Anemia and the GI Tract

Anemia is a condition in which the body does not have enough healthy red blood cells. Red blood cells are essential, as they carry oxygen to body tissues. Patients with mild anemia may have no symptoms, but when they do, the first symptoms often include:

  • Feeling weak or tired more often than usual, or with exercise
  • Headaches
  • Problems concentrating or thinking

If a patient has underlying cardiovascular disease, symptoms can include worsening or recurrence of their vascular symptoms, such as:

  • Chest pain for heart disease
  • Leg pain and weakness for peripheral vascular disease
  • Stroke symptoms for patients with prior stroke or transient ischemic attack (TIA)

If anemia is more severe, symptoms depend on whether the anemia has been slow to develop, or happens abruptly. These symptoms may include:

  • Lightheadedness upon standing up
  • Pale skin color
  • Shortness of breath with mild activity or even at rest
  • Worsening cardiovascular symptoms
  • Sore tongue
  • Blue color to the whites of the eyes
  • Brittle nails
  • Desire to eat ice or other non-food things

There are many types of anemia, and some of them involve conditions related to the digestive system.

Iron Deficiency Anemia
Iron deficiency anemia is the most common form of anemia. It occurs when the body does not have enough iron. Iron helps make red blood cells, so if there isn't enough iron, the body can't make enough red blood cells.

Normally, the body absorbs iron from food and also reuses iron from old red blood cells. Iron deficiency anemia develops when the body's iron stores run low. Causes of iron deficiency can include:

  • Iron deficient diet: There aren't enough foods containing iron in the diet. Foods that naturally contain iron include meat (red meat has the most, followed by pork, chicken, and fish or seafood), leafy green vegetables like spinach, dried raisins and apricots, iron-fortified breads and cereals, and others. Strict vegetarians may not get enough iron in their diet, and many older adults who eat a limited diet don't get enough iron.
  • Poor iron absorption: The body does not do a good job of absorbing iron. This can be caused by dysfunction of the stomach, which is needed to liberate dietary iron, the small intestine, which is needed to absorb the iron, or by surgical changes. Some conditions that can cause iron deficiency include celiac disease and Crohn's disease, gastric bypass surgery, and taking too many antacids that contain calcium.
  • Bleeding: When a person bleeds, they lose red blood cells and the iron in them, causing the red blood cell count to drop as fast as the person is bleeding. Bleeding can occur for many reasons, and involve many different organ systems. For example, patients can have nosebleeds, cough up blood, lose small or large amounts of blood in the urine, lose blood from trauma or surgery, and lose blood during menstruation. The digestive tract can also be the source of bleeding. This can be caused by cancer in the esophagus, stomach, small intestine, or colon; aberrant blood vessels known as arterio-venous malformations (AVMs) or angioectasias; varices (abnormally enlarged blood vessels) in the esophagus, stomach, duodenum, or rectum, often caused by cirrhosis; peptic ulcer disease; and medication-related bleeding.
  • High iron needs: The body needs more iron than normal -- for example, women who are pregnant or breastfeeding.

Vitamin B12 Deficiency Anemia
Vitamin B12 deficiency anemia is a low red blood cell count due to a lack of vitamin B12. The body needs vitamin B12 to make red blood cells, just like it needs iron. In addition to the symptoms common to all types of anemia, vitamin B12 deficiency anemia can cause other symptoms, such as:

  • Diarrhea or constipation
  • Loss of appetite
  • Swollen, red tongue or bleeding gums
  • Nerve damage that can lead to numbness and tingling of hands and feet, loss of balance, confusion or change in mental status, or depression

In order to provide vitamin B12 to the body's cells, a person must eat plenty of foods containing vitamin B12, such as meat, poultry, shellfish, eggs, and dairy products. A poorly planned vegetarian diet may not provide enough vitamin B12.

In addition to eating foods that contain vitamin B12, the body must be able to effectively absorb vitamin B12. A special protein released by cells in the stomach, called intrinsic factor, helps the body do this. Certain health conditions interfere with this process and can make it difficult for the body to absorb enough vitamin B12, including:

  • Chronic alcoholism
  • Crohn's disease and celiac disease
  • Pernicious anemia, which is a type of vitamin B12 deficiency anemia that occurs when the body destroys the stomach cells that make intrinsic factor
  • Autoimmune gastritis, which leads to the same changes causing pernicious anemia
  • Surgery that removes certain parts of the stomach or small intestine
  • Taking antacids and other heartburn medicines for a long period of time

Anemia of Chronic Disease (ACD)
Anemia of chronic disease, or ACD, is anemia that is found in people with certain long-term, or chronic, medical conditions that often involve inflammation. Some gastrointestinal conditions that can lead to ACD include:

  • Crohn's disease and ulcerative colitis
  • Long-term infections, such as hepatitis B and hepatitis C