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Purpose: Enterometabolic disturbances may cause meal-related symptoms. We performed a functional evaluation of the intestinal microflora in patients with unexplained, self-reported food hypersensitivity by measuring fecal short-chain fatty acids (SCFAs). Patients and methods: Thirty-five consecutive patients with self-reported food hypersensitivity and 15 healthy volunteers of similar age, gender, and body mass index collected all feces for 72 hours. Fecal concentrations of acetic, propionic, n-butyric, i-butyric, n-valeric, i-valeric, n-caproic, and i-caproic acids were analyzed by gas-liquid chromatography. Concentrations and excretions (output) of SCFAs in patients and controls were compared and related to gastrointestinal symptoms. Results: Despite nonsignificant differences between patients and controls for both total and individual SCFA concentrations and excretions, n-butyric acid comprised a higher (P = 0.035) and acetic acid a lower (P = 0.012) proportion of total SCFA in patients compared to controls. There were no significant correlations between symptom scores and concentrations or excretions of individual or total SCFAs, but the proportion of n-butyric acid was significantly higher in patients with severe symptoms compared to patients with moderate symptoms (P = 0.016). Conclusion: The results indicate an enterometabolic disturbance in patients with self-reported food hypersensitivity. Higher proportions of n-butyric acid may be related to abdominal symptom generation, but may also protect against organic bowel disease. Further studies are needed to clarify these aspects. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]