Alcoholism is a common cause of macrocytic anemia. Even before anemia develops, some alcoholic patients can have macrocytic cells. These are due to vacuole formation in the cytoplasm of the developing erythrocytes, leaving behind larger than normal red blood cells.
In fact, together with blood alcohol levels and liver function tests, an elevated MCV is considered a biomarker for alcohol abuse. Of all the biomarkers for alcoholism, elevated MCV often takes the longest to show up, but together with the other biomarkers, makes a pretty strong case for chronic high levels of alcohol.
It should be noted that alcoholism can sometimes also cause megaloblastic macrocytic anemia, mainly due to concomitant nutritional deficiencies or liver disease associated with high alcohol intake.
