Anemia is a condition common to those with Inflammatory Bowel Disease where there is not enough hemoglobin or healthy red blood cells in the blood. Hemoglobin carries iron and is used in red blood cells to carry oxygen to all the cells of the body, and carry carbon dioxide back to the lungs to be expelled.


The Department of Health and Human services classifies the severity of anemia based upon hemoglobin levels in the blood. The five levels are:
  • Level 1 - Mild
    Lower Limit of Normal (LLN) - 10.0 g/dL
    LLN - 6.2 mmol/L
    LLN - 100 g/L
  • Level 2 - Moderate
    10.0 - 8.0 g/dL
    6.2 - 4.9 mmol/L
    100 - 80g/L
  • Level 3 - Severe - Blood transfusion indicated
    Less than 8.0 g/dL
    Less than 4.9 mmol/L
    Less than 80 g/Ld
  • Level 4 - Life threatening consequences, urgent intervention required
  • Level 5 - Death


Fatigue, chest pain, dizziness, shortness of breath, feeling cold, sore/swollen tongue, headaches, problems concentrating, rapid heart beat, black circles around the eyes, pale skin, cold hands or feet, irritability.

Categories of Anemia

- Hypoproliferative anemias - there is an inability to produce an adequate number of red blood cells.
- Hyperproliferative anemias, the bone marrow is consistently producing sufficient red blood cells but they are destroyed elsewhere faster than the bone marrow can replace them.
- Loss of blood - causes a consequent reduction in the oxygen carrying ability of the blood.

Classification of Anemia

- Microcytic Anemia - Low MCV
- Normocytic Anemia - Normal MCV
- Macrocytic Anemia - Elevated MCV

Types of Anemia

There are a variety of types of anemia that affect those with Crohn's Disease, Ulcerative Colitis, and other forms of IBD. It is important to understand the differences as many are only familiar with iron deficiency anemia.

Iron Deficiency Anemia

Iron deficiency anemia, as the name implies, is caused by a deficiency in iron in the bone marrow which subsequently limits red blood cell production. This may be caused by blood loss, heavy menstruation, a diet deficient in iron, an inability to absorb iron due to resection, inflammation, or diseases such as Celiac Disease and of course IBD with 36% of patients with inflammatory bowel disease suffering from iron deficiency anemia[2].


The gold standard for diagnosing IDA is a bone marrow biopsy but due to its expense and pain involved, is rarely done. A ferritin level less than 15 ng/mL is almost as good of a diagnostic of IDA as it has a specificity of 99%.[1] Unfortunately, ferritin is often elevated when inflammation is present thus making the marker less than perfect for people with IBD.


Supplementation of iron, treatments to stop acute blood loss, transfusions.

Vitamin B12 Deficiency Anemia

Symptoms of vitamin B12 deficiency anemia are the same as outlined above but also include the potential symptoms of vitamin B12 deficiency


Proper supplementation of vitamin B12.

Folate Deficiency Anemia

Folate is needed for red blood cells to be formed and grow. Symptoms of folate deficiency are the same as outlined above but also include the potential symptoms of folate deficiency.


Proper supplementation of folate.

Megaloblastic Anemia

Megaloblastic anemia is characterized by an increase in the size of red blood cells. The most common cause in people with Crohn's Disease is vitamin B12 deficiency.

Pernicious Anemia

Pernicious anemia is a megaloblastic anemia caused specifically by impaired vitamin B12 absorption due to atrophic gastritis and a lack of parietal cells which produce intrinsic factor.

Anemia of Chronic Disease

Anemia of Chronic Disease (ACD), also known as Anemia of Inflammation. It is a form of anemia where the body is not deficient in iron but instead stores the iron as ferritin within cells and doesn't release it as to keep it away from pathogens that need it for proliferation. As a result, signs of anemia may develop. It is not uncommon in those with Crohn's Disease, other IBD, and other chronic conditions. Iron Deficiency Anemia (IDA) and Anemia of Chronic Disease have many similarities and can be confused.

Similarities Between ACD and IDF

  • In both Iron Deficiency Anemia and Anemia of Chronic Disease, serum iron levels will be low.
  • Both usually have lowered levels of hemoglobin.


Tests to help determine if someone has Anemia of Chronic Disease instead of Iron Deficiency Anemia include:
  • Ferritin levels should be normal or high in people with ACD which showcases sufficient levels of iron stored within the cells. Those with iron deficiency anemia should have low levels of ferritin. However, inflammation can affect ferritin levels.
  • Total Iron Binding Capacity (TIBC) should be high in those with iron deficiency anemia which reflects the body trying to bind up as much iron as possible. Those with Anemia of Chronic Disease should have low or normal TIBC. Transferrin, a protein that transports iron, is elevated in iron-deficiency anemia (and low in ACD). TIBC is an indirect check of Transferrin levels.
  • Hemoglobin levels will generally experience a modest decline to around 9.510.5 g/dL but may drop to 7.0 g/dL depending on the extent of inflammation.
  • Examination of bone marrow can be done to determine the presence or lack of iron.
  • Iron supplementation can be provided. Those with ACD should not show improvement whereas those with iron deficiency should improve quite quickly.


Some feel there should be no treatment of Anemia of Chronic Disease as the body is acting in defense. Other times, Erythropoietin plus iron is given. Erythropoietin is a hormone that stimulates the production of red blood cells. Other times transfusions are warranted.

Hemolytic Anemia

Hemolytic when red blood cells are destroyed faster than the bone marrow can replace them. It is usually caused by autoimmune disorders or medications.


Treatment usually consists of corticosteroids such as prednisone to suppress the immune system and control the autoimmune disorder.

Aplastic Anemia

Aplastic anemia is usually caused by some form of autoimmune disease or disorder and is characterized by the bone marrows inability to make all three types of blood cells. Aplastic anemia can be life threatening.


Treatment usually consists of medications that suppress the immune system such as antithymocyte globulin or ATG and cyclosporine. Other times transfusions are warranted and in especially severe cases, a bone marrow or stem cell transplant may be utilized.

Iron Supplementation

Too much iron can be toxic or harsh on the digestive system. Do not supplement iron unless directed by your doctor. Ferrous fumerate, sulfate, or glycerate are the forms of iron your body can absorb easiest. Taking vitamin C with your iron supplement can improve absorption. Common side effects are gastric upset and nausea which can be alleviated by taking the iron with good. However, that will reduce absorption of the iron by about two thirds. Enteric coated forms of iron should be avoided due to it causing it not to be available in the primary area of absorption (the duodenum). Optimal daily doses should be between 150 and 200 mg of elemental iron which translates into three 325 mg (60 mg of elemental iron each) tablets of ferrous sulfate per day.[2] Inhibitors of iron absorption include Phytate, Polyphenols (tea, coffee, red wine), Calcium, Oxalic acid (in spinach), Soy protein, Avidin (in eggs).

If oral supplementation of iron fails, then parenteral (intravenous) iron may be prescribed. The dosage of IV iron is determined by the following equation: Replacement dose (mg) = 0.3 Weight (lbs) (100 [actual Hgb 100/desired Hgb]). There are three forms of IV iron available with iron dextran not being recommended due to the higher incidence of allergic reaction.

Even after optimal iron and hemoglobin levels are reached, it is recommended that supplementation continue for an additional 6-12 months to replete iron stores to a ferritin level of greater than 40.


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