B12 is one of the most widely supplemented vitamins, in part, because of its broad clinical significance. Most people correlate B12 levels to overall energy and vitality, but the broader implications may be more subtle. Below we highlight these lesser known elements:
1. B12 is synthesized by microorganisms and found in only trace amounts mostly in foods of animal origin, such as chicken or fish, yogurt, or cheese. This means that the absorption apparatus into the blood stream is ever so important. The most common cause of B12 deficiency (pernicious anemia) is due to impairment in transport simply because some people lack the critical enzyme to do so
2. B12 deficiency causes low energy through its direct impact on red blood cell production. In fact, B12 is needed for proper cell division which explains why large red blood cells are the diagnostic cue, even before anemia or fatigue develop. These changes are reversible and can be normalized with supplementation.
3. B12 is a critical vitamin involved in the myelin sheath of neuron development. This acts as the outer coat of your body’s electrical pathways. Imagine if you have frayed wires all throughout the circuitry of your old house? B12 deficiency often presents with balance and sensory issues but can evolve into a number of neurological diseases if left untreated.
4. Direct B12 testing is widely available to make a quick clinical diagnosis, but it becomes less clear when the value is borderline. Two other lab tests, homocysteine and methylmalonic acid are involved in B12 metabolism and important to confirm the diagnosis when in this gray zone. If both of these results are elevated it strongly supports a clinical need for supplementation.
5. Homocysteine is emerging as a risk factor for heart disease and stroke when elevated. If your homocysteine level is increased due to low B12 this is an easy solution to protect two of your most critical organs.
6. B12 comes in many formulations: IV, intramuscular, oral, sublingual, intranasal, and even transdermal patches. Patient’s even with pernicious anemia can find relief with high dose oral formulations (1-2mg daily), but intravenous and intramuscular formulations reach higher levels more quickly and reliably especially if pathology exists in the stomach or small intestine. Effective treatment will often correct blood abnormalities within 2 months and neurological symptoms within 6 months.
Stabler, Sally P. New England Journal of Medicine. 2013;368:149-160
Dr Viglione is an internal medicine concierge doctor in Santa Barbara, CA