Use of low-protein staple foods in the dietary management of patients with stage 3-4 chronic kidney disease: a prospective case-crossover study

Abstract

Objective: Maintaining a low-protein diet (LPD) is important for patients with chronic kidney disease (CKD) to delay renal degradation and alleviate clinical symptoms. For most patients with CKD, it is difficult to maintain the necessary low level of dietary protein intake (DPI). To improve the current dietary management of CKD, we conducted an intervention study by administering low-protein staple foods (LPSF).

Design and methods: We conducted a prospective case-crossover study among 25 patients with stage 3-4 CKD. During the initial 12 weeks of the study, we instructed the patients regarding a standard LPD according to the recommendations of a renal dietitian. In the second stage of the study, we requested the patients taking low-protein rice or low-protein flour (250 g/d) as an LPSF diet instead of regular staple food daily, and followed these patients up for 12 weeks. We compared the DPI, dietary energy intake (DEI), normalized protein equivalent of total nitrogen appearance (nPNA), serum creatinine levels, and nutritional index between baseline and the end of the study.

Results: We found no change in dietary variables among the patients during the first 12 weeks of the LPD. After subjecting them to an LPSF diet, the corresponding variables showed a pronounced change. The patients' DPI decreased from 0.88 ± 0.20 to 0.68 ± 0.14 g/kg/d (P < 0.01) and the nPNA value decreased from 0.99 ± 0.18 to 0.87 ± 0.19 g/kg/d (P < 0.01). The high biological value protein intake proportion increased from 42% (baseline) to 57% (P < 0.01) during the 24 weeks. No variation was found in the measured DEI (28.0 ± 5.8 vs 28.6 ± 5.4 kcal/kg/d), nutrition assessment, or renal function and serum creatinine levels.

Conclusion: Our prospective case-crossover study demonstrated that an LPSF diet can help patients with stage 3-4 CKD reduce DPI and nPNA values, improve the proportion of highly bioavailable proteins, ensure adequate calorie intake, and avoid malnutrition. An LPSF diet is an effective and simple therapy for patients with stage 3-4 CKD.

Keywords: Chronic kidney disease; Low-protein diet; Protein energy wasting.