B12 deficiency symptoms are not always relieved by oral supplementation with methyl-B12, despite high levels in the blood. We have proven this in over 20 patients whose blood levels on oral supplementation went sky-high, and yet their symptoms persisted. When we initiated methyl-B12 injections, their symptoms abated, often within a few weeks. In many cases, when we tried to switch them back to the oral form, their symptoms returned. In several cases, daily shots were required to achieve optimum results. A higher dose every few days was not the same as a lower dose every day.

Symptoms of B12 include:

• Fatigue
• Neuropathy (tingling, loss of sensation (vibration) or coordination starting with the feet, then hands)
• Mild to moderate depression
• Mild to moderate cognitive dysfunction
• Autonomic dysfunctions such as irregular blood pressure and temperature (and possibly heart rhythm?)
• Anemia of the macrocytic (larger cells) type
• Joint pains, either focal (a single joint or joints) or diffuse (several)
• Rashes
• Certain psychiatric disorders (usually depression but can also be ADD and anxiety)

While we know that vegetarians and vegans are at risk for B12 deficiency, this can also occur in the older population due to malabsorption. We need stomach acid to properly absorb B12, and as we get older the ability to make acid declines.

Why is the blood test for B12 not helpful in this case? While that is not clear (yet), it is true that some lab tests are  valid in only one part of their range.  If the blood test for B12 is low, then the person is definitely low. However, if it is mid-range or high, for some reason, the person can still have all the signs of B12 deficiency. In such a case, the only way to prove a deficiency is to do a trial of B12 injections and watch the symptoms.

In theory, if the blood levels are high, then this should be as effective as injecting the vitamin subcutaneously (under the skin). In theory, the distribution should be better coming from the blood than the skin.  However, it doesn’t work that way!

At the end of the day, all nutrients must work at the cellular level, which means that the B12 must be transported into the cell.  So, if injections work better than sky-high B12 levels, it implies that there is some defect in transport of B12 that is somehow overcome when the B12 is provided under the skin.

Oral B12 is absorbed by first binding to intrinsic factor, a molecule that is produced by the stomach’s parietal cells and activated by stomach acid. After binding, this complex is then absorbed by the small intestine into the blood stream. So perhaps the B12 blood test is not reflecting the proper form of  B12. This does occur with other nutrients in the blood, such as folate and sometimes vitamin A, where the test does not reflect the relevant form of the vitamin. The folate blood test comes back high in almost everyone due to high levels of a synthetic folate in many foods. It is therefore useless in most cases. So, the form of B12 in the blood test might not represent the functional form of B12.