Crohn’s disease frequently causes iron deficiency anaemia which provides a frustrating problem with patients being treated by diet. Most forms of oral iron cause patients to have symptoms and frequently intravenous iron infusions are necessary to correct anaemia.
This problem does not loom as large in patients treated by drugs where a level of persisting symptoms is often accepted as par for the course. Dietary treatment however depends on complete elimination of symptoms if it is to be successful. Oral iron administration therefore presents a problem. Capsules are worse than liquid preparations such as ferrous fumarate elxir or sodium iron edetate, but frequently it is not possible to restore haemaglobin levels because of the onset of further symptoms.
The reason for this has not been clear, but a report from Kenya published in the May edition of Gut (Jaeggi T et al Gut 2015 64 731-42) casts interesting light on the problem. This was not a study of Crohn’s disease but of supplementing Kenyan infants with iron as they are frequently anaemic. It was found however, that oral iron administration increased the levels of a number of dangerous bacteria including Salmonella, Clostridia and entero bacteria. The latter group are known to be increased in Crohn’s disease and we have suggested that the main cause of Crohn’s disease is the body’s immune system reacting to toxic chemicals produced by such bacteria. (Walton C et al Inflam Bowel dis 2013 19 2069-78).
The increase in these bacteria was associated with an increase in faecal calprotectin levels confirming that there had been an increase in the level of inflammation in the intestine.
Thus the difficulties with oral iron supplementation in Crohn’s disease appear clear. Iron may increase the levels of unpleasant bacteria in the same way as do certain foods and patients on dietary treatment who may have a pre existing anaemia are best advised that this is corrected if possible by iron infusion.
This article was first published on the original crohns.org.uk blog. Research has moved on since, so please check current advice with your IBD team.