<unk>  is a decrease in red blood cells that occurs when the body cannot properly absorb vitamin B12 from the gastrointestinal tract. Vitamin B12 is necessary for the proper development of red blood cells.<unk>  is a type of megaloblastic<unk> .
Pernicious anemia
Hemochromatosis
Zinc deficiency
Iron deficiency anemia
Hookworm infection
Chronic colestites
Taenia infection
Vacinko syndrome