B-12 info

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Symptoms of Overt B12 Deficiency

Ways to Get B12 Deficiency

The two main ways people get vitamin B12 deficiency are inadequate dietary intake and inadequate absorption from loss of intrinsic factor or lack of stomach acid. Other, much less common ways are listed in Appendix: Ways to Get B12 Deficiency.

Elevated Homocysteine: No Symptoms

Please note that the symptoms listed below are found in overt vitamin B12 deficiency. You can be B12 deficient, increasing your risk of disease because of elevated homocysteine without suffering any noticeable symptoms.

Early, Noticeable Symptoms of Overt B12 Deficiency:1

unusual fatigue faulty digestion no appetite nausea loss of menstruation

Other symptoms of Overt B12 Deficiency:

numbness and tingling of the hands and feet1 nervousness1 diarrhea2 mild depression1 striking behavioral changes1 paranoia1 hyperactive reflexes1 fever3 frequent upper respiratory infections4 impotence5 impaired memory5 infertility6 sore tongue2 enlargement of the mucous membranes of the mouth, vagina, and stomach117 macrocytic anemia low platelet count3,7 and increased bleeding3 neutropenia3

Neurological Symptoms

Neurological symptoms, often referred to as subacute combined degeneration (SCD), are the biggest concern regarding B12 deficiency. The damage can be irreversible if not caught early enough. SCD affects peripheral nerves and the spinal cord, and is normally different in children than adults.8 .

Theories of How B12 Deficiency Causes Nerve Damage

There are 3 main theories as to how B12 deficiency causes nerve damage:

1. B12 deficiency produces a lack of methionine for conversion into S-adenosylmethionine (SAM).9 SAM is required for the production of phosphatidylcholine10 which is part of the myelin (the fatty material that insulates many nerves).10 (See Figure: Methionine-Homocysteine-Folate-B12 Cycle.)

2. The inability to convert methylmalonyl-CoA (a 3-carbon molecule) to succinyl-CoA (a 4-carbon molecule) results in an accumulation of propionyl-CoA (a 3-carbon molecule). Fatty acids are normally made by adding 2 carbons at a time to an even numbered carbon molecule. In an overabundance of 3 carbon molecules, large amounts of unusual 15-carbon and 17-carbon fatty acids may be produced and incorporated into nerve sheets, causing altered nerve function.11

3. Nerves are damaged by different hormone-like molecules (cytokines, tumor necrosis factor, and epidermal growth factor) which become unbalanced in the nerve tissue in B12 deficiency.8