The Usefulness of the Low-FODMAP Diet with Limited Tryptophan Intake in the Treatment of Diarrhea-Predominant Irritable Bowel Syndrome.
Study Goal
The researchers aimed to evaluate whether reducing tryptophan (TRP) intake alongside a low-FODMAP diet improves abdominal symptoms and psychological status in patients with IBS-D.
Results Summary
The study found that a low-FODMAP diet with reduced TRP intake (Group IIB) led to significantly greater improvements in gastrointestinal symptoms (GSRS score), anxiety (HAM-A), and depression (HAM-D) compared to the standard low-FODMAP diet (Group IIA). TRP reduction correlated negatively with symptom improvement.
Population
80 patients with irritable bowel syndrome with diarrhea predominance (IBS-D) and 40 healthy controls.
Effective Dosage
TRP intake reduced from 21.3 ± 2.33 mg/kg/b.w./24 h to 14.32 mg/kg/b.w./24 h (34.4% reduction) in Group IIB.
Duration
8 weeks
Interactions
None mentioned
| Intervention | Direction | Endpoint | Population | Dosage | Impact | Claim # |
|---|---|---|---|---|---|---|
low-FODMAP diet | no change | abdominal symptoms | patients with irritable bowel syndrome | null | does not improve | #1 |
low-FODMAP diet with limited tryptophan (TRP) intake | decrease | TRP consumption per mg/kg/b.w./24 h | Group IIB (IBS-D patients) | from 21.3 ± 2.33 to 14.32 (34.4%) | decreased | #2 |
low-FODMAP diet | decrease | TRP consumption per mg/kg/b.w./24 h | Group IIA (IBS-D patients) | from 20.9 ± 2.39 to 17.45 ± 2.41 (16.5%) | decreased | #3 |
low-FODMAP diet with limited tryptophan (TRP) intake | decrease | GSRS score | Group IIB (IBS-D patients) | 49.8% | greater improvement | #4 |
low-FODMAP diet | decrease | GSRS score | Group IIA (IBS-D patients) | 38.1% | improvement | #5 |
low-FODMAP diet with limited tryptophan (TRP) intake | decrease | HAM-A score | Group IIB (IBS-D patients) | 49.9% | greater improvement | #6 |
low-FODMAP diet | decrease | HAM-A score | Group IIA (IBS-D patients) | 38.7% | improvement | #7 |
low-FODMAP diet with limited tryptophan (TRP) intake | decrease | HAM-D score | Group IIB (IBS-D patients) | 35.0% | greater improvement | #8 |
low-FODMAP diet | decrease | HAM-D score | Group IIA (IBS-D patients) | 13.8% | improvement | #9 |
Reducing TRP intake | decrease | degree of improvement in the GSRS score | IBS-D patients | null | showed a negative correlation | #10 |
Lowering the TRP content in a low-FODMAP diet | null | treating IBS-D | IBS-D patients | null | may be useful | #11 |
(1) Background: A low-FODMAP diet is often recommended in the treatment of irritable bowel syndrome, but it does not improve abdominal symptoms in all patients, and an alternative diet is desirable. The purpose of this study was to evaluate the efficacy of a low-FODMAP diet with a concomitant reduction in tryptophan (TRP) intake in irritable bowel syndrome with diarrhea predominance (IBS-D) in relation to its metabolism via the serotonin and kynurenine pathways. (2) Methods: 40 healthy people (Group I, Controls) and 80 patients with IBS-D were included in the study. IBS-D patients were randomly divided into two groups of 40 each (Groups IIA and IIB). In Group IIA, the low-FODMAP diet was recommended, while in Group IIB, the same diet was recommended but with limited TRP intake for 8 weeks. The TRP intake was analyzed with the use of the nutritional calculator. Abdominal complaints were assessed using the Gastrointestinal Symptom Rating Scale (GSRS-IBS), and psychological status was simultaneously determined using two scales: the Hamilton Anxiety Scale (HAM-A) and the Hamilton Depression Scale (HAM-D). TRP and its metabolites: 5-hydoxyindoleacetic acid (5-HIAA), kynurenine (KYN), kynurenic acid (KYNA), and quinolinic acid (QA) were measured in urine using liquid chromatography tandem mass spectrometry (LC-MS/MS). (3) Results: The consumption of TRP per mg/kg/b.w./24 h has decreased in Group IIA from 20.9 ± 2.39 to 17.45 ± 2.41 (16.5%) and in Group IIB from 21.3 ± 2.33 to 14.32 (34.4%). Significantly greater improvement was found after nutritional treatment in patients in Group IIB as compared to Group IIA (GSRS score: 38.1% vs. 49.8%; HAM-A: 38.7% vs. 49.9%; HAM-D: 13.8% vs. 35.0%; p < 0.01). Reducing TRP intake showed a negative correlation with the degree of improvement in the GSRS score. (4) Conclusions: Lowering the TRP content in a low-FODMAP diet may be useful in treating IBS-D.