In the summer of 2012, I suffered from severe, persistent fatigue and episodes of lightheadedness. I went to my doctor, thinking I had iron deficiency anemia once again. My hemoglobin was always normal, but the ironn itself, which is necessary in the production of hemoglobin, had often been low. This time around, however, the cause of my fatigue was vitamin B12 deficiency.
Vitamin B12 deficiency is relatively common but used to be underestimated. It affects between three and six percent of the population, becoming more common as people age (Allen, 2009).
Vitamin B12 deficiency is usually diagnosed through a blood test. A deficiency is defined as a serum level of B12 below 148 pMol/L or 200 pg/mL (Allen, 2009). My level at the time was 120 pMol/L, which my doctor said was “not very low”. This may be so – I have met people on the B12 deficiency foundation forum with levels of 25 or less -, but it’s still cause for concern. Besides, my methylmalonic acid (MMA) was also elevated, which Allen says is the “gold standard” for diagnosing B12 deficiency.
Symptoms of B12 deficiency can be diverse. I only had tiredness and lightheadedness, but you may also experience rapid heartbeat or breathing, pale skin, sore tongue, weakness, an upset stomach, diarrhea or constipation. If B12 deficiency is not treated, it could lead to nerve damage. In fact, Chris Kresser, a natural health specialist, thinks that some symptoms common in the elderly, such as cognitive decline and lessened mobility, may in fact be due to untreated B12 defieciency. Kresser also cites a much higher prevalence than Allen, but this seems to be due to bias.
It is the Dutch B12 deficiency foundation’s position that, unless you’re eating strictly vegan, the cause of B12 deficiency is most likely malabsorption and you need to insist on injections. Malabsorption can, according to WebMD, be due to various causes, such as atrophic gastritis (where the lining of your stomach becomes very thin), pernicious anemia, Crohn’s or Celiac Disease, etc. However, eating a vegetarian diet with few eggs or dairy, as I did, can also cause low B12 levels. I went with injections anyway because I hated the taste of the tablets.
It is also the B12 deficiency foundation’s position that measuring serum levels after you’ve been using injections, won’t be useful. In my case, I was given blood tests after the round of injections anyway, and these showed my B12 level was elevated in fact. It dropped to normal within a few months and stayed within the normal range until at least my last blood test in December of 2013. I eat meat again, so it could be that my low consumption of animal products, even though I wasn’t strictly vegan, was causing me to have a B12 deficiency.
Allen LH (2009), How Common Is Vitamin B12 Deficiency? American Journal of Clinical Nutrition, 89(2):693S-696S. DOI: 10.3945/ajcn.2008.26947A.