I'm a 28 year old very healthy guy. I have never had any medical issues outside of injury. I got a blood test 5 years ago and discovered that I have basically no B12 in my blood, and in all likelihood, never have. Further testing confirmed this result and revealed that I consume plenty of it, but my stomach cannot digest it. Since then I have been taking sublingual B12. I have never felt a negative effect of this, nor have I felt a difference between when I am taking it and when I am not.

I have a very knowledgable doctor who knows all the typical things to test for. I don't have celiacs or any other common condition a doctor would suspect. My doctor has done a lot of research and can't make sense of what the problem is, outside of some weird medical fluke. What's also weird is that I don't seem to suffer from the absence of B12.

It is scary to think that maybe I am effected by it but just don't know it yet. I am thinking of switching to injections to see if I feel a difference. Am I right to be freaked out by this? My doctor has certainly scared me into keeping up with my supplements (usually). Does anyone have an idea of what could be wrong with me?