For many years, food-specific IgG testing has generated considerable discussion within both conventional and functional medicine.
While early studies suggested that personalised elimination diets could improve symptoms in selected patients with Irritable Bowel Syndrome (IBS), questions remained regarding the size and quality of the available evidence.
A newly published systematic scoping review in Nutrition Reviews represents an important milestone in this evolving field by bringing together the available clinical evidence and assessing it as a whole.
The review evaluated 13 clinical studies involving 935 adults with IBS, including randomised controlled trials, providing a broad assessment of the evidence for IgG-guided elimination diets published to date.
What does the evidence show?
Across the studies reviewed, IgG-guided elimination diets were associated with reported improvements in many of the symptoms that define IBS, including:
✓ Abdominal pain
✓ Bloating and abdominal distension
✓ Altered bowel habit
✓ Stool consistency
✓ Overall symptom severity
✓ Quality of life
Several studies also reported improvements beyond the gastrointestinal tract, including fatigue, migraine and anxiety.
Importantly, the evidence base is no longer limited to small observational studies. The review includes multiple randomised controlled trials, including the recent multicentre study by Singh et al. (2025), alongside earlier work by Atkinson and colleagues and subsequent clinical investigations from Europe, North America and Asia.
A Balanced Scientific Perspective
Understanding the evidence in context
One aspect of the review that deserves particular recognition is its balanced interpretation of the evidence.
The authors acknowledge that significant methodological differences remain between studies, including variations in study design, dietary protocols and laboratory methods. They also recognise that larger, well-designed clinical trials will continue to strengthen our understanding of which patients are most likely to benefit.
At the same time, the review reports that IgG-guided elimination diets were associated with improvements in gastrointestinal symptoms and quality of life. The authors identify the approach as an area that merits continued clinical investigation and research.
Why this matters
IBS is now recognised as a disorder of gut-brain interaction involving multiple overlapping mechanisms, including altered gut permeability, immune activation, microbiome changes and visceral hypersensitivity.
It is therefore increasingly unlikely that a single dietary strategy will be appropriate for every patient.
Instead, there is growing interest in personalised nutritional interventions alongside established approaches such as the low FODMAP diet, psychological therapies and pharmacological management.
Personalised Approaches
One comparative study included in the review directly compared an IgG-guided elimination diet with a low FODMAP diet and reported greater improvements in IBS symptoms in patients following the IgG-guided approach, suggesting that personalised elimination strategies may warrant further investigation.
These findings reinforce an increasingly important principle in IBS management: successful dietary intervention is unlikely to be achieved through a single universal diet.
As our understanding of IBS advances, so too does the interest in more personalised nutritional strategies. The growing body of evidence supports continued investigation of IgG-guided elimination diets alongside established interventions and the broader move towards precision nutrition in the management of IBS.