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Vitamin B12 (A VERY LONG THREAD)
Conventional method of testing for B12 deficiency is to test levels in the blood.
The range is quite large: 160 to 950 pg/mL (Canada) and this test is used fairly definitely, but it lacks specificity and misses most deficiencies...
Conventional method of testing for B12 deficiency is to test levels in the blood.
The range is quite large: 160 to 950 pg/mL (Canada) and this test is used fairly definitely, but it lacks specificity and misses most deficiencies...
as only late state deficiencies may be captured. When someone does show up as deficient, they have been for a long time and significant damage has already taken place. This damage is also possible without even showing a deficiency.
Sometimes, MCV is used – and if it is high, this often means low B12, but normal MCV does not mean that B12 levels are normal, thus, the test is not highly specific.
You can have B12 deficiency anemia, where red blood cells are affected. Or, can have deficiency w/o anemia (deficient, but not affecting production of red blood cells enough for it show up on test). Anemia is final stage of deficiency – yet this is often what doctors look for.
Things get even more complex when someone can be deficient/ill where it actually causes an increase in their serum B12 test.
This commonly occurs with anorexia nervosa patients, or those who are highly malnourished, or have liver dysfunction. In this population, serum B12 may be fine (but they are actually deficient) because serum levels do not accurately represent intracellular levels...
https://ods.od.nih.gov/factsheets/VitaminB12-HealthProfessional/, may be low (deficiency easy to catch, but this often doesn’t happen), may be low but have a secondary condition that elevates their B12 (artificially elevates it – meaning they are still deficient)...
so it still looks normal in bloodwork as it is still within the range, or, they have a secondary condition causing deficiency but their B12 is very elevated. This can be due to liver damage as a result of long-term malnutrition: https://www.ncbi.nlm.nih.gov/pubmed/25446249 .
Additional causes for Hypercobalaminemia (elevated B12), despite deficiency: https://academic.oup.com/qjmed/article/106/6/505/1538806
Great references for why B12 deficiency is underdiagnosed and why it is so severe:
“the low end of the laboratory reference range is too low.”
https://chriskresser.com/b12-deficiency-a-silent-epidemic-with-serious-consequences/ https://chriskresser.com/why-b12-deficiency-is-significantly-underdiagnosed/
“the low end of the laboratory reference range is too low.”
https://chriskresser.com/b12-deficiency-a-silent-epidemic-with-serious-consequences/ https://chriskresser.com/why-b12-deficiency-is-significantly-underdiagnosed/
This is why when I see anyone in the lower end of the range, I recommend supplementation. I also use my clinical judgment and evaluate their dietary intake, health condition/age and medications that can cause deficiencies.
This is also why I believe the best clinicians use a combination of critical thinking, quality research evidence, and clinical practice. Many clinicians have not noticed how odd it is that the geriatric population – highly deficient, most often show up as having normal serum B12
The elderly population is most susceptible to deficiency due atrophic gastritis (common) + decrease in intrinsic factor necessary for B12 absorption, medications, decreased absorption in the ileum, and decreased food intake.
However, it is a widespread deficiency and many other populations are at risk including: vegans/vegetarians, pregnant women, those with leaky gut (very common, undiagnosed condition), those with alcohol use issues and pernicious anemia.
B12 is ONLY found in animal foods. It is wrongly thought that seaweed/nutritional yeast is a source as it contains B12 analogues that actually decrease levels of B12 in the body.
Most medications will decrease levels of B vitamins because B vitamins are cofactors and are thus necessary for the metabolization of the medications. However, these medications specifically decrease B12 status: Metformin, PPIs, anti-seizure medications.
Individuals with diabetes, who are already at risk for peripheral neuropathy due to damage from high blood sugar levels, are at increased risk because Metformin depletes B12 – which is necessary for healthy nerves, and as such, further increases risk of peripheral neuropathy.
Serum B12 deficiency is still a useful and simple test of detecting deficiency, but it only detects stage 3-4 (late stage deficiency).
A more sensitive marker of deficiency: Methymalonic acid can detect earlier stage of deficiency. This is critical, as B12 deficiency can produce irreversible neurological damage.
The RDA has been set based on the amount necessary to maintain adequate serum levels, however, serum levels are not a good indicator of adequate B12 status.
Please note that higher folic acid intake due to supplements or widespread fortification of wheat (mandatory in US and Canada), masks B12 deficiency detection. Furthermore, high folic acid status in the presence of B12 deficiency exacerbates anemia and cognitive impairment.
The longer the B12 deficiency goes underdiagnosed, the greater the brain and nervous system undergoes progressive deterioration.
B12 has very important functions for the following. It converts homocysteine to methionine, and is implicated in fatty acid metabolism:
-Brain function (production of myelin sheath in the brain)...
-Brain function (production of myelin sheath in the brain)...
-Mental health (necessary for production of serotonin) and prevention of memory loss and brain atrophy
-Nerve tissue health
-Immune system
-Prevention of brain and spinal cord defects in pregnancy
-Prevention of macular degeneration
-Energy levels
-Nerve tissue health
-Immune system
-Prevention of brain and spinal cord defects in pregnancy
-Prevention of macular degeneration
-Energy levels
-Cardiovascular health by reducing level of homocysteine
-Support healthy hair skin nails
-Support healthy hair skin nails
All B vitamins are also depleted during times of stress, which is why I take a whole foods b complex supplement daily.
You can also take a regular supplement - but quality is critical. Most brands use inactive forms of b vitamins which can actually be detrimental. But supplementing with just B12 is more straight forward, just look for: Methylcobalamin.
If taking B vitamins or B12 causes anxiety, this is due to increased neurotransmitter production in the brain - take less, or get from food. In this case you can also take a well-balanced complex as they work together, instead of just taking B12. https://www.mindbodygreen.com/0-11727/are-vitamins-triggering-your-anxiety.html
