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Vitamin B12 Deficiency and Brain Health.

Vitamin B12 Deficiency and Brain Health.
By Renata Trister DO

Vitamin B12 has a role in red blood cell production. Deficiency states may result in pernicious anemia. B12 supports myelin (which allows nerve impulses to conduct) and when this vitamin is deficient, symptoms of dementia, multiple sclerosis, impaired gait, and sensation may appear. Vitamin B12 also has a role in psychiatric symptoms such as depression, anxiety and fatigue.

The one-carbon cycle refers to the body’s use of B vitamins as a “methylator” in DNA synthesis and the management of gene expression. There are three concepts that relate to B12’s role in chronic, neuropsychiatric symptoms:


This process marks genes for expression (like a small tag); it is also critical for detoxification and elimination of chemicals and hormones (estrogen), building and metabolizing neurotransmitters, and producing energy and cell membranes.

Homocysteine cycling

B12 is a primary player in the one-carbon cycle and a co-factor for the methylation of homocysteine by activated folate, to recycle it back to methionine. Subsequently, SAMe is produced, the body’s methyl donor.

Genetic override

Sufficient supply of an activated/bioavailable form of a vitamin (methylfolate vs folic acid) is even more necessary in the setting of gene variants such as transcobalamin II, MTHFR, and MTRR which may function less optimally in certain individuals and result in pathology under stress. An example of the importance of this is a report of death in a B12-deficient patient with genetic variants who underwent anesthesia with nitrous gas. As the B12 blood level was normal, this fatality was attributed to functional deficiency, indicating that having available B vitamins does not guarantee proper utilization. Therefore, supplementing with activated forms of B vitamins can enhance the ability to support cellular processes.

Causes of B12 Deficiency

If it is established that a person has overt deficiency (in blood) and/or they respond to treatment, it is important to also find the cause. These are some considerations:

1. Achlorhydria or low stomach acid, occurs in low thyroid function, chronic stress, aging, and – acid blocking medications.

An example:

A patient is eating foods that they are unable to properly digest and this causes local inflammation. These foods may include processed dairy, foods fried in vegetable oils, and sugars. Inflammation further perpetuates improper digestion and slow food transit. The patient feels the reflux of this immobile, poorly digested food, and this is often seen as a sign of high stomach acid. Patients begin using long-term antacids because they feel better. Long-term use is linked to pathogenic overgrowth of bacteria, fracture, and nutrient deficiency. Stomach acid is critical for triggering digestive enzymes, “intrinsic factor” for B12 absorption and managing local microbial populations.
When this kind of digestive imbalance goes unattended, B12 deficiency can occur, along with symptoms that will suggest a need for an antidepressant and the medications begin to grow.

2. Dietary Restrictions

Animal foods are primary sources of B12, although algae and fermented foods are promising options for some dedicated vegans. Stores deplete over time, and deficiency-related symptoms may present long after dietary restriction.

3. Autoimmune

One of the possible mechanisms of deficient B12 absorption is pernicious anemia, an autoimmune reaction on parietal cells, associated with atrophic gastritis in the stomach.

4. GMO/Gluten

There seems to be a powerful synergy of gluten-containing and genetically modified processed foods. This may have an impact on digestion of many. The innate immune system responds to gluten in these grains, and food fragments may pass directly into the blood stream through gated tight junctions. Direct inflammation and damage to the cells in the small intestine may result.

Genetically modified corn may be playing a part in small intestinal villous changes as demonstrated in a study of mice consuming corn oil. There is also reason to believe that Bt-toxin from Monsanto’s GMO corn plays a role in intestinal permeability as it was found in the blood of 93% of pregnant women and 80% of their fetuses. The herbicide itself also drastically changes the gut flora, killing beneficial bacteria.

5. Medications Metformin is a risk factor for B12 deficiency in some.


Treating B12 deficiency, while the underlying cause is being determined is needed. The use of the activated form of vitamin B12 is effective at improving levels. Cyanocobalamin is a synthetic form of B12 that has been bound to a cyanide molecule while hydroxy, adeno, and methyl are all forms of B12 that are found naturally, in the body. The injectable form may yield a powerful effect over the oral form. Supplements may take time to improve symptoms (30 days or so).