Gut Bacteria May Help Heart Failure Patients Breathe Better
- Authors
- Aleksandra Mikołajczak, Rafał Seredyński, Marzena Gonerska, Mateusz Sokolski, Bartłomiej Paleczny, Beata Ponikowska
- Journal
- Frontiers in Physiology
- Year
- 2026
- DOI
- 10.3389/fphys.2025.1728753
- Study Type
- Human
- Outcome
- Positive
- Peer Reviewed
- Yes
- Country
- Poland
- Health Condition
- Heart Failure
- Body System
- Cardiovascular
TL;DR
Higher breath hydrogen levels from gut fermentation were linked to stronger respiratory and cardiovascular reflex responses in heart failure patients.
Key Finding
Heart failure patients with higher early gut fermentation showed significantly stronger breathing and blood vessel responses to low oxygen compared to those with lower fermentation activity, suggesting gut bacteria activity may influence oxygen-sensing sensitivity in this population.
Summary
This small preliminary study examined whether stimulating gut bacteria fermentation (using a special meal) could affect how heart failure patients respond to low oxygen levels. Researchers measured hydrogen in patients' breath to identify who had more active gut fermentation, then tested how their bodies responded to temporary oxygen reduction before and after the meal. Patients with higher gut fermentation activity showed stronger breathing and blood vessel responses to low oxygen, suggesting a possible connection between gut bacteria activity and how sensitive the body's oxygen-sensing systems are.
Practical Takeaway
This is a very preliminary study in only 12 heart failure patients with no control group, so findings are exploratory only. While it suggests a possible link between gut fermentation and oxygen-sensing responses, the small size and design limitations mean much larger, controlled studies are needed before any practical recommendations could be made. This research does not yet support any specific dietary or hydrogen-related interventions.
Abstract
Background: The gut microbiota has emerged as a key contributor to cardiovascular regulation. Acute stimulation of microbial fermentation with lactulose enhances hypoxic ventilatory response (HVR) in healthy subjects, indicating increased peripheral chemoreceptor (PCh) responsiveness. Given that heart failure (HF) is characterized by PCh hyperactivity, this study investigated whether enhancing intestinal fermentation could acutely modify chemoreceptor-driven responses in HF patients. Methods: HF patients (n = 12; all males; age: 59.2[15.8]y; 67% in NYHA III) underwent transient hypoxia test twice: before and ∼120 min after ingesting a gut-fermentation-stimulating meal. Hydrogen in expired air was measured repeatedly and used to stratify the patients into high early fermentation (HEF) and low early fermentation (LEF) groups. Ventilatory (HVR) and cardiovascular (heart rate, blood pressure, systemic vascular resistance) responses to hypoxia were measured. Results: HEF patients, as compared with the LEF group, displayed: (1) higher pre-lactulose HVR (mean ± SD, L/min/SpO2: 0.680 ± 0.284 vs. 0.343 ± 0.122; p = 0.024), (2) pre- and post-lactulose SVR response (mean ± SD, dyn s/cm5/SpO2: for pre-lactulose comparison, 35.40 ± 24.41 vs. 9.96 ± 1.80, p = 0.039; for post-lactulose comparison, 37.19 ± 25.75 vs. 9.22 ± 4.33, p = 0.026). HVR in the HEF group correlated with the net hydrogen excretion during the lactulose test (r = 0.85, p = 0.033). Conclusion: Our preliminary results, derived from a small, uncontrolled physiological experiment conducted in 12 H F patients, imply a link between the upper gut microbial fermentation capacity and the baseline peripheral chemoreflex sensitivity in this population. Given the exploratory and non-randomized design, these findings should be interpreted with caution, and larger controlled studies are needed to confirm the nature and clinical relevance of this association.