Background
Ever gotten your B12 levels tested, everything looks fine, but still deal with B12-deficiency symptoms like fatigue, brain fog, or that annoying tingling in your hands and feet? There's a reason for that disconnect, and it has to do with what's happening inside the cell versus what shows up on a standard serum B12 blood test.
This week, I'm diving into the MMUT gene and methylmalonic acid (MMA) testing. Your MMUT gene codes for an enzyme that needs vitamin B12 to work properly in your mitochondria. When you have certain variants in this gene, your cells might not be using B12 effectively – even when your serum levels look great. The result? All those frustrating symptoms that doctors dismiss because "your labs are fine."
Testing MMA (methylmalonic acid) can show what's really going on, and a specific form of B12 (adenosylcobalamin) targets this exact pathway. Plus, if you're a member, you can check your MMUT variants in your genetic data right now. And you can learn why carnitine may be part of the solution.
Key Takeaways
- Your serum B12 levels can be normal while you’re still deficient at the cellular level. MMA (methylmalonic acid) testing can show intracellular B12 status.
- The MMUT gene codes for an enzyme that requires vitamin B12 to convert methylmalonic acid into energy in your mitochondria.
- Adenosylcobalamin is the specific form of B12 that works with the MMUT enzyme.
- Elevated MMA can cause fatigue, brain fog, depression, numbness, and a sore, red tongue.