What could be a reason for high levels of B12 and low levels of methylmalonic acid acid?

Dr Lynch states that high B12 levels may be due to:
- methyl trapping
- supplementing with a lot of B12
- microbiome producing cobalamins but they are inactive
- low glutathione
- low methylfolate
- low zinc
- MTR inhibition for various reasons (see StrateGene Pathways)

He also says that low MMA can be a good sign, because that means that adenosylcobalamin is present.

Adding more B12 isn't the solution, you will need to work with your healthcare professional about addressing the possible reasons above.