 Deficiency Risk From Taking Metformin or Being a Vegetarian

Vitamin B12 is one of those micronutrients that our bodies require in order to live and thrive. Vitamin B12 also goes by the name cyanocobalamin. (No wonder we’ve shortened it to B12!) We need vitamin B12 to:[1]
- Produce red blood cells
- Create new DNA
- Build proteins, hormones, and lipids
- Release energy – without vitamin B12 your body cannot produce the energy it needs[2]
In short, we can’t live without vitamin B12!
Fortunately, most American children and adults obtain adequate amounts of vitamin B12 through the foods we eat. However, vitamin B12 deficiency continues to be a concern in the US. Those most susceptible to vitamin B12 deficiency include: the elderly, pregnant or lactating women, strict vegetarians, those with low levels of stomach acidity, hyperthyroidism, those who have undergone gastric bypass surgery, and people suffering with pernicious anemia.[3]
Approximately one-third of adults over 50 suffer from atrophic gastritis. This is a thinning of the stomach lining that hinders vitamin B12 absorption. As a result, about 3.2 percent of those over 50 are deficient in vitamin B12.[4]
Remarkably, the human body stores enough vitamin B12 in the liver to last several years. So a deficiency in vitamin B12 intake may not show up for a while.[5] As a result, its deficiency can also appear rather suddenly and without warning, or gradually intensifying over time.[6] A blood test is required to confirm vitamin B12 deficiency. The recommended daily allowance for adults is 2.4 micrograms per day.
Symptoms of vitamin B12 deficiency may include:[7]