A broad statement cannot be made about the oral vitamin b12 being beneficial for everyone. I am missing the portion of my stomach that manufactures intrinsic factor, so I could take b12 rich food or oral b12 till the cows come home and still be deficient. There are also those who don't absorb it for other reasons. I was told by my gastric surgeon beforehand that I would have to take b12 sublingually or by injection for the rest of my life. Unfortunately methylcobalamin, the more bioavailable form is not always available to me where I live.
Oral b12 may help some but not all. We are not clones and all have individual systems that react differently to different factors.
I intend to ask my gastro to check my levels this week and also ask for injectable b12 to see if that makes a difference in my symptoms.