Multi-Strain Probiotic Improves Tryptophan Metabolism and Symptoms in CFS Patients with Co-Occurring IBS: An Open-Label Pilot Study, 2025, Chojnacki

[Dolphin]

https://www.mdpi.com/2072-6643/18/1/174

4 January 2026

Multi-Strain Probiotic Improves Tryptophan Metabolism and Symptoms in Chronic Fatigue Syndrome Patients with Co-Occurring Irritable Bowel Syndrome: An Open-Label Pilot Study​

Cezary Chojnacki1,
Marta Mędrek-Socha1,
Jan Chojnacki1,
Anita Gąsiorowska2,
Ewa Walecka-Kapica2,
Michal Bijak3,
Karolina Przybylowska-Sygut4 and
Tomasz Poplawski4,*
1
Department of Clinical Nutrition and Gastroenterological Diagnostics, Medical University of Lodz, 90-647 Lodz, Poland
2
Department of Gastroenterology, Medical University of Lodz, 92-213 Lodz, Poland
3
Biohazard Prevention Centre, Faculty of Biology and Environmental Protection, University of Lodz, Pomorska 141/143, 90-236 Lodz, Poland
4
Department of Pharmaceutical Microbiology and Biochemistry, Medical University of Lodz, 92-215 Lodz, Poland
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Nutrients2026, 18(1), 174;https://doi.org/10.3390/nu18010174
This article belongs to the Section Prebiotics and Probiotics
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Simple Summary​

Chronic Fatigue Syndrome (CFS) is a debilitating condition often accompanied by gut health issues, but effective treatments are scarce.

Recent research suggests that an imbalance in gut bacteria (dysbiosis) may contribute to CFS symptoms by producing harmful substances that affect the nervous system.

We investigated whether a specific multi-strain probiotic (CDS22-formula) could improve symptoms in women with CFS and co-occurring IBS.

Over 12 weeks, patients took a high-dose probiotic supplement.

We monitored their fatigue levels and analyzed urine samples to track changes in tryptophan metabolism—a key pathway linking the gut to the brain.

The results showed that the probiotic intervention was associated with an improved gut bacteria profile.

Importantly, this coincided with a reduction in neurotoxic metabolites and a significant decrease in fatigue severity.

Our findings suggest that targeting the gut microbiome can be a valuable strategy for managing chronic fatigue, potentially by modulating the production of metabolites that affect brain function.

Abstract​

Background/Objectives:

Gut dysbiosis in Chronic Fatigue Syndrome (CFS) drives low-grade inflammation and shifts tryptophan metabolism toward neurotoxic pathways. The causal link between bacterial translocation, kynurenine pathway dysregulation, and symptom severity remains under-defined. We evaluated the impact of a high-concentration multi-strain probiotic on the “gut-kynurenine axis” and clinical status in CFS patients with co-morbid IBS-U and confirmed dysbiosis.

Methods:

Forty female patients with confirmed dysbiosis (GA-map™ Dysbiosis Index > 2) received the CDS22 formula (450 billion CFU/day) for 12 weeks. We compared urinary tryptophan metabolite profiles (LC-MS/MS), gut dysbiosis markers (3-indoxyl sulfate), and fatigue severity (FSS) against 40 age-matched healthy controls.

Results:

Baseline analysis revealed profound metabolic perturbations: elevated bacterial proteolytic markers (3-IS), substrate depletion (low tryptophan), and a neurotoxic signature (high quinolinic acid [QA], low kynurenic acid [KYNA]). Following the intervention, fatigue scores declined by 40.3%, with 97.5% of patients reaching the remission threshold (FSS < 36). Biochemically, 3-IS levels decreased to the range observed in healthy controls and attenuated xanthurenic acid levels. Although absolute QA concentrations remained elevated compared to controls, the neuroprotective KYNA/QA ratio increased significantly (+45%). Increased systemic tryptophan availability correlated directly with clinical symptom reduction (Spearman’s rho = −0.36, p = 0.024).

Conclusions:

The CDS22 formulation was associated with a restoration of intestinal eubiosis and functional tryptophan partitioning. Clinical remission coincides with a metabolic shift favoring neuroprotection (increased KYNA/QA ratio), validating the gut–kynurenine axis as a modifiable therapeutic target. Peripheral metabolic improvement relative to the healthy baseline appeared sufficient for symptom relief in this specific phenotype, despite incomplete clearance of neurotoxic metabolites.
Keywords:
Chronic Fatigue Syndrome; tryptophan metabolism; kynurenine pathway; gut microbiota; probiotics; quinolinic acid; leaky gut

 

[TiredMathematician]

A total of 73 patients presenting with overlapping symptoms of IBS and chronic fatigue were screened for eligibility at the Department of Gastroenterology outpatient clinic.

Patients presented with chronic fatigue, sleep disturbances, and abdominal symptoms persisting for 3 to 11 years. Inclusion required confirmed gut dysbiosis and tryptophan metabolism disorders [23] in the absence of abnormalities in routine laboratory profiles. Organic gastrointestinal, neurological, and psychiatric pathologies were ruled out via comprehensive laboratory and endoscopic evaluation, including histological assessment of duodenal and colonic mucosa.

Sounds like this is just patients with chronic fatigue, not ME/CFS.

From their reference 23:

Chronic fatigue was assessed using two validated instruments: the Chalder Fatigue Questionnaire (CFQ-11) and the fatigue severity scale (FSS).

The CFQ-11 is a widely used screening tool in clinical and epidemiological studies to evaluate the presence and intensity of fatigue-related symptoms [36]. It assesses both the physical and mental components of fatigue, including items related to cognitive impairment, myalgia, arthralgia, headache, sleep disturbances, sore throat, lymphadenopathy, and post-exertional malaise lasting more than 24 h. Each item is rated on a 4-point Likert scale, resulting in a total score ranging from 11 to 44. Higher scores indicate greater fatigue severity. The CFQ-11 was used to support the diagnosis of chronic fatigue syndrome (CFS) following established symptom thresholds.

1. That's not how ME/CFS is diagnosed.
2. Unless I'm very much mistaken, CFQ-11 does not include PEM, myalgia, arthralgia, headache, sleep disturbances, sore throat, or lymphadenopathy.

Fatigue status and severity were quantified using the Chalder Fatigue Scale (CFQ-11) and the Fatigue Severity Scale (FSS)

Meh.

This study was not prospectively registered in a public clinical trial registry.

Not great.