Wheat mystery: which part really upsets IBS sufferers?

NCT ID NCT03664531

First seen Jun 25, 2026 · Last updated Jun 27, 2026 · Updated 1 time

Summary

This study looked at whether purified gluten or whole wheat (which contains gluten plus other proteins) causes stomach and gut symptoms in people with irritable bowel syndrome (IBS). Twenty-nine adults with IBS who had previously felt better on a gluten-free diet took part. They ate special bars containing either purified gluten, whole wheat, or a gluten-free sham bar for one week each, while staying on a gluten-free diet. The goal was to see which bar made their symptoms worse, helping to pinpoint what in wheat might be the real trigger.

What this could mean

Our plain-language read of the trial. This is informational only — not medical advice or a prediction.

Active substance

purified gluten and whole wheat (gluten with amylase-trypsin inhibitors)

What this could lead to

If successful, this could help identify which components of wheat cause symptoms in people with irritable bowel syndrome, leading to better dietary advice.

What could go wrong

This is a small, completed trial with only 29 participants, so results may not apply to everyone with IBS. It tests short-term effects, not long-term outcomes.

Disclaimer Read more

This is a summary of the original study . Summaries may miss details or leave out important information. Before applying or accepting participation, make sure you have read and understood the full study. Curemydisease.com takes no responsibility whatsoever for anything missed, misunderstood, or acted upon as a result of our summary — we know it does not capture everything.

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Conditions

The condition(s) this trial relates to.

irritable bowel syndrome

As listed by the trial registrant

The condition terms exactly as the trial's registrant entered them.

Contacts and locations

Locations

  • McMaster University Medical Centre

    Hamilton, Ontario, L8N 3Z5, Canada