by sweetfruitlover » Sun Oct 16, 2011 4:34 pm
I had (have) celiac disease, and after two years of being mostly vegan I checked my B12 and it was below the lowest detectable level. I think this was too soon to deplete myself of B12 if my body had been able to properly absorb it during my non-vegan years, and celiacs are known for having difficulty absorbing B12 and other nutrients.
So I supplemented this past year. Sublingual supplements don't rely on the body absorbing it in the digestive system, and instead are absorbed under the tongue. But you only absorb a very small fraction of the amount, and that's why you will see typical doses of 1000 ug when you only need a few ug per day. When I checked my blood level again this summer it was at the top of the normal range - yippee!
I think that best thing to do is to check your own levels, and make sure they are high enough. If you need to supplement with B12, this isn't a general multivitamin, just a specific one for if you test low. You can try eating nutritional yeast and if you absorb it, then great. But you won't know unless you get tested. The next time you have your blood drawn for something, just ask you doctor to test for that too.