Influence of Changing Dietary Phosphorus-to-Protein Ratio on Serum Phosphorus and the Nutritional Status in Patients on Hemodialysis

Background: To investigate the impact of altering dietary phosphorus-protein ratio on serum phosphorus and the nutritional status of hemodialysis patients. Methods: A self-controlled clinical study was conducted on patients with serum phosphorus ≥1.78 mmol/L despite low-phosphorus diet education. Subjects replaced staple foods with an equal amount of low-protein rice, and the protein difference between regular rice and low-protein rice was supplemented with an equal amount of low-phosphorus whey protein. After 10 weeks of dietary intervention, changes in phosphorus, albumin, and body composition measurements were analyzed. Results: A total of 29 patients were enrolled, with a mean age of 58.4±14.1 years. At baseline, the dietary phosphorus-protein ratio was (15.85±3.29) mg/g, serum phosphorus was (2.05±0.32) mmol/L, and serum albumin was (39.84±3.23) g/L. After 10 weeks of intervention, the dietary phosphorus-protein ratio decreased to (12.18±2.45) mg/g, serum phosphorus decreased to (1.87±0.44) mmol/L, and serum albumin increased to (42.29±3.51) g/L, with significant differences compared to baseline (p<0.001, 0.048, <0.001，respectively). Total calorie and protein intake showed no significant changes. Additionally, patients experienced an increase in dry weight (65.09±15.30 vs. 64.71±15.07 kg, p=0.030), mid-upper arm muscle circumference (22.57±2.83 vs. 22.00±3.03 cm, p=0.013), and grip strength in the non-fistula upper limb (27.89±7.82 vs. 26.54±7.90 kg, p=0.032). No significant changes were observed in subjective comprehensive assessment or lipid levels. The dialysis regimen remained unchanged throughout the study, and no adverse events occurred. Conclusion: In hemodialysis patients, replacing regular rice with low-protein rice combined with low-phosphorus whey protein can adjust the dietary phosphorus-protein ratio while maintaining calorie and protein intake. This intervention effectively reduces serum phosphorus levels, improves serum albumin levels, and enhances muscle mass and strength.