Her symptoms were years in the making, including tearfulness, anxiety, movement abnormalities, constipation, lethargy, and eventually perceptual disturbances (hearing her name called), and the ultimate in severe psychiatric pathology: catatonia. Despite her inpatient treatment, she remained suicidal, depressed, and lethargic.
How Can B12 Impact Brain Health?
B12 supports myelin (which allows nerve impulses to conduct), and when this vitamin is deficient, it has been suspected to drive symptoms such as dementia, multiple sclerosis, impaired gait, and sensation. Clinically, B12 may be best known for its role in red blood cell production. Deficiency states may result in pernicious anemia. But what about B12’s role in psychiatric symptoms such as depression, anxiety, fatigue, and even psychosis?- Methylation: This process of marking genes for expression, like little “read me!” signs, is also critical for detox and elimination of chemicals and hormones (estrogen), building and metabolizing neurotransmitters, and producing energy and cell membranes.
- Homocysteine recycling: B12 is a primary player in the one-carbon cycle and a co-factor for the methylation, by activated folate, of homocysteine, to recycle it back to methionine. From there, S-adenosyl-L-methionine (SAMe) is produced, the body’s busiest methyl donor.
- Genetic override: A sufficient supply of an activated/bioavailable form of a vitamin (i.e., methylfolate versus 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 this is a report of death in a B12-deficient patient with genetic variants who underwent anesthesia with nitrous (which causes stress to the system). Notably, the B12 blood level was normal, so this fatal case was attributed to functional deficiency, suggesting that access to B vitamins may not always guarantee proper utilization. For this reason, supplementing with activated forms of B vitamins enhances their likelihood of effectively supporting cellular processes.
How Do We Test?
In functional medicine, there are few empirical treatments, meaning treatments that apply to everyone, but I believe B12 to be one of them, particularly in light of the fact that up to 15 percent of the population are deficient. Testing is available, and most data on deficiency has relied on blood levels, with deficiency defined as being below 150 to 200 pg/ml. It turns out that testing for deficiency by blood level is not always a reliable indicator of what is going on in the brain, or functionally, in the body.- Homocysteine: May be elevated in the setting of either B12 or folate insufficiency or dysfunction (often related to genetic variants).
- Methylmalonic acid (urine or serum): This value is more specific for B12 deficiency but potentially insufficiently sensitive.
What Causes Deficiency?
Once it is established that a patient has overt serologic evidence of deficiency (in the blood) and/or they respond to treatment, we must ask how they became deficient in the first place. Here are some considerations:1. Achlorhydria
This is the fancy term for low stomach acid, something that sometimes occurs in the setting of low thyroid function, chronic stress, aging, and most salient to a December 2013 paper—acid-blocking medications.Here’s a common scenario.
A patient is eating foods that they are unable to properly digest and that promote local inflammation, further perpetuating poor digestion and transit. These may include processed dairy, foods fried in vegetable oils, and cereal grains. The patient experiences the reflux of this poorly mobile, poorly digested sludge, or chyme, as a sign that they have high stomach acid.
They are put on a medication (or buy one over the counter) that has never been studied for long-term use, and that population-based observational studies link to pathogenic overgrowth of bacteria, fractures, and nutrient deficiency. Why? Because stomach acid is critical for triggering digestive enzymes along with an escort called “intrinsic factor” for B12 absorption and managing local microbial populations.
If this patient’s B12 deficiency and digestive imbalance go unattended, the patient will likely develop symptoms that will earn them a prescription for an antidepressant, and the medications start to pile up.
2. Dietary Restrictions
Animal foods are primary sources of B12, although algae and fermented foods may represent promising options for some diligent individuals. Stores deplete over time, and deficiency-related symptoms may present long after dietary restriction. Carefully sourced animal foods are also a unique source of pre-formed fat-soluble vitamins, creatine, choline, and carnitine.3. Autoimmunity
One of the possible mechanisms of deficient B12 absorption is pernicious anemia, an autoimmune response to parietal cells, associated with atrophic body gastritis in the stomach. H. pylori infection and associated molecular mimicry are thought to represent a plausible trigger.4. GMOs/Gluten
The powerful synergy of gluten-containing and genetically modified processed foods may have an impact on everyone’s guts, not just those people with biopsy-confirmed celiac disease. In fact, the biopsy is fast losing position as the gold standard diagnosis because of extraintestinal manifestations of gluten immune response that don’t cause observable changes to the small intestinal villi (joint pain, rash, or gait instability without obvious gut symptoms). In these individuals, the innate immune system responds to gluten in these grains, and food fragments may pass into the bloodstream through zonulin-gated tight junctions. Direct damage to the cells in the small intestine may result from whole-grain foods with high amounts of inflammatory lectin.5. Medications
Notably, metformin, the blood sugar-regulating medication, has been demonstrated to be a risk factor for deficiency, a fact that few patients are informed of before complying with their prescribed treatment.