Chronic kidney disease (CKD) is a debilitating condition that affects the emotional, physical and social well-being of affected patients, reducing their quality of life (QoL). A new study published in the journal Nutrients examines how health-related quality of life (HRQoL) in patients with CKD is affected by the New Nordic Renal Diet (NNRD).
Study: Health-related quality of life during a 26-week intervention with the New Nordic kidney dietPhoto credit: monticello / Shutterstock.com
What is NNRD?
The NNRD, created to help patients with moderate CKD, is a modified version of the New Nordic Diet (NND), a Scandinavian alternative to the Mediterranean diet.
The national diet consists of 80% plant-based foods, with the remainder consisting of animal products that provide 30-35 kcal/day. The amount and type of each food is tailored to the patient.
A previous randomized controlled trial (RCT) reported favorable effects of NNRD on metabolic and physiological outcomes. Specifically, patients with CKD prescribed NNRD had lower urinary protein and phosphorus levels, loss of fat mass, and lower blood pressure.
Diets recommended for patients with CKD are often restrictive and target only one nutrient. In contrast, the diet recommended for patients with CKD is a nutritionally balanced approach.
Although the feasibility and effectiveness of the NNRD have been previously reported, its impact on the quality of life of patients with CKD remains uncertain. This type of patient-reported outcome measure (PROM) is useful for evaluating medical interventions from the patient’s perspective.
About the study
The current study involved 58 participants who followed either a control diet or the NNRD diet. NNRD participants received weekly recipes and food boxes consistent with the specified diet, while controls continued to consume their usual diet.
Health-related quality of life was assessed at baseline and at the end of the 26-week intervention.
What did the study show?
People following the NNRD lost an average of -1.7 kg after 26 weeks, which is equivalent to a 2% reduction in body mass and a difference of 2 kg between the two groups. The NNRD also reduced body mass index (BMI) values compared with controls.
The NNRD group observed a 5% and 2.5% reduction in fat mass and lean mass, respectively. Waist circumference measurements were reduced by more than one centimeter in the NNRD group, with a difference of -2.1 cm compared to the control group.
The NNRD group experienced 26% less pain and discomfort during the intervention period, compared with no changes reported in the control group. A positive association was observed between body fat loss and reduction in pain/discomfort.
Ease of performing daily activities improved by 23% in the NNRD group, with no changes reported in the control group.
To assess compliance, urinary phosphorus levels were measured for 24 hours. The NNRD group had approximately 20% lower phosphorus levels than the control group, which showed no change. As urinary phosphorus levels decreased, greater improvement in daily activities was observed.
The study results indicate that the NNRD diet provides adequate protein intake of 0.8 g protein/kg/day without causing loss of muscle mass. In fact, participants in the NNRD group had 39% lower urinary protein excretion. Plasma and urinary urea and urinary sodium levels were also reduced in the NNRD group, while plasma albumin levels increased.
Conclusions
The NNRD group experienced clinically relevant improvement in various health-related quality of life outcomes.”
Participants in the NNRD group reported improvements in quality of life, energy, mood, sleep quality, and skin health. These benefits may be attributed to a reduction in the need for blood pressure medications, as blood pressure levels were reduced through adherence to the NNRD.
Although weight loss was not a goal of the program, approximately 2% of participants’ body weight was lost during the 26-week intervention. With less body fat, participants experienced less pain and discomfort, suggesting a beneficial effect of reducing fat mass. The observed fat loss occurred primarily in the abdominal region, as indicated by waist circumference measurements.
Polyphenols and other antioxidants found in the non-diet diet, such as those in the Mediterranean diet, may also have contributed to the improved health-related quality of life. The polyunsaturated fatty acids found in this type of diet are anti-inflammatory and can activate neurotransmitters in the brain, improving mental health.
The involvement of counselors to monitor adherence to the diet, the use of recipes created by celebrity chefs, and the provision of free fresh food each week may have motivated participants and increased their enjoyment of eating. This approach also promotes self-management rather than passive receipt of medical care or knowledge, which could also contribute to a better health-related quality of life.
Journal reference:
- Hansen, NM, Kamper, A.-, Rix, M., et al. (2024). Health-related quality of life during a 26-week intervention with the New Nordic Renal Diet. Nutrients. doi:10.3390/nu16132038.
