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Gastrointestinal conditions and iron deficiency with or without anemia

"Gastrointestinal conditions and iron deficiency anaemia, Learn when to watch out for it”

Iron deficiency anaemia (IDA) in gastrointestinal conditions

There are multiple gastrointestinal (GI) conditions and factors that lead to an increased risk of iron deficiency. Dietary iron absorption primarily occurs in the duodenum and upper jejunum, and so a dysfunction of these structures can result in malabsorption of iron and iron deficiency. In addition, the GI tract is also a common site of chronic blood loss, which can deplete the body’s iron stores.

GI conditions that lead to an increased risk of iron deficiency anaemia include stomach ulcers, GI cancers, and chronic use of non-steroidal anti-inflammatory drugs (NSAIDs) as well as inflammatory bowel disease (IBD), coeliac disease22 and bariatric surgery.2


Inflammatory bowel disease (IBD) refers to ulcerative colitis and Crohn’s disease, two autoimmune conditions that cause inflammation of the GI tract. Ulcerative colitis only affects the colon (large intestine), whereas Crohn’s disease can affect any portion of the GI tract from mouth to anus.3

A major symptom of IBD is intestinal bleeding, which may occur as occult blood loss for patients with Crohn’s disease, and may become apparent as visible bleeding in ulcerative colitis.4

Iron deficiency in IBD can also result from inflammation, which can reduce the absorption of iron from food, and from oral iron supplements (by increased hepcidin release).5

On average, 45% of people with IBD suffer from ID.6

Coeliac disease

Coeliac disease, also known as gluten-sensitive enteropathy, is an inflammatory disease of the small intestine.7

Coeliac disease causes chronic inflammation within the small intestine when gluten is ingested, which results in villous atrophy and the flattening of mucosa.7,8 This can reduce the absorption of iron and other nutrients such as folic acid and vitamin B12 from the diet.7,9 It also leads to occult blood loss from the gastrointestinal tract in 25–54% of patients with coeliac disease.10

The prevalence of IDA for those with coeliac disease is approximately 10-15%.11

This prevalence can raise between 32-69% if we consider both conditions iron deficiency or anaemia.22

Bariatric surgery

Bariatric surgery is weight-loss surgery for obese individuals. It includes gastric banding, gastric bypass, biliopancreatic diversion and duodenal switch. Each type of gastric surgery has a different risk of iron deficiency. Generally, gastric bypass procedures are more likely to lead to iron deficiency than gastric bands.2

Both gastric bands and gastric bypass reduce the production of gastric acid, which is required to convert non-haem iron (that is iron from non-meat sources such as vegetables, fortified cereals etc.) into an absorbable form.12 Gastric bypass procedures can also cause malabsorption by excluding the intestinal sections where iron absorption naturally occurs.13 Additionally, some patients may reduce their intake of some iron-rich foods, especially red meat, due to no longer being able to tolerate them.12

Fifty percent of people who have had surgery gastric bypass are iron deficient within one year of surgery. This rises to up to 62% (according to the type of surgery) over a 4–12-year period after surgery.14

Other gastrointestinal bleeding disorders

Any other causes of internal bleeding within the GI tract can also lead to iron deficiency. For example, peptic ulceration including duodenal ulcers, gastric ulcers and anastomotic ulcers may be found in patients with IDA.15 Angiodysplasia and colorectal cancers are further causes of gastrointestinal bleeding.16,17,23

The importance of treating IDA in patients with GI conditions

Iron deficiency without anaemia can be associated with fatigue23 , restless legs syndrome24, impaired physical performance25, impaired cognitive function26,27, hairloss28 and body temperature deregulation29. When iron deficiency progresses to IDA, additional symptoms can include headache, dizziness, tachycardia and dyspnoea.18

The most common systemic complication in IBD patients is anemia.19 , 18 , 20 , 21 The negative effects of anemia in IBD are considerable20:

  • Impairment of the quality of life (physical, emotional, cognitive) and workability
  • More frequent hospitalization
  • Increased treatment costs

For this reason, the European Crohn`s and Colitis Organization (=ECCO) recommends, in its current guidelines, to check the iron status of IBD patients and to treat a present iron deficiency consistently.20

Gastroenterology: Compared to intravenous iron treatment, oral treatment distinctly alters the intestinal microbiota and metabolome in IBD patients.30


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Gastroenterology & Iron Deficiency | Ferinject CH
Learn about multiple gastrointestinal (GI) conditions and factors that lead to an increased risk of iron deficiency.