Key Findings
- Purpose
The study will investigate whether a MedDiet affects chronic non-vaso-occlusive pain, gut microbiome composition, and microbial metabolites in adults with SCD. It explores diet and the gut–brain axis as potential areas of research, rather than testing an established treatment.
- Population (Model)
The study plans to recruit 30 adults with SCD from the University of Illinois Hospital and Health Sciences Sickle Cell Center in Chicago, with 24 expected to complete the trial. Participants must have chronic pain at least three days per week for more than six months and a Mediterranean Eating Pattern for Americans III (MEPA-III) score below 13. Key exclusions include vegan diets, pregnancy or breastfeeding, certain gastrointestinal conditions, recent antimicrobial use, and more than seven inpatient hospitalizations in the previous year. Participants are randomized to one of two sequences: 28 days of MedDiet followed by 28 days of habitual diet, or the reverse, with a 28-day washout between conditions. Meals and grocery items will be provided, with calories individualized to maintain body weight.
- Headline Result
This is a study-design article; no clinical outcome results are reported. The primary outcome is patient-reported pain, assessed using Patient-Reported Outcomes Measurement Information System (PROMIS) pain measures and Adult Sickle Cell Quality of Life Measurement Information System (ASCQ-Me) pain episode frequency and severity. Secondary outcomes include gut microbiome composition, fecal and circulating metabolites, inflammatory markers, and body composition. Metabolomic analyses target short-chain fatty acids (SCFAs) and bile acids. The trial is registered as NCT06886477. The article reports recruitment began in July 2025 and expected completion in March 2026; these timelines do not confirm actual recruitment or completion status.
- Why It Matters
The protocol examines whether a structured dietary intervention may influence chronic pain and biological measures related to the gut–brain axis. Its controlled feeding design, within-participant comparison, and combination of patient-reported and biological outcomes may help generate preliminary evidence about a potential nonpharmacologic research direction.
The proposed relationships between diet, microbiome activity, and pain remain hypotheses. The study cannot establish that microbiome changes cause pain changes or that a MedDiet reduces SCD-related pain. - Evidence Gaps & Limitations
The planned sample is small and drawn from one clinical center. Eligibility criteria further limit generalizability to people with different pain patterns, dietary habits, or clinical circumstances. The 28-day diet periods can assess short-term changes but not long-term effectiveness, sustainability, or healthcare use.The crossover design includes a washout period, but results will be needed to assess possible carryover effects. Targeted metabolomics will examine selected SCFAs and bile acids rather than the full range of fecal metabolites. Adherence, attrition, and variability in pain and biological measures will also affect interpretation.
Source: Journal of Sickle Cell Disease- “Treating pain in SCD: design of a randomized crossover controlled Mediterranean diet feeding study”
Regulatory & Guideline Watch
This is a research protocol, not a completed efficacy trial or clinical practice guideline. It does not establish a new recommendation or support changes to SCD pain-management protocols. Nutrition may be considered within individualized supportive care, but this study does not establish a MedDiet as a proven treatment for SCD-related pain.