Pistachio Consumption in Patients With Chronic Kidney Disease

NCT07815600 | Not Yet Recruiting

• 1 other identifier: 43015296
• Study Type: interventional
• Target: 20
• Locations: 1 country
• Sites: 1

Brief Summary

Standard chronic kidney disease (CKD) guidelines frequently restrict nut intake due to concerns regarding their phosphorus and potassium content. While uncontrolled phosphorus loading exacerbates secondary hyperparathyroidism, vascular calcification, and mortality, overly restrictive diets can preclude the intake of essential cardioprotective nutrients. Phytate (myo-inositol hexaphosphate), abundant in fiber-rich foods like pistachios, acts as a natural inhibitor of calcium salt deposition, potentially mitigating vascular calcification. Crucially, the phosphorus in nuts is largely organically bound as phytate, which resists enzymatic cleavage in the human gastrointestinal tract, significantly reducing its intestinal bioavailability. Given these properties, moderate pistachio consumption may offer cardiovascular benefits without compromising mineral metabolism. This study aims to evaluate the short-term effects of pistachio supplementation on circulating and urinary phosphorus, parathyroid hormone (PTH) in patients with CKD. This study is an open-label, randomized, controlled crossover clinical trial involving patients with stage 4 and 5 (non-dialysis) CKD. All participants will undergo a 1-week run-in period to initiate a standardized pre-dialysis renal diet (protein 0.8 g/kg/day, potassium 39 mg/kg/day, phosphorus 12 mg/kg/day). Following the run-in, participants will be randomized (1:1 ratio) to one of two 4-week dietary sequences of Pistachio Diet period (30 g/day of pistachios) or Control Diet period. The sequences will be separated by a 4-week washout period. Venous blood and 24-hour urine samples will be collected and serum biomarkers: Phosphorus, potassium, PTH, FGF23, MDA, fasting glucose, creatinine, lipid profile, high-sensitivity C-reactive protein (CRP), and alkaline phosphatase and urinary phosphorus, sodium, uric acid, and potassium will be measured.

Conditions

Chronic Kidney Disease (Stages 3b-5)

Outcome Measures

Primary Outcomes (3)

• Urinary Phosphorus

  Phosphorus concentration in 24-hour urine sample

  4 weeks

• Serum phosphorus

  Serum concentration of phosphorus

  4 weeks

• Serum PTH

  Serum concentrations of parathyroid hormone

  4 weeks

Other Outcomes (5)

• Urinary K

  4 weeks

• Serum FGF23

  4 weeks

• Serum MDA

  4 weeks

Study Arms (2)

Pistachio-Supplemented Diet

EXPERIMENTAL

Other: Pistachio

Control diet:

ACTIVE COMPARATOR

Other: Control

Interventions

Pistachio OTHER

A pre-dialysis renal diet providing targeted macronutrient and mineral allotments (protein: 0.8 g/kg/day, potassium: 39 mg/kg/day, phosphorus: 12 mg/kg/day supplemented with 30 g/day of pistachios. A low-sodium guideline will be maintained.

Pistachio-Supplemented Diet

Control OTHER

The identical baseline renal diet without pistachios, isoenergetically substituted with 60 g of white bread and one tablespoon of olive oil.

Control diet:

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Age ≥18
• Stage 4 or 5 non-dialysis CKD, defined as an estimated glomerular filtration rate (eGFR) \<30 mL/min/1.73 m2

You may not qualify if:

• Unwillingness or inability to provide informed consent.
• History of renal replacement therapy (maintenance dialysis or renal transplantation).
• Baseline hyperphosphatemia.
• Known allergy to pistachios.
• Pregnancy or lactation.
• Active malignancy under treatment.
• Consumption of \<80% of the provided pistachio ration during the intervention period.

Sponsors & Collaborators

• Shahid Beheshti University of Medical Sciences: lead

Study Sites (1)

Keshavarz Boulevard, end of Royan Alley - Royana Dead End - Amir Ali Clinic

Tehran, Tehran Province, Iran

Location

MeSH Terms

Conditions

Renal Insufficiency, Chronic

Condition Hierarchy (Ancestors)

Renal Insufficiency; Kidney Diseases; Urologic Diseases; Female Urogenital Diseases; Female Urogenital Diseases and Pregnancy Complications; Urogenital Diseases; Male Urogenital Diseases; Chronic Disease; Disease Attributes; Pathologic Processes; Pathological Conditions, Signs and Symptoms

Central Study Contacts

Zahra Salimi

CONTACT

+989135112099; zf.salimi@gmail.com

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: OUTCOMES ASSESSOR
• Purpose: PREVENTION
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Associate professor

Study Record Dates

• First Submitted: September 8, 2026
• First Posted: September 11, 2026
• Study Start: September 19, 2026
• Primary Completion (Estimated): January 16, 2027
• Study Completion (Estimated): March 4, 2027
• Last Updated: September 11, 2026

Record last verified: 2026-09

Locations

IR (1)