Here are some great articles available online:
AAFP on Vitamin B12 Deficiency
ORAL SUPPLEMENTATION WORKS FOR MOST (AFP article)
eMedicine link on vitamin B12 associated neurological diseases:
eMedicine on Nutritional Neuropathy
Emedicine on Pernicious Anemia
I also have a great article, not available online, but I could email to you if interested:
Laboratory Diagnosis of Vitamin B12 and Folate Deficiency
A Guide for the Primary Care Physician
Christopher F. Snow, MD
Any of these would be good to hand off to your doctor, but the Snow article is probably the best. It discusses the significance of low normal B12 level.
Lab lows are typically set around 150-200 depending upon the lab, but anything under 400 should be considered suspicious, especially when accompanied by neurologic symptoms.
It took me eight specialists and 3 years before a doctor thought to test me for B12 deficiency, but luckily the one who did realized that 294, although still in low NORMAL range... was too low.
You should actually be taking 1000mcg daily, which is 16,666% of RDA. I know it sounds hefty
, but it is standard treatment for B12 deficiency.
I suspect your symptoms could all very well be related to the low B12... your level is lower than my level was... and I had a a very long laundry list of symptoms by the end... that all resolved over time with B12 supplements.
If you didn't improve in three months time, it wouldn't hurt to continue looking for other causes. Many things can cause neurologic symptoms, and often times several conditions can co-exist.
Your doctor, if s/he understood that your low B12 was in fact a problem, should start by considering what may be causing your low B12.
The most common cause is pernicious anemia, an autoimmune disease that causes a lack of intrinsic factor needed to process B12. There are antibody tests than can be run. (anti-parietal, anti-intrinsic factor)
Celiac disease, another autoimmune disease triggered by dietary gluten (wheat, barley, rye) can cause B12 and other nutritional deficiency, due to malabsorption. You can have gluten sensitivity without testing positive for celiac disease, something often not understood by our doctors. There are antibody tests that can be run (anti-tTG (shows celiac disease), antigliadin Iga,IgG (shows gluten sensitivity), total Iga (rules out IgA deficiency, a condition which can false negavive results on the other tests)
Over use of antacids or a strict vegetarian diet can cause B12 deficiency.
Achlorhydria, low stomach acid can cause B12 deficiency.
Tapeworms can cause B12 deficiency, and believe it or not, I've met two people via the Internet who had B12 deficiency caused by tapeworm!
Exposure to nitrous oxide can cause B12 deficiency.
And... there are yet other causes.
If your doctor is willing to keep looking, s/he might want to start by ruling out these things. Sometimes a B12 deficiency may be related to a temporary problem, like in the case of a tapeworm, but more often that not it is with you for life. Don't let any doctor tell you that you can stop with the supplements once your level comes up. Do you have any family history of autoimmune disease? That would make pernicious anemia or celiac disease more likely possibilities.
An elevation of methylmalonic acid or homocystein levels can indicate B12 deficiency despite normal B12 levels, but these can normalize quickly. If you've already been supplementing, I'm not sure these tests would be that useful anymore.
Also, I have some sources I can share on diagnosis and dosage:
Quote:
From: Laboratory Diagnosis of Vitamin B12 and Folate Deficiency
A Guide for the Primary Care Physician
Christopher F. Snow, MD
"As discussed above, patients with Cbl deficiency may have overt neurologic disease in the absence of hematologic findings. Patients with neurologic symptoms and signs and a normal complete blood cell count
require a modified diagnostic approach because of several considerations.
First, folate deficiency is an unlikely cause of neurologic disease. Second, the neurologic disease of Cbl deficiency may be irreversible if treatment is withheld or delayed; because Cbl therapy is non-toxic, the risk-benefit ratio favors treatment in questionable cases. "
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Quote:
From: AAFP on Vitamin B12 Deficiency
"Diagnosis of vitamin B12 deficiency is typically based on measurement of serum vitamin B12 levels; however, about 50 percent of patients with subclinical disease have normal B12 levels."
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Quote:
Vitamin B12 Deficiency
ROBERT C. OH, CPT, MC, USA, U.S. Army Health Clinic, Darmstadt, Germany
DAVID L. BROWN, MAJ, MC, USA,Madigan Army Medical Center, Fort Lewis,Washington
"Contrary to prevailing medical practice, studies show that supplementation with oral vitamin B12 is a safe and effective treatment for the B12 deficiency state. Even when intrinsic factor is not present to aid in the absorption of vitamin B12 (pernicious anemia) or in other diseases that affect the usual absorption sites in the terminal ileum, oral therapy remains effective.
"Although the daily requirement of vitamin B12 is approximately 2 mcg, the initial oral replacement dosage consists of a single daily dose of 1,000 to 2,000 mcg (Table 4). This high dose is required because of the variable absorption of oral vitamin B12 in doses of 500 mcg or less.19 This regimen has been shown to be safe, costeffective, and well tolerated by patients."
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Quote:
Regarding oral B12:
Goldman: Cecil medical textbook --- Saunders 2000
COBALAMIN DEFICIENCY.
"One option is intramuscular or subcutaneous administration of cyanocobalamin. . . . Oral cobalamin therapy in a dose of 1000 to 2000 mug/day has recently been shown to be as effective and possibly superior to the standard parenteral regimen. Both regimens give prompt and equivalent hematologic and neurologic responses, but post-treatment serum cobalamin levels are significantly higher and post-treatment methylmalonic acid levels are significantly lower with the oral regimen. Oral cobalamin, 1000 to 2000 mug [mcg]/day, is the treatment of choice for most patients."
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Hope this helps! It is important you understand all this, even if your doctor doesn't! B12 deficiency is nothing to mess with or take lightly!
Cara