Balneotherapy (Mud-Bath Therapy) with a Peloid Enriched with Rosmarinic Acid Enhances Clinical Outcomes and Innate Immune Benefits in Elderly Patients with Osteoarthritis: A Pilot Study
Key Findings
- Pilot study: 23 elderly OA patients, 10-day mud-bath with rosmarinic acid-enriched peloid at 40°C
- Significant increases in cortisol levels with decreased IL-8 — immuno-neuroendocrine stabilization
- Enhanced phagocytic and microbicidal activity of neutrophils post-intervention
- Improved knee mobility and reduced pain
- Rosmarinic acid (polyphenolic acid) enhances anti-inflammatory properties of peloid
Open-access pilot study in Applied Sciences (2024) evaluating a novel peloid enriched with rosmarinic acid (RosA) — a polyphenolic compound found naturally in rosemary and other plants — for elderly osteoarthritis patients. The companion paper to Ortega-Collazos 2025, which uses the same cohort (n=23, 10-day protocol, 40°C mud baths) to examine neuroimmunomodulatory mechanisms in depth.
What Was Being Tested
The core hypothesis: adding a potent anti-inflammatory polyphenol (rosmarinic acid) to a standard peloid would enhance therapeutic outcomes and produce measurable changes in immune and endocrine markers. This is the “enriched peloid” paradigm — using a natural additive to boost an already-active base material.
What It Found
Clinically: improved knee mobility, reduced pain. Immunologically: significant increase in cortisol (HPA axis activation) and decrease in IL-8 (pro-inflammatory chemokine). Functionally: enhanced phagocytic and microbicidal activity of neutrophils — meaning the innate immune system became more effective, not less, despite the anti-inflammatory effect. This pattern of simultaneous anti-inflammatory and immune-stimulating effects is characteristic of what the authors call “immuno-neuroendocrine stabilisation.”
Relevance to Peat
Peat is not rosmarinic acid peloid. But peat naturally contains polyphenolic compounds — phenolic acids, tannins, humic acids with phenolic moieties — that share mechanism with the added RosA in this study. The ortega-collazos papers establish that polyphenolic compounds in peloids activate the HPA axis and shift innate immune function; this provides a mechanistic framework applicable to peat’s natural polyphenolic fraction.