Researchers observed that dietary fermentable oligosaccharides, disaccharides and monosaccharides and polyols — or FODMAPs — were linked to symptoms of irritable bowel syndrome and variations in the metabolome, according to results from a controlled, single blind study.
Further, FODMAPs were also shown to alter histamine levels and the microbiota in subsets of patients.
The researchers conducted the randomized, controlled, single blind study to compared low and high FODMAP diets in patients with IBS, and examined how these diets affect symptoms, the metabolome and the microbiome.
They randomly assigned 40 patients with IBS to consume either a low FODMAP diet (n = 20) or a high FODMAP diet (n = 20) for a duration of 3 weeks. None of the patients reported they were taking probiotics.
The researchers used the IBS symptom severity scoring (IBS-SSS) to assess symptoms; the lactose breath test to evaluate the metabolome; mass spectrometry to assess metabolic profiling in the urine; and 16S rRNA gene profiling to assess stool microbiota composition.
One patient in the low FODMAP group and two patients in the high FODMAP group did not complete the 3-week diet. Of those who completed the diets, IBS-SSS was reduced in the low FODMAP group (P < .001); however, there was no significant change in the high FODMAP group.
Researchers observed a small reduction in H2 production as shown by the lactose breath test in the low FODMAP group, compared with the patients in the high FODMAP group.
In certain subsets of patients, researchers found significant differences when patients were assessed by metabolic profiling of the urine (P < .01). The main differences were metabolites histamine, p-hydroxybenzoic acid and azelaic acid.
There was an eightfold reduction of histamine in the low FODMAP group (P < .05). Actinobacteria richness and diversity was increased in patients consuming the low FODMAP diet, whereas the relative abundance of bacteria involved in gas consumption was decreased in the patients consuming the high FODMAP diet.
“We found that patients with IBS who consumed a low FODMAP diet had a significant improvement in symptoms and changes in their metabolome suggesting that immune signaling and alterations in the microbiota could be important mechanistic pathways in subsets of patients with IBS,” the researchers concluded. “Metabolic profiling of urine samples from patients with IBS provides a practical means of testing and this study sets the stage for larger trials designed to examine how changes in histamine and possibly other metabolites correlate with symptoms and whether they provide important biomarkers for enriching clinical studies.” – by Suzanne Reist
Disclosures: The researchers report no relevant financial disclosures.