Food elimination based on IgG antibodies in irritable bowel syndrome: a randomised controlled trial.
BACKGROUND
Patients with irritable bowel syndrome (IBS) often feel they have some form of dietary intolerance and frequently try exclusion diets. Tests attempting to predict food sensitivity in IBS have been disappointing but none has utilised IgG antibodies.


OBJECTIVE
To assess the therapeutic potential of dietary elimination based on the presence of IgG antibodies to food.


METHODS
A total of 150 outpatients with IBS were randomised to receive, for three months, either a diet excluding all foods to which they had raised IgG antibodies (enzyme linked immunosorbant assay test) or a sham diet excluding the same number of foods but not those to which they had antibodies.


METHODS
Primary outcome measures were change in IBS symptom severity and global rating scores. Non-colonic symptomatology, quality of life, and anxiety/depression were secondary outcomes. Intention to treat analysis was undertaken using a generalised linear model.


RESULTS
After 12 weeks, the true diet resulted in a 10% greater reduction in symptom score than the sham diet (mean difference 39 (95% confidence intervals (CI) 5-72); p = 0.024) with this value increasing to 26% in fully compliant patients (difference 98 (95% CI 52-144); p<0.001). Global rating also significantly improved in the true diet group as a whole (p = 0.048, NNT = 9) and even more in compliant patients (p = 0.006, NNT = 2.5). All other outcomes showed trends favouring the true diet. Relaxing the diet led to a 24% greater deterioration in symptoms in those on the true diet (difference 52 (95% CI 18-88); p = 0.003).


CONCLUSIONS
Food elimination based on IgG antibodies may be effective in reducing IBS symptoms and is worthy of further biomedical research.
Atkinson
W
W
Department of Medicine, University Hospital of South Manchester, Manchester M20 2LR, UK.
Sheldon
T A
TA
Shaath
N
N
Whorwell
P J
PJ
D000293:Adolescent; D000328:Adult; D000368:Aged; D004311:Double-Blind Method; D005260:Female; D005512:Food Hypersensitivity / Q000150:complications* / Q000178:diet therapy / Q000276:immunology; D006801:Humans; D007074:Immunoglobulin G / Q000096:biosynthesis*; D043183:Irritable Bowel Syndrome / Q000178:diet therapy* / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D010349:Patient Compliance; D012720:Severity of Illness Index; D016896:Treatment Outcome
D007074:Immunoglobulin G