🟡 Moderate clinical evidence (comparative study)

Study at a glance

• Participants: 73 women
• Condition: Irritable Bowel Syndrome (mixed-type IBS)
• Study type: Open-label comparative study
• Duration: 8 weeks

What was done

Participants with IBS were assigned to follow one of three diets:

• A diet based on food-specific IgG test results
• A low FODMAP diet (a commonly used IBS diet)
• A standard control diet

The IgG-guided diet involved removing foods identified by the blood test, while the other groups followed their respective dietary approaches.

What improved

After 8 weeks:

• All groups showed improvement, but the IgG-guided diet showed the greatest overall reduction in IBS symptoms
• Participants following the IgG-guided diet reported greater improvements in abdominal pain, bloating and bowel symptoms compared to both the FODMAP and control diets
• Quality of life improvements were also greater in the IgG-guided group

In practical terms, this means the personalised IgG-based approach led to greater symptom relief than both a standard IBS diet (FODMAP) and a general diet.

Key takeaway

A personalised diet based on IgG test results was associated with greater improvement in IBS symptoms and quality of life compared to both a low FODMAP diet and a standard diet.

What this means

This study suggests that targeted, personalised dietary changes may be more effective than general dietary approaches for some people with IBS. Rather than removing broad food groups, identifying specific foods may help achieve better symptom control.

🟡 Evidence strength

Moderate clinical evidence (comparative, non-blinded study)

Full citation

Ostrowska et al. 2021 IgG vs FODMAP IBS study

Ostrowska L, Wasiluk D, Lieners CFJ, Gałęcka M, Bartnicka A, Tveiten D.
IgG food antibody guided elimination-rotation diet was more effective than FODMAP diet and control diet in the treatment of women with mixed IBS.
J Clin Med. 2021;10(19):4317.

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