Vitamin B12

Research: Are more people deficient in vitamin B₁₂ than we think?

Most doctors think about testing your vitamin B₁₂ levels if you have neurological symptoms such as tingling, numbness, or burning sensations in your arms or legs, weakness, or loss of balance.  They may also think of testing it if your red blood cells are large, to see if you have a type of anemia called pernicious anemia.

However, in the past decades, newer research has shown that many other symptoms or illnesses have been associated with low levels of this crucial vitamin.  These newer associations include cold hands and feet, tiring easily, bruising easily, low blood pressure, incontinence, anxiety, depression and poor cognitive/mental function – e.g.: poor memory and even seizures.

In fact, the usual (and most common) way to test your levels of vitamin B₁₂ has been through your blood, to literally test the level of B₁₂ in your blood serum.  However, serum testing has proven not to be very predictive of the actual levels in your body, or what is actually available in your tissues and cells.  Instead, a newer and much more accurate and sensitive way to test your functional level of tissue-containing B₁₂ is through a specific marker called methylmalonic acid, or MMA.  This is a substance that builds up in your blood or urine if there isn’t enough functional vitamin B₁₂ in your tissues.  Note, when your tissues are deficient, then you develop symptoms.

This research link indicates that the MMA test would be a more effective way to determine earlier vitamin B₁₂ deficiency.  http://www.ncbi.nlm.nih.gov/pubmed/16385831

Another 2009 research link (below) refers to a person who developed significant brain and spinal cord neurological damage, due to delayed detection of vitamin B₁₂, having relied on the standard method of serum vitamin B₁₂ testing:  http://www.ncbi.nlm.nih.gov/pubmed/19151237.  It makes you wonder how many people are suffering with such profound neurological damage due to outdated methods of testing.  This last reference also relates to how methylmalonic acid can help predict decline in cognitive function http://www.ncbi.nlm.nih.gov/pubmed/17991650 in an elderly population.

In my naturopathic practice, I suspect a vitamin B₁₂ functional deficiency in about one-third of my patients.  Often, I use a B₁₂ ‘challenge’ test, where I give a 1000 microgram intramuscular injection of preservative-free vitamin B₁₂, and wait up to two days for a response.  Often, patients will tell me that their energy improved, they slept better, their mind felt a bit sharper, or some other specific improvement.  Usually you would need a few injections to correct the deficiency, to notice a lasting improvement.

Vitamin B₁₂ is a fascinating essential factor in our health.  It is likely that many people are low in this vitamin, but are not aware of it themselves, or to their doctors.  In time, I expect the methylmalonic acid test will likely replace the serum vitamin B₁₂ test, as a more accurate method of testing vitamin B₁₂ levels.