Walnuts and a Mediterranean-style diet to protect kidney and heart health

Is this trial a fit for you?

A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.

What this trial studies

Participants with stable mild to moderate CKD follow a Mediterranean diet counseling program, with one group also receiving daily walnut supplementation (30 g). The trial aims to see if walnuts influence kidney function, CKD progression, and cardiovascular risk markers, as well as inflammation, oxidative stress, endothelial function, and gut microbiota. The study uses a randomized design to compare the MedDiet with and without walnuts, focusing on adults aged 45–75 with overweight or obesity and CKD stages G3a-b. Primary outcomes include kidney-related measures; secondary outcomes explore broader cardiovascular and metabolic indicators. The intervention is implemented within a public health and nutrition research setting in Tarragona, Spain.

Why it matters

Who can join: the full rules

Inclusion Criteria:

* Men and women with stable mild to moderate chronic kidney disease \[CKD\] (stage G3a-b (estimated glomerular filtration rate \[eGFR\] 30-\<60mL/min/1.73 m²) and albuminuria stages A1-3 (UACR from \< 30mg/g to ≥ 300 mg/g))
* 45-75 years old at screening
* Overweight/obesity (Body Mass Index \[BMI\] ≥25 and ≤40 kg/m²)
* Meet at least one of the following conditions:

  (i) Systolic blood pressure ≥140 mmHg or diastolic blood pressure ≥90 mmHg, or use of antihypertensive agents (ii) Triglycerides ≥150 mg/dL, LDL cholesterol ≥160 mg/dL, HDL cholesterol ≤40 mg/dL in men or ≤50 mg/dL in women, or use of lipid-modifying medication (iii) Prediabetes or type 2 diabetes according to the American Diabetes Association (ADA) Standards, or use of glucose-lowering medication.

Exclusion Criteria:

* Inability to give written informed consent
* CKD caused by polycystic kidney disease, chronic pyelonephritis, and renal dysplasia
* CKD on renal replacement therapy (hemodialysis, peritoneal dialysis, and kidney transplant recipients)
* Acute exacerbation of CKD, whether due to extrarenal causes (decompensated heart failure, infectious disease or sepsis, surgical intervention) or due to an outbreak of underlying glomerular or systemic renal pathology, with changes in treatment in the last 2 months.
* Nut allergy
* Alcoholism (\>50 g/day) or drug abuse
* Treatment with immunosuppressant drugs or cytotoxic agents
* Any other medical condition that interferes with the completion of the protocol (pregnancy/breastfeeding, history of inflammatory bowel disease, liver failure, cancer or active neoplasms, psychiatric problems)
* Institutionalization of the participant.

Where it's running

• Unit for Public Health and Nutritional Epidemiology, Faculty of Medicine and Health Sciences, Universitat Rovira i Virgili
  Reus, Tarragona, Spain Recruiting

Study contacts

• Study coordinator: Andrés Díaz López, PhD
• Email: andres.diaz@urv.cat
• Phone: +34 977759372

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How to take part

1. Review the eligibility criteria above with your treating physician.
2. Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
3. Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.