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Accurate Detection of a B12 Deficiency

gracee41

Senior Member
Messages
115
I've posted before about my serum B12 levels being over 2000 without supplementing. I was told that could mean a functional deficiency. I've also read that in several places. I've had two homocysteine tests and a methylmalonic acid test. They were both negative for a B12 deficiency. I've also had a CBC done twice and my MCV was normal.

I know a high level of B12 can mean you have a lot circulating in your blood but not in your cells. Is it possible those tests might miss a deficiency since there is a lot of circulating B12? It was my,understanding a true deficiency would be detected with a homocysteine test or a MMA test for sure because of the sensitivity level.

I just found out I have a severe B6 deficiency. I know many times people have both B6 and B12 deficiency.
 

PeterPositive

Senior Member
Messages
1,426
If homocysteine and MMA are fine it's unlikely a deficiency. At least not a critical one, you may still have some benefits from taking B12 but it's unlikely it will be a game changer.

2000 without supplementing at all? Or without supplementing recently? The former it could indicate liver issues.

Peter
 

gracee41

Senior Member
Messages
115
If homocysteine and MMA are fine it's unlikely a deficiency. At least not a critical one, you may still have some benefits from taking B12 but it's unlikely it will be a game changer.

2000 without supplementing at all? Or without supplementing recently? The former it could indicate liver issues.

Peter
My B12 level was normal 2 yrs ago. Several months ago, I took methyl B12 for for a while because I had many symptoms of a B12 deficiency. I started feeling much better but then developed some thyroid issues and felt too sick to take much of anything. Surely if the supplementation months ago caused the high levels, they would have dropped some by now. I do have MTHFR and also have the FUT2 mutation with an AG genotype. Livewello says people with this mutation and genotype are likely to have increased B12 levels. Although, nothing is said about the consequences of the high B12.. I don't seem to have any symptoms of a deficiency now. Although, the low B6 has shown some symptoms.
 

Hip

Senior Member
Messages
17,795
It is a hard concept for many to understand, but supplementing vitamins at levels well over daily requirements can provide pharmacodynamic effects that are nothing to do with the normal functioning of that vitamin.

For example, vitamin B12 in the hydroxocobalamin form is a nitric oxide scavenger, so taking megadoses of hydroxocobalamin is going to have an affect on nitric oxide that you will not get if you are just taking relatively small doses of B12 just to meet your daily vitamin requirements.
 

PeterPositive

Senior Member
Messages
1,426
My B12 level was normal 2 yrs ago. Several months ago, I took methyl B12 for for a while because I had many symptoms of a B12 deficiency. I started feeling much better but then developed some thyroid issues and felt too sick to take much of anything. Surely if the supplementation months ago caused the high levels, they would have dropped some by now. I do have MTHFR and also have the FUT2 mutation with an AG genotype. Livewello says people with this mutation and genotype are likely to have increased B12 levels. Although, nothing is said about the consequences of the high B12.. I don't seem to have any symptoms of a deficiency now. Although, the low B6 has shown some symptoms.
What was the dosage of B12 you were taking and how much time passed between stopping the B12 and doing the blood test?

p.s. = I too have homozygous MTHFR and FUT2 (see signature) but I have never seen significant or suspicious elevation of B12 levels.