Very low-protein diet to postpone renal failure: Pathophysiology and clinical applications in chronic kidney disease

Is there anything left to eat? A lived experience insight of following a restrictive type 1 diabetes and dialysis diet

OBJECTIVES

Chronic kidney disease has a global morbidity burden of >10%, with diabetes being a major cause.  Nutrition therapy is vital in managing both chronic conditions, yet CKD dietary guidelines contradict healthy eating advice, and can result in major psychological and social burdens. Few studies investigate the patient's experience of being placed on such a restrictive diet. This auto/biographical review provides a unique perspective and aims to assist practitioners as they guide patients on 'what is left to eat.'

METHOD

An auto/biographical approach, supported by a comprehensive literature review using data from MEDLINE, Embase, and PsychoINFO, was used to answer the question: 'What are the diet and lifestyle challenges of following a restrictive Type 1 Diabetes/CKD dialysis diet?'

RESULTS

Restrictive dietary and fluid regimes have a major effect on patients' illness beliefs, anxieties, and independence. This is discussed through five themes: Food is belonging; Normal is a Fallacy; Your numbers define you; A disease disguised as a virtue and Meeting the Elephant: ESKD diagnosis and the burden of dialysis.

CONCLUSION

Dietary intervention is crucial in the management of T1D and ESKD, but equally important is to consider the implications of strict dietary regimes without sufficient evidence, guidance, and support.

A practical approach to nutritional intervention for people with chronic kidney disease in Vietnam

BACKGROUND AND OBJECTIVES

A comprehensive nutritional management is necessary for favourable outcomes in patients with chronic kidney disease (CKD). We aimed to assess the changes in nutritional status and disease progression with nutritional management where renal replacement therapy (RRT) was not in place.

METHODS AND STUDY DESIGN

A quasi-experiment intervention was conducted on 70 CKD patients at stages 3-5 from July to December 2022. Participants were excluded if they underwent RRT, including dialy-sis (hemodialysis or peritoneal dialysis), or kidney transplantation. The nutritional regimen covered nutrition-al counseling, samples of the dietary menu, and supplement products. We evaluated nutritional status using Subjective Global Assessment (SGA) scale and sub-clinical blood test at T0 (hospital admission) and T1 (two weeks after the admission or 24 hours before the discharge).

RESULTS

After the intervention, the number of patients classified as malnutrition or at risk of malnourished reduced significantly (65.7% to 54.3% and 25.7% and 5.7%, respectively). The serum concentration of urea, creatinine and parathyroid hormone decreased remarkably, especially in patients receiving nutritional management. In the intervention group, the dietary pattern provided increased intakes of calcium and iron at T1, while phosphorus, sodium and potassium decreased after follow-up. Nausea/vomiting, loss of appetite, tiredness and sleep disorders were improved in the intervention compared to the control group.

CONCLUSIONS

Nutritional therapy enhanced the nutritional sta-tus, and quality of dietary and renal function in CKD patients without RRT. Applying nutrition education and treatment at an early stage can slow CKD progression, which should be applicable elsewhere in Vietnam.

The effect of the diet of nitrogen-free analogs of essential amino acids on chronic kidney disease deterioration: A meta-analysis

INTRODUCTION

We performed a meta-analysis to evaluate the effect of the diet of nitrogen-free analogs of essential amino acids on chronic kidney disease deterioration.

METHODS

A systematic literature search up-to September 2021 was done and 14 studies included 1574 subjects with chronic kidney disease at the start of the study; 786 of them had the very low-protein diets supplemented with nitrogen-free analogs and 788 had the conventional low-protein diet.

RESULTS

Very low-protein diet supplemented with nitrogen-free analogs had significantly higher estimated glomerular filtration rate, lower serum creatinine, and lower blood urea nitrogen; however, it had no significant difference in serum albumin, serum cholesterol, serum phosphorous, serum calcium, and parathyroid hormone compared to conventional low-protein diet in subjects with chronic kidney disease.

CONCLUSION

The very low-protein diets supplemented with nitrogen-free analogs had significantly better kidney functions results compared to the conventional low-protein diets in subjects with chronic kidney disease. Further studies are required to validate these findings.

Exercise intolerance in kidney diseases: physiological contributors and therapeutic strategies

Exertional fatigue, defined as the overwhelming and debilitating sense of sustained exhaustion that impacts the ability to perform activities of daily living, is highly prevalent in chronic kidney disease (CKD) and end-stage renal disease (ESRD). Subjective reports of exertional fatigue are paralleled by objective measurements of exercise intolerance throughout the spectrum of the disease. The prevalence of exercise intolerance is clinically noteworthy, as it leads to increased frailty, worsened quality of life, and an increased risk of mortality. The physiological underpinnings of exercise intolerance are multifaceted and still not fully understood. This review aims to provide a comprehensive outline of the potential physiological contributors, both central and peripheral, to kidney disease-related exercise intolerance and highlight current and prospective interventions to target this symptom. In this review, the CKD-related metabolic derangements, cardiac and pulmonary dysfunction, altered physiological responses to oxygen consumption, vascular derangements, and sarcopenia are discussed in the context of exercise intolerance. Lifestyle interventions to improve exertional fatigue, such as aerobic and resistance exercise training, are discussed, and the lack of dietary interventions to improve exercise tolerance is highlighted. Current and prospective pharmaceutical and nutraceutical strategies to improve exertional fatigue are also broached. An extensive understanding of the pathophysiological mechanisms of exercise intolerance will allow for the development of more targeted therapeutic approached to improve exertional fatigue and health-related quality of life in CKD and ESRD.

Diet and Skin Aging-From the Perspective of Food Nutrition

We regularly face primary challenges in deciding what to eat to maintain young and healthy skin, defining a healthy diet and the role of diet in aging. The topic that currently attracts maximum attention is ways to maintain healthy skin and delay skin aging. Skin is the primary barrier that protects the body from external aggressions. Skin aging is a complex biological process, categorized as chronological aging and photo-aging, and is affected by internal factors and external factors. With the rapid breakthrough of medicine in prolonging human life and the rapid deterioration of environmental conditions, it has become urgent to find safe and effective methods to treat skin aging. For diet, as the main way for the body to obtain energy and nutrients, people have gradually realized its importance to the skin. Therefore, in this review, we discuss the skin structure, aging manifestations, and possible mechanisms, summarize the research progress, challenges, possible directions of diet management, and effects of foodborne antioxidants on skin aging from the perspective of food and nutrition.

The Effect of Ketoanalogues on Chronic Kidney Disease Deterioration: A Meta-Analysis

The effects of ketoanalogues (KA) on chronic kidney disease (CKD) deterioration have not yet been fully confirmed. To strengthen the evidence of the role of KA in CKD, PubMed and Embase were searched for studies published through February 2019. Effect sizes from ten randomized control trials (RCTs) and two non-RCTs comprising a total of 951 patients were pooled and analyzed. A restricted protein diet supplemented with ketoanalogues (RPKA) was found to significantly delay the progression of CKD (p = 0.008), particularly in patients with an estimated glomerular filtration rate (eGFR) > 18 mL/min/1.73 m² (p < 0.0001). No significant change in eGFR was found when comparing a very-low-protein diet and a low-protein diet (p = 0.10). In addition, compared with the placebo, RPKA did not cause malnutrition (albumin: p = 0.56; cholesterol: p = 0.50). Moreover, RPKA significantly decreased phosphorous levels (p = 0.001), increased calcium levels (p = 0.04), and decreased parathyroid hormone (PTH) levels (p = 0.05) in patients with eGFR < 18 mL/min/1.73 m². In conclusion, RPKA could slow down the progression of CKD in patients with eGFR > 18 mL/min/1.73 m² without causing malnutrition and reverse CKD-MBD in patients with eGFR < 18 mL/min/1.73 m².

Dialysis Reimbursement: What Impact Do Different Models Have on Clinical Choices?

Allowing patients to live for decades without the function of a vital organ is a medical miracle, but one that is not without cost both in terms of morbidity and quality of life and in economic terms. Renal replacement therapy (RRT) consumes between 2% and 5% of the overall health care expenditure in countries where dialysis is available without restrictions. While transplantation is the preferred treatment in patients without contraindications, old age and comorbidity limit its indications, and low organ availability may result in long waiting times. As a consequence, 30–70% of the patients depend on dialysis, which remains the main determinant of the cost of RRT. Costs of dialysis are differently defined, and its reimbursement follows different rules. There are three main ways of establishing dialysis reimbursement. The first involves dividing dialysis into a series of elements and reimbursing each one separately (dialysis itself, medications, drugs, transportation, hospitalisation, etc.). The second, known as the capitation system, consists of merging these elements in a per capita reimbursement, while the third, usually called the bundle system, entails identifying a core of procedures intrinsically linked to treatment (e.g., dialysis sessions, tests, intradialyitc drugs). Each one has advantages and drawbacks, and impacts differently on the organization and delivery of care: payment per session may favour fragmentation and make a global appraisal difficult; a correct capitation system needs a careful correction for comorbidity, and may exacerbate competition between public and private settings, the latter aiming at selecting the least complex cases; a bundle system, in which the main elements linked to the dialysis sessions are considered together, may be a good compromise but risks penalising complex patients, and requires a rapid adaptation to treatment changes. Retarding dialysis is a clinical and economical goal, but the incentives for predialysis care are not established and its development may be unfavourable for the provider. A closer cooperation between policymakers, economists and nephrologists is needed to ensure a high quality of dialysis care.

Very low protein diet plus ketoacid analogs of essential amino acids supplement to retard chronic kidney disease progression

Background

A very low protein diet (VLPD) with ketoacid analogs of essential amino acids (KA/EAA) administration can remarkably influence protein synthesis and metabolic disturbances of patients with advanced chronic kidney disease (CKD), and may also slow the decline in renal function.

Methods

A retrospective cohort study was carried out to monitor renal progression and metabolic and nutritional status among 140 patients with CKD stage III or IV. One group (n = 70) was on a low protein diet (LPD) with 0.6 g of protein intake, and another group (n = 70) was on a VLPD with 0.3 g of protein and KA/EAA supplementation of 100 mg/kg/day for 12 months.

Results

At 12-month follow-up, estimated glomerular filtration rate (GFR) significantly decreased from 41.6 ± 10.2 to 36.4 ± 8.8 mL/min/1.73 m² (P < 0.001) and urine protein increased from 0.6 ± 0.5 to 0.9 ± 1.1 g/day (P = 0.017) in the LPD group, but no significant changes in estimated GFR and urine protein were found in the VLPD plus KA/EAA group. A significant mean difference in rate of change in estimated GFR (-5.2 ± 3.6 mL/min/1.73 m² per year; P < 0.001) was observed between the two groups. After Cox regression analysis, treatment with VLPD plus KA/EAA significantly protected against the incidence of declining GFR > 10% annually (adjusted hazard ratio, 0.42; 95% confidence interval, 0.23-0.79; P = 0.006) and significant correlations were found between using VLPD plus KA/EEA and increased GFR.

Conclusion

VLPD supplementation with KA/EAA is associated with delayed renal progression while preserving the nutritional status in the patients with CKD. Co-administration of VLPD and KA/EAA may prove an effective alternative to conservative management of CKD.