There are multiple gastrointestinal 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 gastrointestinal tract is also a common site of chronic blood loss, which can deplete the body’s iron stores.

Gastrointestinal conditions that lead to an increased risk of iron deficiency include stomach ulcers, gastrointestinal cancers, and chronic use of Non-steroidal anti-inflammatory drugs (NSAIDs) as well as inflammatory bowel disease (IBD), coeliac disease and bariatric surgery.15

Inflammatory bowel disease (IBD) refers to ulcerative colitis and Crohn’s disease, two autoimmune conditions that cause inflammation of the gastrointestinal tract. 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 rectal bleeding and loose bloody stools in ulcerative colitis.5

Iron deficiency in IBD can also result from inflammation in the duodenum and upper jejunum of patients, which can reduce the absorption of iron from food, as well as from oral iron supplements.6 To compound this clinical challenge, IBD patients may avoid certain iron-rich foods such as leafy green vegetables, if they are known to increase abdominal symptoms.6

Multiple studies have shown that between 36% and 76% of people with IBD develop iron deficiency anaemia.7,8

Coeliac disease causes chronic inflammation within the small intestine when gluten is ingested, which results in villous atrophy and the flattening of mucosa.1 This can reduce the absorption of iron and other nutrients from the diet2 and can also lead to occult blood loss from the gastrointestinal tract.3

The prevalence of iron deficiency anaemia for those with coeliac disease is approximately 10-15%.4

Bariatric surgery includes gastric banding, gastric bypass, biliopancreatic diversion and duodenal switch.9 Both gastric bands and gastric bypasses reduce the production of gastric acid, which is required to convert iron into an absorbable form.10 Gastric bypass procedures can also cause malabsorption by excluding the intestinal sections where iron absorption naturally occurs.11 Additionally, some patients may reduce their intake of some iron-rich foods, especially red meat, due to no longer being able to tolerate them.10

50% of people who have had bariatric surgery are iron deficient within one year of surgery. This rises to up to 62% over a 4-12 year period after surgery.12

Treating iron deficiency in IBD

Iron deficiency is associated with fatigue in patients, as well as with a number of other symptoms such as hair loss and restless legs syndrome. When iron deficiency progresses to iron deficiency anaemia, additional symptoms can include a reduction in physical performance, headache, dizziness and tachycardia and dyspnoea.13

In order to help modify these symptoms and improve the quality of life of IBD patients, iron supplementation should be considered in all iron deficient patients with IBD and initiated in those in whom haemoglobin concentrations fall below normal.14 Both oral and intravenous iron can be considered, with first-line treatment choice dependent on the severity and cause of the iron deficiency anaemia, as well as other patient factors.14

Iron deficiency is often a recurrent problem in patients with gastrointestinal conditions, which requires continuous attention and follow-up by gastroenterologists. Regular controls are advocated with treatment to be re-initiated, if iron deficiency anaemia recurs.14