Oral iron supplements on the gastrointestinal tract

Oral iron supplements on the gastrointestinal tract

Investigating the effect of oral iron supplements on the gastrointestinal tract in healthy volunteers.

Study status  – Recruiting


Over recent years there has been a lot of research looking at how the bacteria in our gut affects our
health. Some medications are known to cause changes in gut bacteria.

Many patients that are prescribed iron report gastrointestinal side effects.

This research project aims to see if the cause of the gastrointestinal side effects is due to iron causing changes in the gut bacteria. This can be detected via measuring the levels of hydrogen and methane and other compounds in the breath and stool.

Inclusion Criteria

To participate you must meet the following criteria:

  1. Aged 18-60 years
  2. BMI of 18.5 – 34.9 kg/m2 (bounds included)
  3. Healthy, with no significant medical conditions
  4. Not received prescribed iron therapy within the last 12 months
  5. Will follow the required preparation before the study visits

Significant medical conditions, pregnancy or certain medications may exclude you from taking part in the study. Study eligibility will be assessed in more detail by a member of the research team before enrolment in the study.


The Functional Gut Clinic, 262 Deansgate, Manchester, M3 4BG

Participant involvement

This study involves 2 visits to the clinic (each lasting 3.5hours), 4 weeks apart. At each study visit participants will be asked to complete questionnaires, provide a stool sample and complete a breath test. For the 4 week duration between study visits participants will be asked to take oral iron supplements twice daily and complete a daily study diary about their bowel habit. The participant information sheet gives more details about participant involvement.


Upon completion of the study, participants will receive £250 to compensate for time and travel expenses.

Contact details 

Sarah Bloor – sarah@functionalgutdiagnostics.com