44 y/o male with mcv of 71 for 10 years with low iron even with supplements. h&h is normal (14.5). no overt gi bleed. possible causes?

Iron deficiency: Have you gone to see a hematologist? If not, you should consider.How low is your ferritin, ? There are other things that can cause low mcv. If ferritin is low-you need to complete GI work-up i.e. Colonoscopy and egd to completely rule out bleeding. In addition to bleeding, iron malabsorption can cause low iron.. If your stomach can't absorb the iron tablet- intravenous iron could be an option.