Carbohydrate intolerance in patients with self-reported food hypersensitivity: Comparison of lactulose and glucose

Abstract

Objective. Malabsorption of low-digestible carbohydrates is physiological, but poorly tolerated in some patients. We investigated symptom anticipation and microbial fermentation as possible mechanisms of carbohydrate intolerance in patients with self-reported food hypersensitivity. Material and methods. In a randomized, double-blind, cross-over study, 27 consecutive patients with unexplained, self-reported food hypersensitivity were given 10 g lactulose and 10 g glucose (placebo). Symptoms and pulmonary excretion of hydrogen and methane were assessed. Short-chain fatty acids (SCFAs), lactate and prostaglandin E₂ (PGE₂) were analyzed in rectal dialysis fluid, and compared to dialysates from nine healthy volunteers. Results. Post-lactulose symptom scores were correlated with habitual symptom scores (r = 0.6, p = 0.001), significantly higher than post-glucose symptom scores (p = 0.01) and significantly higher in patients than controls (p = 0.0007). Levels of SCFAs, lactate and PGE₂ in rectal dialysates were not significantly different after lactulose and glucose, or between patients and controls. Hydrogen excretion was not correlated with symptom scores. Conclusions. The findings suggest that self-reported food hypersensitivity is related to microbial fermentation of malabsorbed carbohydrates and not to symptom anticipation solely. Levels of SCFAs, lactate and PGE₂ in rectal dialysates could not explain the fermentation-associated hypersensitivity.

Key Words::

• Dialysis
• dietary carbohydrates
• fermentation
• food hypersensitivity
• irritable bowel syndrome
• rectum

Acknowledgements

We thank Behzad Gharehnia, Inderjit Kaur Daphu, Natalia Vik, Nathalie Puaschitz, Ragna Lind and Anna-Karin Persson for invaluable technical assistance. The authors report no conflict of interest. The authors alone are responsible for the content and writing of the paper.