Alcoholism is the second most common cause of macrocytosis due to damage to the liver, which reduces the body's ability to absorb vitamin B12 and folate. Cholesterol deposits in blood cell membranes and chronic malnutrition that are associated with the alcoholism also worsen the likelihood of severe vitamin B12 and folate deficiency. Due to the strong correlation between macrocytosis and alcoholism, its appearance can be a warning indicator or a way of testing for chronic alcoholism in otherwise healthy-looking adults.
The liver has the ability to store high levels of B12 and folate, so a severe enough deficiency to cause macrocytosis usually takes four or five years of chronic alcoholism. The inability of the body to absorb these nutrients due to chronic alcohol intake is amplified if a patient takes certain prescription medications that affect the liver or suffers from existing conditions such as celiac or Crohn's disease, which further impair vitamin intake.
In cases of alcohol use, macrocytosis can present with hormone imbalances, especially in men; jaundice, and caput medusae, which are enlarged veins across the abdomen. Macrocytosis can also appear in patients with a normal liver biopsy, and abstinence from alcohol can quickly lead to a reversal of its effects. Anemia is commonly associated with liver disease caused by alcoholism; however, there is no correlation between anemia and macrocytosis.