After struggling with Celiac's for 16 years and being diagnosed with EVERYTHING UNDER THE SUN (including hypochondria) but having Celiac's suggested by a pharmacist (!), I'm tired of trying to educate doctors. I do my own best research, and if they say something stupid that I know to be untrue, I go out the door. To be fair, I think doctors in general do not expect patients to do the right thing. They're all, "here, take this statin since you will never change your diet and maybe you will live slightly longer and I won't have to feel guilty about doing nothing". When you have a patient changing his life... maybe they find this hard to believe or to trust.
I vote you find another doctor.