Vitamin B12 in the cerebrospinal fluid (CSF) helps to metabolize homocysteine. A low B12 level in the CSF is likely the contributing factor for the increase in homocysteine. The potential problem with elevated homocysteine in the CSF is that it can cause deterioration of the mylin sheath that covers the nerve fibers. When this mylin sheath is damaged a person may experience symptoms similar to multiple sclerosis (MS). This may be why some people with fibromyalgia are sometimes initially tested for MS.
The above information is provided to help support the supposition that the person with fibromyalgia may be low in vitamin B12. It may be this deficiency in vitamin B12 that has contributed to the low RBC count.
Vitamin B12
As you can see on the bottom chart, the bodies daily need for vitamin
B12 is very small, less than 1 microgram (mcg). The recommended
dietary allowance for B12 is only 2.4 mcg. The liver can store
enough B12 to supply the bodies needs of this vitamin for 3 to 6 years.
It is possible that a person could develop problems with vitamin B12
absorption and not notice symptoms of the problem for 3 years while the
body uses B12 stores from the liver.
The typical dosage of over the counter B12 supplements range from 1,000 mcg to 3,000 mcg. If the body were able to absorb all the B12 from a single supplement tablet, that would represent about a three year supply of B12. Since the daily need is so small in comparison to the amount delivered by supplements, I suspect that the body is not absorbing any of the B12 in these tablet or capsule forms.
Many people with fibromyalgia have B12 injections either into the muscle or directly into the vein. Depending on the amount of B12 and the persons individual needs for the vitamin, most people with fibromyalgia will see short term benefit to receiving the vitamin in this manner.
A couple other points of interest here is that the Japanese seem to have followed the available research on vitamin B12, and recognized that the current recommended blood serum range for this vitamin may be too low. The Japanese have established recommended serum B12 levels higher than the accepted "normal" range for the vitamin in the United States.
Where does the body get B12? It is primarily found in meats as part of our diet. As noted previously, the body has a 3 to 6 year store of B12 in the liver. This B12 is also recycled in our body. B12 in bile is reabsorbed in the small intestine. More on this later.