Dietary protein restriction as a treatment for slowing chronic kidney disease progression: The case against (Review Article)

Abstract

Low-protein diets (<or=0.7 g/kg per day) have been advocated for over 70 years as a means of slowing the rate of progression of kidney disease and delaying the appearance of uraemic symptoms and need for dialysis. However, the available evidence to date suggests that the benefit : risk ratio of dietary protein restriction is not favourable in that: (i) compliance is generally sub-optimal; (ii) most of the published randomised controlled trials demonstrate that low-protein diets do not significantly slow the rate of kidney disease progression; (iii) meta-analyses of controlled trials have demonstrated strong evidence of publication bias favouring studies with positive, rather than negative, results; (iv) the optimal level and duration of dietary protein intake have not been defined; (v) there is no convincing clinical evidence that dietary protein restriction provides any benefit beyond that afforded by angiotensin blockade; and (vi) low-protein diets are associated with both statistically and clinically significant declines in nutritional markers in chronic kidney disease populations, which already have a high prevalence of malnutrition. Patients with progressive kidney disease are therefore likely to be better served by avoiding dietary protein restriction (thereby ensuring optimal preservation of their nutrition) and instituting alternative, proven renoprotective measures (e.g. renin-angiotensin system blockade, blood pressure reduction and statin therapy).

Is There a Role for Ketoacid Supplements in the Management of CKD?

“…These studies generally provided KA/EAA supplementation of w0.28 g/kg/d with protein at a level of w0.30 g/kg/d. 9,42,66,71 The MDRD Study maintained good nutrition with similar KA/EAA supplementation. 67,68 Currently, KA/EAA levels of w100 to 126 mg/kg/d often are prescribed 61,69 ; this reduces the cost of treatment and should facilitate patient acceptance.…”

Ketoanalogue-Supplemented Vegetarian Very Low–Protein Diet and CKD Progression

“…They had stable renal function for at least 12 weeks before enrollment (defined as a reduction in eGFR,4 ml/min per year 24 , proteinuria ,1 g/g urinary creatinine, good nutritional status as indicated by an SGA score A/B, and serum albumin $3.5 g/dl). Only the patients who declared a potentially good compliance with an LPD and agreed to follow the monitoring schedule were considered.…”

“…21 Notably, patients' adherence to LPD was also a problem. 21 Because the efficacy of protein-restricted regimens seemed uncertain, 20 their feasibility was repeatedly questioned; because the adherence and compliance of patients to the diet were reported as poor and the risk of malnutrition was frequently invoked, [22][23][24][25] the use of KD and VLPDs was not extended.…”

The Roles of Indoxyl Sulphate and p-Cresyl Sulphate in Patients with Chronic Kidney Disease: A Review of Therapeutic Options

“…The authors found that patients treated with a VLPD experienced a signiicant 36% reduction in serum IS levels compared with those treated with a LPD (7.12 ± 3.89 μM during VLPD vs. 11.1 ± 6.6 μM during LPD, p < 0.0001). Although a meta-analysis has identiied reduction in the occurrence of renal death with a lowprotein intake in CKD patients, the overall value of these diets remains a subject of debate, given that the risks of malnutrition may present a greater danger [30][31][32]. Furthermore, poor compliance is also likely to be an issue, as participants often did not meet dietary targets even with the intensive support provided within a trial seting.…”