Validation of a Simple Questionnaire to Assess Gastrointestinal Symptoms After Oral Ferrous Sulphate Supplementation.

Oral iron supplementation is often associated with rapid onset of gastrointestinal side-effects. The aim of this study was to develop and trial a short, simple questionnaire to capture these early side-effects and to determine which symptoms are more discriminating.

The study was a double-blind placebo-controlled randomized parallel trial with one week treatment followed by one week wash-out. Subjects were randomized into two treatment groups (n=10/group) to receive either ferrous sulphate (200 mg capsules containing 65 mg of iron) or placebo, both to be taken at mealtimes twice daily during the treatment period. Subjects completed the questionnaires daily for 14 days. The questionnaire included gastrointestinal symptoms commonly reported to be associated with the oral intake of ferrous iron salts (i.e. nausea, vomiting, heartburn, abdominal pain, diarrhoea, and constipation).