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Vitamin B12
Vitamin B12 is an
essential nutrient that plays a major role in neurologic and
mental functioning as well as in the production of folic acid.
Folic acid plays a major role in reducing homocysteine levels and in
cell repair (specifically DNA synthesis).
B12 is released
from animal food sources by the action of Intrinsic Factor in the
stomach and then it is absorbed from the last part of the intestines.
Because
the stomach and intestines play a major role in absorption of B12, any
disease of either of these organs can cause malabsorption of Vitamin
B12. Patients who are on chronic acid suppressants (for example,
Prilosec) owing to ulcers cannot synthesize Intrinsic Factor.
Patients who have Crohn's disease, inflammatory bowel disease or celiac
disease also have difficulties absorbing Vitamin B12.
Vitamin
B12 is found primarily in animal food sources. Vegetarians, and vegans
especially, do not ingest any food sources containing B12. The
only exception is that blue-green algae is a source of B12.
The best sources of B12 include liver, clams, oysters, sardines, and egg yolks.
Symptoms or B12 deficiency include migraine headaches, numbness,
tingling, depression and other mood disorders. In addition,
B12 deficiency can present as anemia multiple sclerosis,
infertility, fatigue, psychosis, and dizziness.
Although
most physicians use serum B12 levels as the indicator for deficiency,
it is actually an inaccurate test. Having circulating B12 in
serum does not mean that it is utilized by the body's cells and the
current standard is set too low. A normal serum B12 level should
be at least 450pg, but may need to be higher depending upon your
genetic makeup. A much better test for B12 adequacy is
measuring methyl malonyl CoA levels in the urine.
Vitamin
B12 supplementation comes in several forms: cyanocobalamin,
hydroxocobalamin and methylcobalamin. B12 supplements do not
require Intrinsic Factor for absorption. Methylcobalamin is the
only active form, and all other forms need to be converted to the
methylated version for it to fully function.
It is my
opinion that anyone who is chronically ill should only use the
methylcobalamin form. It requires energy to absorb and transform
the non-methylated B12 and patients who are ill do not have the energy
to do this. In addition, for those patients with absorption
issues, oral vitamin B12 is ineffective and other routes of
administration ( intramuscular injections and intravenous infusions)
are far superior. Sublingual (under the tongue) administration in
high enough doses will overcome the absorption difficulty as it is
absorbed through the oral mucosa.
It should be noted that
there has never been a report of adverse side effects from vitamin B12,
nor has there been any toxicity associated from an overdosage.
Excess B12 is stored in the liver.
For chronically
ill patients, I recommend a minimum of 5000 mcg (5 mg) of sublingual
B12 daily. To maintain good health, and for all vegetarians and
vegans doses of 500 mcg to 1000 mcg should suffice.
Recommended Vitamin B12 supplements:
Pathway Methylcobalamin 5000 mcg. sublingual tablets Available through myvillagegreen.com
Village Green Pharmacy 800-869-9159
Perque sublingual B12 - uses hydroxocobalamin
available at Summit Spinal Care 741-9355 and at South River Compounding Pharmacy 897-6447
References
Spiritual Nutrition by Gabriel Cousins M.D. pages 275-287
Weston Price article about vitamin B12 - very comprehensive
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