Vitamin B12

why i test:

Vitamin B12 is key for promoting healthy nerves, for mood, energy and for keeping your heart healthy.  Interestingly neither animals nor humans can make this vitamin and it is not found in plants.  Instead it is synthesized by micro organisms (aka the microbiome the body’s friendly bacteria)or ingested from animal products.  For this reason patients who have taken lots of antibiotics, as well as vegetarians, are at risk for being B12 deficient.  B12 absorbtion is reliant on having adequate stomach acid and a healthy small intestine, so patients who use acid blocking medicines as well as patients with inflammatory bowl diseases like celiac diseases and Chron’s disease are often deficient. 

what i test:

Vitamin B12 is not a perfectly accurate blood test, so if the patient has symptoms of B12 deficiency I still often recommend replacement.  I am amazed by how many blood tests do show low levels of this important vitamin.  The normal range is 232-1245 g/mL, I aim for the higher end of this range.  Often patients taking the vitamin will show high levels on the blood test, however, this is not worrisome as there is no risk of toxicity, because it is a water soluble vitamin. If your urine changes color dramatically on this vitamin it can mean you are taking too much or that your body is not absorbing it.

who i test:

I test patients with digestive problems, those with nerve pain or symptoms like numbness and tingling, with fatigue or depression, vegans/vegetarians, patients with a history of frequent antibiotic use, and those taking oral birth control.  I also test patients who are pregnant or breast feeding as this increases your need for B12.