Low-protein diets in CKD: how can we achieve them? A narrative, pragmatic review

Vegetarian Nutrition in Chronic Kidney Disease

There is rising interest globally with respect to the health implications of vegetarian or plant-based diets. A growing body of evidence has demonstrated that higher consumption of plant-based foods and the nutrients found in vegetarian and plant-based diets are associated with numerous health benefits, including improved blood pressure, glycemic control, lipid levels, body mass index, and acid-base parameters. Furthermore, there has been increasing recognition that vegetarian and plant-based diets may have potential salutary benefits in preventing the development and progression of chronic kidney disease (CKD). While increasing evidence shows that vegetarian and plant-based diets have nephroprotective effects, there remains some degree of uncertainty about their nutritional adequacy and safety in CKD (with respect to protein-energy wasting, hyperkalemia, etc.). In this review, we focus on the potential roles of and existing data on the efficacy/effectiveness and safety of various vegetarian and plant-based diets in CKD, as well as their practical application in CKD management.

Association of carbohydrate intake from different sources with all-cause and cardiovascular mortality among chronic kidney disease populations: assessment of 1999-2018 National Health and Nutrition Examination Survey participation

This study analysed the data from the NHANES (1999-2018) to examine how different sources of carbohydrate intake affected the all-cause and cardiovascular mortality of 11,302 chronic kidney disease (CKD) patients. The data were adjusted for other factors using various methods. The results showed that CKD patients (stages 1-2 and 3-5) who consumed more carbohydrates from whole grains, fruits, vegetables and less carbohydrates from fruit juice or sauces had lower mortality rates. Replacing fat intake with carbohydrates from whole grains (HR = 0.86[0.78-0.95]), fruits (raw) (HR = 0.79[0.70-0.88]) and non-starchy vegetables (HR = 0.82[0.70-0.96]), but not protein intake, was linked to lower all-cause mortality. The fibre content in carbohydrates might partly account for the benefits of selected carbohydrate intake. This study provided practical recommendations for optimising the carbohydrate sources in CKD patients.

Efficacy of Low-Protein Rice for Dietary Protein Restriction in CKD Patients: A Multicenter, Randomized, Controlled Study

Background

The benefits of dietary protein restriction in CKD remain unclear, largely due to inadequate adherence in most clinical trials. We examined whether low-protein rice (LPR) previously developed to reduce the protein content of rice, a major staple food, would help improve adherence to dietary protein restriction.

Methods

This open-label, multicenter, randomized, controlled trial evaluated the efficacy of LPR use for reducing dietary protein intake (DPI) in patients with CKD stages G3aA2-G4. Participants were randomly assigned in a 1:1 ratio to an LPR or control group and were followed up for 24 weeks. Both groups received regular counseling by dietitians to help achieve a target DPI of 0.7 g/kg ideal body weight (IBW) per day. The amount of protein in LPR is about 4% of that in ordinary rice, and the participants in the LPR group were instructed to consume LPR with at least two meals per day. The primary outcome was estimated dietary protein intake (eDPI) determined using the Maroni formula. The secondary outcomes included creatinine clearance (CCr) and urinary protein on the basis of 24-hour urine collection.

Results

In total, 51 patients were randomized to either the LPR group or the control group. At baseline, mean age was 62.5 years, 70% were men, mean CCr was 52.0 ml/min, and mean eDPI was 0.99 g/kg IBW per day. At 24 weeks, mean eDPI decreased to 0.80 g/kg IBW per day in the LPR group and to 0.91 g/kg IBW per day in the control group, giving a between-group difference of 0.11 g/kg IBW per day (95% confidence interval, 0.03 to 0.19 g/kg IBW per day; P=0.006). There was no significant between-group difference in CCr, but urinary protein was lower at 24 weeks in the LPR group than in the control group.

Conclusions

LPR is a feasible tool for efficiently reducing DPI in patients with CKD.

Clinical Trial registry name and registration number

Randomized, Multicenter, Controlled Study for the Efficacy of Low-Protein Rice Diet in Patients with Chronic Kidney Disease, UMIN000015630.

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

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.

Plant-Based versus Animal-Based Low Protein Diets in the Management of Chronic Kidney Disease

Recent data reiterate low-protein diets (LPDs) as cornerstones in the conservative management of chronic kidney disease (CKD). The reduction in proteinuria, better blood pressure control and the reduction in the rate of decline in kidney function with LPDs were reported, both in non-diabetics and diabetics patients. Supplemented, vegetarian, very-low-protein diets (sVLPD, 0.3 g/kg-day) could postpone kidney replacement therapy (KRT) initiation, mainly through the better control of metabolic disorders of advanced CKD in non-diabetic patients. Plant-based diets could ameliorate gut microbiota and appear to be superior to mixed hypoproteic diets in treating advanced CKD: better control of nitrogen balance, acid-base metabolism and bone mineral disorders. Vegetarian diets generate fewer uremic toxins and reduce salt intake and acid overload. At the same time, they can improve lipid metabolism, providing a high ratio of unsaturated to saturated fatty acids, as well as insulin resistance.

Dietary patterns and chronic kidney disease outcomes: A systematic review

Chronic kidney disease (CKD) is a serious public health problem and its prevalence is growing in many countries, often related to issues resulting from the lifestyle in growing economies and the population's life expectancy. Nutritional therapy is a beneficial but still neglected strategy for preventing CKD and delaying disease progression. The aim of this study was to assess the association of dietary patterns with CKD development and progression. Observational studies conducted in adult humans and the correlation between the adopted dietary pattern and prevalent and incident cases of CKD were assessed. A significant association was observed between unhealthy dietary patterns and an increased risk of developing or worsening CKD, as well as an adverse effect. Whereas healthy eating patterns characterized by the consumption of fruit, vegetables and dietary fibre showed nephroprotective outcomes.

Long-Term Effects of Ketoanalogues on Mortality and Renal Outcomes in Advanced Chronic Kidney Disease Patients Receiving a Low-Protein Diet

The effects of ketoanalogues (KA) supplementation on mortality and progression to dialysis in patients with pre-dialysis stage 5 chronic kidney disease (CKD) receiving a low-protein diet (LPD) remain ambiguous. From Taiwan’s National Health Insurance Research Database during 1996–2011, 165 patients with pre-dialysis CKD on an LPD (0.6 g/kg/day) with KA supplementation were matched with 165 patients with pre-dialysis CKD on an LPD without KA supplementation. Of the 165 patients with advanced CKD receiving KA supplementation, 34 (20.6%) died, and 124 (75.2%) underwent long-term dialysis during the study period. There was no significant difference in mortality between the KA-user group and the KA-nonuser group (adjusted hazard ratio [HR], 1.41; 95% confidence interval [CI], 0.68–2.93; p = 0.355). KA supplementation significantly increased long-term dialysis risk (adjusted HR, 1.41; 95% CI, 1.04–1.90; p = 0.025) and combined outcome risk (defined as long-term dialysis and death; adjusted HR, 1.37; 95% CI, 1.02–1.83; p = 0.034). KA supplementation also increased long-term dialysis risk (adjusted HR, 1.49; 95% CI, 1.00–2.20; p = 0.048) in the subgroup of pre-dialysis patients with diabetes mellitus (DM), but not in those patients without DM. In conclusion, KA supplementation might increase long-term dialysis risk in patients with advanced CKD receiving an LPD, but it did not increase mortality.

Healthy adult vegetarians have better renal function than matched omnivores: a cross-sectional study in China

Background

An appropriate diet is an important determinant of kidney health. However, the association between vegetarian diets and renal function is unclear. We aimed to study the association between vegetarian diets and renal function in healthy adults.

Methods

A total of 269 vegetarians and 269 sex- and age-matched nonvegetarian omnivores were enrolled in this cross-sectional study. Basic characteristics and daily dietary intakes were assessed by face-to-face interviews. Blood samples were collected, and renal function was assessed by measuring blood urea nitrogen (BUN), serum creatinine (SCr), uric acid (UA) and the estimated glomerular filtration rate (eGFR). Blood pressure, fasting blood glucose and blood lipid profiles were also assessed.

Results

The average age of the vegetarians was 35.4 ± 8.6 years, 82.2% of whom were female. We evaluated the association between vegetarian diets and renal function using multivariate analysis. Compared with omnivores, vegetarians had lower BUN [β = − 0.63, 95% confidence interval (CI): (− 0.88, − 0.38)], SCr [β = − 2.04, 95% CI:(− 4.10, 0.02)], and UA levels [β = − 15.15, 95% CI: (− 27.81, − 2.50)] and higher eGFRs [β = 4.04, 95% CI: (0.30, 7.78)] after adjusting for sex, age, body mass index (BMI), physical activity, alcohol consumption, smoking status, low-density lipoprotein cholesterol (LDL), high-density lipoprotein cholesterol (HDL), systolic pressure and fasting blood glucose. Further analysis of food composition and renal function showed that dietary fiber intake was significantly negatively associated with BUN [β = − 0.02, 95% CI: (− 0.03, 0.00)], SCr [β = − 0.14, 95% CI: (− 0.25, 0.04)], and UA levels [β = − 0.72, 95% CI: (− 1.36, 0.07)] and positively associated with the eGFR [β = 0.20, 95% CI: (0.00, 0.40)].

Conclusions

Healthy adult vegetarians have better renal function than omnivores, and the higher dietary fiber intake associated with vegetarian diets may contribute to the protective effect on renal function.

Plant-based diets to manage the risks and complications of chronic kidney disease

Traditional dietary recommendations for patients with chronic kidney disease (CKD) focus on the quantity of nutrients consumed. Without appropriate dietary counselling, these restrictions can result in a low intake of fruits and vegetables and a lack of diversity in the diet. Plant nutrients and plant-based diets could have beneficial effects in patients with CKD: increased fibre intake shifts the gut microbiota towards reduced production of uraemic toxins; plant fats, particularly olive oil, have anti-atherogenic effects; plant anions might mitigate metabolic acidosis and slow CKD progression; and as plant phosphorus has a lower bioavailability than animal phosphorus, plant-based diets might enable better control of hyperphosphataemia. Current evidence suggests that promoting the adoption of plant-based diets has few risks but potential benefits for the primary prevention of CKD, as well as for delaying progression in patients with CKD G3-5. These diets might also help to manage and prevent some of the symptoms and metabolic complications of CKD. We suggest that restriction of plant foods as a strategy to prevent hyperkalaemia or undernutrition should be individualized to avoid depriving patients with CKD of these potential beneficial effects of plant-based diets. However, research is needed to address knowledge gaps, particularly regarding the relevance and extent of diet-induced hyperkalaemia in patients undergoing dialysis.

Branched-chain amino acid and branched-chain ketoacid ingestion increases muscle protein synthesis rates in vivo in older adults: a double-blind, randomized trial

BACKGROUND

Protein ingestion increases muscle protein synthesis rates. However, limited data are currently available on the effects of branched-chain amino acid (BCAA) and branched-chain ketoacid (BCKA) ingestion on postprandial muscle protein synthesis rates.

OBJECTIVE

The aim of this study was to compare the impact of ingesting 6 g BCAA, 6 g BCKA, and 30 g milk protein (MILK) on the postprandial rise in circulating amino acid concentrations and subsequent myofibrillar protein synthesis rates in older males.

METHODS

In a parallel design, 45 older males (age: 71 ± 1 y; BMI: 25.4 ± 0.8 kg/m2) were randomly assigned to ingest a drink containing 6 g BCAA, 6 g BCKA, or 30 g MILK. Basal and postprandial myofibrillar protein synthesis rates were assessed by primed continuous l-[ring-13C6]phenylalanine infusions with the collection of blood samples and muscle biopsies.

RESULTS

Plasma BCAA concentrations increased following test drink ingestion in all groups, with greater increases in the BCAA and MILK groups compared with the BCKA group (P < 0.05). Plasma BCKA concentrations increased following test drink ingestion in all groups, with greater increases in the BCKA group compared with the BCAA and MILK groups (P < 0.05). Ingestion of MILK, BCAA, and BCKA significantly increased early myofibrillar protein synthesis rates (0-2 h) above basal rates (from 0.020 ± 0.002%/h to 0.042 ± 0.004%/h, 0.022 ± 0.002%/h to 0.044 ± 0.004%/h, and 0.023 ± 0.003%/h to 0.044 ± 0.004%/h, respectively; P < 0.001), with no differences between groups (P > 0.05). Myofibrillar protein synthesis rates during the late postprandial phase (2-5 h) remained elevated in the MILK group (0.039 ± 0.004%/h; P < 0.001), but returned to baseline values following BCAA and BCKA ingestion (0.024 ± 0.005%/h and 0.024 ± 0.005%/h, respectively; P > 0.05).

CONCLUSIONS

Ingestion of 6 g BCAA, 6 g BCKA, and 30 g MILK increases myofibrillar protein synthesis rates during the early postprandial phase (0-2 h) in vivo in healthy older males. The postprandial increase following the ingestion of 6 g BCAA and BCKA is short-lived, with higher myofibrillar protein synthesis rates only being maintained following the ingestion of an equivalent amount of intact milk protein. This trial was registered at Nederlands Trial Register (www.trialregister.nl) as NTR6047.

Vegetable-Based Diets for Chronic Kidney Disease? It Is Time to Reconsider

Traditional dietary recommendations to renal patients limited the intake of fruits and vegetables because of their high potassium content. However, this paradigm is rapidly changing due to the multiple benefits derived from a fundamentally vegetarian diet such as, improvement in gut dysbiosis, reducing the number of pathobionts and protein-fermenting species leading to a decreased production of the most harmful uremic toxins, while the high fiber content of these diets enhances intestinal motility and short-chain fatty acid production. Metabolic acidosis in chronic kidney disease (CKD) is aggravated by the high consumption of meat and refined cereals, increasing the dietary acid load, while the intake of fruit and vegetables is able to neutralize the acidosis and its deleterious consequences. Phosphorus absorption and bioavailability is also lower in a vegetarian diet, reducing hyperphosphatemia, a known cause of cardiovascular mortality in CKD. The richness of multiple plants in magnesium and vitamin K avoids their deficiency, which is common in these patients. These beneficial effects, together with the reduction of inflammation and oxidative stress observed with these diets, may explain the reduction in renal patients' complications and mortality, and may slow CKD progression. Finally, although hyperkalemia is the main concern of these diets, the use of adequate cooking techniques can minimize the amount absorbed.

The new Clinical Kidney Journal, 4 years later

The February 2015 issue of ckj started a new era with renewed efforts to be useful to the training and practicing nephrologists and a new focus on Clinical and Translational Nephrology. Four years later, it has become a truly global journal with contributors and readers from all over the world. The increase in quality of the published material has resulted in a nearly exponential growth of citations. Since 2016, ckj is listed in the new Emerging Sources Citation Index (ESCI) database from Clarivate Analytics and from January 2019 it will be listed in the full Science Citation Index. ckj will therefore receive its first official impact factor based upon 2018 citation to 2016 and 2017 articles. While no official impact factor was awarded for 2017, the estimated impact factors calculated from data available in Clarivate's Web of Science database rose to 2.987 in 2017, which would correspond to an estimated journal impact factor percentile of 72.4% in the Urology and Nephrology field.

Dietary Protein Intake, Protein Energy Wasting, and the Progression of Chronic Kidney Disease: Analysis from the KNOW-CKD Study

Studies on the effect of dietary protein intake (DPI) on chronic kidney disease (CKD) progression, along with the potential hazard of protein-energy wasting (PEW), are scarce. We evaluated the association between DPI and kidney function both cross-sectionally and longitudinally, particularly emphasizing the role of PEW, in a large-scale, observational, multicenter, prospective study. We enrolled 1572 patients with non-dialysis CKD between 2011 and 2016. CKD progression was defined by a >50% estimated glomerular filtration rate (eGFR) decrease, serum creatinine doubling, or dialysis initiation. A Cox proportional hazard regression analysis was conducted. During the mean follow-up period of 41.6 months, CKD progression was observed in 296 patients. Cross-sectionally, increased DPI was significantly associated with increased eGFR. Similarly, increased DPI tertile was significantly associated with increased renal survival in a Kaplan–Meier curve analysis. In the multivariate Cox proportional hazard regression analysis, the statistical significance of the DPI tertile group in CKD progression was lost when PEW-related variables were added as covariates. In penalized spline curve analysis, the adjusted odds ratio of PEW significantly increased as DPI decreased. DPI, per se was not a major determinant of CKD progression. An intimate association between reduced DPI and PEW may be a more important predictor of CKD progression than DPI.

The metabolomic quest for a biomarker in chronic kidney disease

Chronic kidney disease (CKD) is a growing burden on people and on healthcare for which the diagnostics are niether disease-specific nor indicative of progression. Biomarkers are sought to enable clinicians to offer more appropriate patient-centred treatments, which could come to fruition by using a metabolomics approach. This mini-review highlights the current literature of metabolomics and CKD, and suggests additional factors that need to be considered in this quest for a biomarker, namely the diet and the gut microbiome, for more meaningful advances to be made.

Adequacy of Plant-Based Proteins in Chronic Kidney Disease

Concerns regarding protein and amino acid deficiencies with plant-based proteins have precluded their use in chronic kidney disease (CKD) patients. Many of these concerns were debunked years ago, but recommendations persist regarding the use of "high-biological value" (animal-based) proteins in CKD patients, which may contribute to worsening of other parameters such as blood pressure, metabolic acidosis, and hyperphosphatemia. Plant-based proteins are sufficient in meeting both quantity and quality requirements. Those eating primarily plant-based diets have been observed to consume approximately 1.0 g/kg/day of protein, or more. CKD patients have been seen to consume 0.7-0.9 g/kg/day of mostly plant-based protein without any negative effects. Furthermore, those substituting animal-based proteins for plant-based proteins have shown reductions in severity of hypertension, hyperphosphatemia, and metabolic acidosis. Plant-based proteins, when consumed in a varied diet, are not only nutritionally adequate but have pleiotropic effects which may favor their use in CKD patients.

Use of phosphate-binders and risk of infection-related and all-cause mortality in patients undergoing hemodialysis: The Q-Cohort Study

The use of phosphate (P)-binders allows hemodialysis patients to take in more protein and thus may maintain a good nutritional status. Protein-energy-malnutrition increases the risk of infection-related death. The association between use of P-binders and the relative risks of infection-related death remains unknown in hemodialysis patients. A total of 2926 hemodialysis patients registered to the Q-Cohort Study was followed up for 4-years. The association between use of P-binders and the risks for infection-related and all-cause mortality were estimated by Cox proportional hazards risk model with multiple adjustments by conventional and propensity-score based approaches. During the follow-up period, 106 patients and 492 patients died of infection and any cause, respectively. Cox proportional hazards models with multivariable adjustments including nutritional confounders showed that the incidence of infection-related death was significantly lower in patients with P-binders use compared with those without (hazard ratio [95% confidence interval] for infection-related mortality 0.63 [0.40-0.99]). The results remained significant even after applying four different propensity score-based analyses. Notably, use of P-binders was associated with a lower risk of all-cause mortality. Further studies including randomized controlled clinical trials and observational studies analyzed by an instrumental variable model will provide more robust evidences for the associations observed in our study.

Does Low-Protein Diet Influence the Uremic Toxin Serum Levels From the Gut Microbiota in Nondialysis Chronic Kidney Disease Patients?

OBJECTIVES

To evaluate the effects of low-protein diet (LPD) on uremic toxins and the gut microbiota profile in nondialysis chronic kidney disease (CKD) patients.

DESIGN AND METHODS

Longitudinal study with 30 nondialysis CKD patients (stage 3-4) undergoing LPD for 6 months. Adherence to the diet was evaluated based on the calculation of protein equivalent of nitrogen appearance from the 24-hour urine analysis. Good adherence to LPD was considered when protein intake was from 90% to 110% of the prescribed amount (0.6 g/kg/day). Food intake was analyzed by the 24-hour recall method. The anthropometric, biochemical and lipid profile parameters were measured according to standard methods. Uremic toxin serum levels (indoxyl sulfate, p-cresyl sulfate, indole-3-acetic acid) were obtained by reversed-phase high-performance liquid chromatography (RP-HPLC). Fecal samples were collected to evaluate the gut microbiota profile through polymerase chain reaction and denaturing gradient gel electrophoresis. Statistical analysis was performed by the SPSS 23.0 program software.

RESULTS

Patients who adhered to the diet (n = 14) (0.7 ± 0.2 g/kg/day) presented an improvement in renal function (nonsignificant) and reduction in total and low-density lipoprotein cholesterol (183.9 ± 48.5-155.7 ± 37.2 mg/dL, P = .01; 99.4 ± 41.3-76.4 ± 33.2 mg/dL, P = .01, respectively). After 6 months of nutricional intervention, p-cresyl sulfate serum levels were reduced significantly in patients who adhered to the LPD (19.3 [9.6-24.7] to 15.5 [9.8-24.1] mg/L, P = .03), and in contrast, the levels were increased in patients who did not adhere (13.9 [8.0-24.8] to 24.3 [8.1-39.2] mg/L, P = .004). In addition, using the denaturing gradient gel electrophoresis technique, it was observed change in the intestinal microbiota profile after LPD intervention in both groups, and the number of bands was positively associated with protein intake (r = 0.44, P = .04).

CONCLUSION

LPD seems be a good strategy to reduce the uremic toxins production by the gut microbiota in nondialysis CKD patients.

Comparison of vegetarian versus animal-based low protein diets on estimated glomerular filtration rates in chronic kidney disease patients: a systematic review protocol

REVIEW QUESTION/OBJECTIVE

The objective of this review is to evaluate studies to determine the effect of a low-protein, vegetarian diet as compared to a low-protein, animal-based diet on estimated glomerular filtration rates (eGFR) in adults with chronic kidney disease (CKD).

Low-protein diet supplemented with ketoacids delays the progression of diabetic nephropathy by inhibiting oxidative stress in the KKAy mice model

Diabetic nephropathy (DN) is a major cause of chronic kidney disease. We aimed to investigate the effect of the low-protein diets (LPD) supplemented with ketoacids (LPD+KA) in KKAy mice, an early type 2 DN model. KKAy mice were treated with normal protein diet (NPD), LPD or LPD+KA from 12 to 24 weeks of age. A period of 12-week treatment with LPD significantly reduced albuminuria as compared with that observed after NPD treatment. Treatment with LPD+KA further reduced albuminuria as compared with that observed with LPD treatment alone. Moreover, LPD treatment reduced mesangial expansion, thickness of glomerular basement membrane and the severity of the podocyte foot process effacement in KKAy mice; these effects were more pronounced in KKAy mice treated with LPD+KA. Both LPD and LPD+KA treatments slightly reduced total body weight, but had no significant effect on kidney weight and blood glucose concentrations when compared with NPD-treated KKAy mice. LPD treatment slightly attenuated oxidative stress in kidneys as compared with that observed in NPD-treated KKAy mice; however, LPD+KA treatment remarkably ameliorated oxidative stress in diabetic kidneys as shown by decreased malondialdehyde concentrations, protein carbonylation, nitrotyrosine expression and increased superoxide dismutase expression. Nutritional therapy using LPD+KA confers additional renal benefits as compared with those of LPD treatment alone in early type 2 DN through inhibition of oxidative stress.

Chronic kidney disease progression: a retrospective analysis of 3-year adherence to a low protein diet

The potential benefits and dangers of dietary protein restriction in chronic kidney disease (CKD) are still controversial. Thus, the aim of this study is to evaluate the effect of low protein diet (LPD) on the renal function in nondialysis CKD patients. A retrospective study was conducted from 321 nondialysis CKD patient's medical files (65.1 ± 12.7 yrs, 58.2% men). These patients received individualized dietary protein prescription (0.6-0.8 g protein/kg/day). Protein intake was evaluated by food diary and 24 h-food recall. Adherence to the LPD was considered when patients intake from 90 to 110% of the prescribed amount of protein. The patients were divided into 4 groups: (G1) adherent diabetes mellitus (DM) patients (n = 83); (G2) non-adherent DM patients (n = 106); (G3) adherent non-DM patients (n = 75); (G4) non-adherent non-DM patients (n = 57). Renal function was assessed by estimated glomerular filtration rate (eGFR). Both groups of patients (DM and non-DM) that adhered to the LPD showed significant improvement in eGFR (G1: 38.7 ± 13.2 mL/min to 51.1 ± 17.0 mL/min (p < 0.001); G3: 35.1 ± 16.8 mL/min to 46.8 ± 21.4 mL/min (p < 0.001)). In adherent patients, no differences in albumin and BMI were observed at the end of follow up. In non-adherent patients, eGFR significantly decreased in DM group (G2: 44.2 ± 18.5 mL/min to 38.2 ± 15.8 mL/min (p = 0.003)). According to multivariate analysis, annual changes in eGFR were not independent associated with age, gender, BMI, lipid profile, bicarbonate or smoking status. In summary, adherence to low protein diet could be able to improve serum creatinine and eGFR, well-known markers of renal function. However, prospective studies are needed to control confounders which affect renal function and CKD progression.

Successful pregnancy in a CKD patient on a low-protein, supplemented diet: an opportunity to reflect on CKD and pregnancy in Mexico, an emerging country

Pregnancy is probably the most important challenge in young women with chronic kidney disease (CKD). The challenge is greater in developing countries, in which access to dialysis is uneven, and prenatal care for CKD patients is not uniformly available. This case report summarizes some of the challenges faced by pregnant CKD women in a developing country. A 35-year-old woman, affected by an undiagnosed kidney disease, experienced preeclampsia at 24 years of age, and started dialysis in emergency at age 31 in the context of severe preeclampsia in her second pregnancy. Following slow recovery of kidney function, after 18 months of dialysis she started a moderately restricted, supplemented, low-protein diet, which allowed her to discontinue dialysis. A few months after dialysis discontinuation, she started a new pregnancy in the presence of severely reduced kidney function (serum creatinine 4.6 mg/dl at the last pre-pregnancy control). Interestingly, she discontinued nephrology and nutritional follow-up, mainly because she was worried that she would be discouraged from continuing the pregnancy, but also because she continued to feel well. She self-managed her diet in pregnancy and delivered a healthy baby, with normal intrauterine growth, at term; while the last laboratory data confirmed the presence of severe kidney function impairment, she is still dialysis-free at the time of the present report. Her story, with its happy ending, underlines the importance of dedicated programs for CKD pregnancies in developing countries and confirms the safety of moderately protein-restricted diets in pregnancy.

Adherence to a Vegetarian Diet and Diabetes Risk: A Systematic Review and Meta-Analysis of Observational Studies

We quantitatively assessed the association between a vegetarian diet and diabetes risk using pooled estimates from observational studies. Electronic database searches for articles published from January 1980 to May 2016 were independently performed by two investigators, and 13 articles (14 studies) were identified. The pooled odds ratio (OR) for diabetes in vegetarians vs. non-vegetarians was 0.726 (95% confidence interval (CI): 0.608, 0.867). In the subgroup analyses, this inverse association was stronger for the studies conducted in the Western Pacific region (OR 0.514, 95% CI: 0.304, 0.871) and Europe/North America (OR 0.756, 95% CI: 0.589, 0.971) than studies conducted in Southeast Asia (OR 0.888, 95% CI: 0.718, 1.099). No study had a substantial effect on the pooled effect size in the influence analysis, and the Egger's (p = 0.465) and Begg's tests (p = 0.584) revealed no publication bias. This meta-analysis indicates that a vegetarian diet is inversely associated with diabetes risk. Our results support the need for further investigations into the effects of the motivations for vegetarianism, the duration of the adherence to a vegetarian diet, and type of vegetarian on diabetes risk.

'Let food be thy medicine…': lessons from low-protein diets from around the world

In this editorial we present the special issue dedicated to low-protein diets (LPDs) in chronic kidney disease, from a global perspective.The experiences gathered from several countries across all continents have created an issue which we hope you will find insightful, and lead to further discussion on this interesting topic.We discover that LPDs are feasible in both developed and low income countries, in patients where literacy is an issue, and are also safe, including during pregnancy and in old age.Patients prescribed a low protein diet are more inclined to follow and adhere to this change in lifestyle, provided the diet has been adapted to meet their own individual needs. With an increasing list of different menu options and better medical advice being offered we no longer need to identify low protein diets with a specific menu, ingredient or supplement, or with a specific level of protein restriction. Evidence shows how the best diet is often the one chosen by the patients, which doesn't drastically affect their day-to-day life, and delays the start of dialysis for as long as is safe under careful clinical control. The colourful menus gathered from all over the world remind us that a low protein diet does not necessarily mean that the pleasure of preparing a delicious meal is lost. The final comment is therefore dedicated to our patients: low protein diets can be beautiful.

Dietary Modeling of Foods for Advanced CKD Based on General Healthy Eating Guidelines: What Should Be on the Plate?

Chronic kidney disease (CKD) is a major public health problem with significant clinical, societal, and psychosocial burdens. Nutrition therapy has been an integral part of the medical management of patients with CKD for more than a century, with the main goals of preserving kidney function and preventing complications. Nutrition abnormalities may emerge well before dialysis therapy is initiated and are associated with poor outcomes. It is therefore important to revisit nutrition management in the advanced stages of CKD to gain a broader insight into its role and effect on patient outcomes. Traditionally, nutrition recommendations have focused on the prescription of energy (calories) and macro- and micronutrients. Today, dietary modeling also focuses on the evidence for food consumption on health. This review argues that advanced non-dialysis-dependent CKD nutrition requirements to a large extent align with healthy eating guidelines for the general population and should not be based on deprivation or be unusually restrictive. The best currently available evidence for the CKD diet is likely to be derived from CKD nutrition prescriptions in conjunction with evidence underpinning national dietary guidelines and evidence of healthy dietary patterns, such as Mediterranean-style and Dietary Approaches to Stop Hypertension (DASH)-style eating. Positive messages from these dietary patterns should improve acceptance of CKD dietary interventions among patients.

Diet in chronic kidney disease in a Mediterranean African country

BACKGROUND

Mediterranean diet is characterized by low to moderate consumption of animal protein and high consumption of fruits, vegetables, bread, beans, nuts, seeds and other cereals. It has been associated with reduced risk of cardiovascular disease. However, it is not suitable for chronic kidney disease because of high potassium intake.

DISCUSSION

Tunisia is an emerging Mediterranean country with limited resources, a high prevalence of chronic hemodialysis treatment and high dialysis expenditures. In order to limit dialysis cost, primary and secondary prevention of chronic renal disease are of paramount importance. In addition to drugs, secondary prevention includes diet measures (e.g. salt diet, protein diet). The aims of diet practice in chronic kidney disease are to slow chronic renal failure progression and to prevent its complications like hyperphosphatemia and hyperkaliemiae. A few decades ago, a Tunisian diet was exclusively Mediterranean, and protein consumption was not excessive. However, today, protein consumption is more comparable to western countries. Salt consumption is also excessive. Some Tunisian diets still include food with high potassium intake, which are not suitable for patients with chronic kidney disease. Therefore, the role of the dietician is extremely important to help calculate and create a dietary regimen tailored to each of our patients. Advice about diets should be adapted to both the patient and population habits to improve adherence rate. As such, the purpose of this article is to provide our own experience regarding medical nutrition therapy in patients with chronic kidney disease in Tunisia, with some changes in food habits. Prevention is far better than treatment. In this perspective, dietary measures must be at the core of our intervention.

Role of Gut-derived Uremic Toxins on Oxidative Stress and Inflammation in Patients with Chronic Kidney Disease

Several cardiovascular disease (CVD) risk factors have been identified among patients with chronic kidney disease (CKD). Gut-derived uremic toxins (GDUT) are important modifiable contributors in this respect. There are very few Indian studies on GDUT changes in CKD. One hundred and twenty patients older than 18 years diagnosed with CKD were enrolled along with forty healthy subjects. The patients were classified into three groups of forty patients based on stage of CKD. Indoxyl sulfate (IS), para cresyl sulfate (p-CS), indole acetic acid (IAA), and phenol were estimated along with the assessment of oxidative stress (OS), inflammatory state, and bone mineral disturbance. All the GDUT increased across the three groups of CKD. All patients had higher levels of malondialdehyde (MDA), ferric reducing ability of plasma (FRAP), high-sensitivity C-reactive protein (hsCRP), and interleukin-6 (IL-6) as compared to controls. IS and IAA showed positive association with MDA/FRAP corrected for uric acid, whereas IS and p-CS showed positive association with IL-6. IS, IAA, and phenol showed a positive association with calcium × phosphorus product. GDUT increase OS and inflammatory state in CKD and may contribute to CVD risk.

Diet as a system: an observational study investigating a multi-choice system of moderately restricted low-protein diets

BACKGROUND

There is no single, gold-standard, low-protein diet (LPD) for CKD patients; the best compliance is probably obtained by personalization. This study tests the hypothesis that a multiple choice diet network allows patients to attain a good compliance level, and that, in an open-choice system, overall results are not dependent upon the specific diet, but upon the clinical characteristics of the patients.

METHODS

Observational study: Three LPD options were offered to all patients with severe or rapidly progressive CKD: vegan diets supplemented with alpha-ketoacids and essential aminoacids; protein-free food in substitution of normal bread and pasta; other (traditional, vegan non supplemented and tailored). Dialysis-free follow-up and survival were analyzed by Kaplan Meier curves according to diet, comorbidity and age. Compliance and metabolic control were estimated in 147 subjects on diet at March 2015, with recent complete data, prescribed protein intake 0.6 g/Kg/day. Protein intake was assessed by Maroni Mitch formula.

RESULTS

Four hundreds and forty nine patients followed a LPD in December, 2007- March, 2015 (90% moderately restricted LPDs, 0.6 g/Kg/day of protein, 10% at lower targets); age (median 70 (19-97)) and comorbidity (Charlson index: 7) characterized our population as being in line with the usual CKD European population. Median e-GFR at start of the diet was 20 mL/min, 33.2% of the patients were diabetics. Baseline data differ significantly across diets: protein-free schemas are preferred by older, high-comorbidity patients (median age 76 years, Charlson index 8, GFR 20.5 mL/min, Proteinuria: 0.3 g/day), supplemented vegan diets by younger patients with lower GFR and higher proteinuria (median age 65 years, Charlson index 6, GFR 18.9 mL/min; Proteinuria: 1.2 g/day); other diets are chosen by an intermediate population (median age 71 years, Charlson index 6; GFR 22.5 mL/min; Proteinuria: 0.9 g/day); (p <0.001 for age, Charlson index, proteinuria, GFR). Adherence was good, only 1.1% of the patients were lost to follow-up and protein intake was at target in most of the cases with no differences among LPDs (protein intake: 0.47 (0.26-0.86) g/Kg/day). After adjustment for confounders, and/or selection of similar populations, no difference in mortality or dialysis start was observed on the different LPDs. Below the threshold of e-GFR 15 mL/min, 50% of the patients remain dialysis free for at least two years.

CONCLUSION

A multiple choice LPD system may allow reaching good adherence, without competition among diets, and with promising results in terms of dialysis-free follow-up. The advantages with respect to a non-customized approach deserve confirmation in further comparative studies or RCTs.

Patient Survival and Costs on Moderately Restricted Low-Protein Diets in Advanced CKD: Equivalent Survival at Lower Costs?

The indications for delaying the start of dialysis have revived interest in low-protein diets (LPDs). In this observational prospective study, we enrolled all patients with chronic kidney disease (CKD) who followed a moderately restricted LPD in 2007-2015 in a nephrology unit in Italy: 449 patients, 847 years of observation. At the start of the diet, the median glomerular filtration rate (GFR) was 20 mL/min, the median age was 70, the median Charlson Index was 7. Standardized mortality rates for the "on-diet" population were significantly lower than for patients on dialysis (United States Renal Data System (USRDS): 0.44 (0.36-0.54); Italian Dialysis Registry: 0.73 (0.59-0.88); French Dialysis Registry 0.70 (0.57-0.85)). Considering only the follow-up at low GFR (≤15 mL/min), survival remained significantly higher than in the USRDS, and was equivalent to the Italian and French registries, with an advantage in younger patients. Below the e-GFR of 15 mL/min, 50% of the patients reached a dialysis-free follow-up of ≥2 years; 25% have been dialysis-free for five years. Considering an average yearly cost of about 50,000 Euros for dialysis and 1200 Euros for the diet, and different hypotheses of "spared" dialysis years, treating 100 patients on a moderately restricted LPD would allow saving one to four million Euros. Therefore, our study suggests that in patients with advanced CKD, moderately restricted LPDs may allow prolonging dialysis-free follow-up with comparable survival to dialysis at a lower cost.

Vitamin D Status and Bone Mineral Density is Influenced by Vitamin D Supplementation and Vitamin K1 Intake in Adults with Diabetes and Chronic Kidney Disease

PURPOSE

Patients with diabetes (DM) and chronic kidney disease (CKD) are at increased risk for suboptimal bone health. The study objective was to investigate the relationships between vitamin D (vitD), vitamin K1 (vitK₁), and calcium intake with bone mineral density (BMD) and vitamin D status in an ambulatory population with DM and CKD.

METHODS

Adults (age 18-80 years; n = 62) with DM and CKD (stages 1-4) were recruited from the Northern Alberta Renal Program. Primary outcome variables included vitD, vitK₁, and calcium intake; serum 25(OH)D, 1,25(OH)₂D; and BMD as measured by dual X-ray absorptiometry. Statistical significance was determined at P < 0.05.

RESULTS

Participants met the estimated average requirement or adequate intake for vitD, vitK₁, and calcium intake in 73% (n = 45), 66% (n = 39), and 52% (n = 31), respectively, with a combined intake of micronutrient supplementation and diet. Participants had serum 25(OH)D concentrations ≥75 nmol/L (n = 41), normal BMDs (n = 48), and 66% (n = 41/62) were taking vitD supplements (>1000 IU/D). BMD was positively influenced by serum 25(OH)D. However, serum 25(OH) ≥100 nmol/L was associated with lower BMD (absolute and T-scores) for whole-body and spine (P ≤ 0.05). VitK₁ intake (≥200 μg/day) was associated with higher whole-body and femoral-neck BMDs (absoluteand T-scores; P ≤ 0.05).

CONCLUSION

VitD status and BMD in adults with DM and CKD was influenced by vitD supplementation and vitK₁ intake.

Low-Protein Diets in Diabetic Chronic Kidney Disease (CKD) Patients: Are They Feasible and Worth the Effort?

Low-protein diets (LPDs) are often considered as contraindicated in diabetic patients, and are seldom studied. The aim of this observational study was to provide new data on this issue. It involved 149 diabetic and 300 non-diabetic patients who followed a LPD, with a personalized approach aimed at moderate protein restriction (0.6 g/day). Survival analysis was performed according to Kaplan-Meier, and multivariate analysis with Cox model. Diabetic versus non-diabetic patients were of similar age (median 70 years) and creatinine levels at the start of the diet (2.78 mg/dL vs. 2.80 mg/dL). There was higher prevalence of nephrotic proteinuria in diabetic patients (27.52% vs. 13.67%, p = 0.002) as well as comorbidity (median Charlson index 8 vs. 6 p = 0.002). Patient survival was lower in diabetic patients, but differences levelled off considering only cases with Charlson index > 7, the only relevant covariate in Cox analysis. Dialysis-free survival was superimposable in the setting of good compliance (Mitch formula: 0.47 g/kg/day in both groups): about 50% of the cases remained dialysis-free 2 years after the first finding of e-GFR (estimated glomerular filtration rate) < 15 mL/min, and 1 year after reaching e-GFR < 10 mL/min. In patients with type 2 diabetes, higher proteinuria was associated with mortality and initiation of dialysis. In conclusion, moderately restricted LPDs allow similar results in diabetic and non non-diabetic patients with similar comorbidity.

Compliance, illiteracy and low-protein diet: multiple challenges in CKD and a case of self-empowerment

BACKGROUND

Low-protein diets (LPD) are an important means of delaying the need for dialysis and attaining a stable metabolic balance in chronic kidney disease (CKD). Many authors consider a low educational level and illiteracy to be adverse features for a good dietary compliance.

CASE PRESENTATION

We report the case of a 77-year old woman, illiterate, affected by advanced CKD (stage 4 according to KDIGO guidelines). She was initially ashamed of her problem and did not declare it, leading to an overzealous reduction in protein intake. However, with her daughter's help, who translated the dietary prescription into images, she overcame the barrier represented by illiteracy and was able to correctly follow the prescriptions, attaining good kidney function stability and preserving an adequate nutritional status.

CONCLUSIONS

The case underlines the importance of a personalized approach to dietary prescriptions and suggests that it is possible to achieve a good compliance to the dietary treatment of CKD also in patients with relevant cultural barriers.

Very low protein diets supplemented with keto-analogues in ESRD predialysis patients and its effect on vascular stiffness and AVF Maturation

Background

Native arteriovenous fistula (AVF) is the most appropriate type of vascular access for chronic dialysis. Its patency rates depend on vascular wall characteristics. Ketoacid analogues of essential amino acids (KA/EAA) are prescribed in end-stage renal disease (ESRD) pre-dialysis patients to lower toxic metabolic products generation and improve nutritional status. We hypothesized that very-low protein diet (VLPD) supplemented with KA/EAA may influence arterial wall stiffness and affect AVF maturation rates and duration in pre-dialysis ESRD patients.

Methods

In a prospective, cohort, 3 years study we enrolled 67 consecutive non-diabetic early referral ESRD patients that underwent AVF creation in our hospital. Patients were divided in two groups based on their regimen 12 months prior to surgery: a VLPD supplemented with KA/EAA study group versus a low protein diet non-KA/EAA-supplemented control group. For each patient we performed serum analysis for the parameters of bone mineral disease, inflammation and nutritional status, one pulse wave velocity (PWV) measurement and one Doppler ultrasound (US) determination prior the surgery, followed by consequent Doppler US assessments at 4, 6, 8 and 12 weeks after it. Rates and duration of mature AVF achievement were noted. We used logistic regression to analyze the association between AVF maturation and KA/EAA administration, by comparing rates and durations between groups, unadjusted and adjusted for systolic blood pressure, C-reactive protein, PWV, phosphorus values. All parameters in the logistic model were transformed in binary variables. A p-value < α = 0.05 was considered significant; data were processed using SPSS 16 software and Excel.

Results

In the study group (n = 28, aged 57 ± 12.35, 13 females) we registered better serum phosphate (p = 0.022) and C-reactive protein control (p = 0.021), lower PWV (p = 0.007) and a higher percent of AVF creation success (33.3 % versus 17.8 %, p < 0.05). AVF maturation duration was lower in study group (5.91 versus 7.15 weeks, p < 0.001).

Conclusions

VLPD supplemented with KA/EAA appear to improve the native AVF primary outcome, decreasing the initial vascular stiffness, possible by preserving vascular wall quality in CKD patients through a better serum phosphate levels control and the limitation of inflammatory response.

Vegan-vegetarian low-protein supplemented diets in pregnant CKD patients: fifteen years of experience

BACKGROUND

Pregnancy in women with advanced CKD becoming increasingly common. However, experience with low-protein diets in CKD patients in pregnancy is still limited. Aim of this study is to review the results obtained over the last 15 years with moderately restricted low-protein diets in pregnant CKD women (combining: CKD stages 3-5, proteinuria: nephrotic at any time, or > =1 g/24 at start or referral; nephrotic in previous pregnancy). CKD patients on unrestricted diets were employed for comparison.

METHODS

STUDY PERIOD

January, 2000 to September, 2015: 36 on-diet pregnancies (31 singleton deliveries, 3 twin deliveries, 1 pregnancy termination, 1 miscarriage); 47 controls (42 singleton deliveries, 5 miscarriages). The diet is basically vegan; since occasional milk and yoghurt are allowed, we defined it vegan-vegetarian; protein intake (0.6-0.8 g/Kg/day), keto-acid supplementation, protein-unrestricted meals (1-3/week) are prescribed according to CKD stage and nutritional status. Statistical analysis was performed as implemented on SPSS.

RESULTS

Patients and controls were similar (p: ns) at baseline with regard to age (33 vs 33.5), referral week (7 vs 9), kidney function (CKD 3-5: 48.4 % vs 64.3 %); prevalence of hypertension (51.6 % vs 40.5 %) and proteinuria >3 g/24 h (16.1 % vs 12.2 %). There were more diabetic nephropathies in on-diet patients (on diet: 31.0 % vs controls 5.3 %; p 0.007 (Fisher)) while lupus nephropathies were non-significantly higher in controls (on diet: 10.3 % vs controls 23.7 %; p 0.28 (Fisher)). The incidence of preterm delivery was similar (<37 weeks: on-diet singletons 77.4 %; controls: 71.4 %). The incidence of other adverse pregnancy related outcomes was non-significantly lower in on-diet patients (early preterm delivery: on diet: 32.3 % vs controls 35.7 %; birth-weight = <1.500 g: on diet: 9.7 % vs controls 23.8 %). None of the singletons in the on-diet series died, while two perinatal deaths occurred among the controls (p = 0.505). The incidence of small for gestational age (SGA <10th centile) and/or extremely preterm babies (<28th week) was significantly lower in singletons from on-diet mothers than in controls (on diet: 12.9 % vs controls: 33.3 %; p: 0.04 (Fisher)).

CONCLUSION

Moderate protein restriction in the context of a vegan-vegetarian supplemented diet is confirmed as a safe option in the management of pregnant CKD patients.

Protein-controlled versus restricted protein versus low protein diets in managing patients with non-dialysis chronic kidney disease: a single centre experience in Australia

Nutrition has been an important part of medical management in patients with chronic kidney disease for more than a century. Since the 1970s, due to technological advances in renal replacement therapy (RRT) such as dialysis and transplantation, the importance of nutrition intervention in non-dialysis stages has diminished. In addition, it appears that there is a lack of high-level evidence to support the use of diet therapy, in particular the use of low protein diets to slow down disease progression. However, nutrition abnormalities are known to emerge well before dialysis is required and are associated with poor outcomes post-commencing dialysis. To improve clinical outcomes it is prudent to incorporate practice research and quality audits into routine care, as part of the continuous clinical practice improvement process. This article summarises the experience of and current practices in a metropolitan tertiary teaching hospital in Sydney, Australia.

A practical approach to low protein diets for patients with chronic kidney disease in Cameroon

Cameroon is a low–middle income country with a rich diversity of culture and cuisine. Chronic kidney disease (CKD) is common in Cameroon and over 80 % of patients present late for care, precluding the use of therapies such as low protein diets (LPDs) that slow its progression. Moreover, the prescription of LPDs is challenging in Cameroon because dieticians are scarce, there are no renal dieticians, and people often have to fund their own healthcare. The few nephrologists that provide care for CKD patients have limited expertise in LPD design. Therefore, only moderate LPDs of 0.6 g protein per kg bodyweight per day, or relatively mild LPDs of 0.7–0.8 g protein per kg bodyweight per day are prescribed. The moderate LPD is prescribed to patients with stage 3 or 4 CKD with non-nephrotic proteinuria, no evidence of malnutrition and no interrcurrent acute illnesses. The mild LPD is prescribed to patients with stage 3 or 4 CKD with nephrotic proteinuria, non-symptomatic stage 5 CKD patients or stage 5 CKD patients on non-dialysis treatment. In the absence of local sources of amino and keto acid supplements, traditional mixed LPDs are used. For patients with limited and sporadic access to animal proteins, the prescribed LPDs do not restrict vegetable proteins, but limit intake of animal proteins (when available) to 70 % of total daily protein intake. For those with better access to animal proteins, the prescribed LPDs limit intake of animal proteins to 50–70 % of total daily protein intake, depending on their meal plan. Images of 100 g portions of meat, fish and readily available composite meals serve as visual guides of quantities for patients. Nutritional status is assessed before LPD prescription and during follow up using a subjective global assessment and serum albumin. In conclusion, LPDs are underutilised and challenging to prescribe in Cameroon because of weakness in the health system, the rarity of dieticians, a wide diversity of dietary habits, the limited nutritional expertise of nephrologists and the unavailability of amino and keto acid supplements.

A practical approach to a low protein diet in Brazil

BACKGROUND

Chronic kidney disease (CKD) is an emerging health public problem in Brazil. Nutritional counseling with focus on protein restriction is a promising strategy to treatment of nondialysis CKD patients due its effects on slowing renal loss. However, Brazilian people have high protein intake, which is a challenge when low protein diet (LPD) should be prescribed. This review describes a practical approach to the dietetic management of nondialysis CKD patients in Brazil.

DISCUSSION

Although Brazilian cuisine varies greatly by region, Brazil has current trends of incorporating Western dietary habits, including high intake of red meat. Traditional plant-based foods, such as rice and beans, are also important contributors to the high protein content to the Brazilian diet. Thus, a successful implementation of LPD requires adaptation of these dietary habits, with reduction of portion sizes and adequate food substitution options. Intensive nutritional counseling with specialized renal dietitians is also important to improve compliance to the LPD. Moreover, the precarious health system organization and economic problems are barriers to nutritional care, which could be solved with intensive and specialized perspectives of treatment. The adherence to protein restriction is important for better metabolic and clinical control of nondialysis CKD patients. Early dietetic attention, nutrition education strategies and intensive specialized nutritional counseling are essential to achieve diet habits that promote adherence to the LPD without excluding cultural characteristics of the Brazilian diet.

Low protein diets in patients with chronic kidney disease: a bridge between mainstream and complementary-alternative medicines?

Dietary therapy represents an important tool in the management of chronic kidney disease (CKD), mainly through a balanced reduction of protein intake aimed at giving the remnant nephrons in damaged kidneys a "functional rest". While dialysis, transplantation, and pharmacological therapies are usually seen as "high tech" medicine, non pharmacological interventions, including diets, are frequently considered lifestyle-complementary treatments. Diet is one of the oldest CKD treatments, and it is usually considered a part of "mainstream" management. In this narrative review we discuss how the lessons of complementary alternative medicines (CAMs) can be useful for the implementation and study of low-protein diets in CKD. While high tech medicine is mainly prescriptive, prescribing a "good" life-style change is usually not enough and comprehensive counselling is required; the empathic educational approach, on which CAMs are mainly, though not exclusively based, may support a successful personalized nutritional intervention.There is no gold-standard, low-protein diet for all CKD patients: from among a relatively vast choice, the best compliance is probably obtained by personalization. This approach interferes with the traditional RCT-based analyses which are grounded upon an assumption of equal preference of treatments (ideally blinded). Whole system approaches and narrative medicine, that are widely used in the study of CAMs, may offer ways to integrate EBM and personalised medicine in the search for innovative solutions respecting individualization, but gaining sound data, such as with partially-randomised patient preference trials.

Efficacy of the Essential Amino Acids and Keto-Analogues on the CKD progression rate in real practice in Russia - city nephrology registry data for outpatient clinic

Background

Renal replacement therapy (RRT) is growing by 10 % per year in Russia, but pre-dialysis care which can retard CKD progression and delay the start of RRT remains limited. We evaluate the effect of Essential Amino Acids and Keto-analogues (EAA/KA) on CKD progression.

Methods

The effect of low protein diet (LPD), supplemented by EAA/KA, on GFR slope changes between first and second treatment period (five sequential visits per period) in 96 patients withs CKD Stage 3B-5 was compared to GFR slope changes in the control group of 96 patients, randomly selected from matched (by gender, age, diagnosis and CKD Stage) cohort of 320 patients from the city Registry. The mean baseline eGFR was 23 ± 9 ml/min/1.73 m2; 29 % had CKD3B, 45 % - CKD4, 26 % - CKD5.

Results

The rate of eGFR decline changed from −2.71 ± 2.38 to −2.01 ± 2.26 ml/min/1.73 m2 per year in the treatment group and from −2.18 ± 2.01 to −2.04 ± 2.18 ml/min/1.73 m2 per year in the control group. Only in the treatment group the difference was significant (p = 0.04 and p = 0.6). Standardized effect size for intervention was significant in treatment group: −0.3 (of pooled SD), 95 % CI −0.58 ÷  −0.02 and non-significant in control group: −0.07 (−0.35 ÷ +0.22). The univariate and multivariate analysis of EAA/KA therapy effect demonstrated that it was probably more effective in patients of older age, with higher time-averaged proteinuria (PU), lower phosphate level, in patients with glomerular v. interstitial diseases, and in females. Only the latter factor was significant at pre-specified level (<0.05).

Conclusions

LPD combined with EAA/KA supplementation lead to the decrease of the CKD progression both in well-designed clinical study and in real nephrology practice in wide variety diseases and settings. Registry data can be helpful to reveal patients with optimal chances for beneficial effect of LPD supplemented by EAA/KA.

Trial registration

ISRCTN28190556 06/05/2016.

Keto-supplemented Low Protein Diet: A Valid Therapeutic Approach for Patients with Steroid-resistant Proteinuria during Early-stage Chronic Kidney Disease

BACKGROUND AND OBJECTIVES

Low protein diets supplemented with keto acid (sLPD) are recommended for patients with stage 3-5 chronic kidney disease (CKD). This study assessed whether sLPD is beneficial for patients with steroid-resistant proteinuria during early-stage CKD.

DESIGN, SETTING, PARTICIPANTS, AND MEASUREMENTS

A 1-year randomized controlled trial was conducted from 2010 to 2012. In this study, 108 proteinuric patients who were steroid-resistant were assigned to a sLPD group (0.6 g/kg/d with 0.09 g/kg/d keto acids) or a normal protein diet group (NPD, 1.0 g/kg/d). Estimated dietary protein intake, urinary protein excretion, remission rate, renal function, nutritional status, and blood pressure were measured.

RESULTS

Baseline characteristics were comparable between the sLPD group (47 patients) and the NPD group (49 patients). Urinary protein excretion significantly decreased in sLPD compared to NPD in months 6, 9, and 12 (P<0.05). Proteinuria reduction was higher in sLPD than in NPD (P<0.001) at the end of the study. Complete remission and partial remission rates were higher in sLPD than in NPD. Serum albumin and pre-albumin levels were higher in sLPD than in NPD in months 9 and 12 (P<0.05). Serum total cholesterol and triglyceride levels declined more significantly in sLPD than in NPD (P<0.01) at the end of the study. There were no differences in nutritional status, renal function, hemoglobin, or blood pressure between the two groups.

CONCLUSIONS

sLPD is both nutritionally safe and beneficial, providing nephroprotective effects for early-stage CKD patients with steroid-resistant proteinuria.

Strategies to promote adherence to nutritional advice in patients with chronic kidney disease: a narrative review and commentary

Chronic kidney disease (CKD) requires extensive changes to food and lifestyle. Poor adherence to diet, medications, and treatments has been estimated to vary between 20% and 70%, which in turn can contribute to increased mortality and morbidity. Delivering effective nutritional advice in patients with CKD coordinates multiple diet components including calories, protein, sodium, potassium, calcium, phosphorus, and fluid. Dietary intake studies have shown difficulty in adhering to the scope and complexity of the CKD diet parameters. No single educational or clinical strategy has been shown to be consistently effective across CKD populations. Highest adherence has been observed when both diet and education efforts are individualized to each patient and adapted over time to changing lifestyle and CKD variables. This narrative review and commentary summarizes nutrition education literature and published strategies for providing nutritional advice in CKD. A cohort of practical and effective strategies for increasing dietary adherence to nutritional advice are provided that include communicating with "talking control" principles, integrating patient-owned technology, acknowledging the typical food pattern may be snacking rather than formal meals, focusing on a single goal rather than multiple goals, creating active learning and coping strategies (frozen sandwiches, visual hands-on activities, planting herb gardens), and involving the total patient food environment.

Chronic kidney disease influences multiple systems: describing the relationship between oxidative stress, inflammation, kidney damage, and concomitant disease

Chronic kidney disease (CKD) is characterized by increased levels of oxidative stress and inflammation. Oxidative stress and inflammation promote renal injury via damage to molecular components of the kidney. Unfortunately, relationships between inflammation and oxidative stress are cyclical in that the inflammatory processes that exist to repair radical-mediated damage may be a source of additional free radicals, resulting in further damage to renal tissue. Oxidative stress and inflammation also have the ability to become systemic, serving to injure tissues distal to the site of original insult. This review describes select mediators in the exacerbatory relationship between oxidative stress, inflammation, and CKD. This review also discusses oxidative stress, inflammation, and CKD as they pertain to the development and progression of common CKD-associated comorbidities. Lastly, the utility of several widely accessible and cost-effective lifestyle interventions and their ability to reduce oxidative stress and inflammation are discussed and recommendations for future research are provided.