Medical Nutritional Therapy for Patients with Chronic Kidney Disease not on Dialysis: The Low Protein Diet as a Medication

Abstract

The 2020 Kidney Disease Outcome Quality Initiative (KDOQI) Clinical Practice Guideline for Nutrition in chronic kidney disease (CKD) recommends protein restriction to patients affected by CKD in stages 3 to 5 (not on dialysis), provided that they are metabolically stable, with the goal to delay kidney failure (graded as evidence level 1A) and improve quality of life (graded as evidence level 2C). Despite these strong statements, low protein diets (LPDs) are not prescribed by many nephrologists worldwide. In this review, we challenge the view of protein restriction as an “option” in the management of patients with CKD, and defend it as a core element of care. We argue that LPDs need to be tailored and patient-centered to ensure adherence, efficacy, and safety. Nephrologists, aligned with renal dietitians, may approach the implementation of LPDs similarly to a drug prescription, considering its indications, contra-indications, mechanism of action, dosages, unwanted side effects, and special warnings. Following this framework, we discuss herein the benefits and potential harms of LPDs as a cornerstone in CKD management.

Nutritional Approaches for the Management of Metabolic Acidosis in Chronic Kidney Disease

“…Modulating the type and quality of diet is pivotal for CKD management. Due to kidney damage, CKD patients exhibit impaired toxin and nitrogen waste product elimination [ 14 ]. The main dietary approaches to counteract metabolic acidosis in CKD patients are illustrated in Figure 2 .…”

“…per day. Cupisti et al defined the vegan LPD as a low-phosphorus diet based on strict combinations of cereals and legumes to provide the essential amino acids as an option for patients who refuse the use of protein-free products or when they result unavailable [ 14 ]. A vegan LPD is set up by encouraging the consumption of plant-based foods such as legumes, vegetables, cereals, and tubers.…”

“…Eventual cardiovascular comorbidities should be treated by keeping the lipid profile in check with diet and lipid-lowering drugs, decreasing blood pressure values, regulating calcium-phosphorus metabolism impairments, counteracting metabolic acidosis, and reducing albuminuria [ 2 ]. According to the 2020 Kidney Disease Outcome Quality Initiative (K/DOQI), besides the pharmacological therapy, the nutritional treatment plays a pivotal role in the management of CKD [ 14 , 15 ].…”

“…Given the epidemiological importance of CKD and its morbidity and mortality, it is of utmost relevance to research novel approaches to prevent it and control its progression. The present review sets out to elucidate the ways in which this can be done by using different nutritional-dietary regimens potentially useful for the metabolic acidosis management in CKD patients [ 14 , 16 , 17 ].…”

Protection of Residual Renal Function and Nutritional Treatment: First Step Strategy for Reduction of Uremic Toxins in End-Stage Kidney Disease Patients

“…Retained nitrogen compounds originate mainly from dietary proteins; hence, dietary intake must be considered as the most important source of substrates from which uremic toxins can originate. Both the amount and the quality of protein intake (plant-or animal-based) are important determinants of uremic solutes production, so that a low-protein diet is the mainstay of nutritional therapy of advanced CKD [6][7][8][9]. Uremic solutes can be defined uremic toxins when their increased levels are associated with clinical manifestations.…”