6-Week Mediterranean Diet Intervention on Dietary Adherence, Body Composition, and Physical Function in Kidney Transplant Recipients: A Pilot Randomized Controlled Trial

In recent years, increasing attention has been directed toward the role of diet and lifestyle factors in influencing graft function and patient survival after kidney transplantation (KT). Among the dietary patterns investigated, the Mediterranean diet (MedDiet) is among most studied diets in KT recipients. Data from observational studies show that greater adherence to the MedDiet is beneficial in kidney transplant recipients and is associated with improved lipid profile, lower oxidative stress, less frequent new-onset diabetes mellitus after transplantation, metabolic syndrome, better kidney function, and mortality. Unfortunately, adherence to MedDiet in kidney transplant recipients is low, and ranges between 25 % and 44.7%. Data from a Dutch cross-sectional study showed that higher levels of food literacy are associated with better adherence to MedDiet. Nevertheless, evidence from randomized dietary interventions aimed at improving MedDiet adherence in this population remains limited. Therefore, the aim of our pilot randomized controlled trial was to evaluate whether a six-week MedDiet intervention could improve adherence to the Mediterranean dietary pattern, assessed using the Mediterranean Diet Adherence Screener (MEDAS), and to explore the effects of MedDiet on body composition and physical function. We conducted an interventional, randomized study at the Kidney Transplantation Centre, Department of Nephrology, University Medical Centre Ljubljana. The intervention duration was six weeks and was performed by a Master's student in nutrition. We included kidney transplant recipients undergoing regular follow-up at the Kidney Transplantation Centre. Patients were invited to participate verbally via telephone contact one week prior to their scheduled physician appointment. Participation was voluntary and confirmed by a signed informed consent. The following exclusion criteria were applied: body mass index (BMI) > 25 kg/m², age > 45 years, female sex, serum creatinine > 250 µmol/L, a MEDAS score ≥ 10 points, and systolic blood pressure > 160 mmHg. Patients were randomized to the intervention and control group.

The primary study outcome was the MEDAS score. Secondary outcomes were lean tissue index (LTI; kg/m²), fat tissue index (FTI; kg/m²), handgrip strength (kg), and chair-stand performance (number of repetitions).