Design and rationale for an open-label, randomized, controlled pilot trial to evaluate the changes in blood uremic toxins in patients with chronic kidney disease by dietary therapy with sake lees.

BACKGROUND: Patients with chronic kidney disease (CKD) reportedly show dysbiosis, which is the imbalance of gut microbiome. Dysbiosis increases the uremic toxin level in the intestine, and uremic toxins transfer into the blood, causing CKD progression. Sake lees, a traditional Japanese fermented food, may help reduce uremic toxins by altering the gut microbiome. Additionally, D-alanine, which is present in sake lees, may have a renoprotective effect. The present pilot study aims to evaluate the effect of adding sake lees to the standard CKD dietary therapy in reducing blood uremic toxins. METHODS: This pilot study is a single-center, open-label, randomized controlled trial. Twenty-four patients with CKD will be enrolled and allocated 1:1 to the intervention and control groups. The intervention group will receive standard CKD dietary therapy with an additional intake of 50 g of sake lees per day for 8 weeks, whereas the control group will only receive standard CKD dietary therapy. The primary endpoint is the change in serum indoxyl sulfate after 8 weeks. The secondary endpoint is the plasma D-alanine and fecal microbiome changes. CONCLUSION: This pilot study provides insight into the development of a new diet focused on gut microbiome and D-amino acids in patients with CKD. CLINICAL TRIAL REGISTRATION: This protocol was approved by the Clinical Trial Review Board of Kanazawa University Hospital on October 27, 2022 (2022-001 [6139]) and available to the public on the website of the Japan Registry of Clinical Trials on November 22, 2022 (jRCT1040220095).

Adherence to Plant-Based Diets and Risk of CKD Progression and All-Cause Mortality: Findings From the Chronic Renal Insufficiency Cohort (CRIC) Study.

RATIONALE & OBJECTIVE: Studies have shown that generally healthy individuals who consume diets rich in plant foods have a lower risk of incident chronic kidney disease (CKD) and cardiovascular disease. This study investigated the prospective associations of plant-based diets with the risk of CKD progression and all-cause mortality in individuals with CKD. STUDY DESIGN: Prospective cohort study. SETTING & PARTICIPANTS: 2,539 participants with CKD recruited between 2003-2008 into the Chronic Renal Insufficiency Cohort (CRIC) Study. EXPOSURE: Responses on the Diet History Questionnaire were used to calculate scores for the overall plant-based diet index, healthy plant-based diet index, and unhealthy plant-based diet index. OUTCOME: (1) CKD progression defined as≥50% estimated glomerular filtration rate decline from baseline or kidney replacement therapy (dialysis, transplant) and (2) all-cause mortality. ANALYTICAL APPROACH: Cox proportional hazards models to compute hazard ratios and 95% confidence intervals adjusting for lifestyle, socioeconomic, and clinical covariates. RESULTS: There were 977 CKD progression events and 836 deaths during a median follow-up period of 7 and 12 years, respectively. Participants with the highest versus lowest adherence to overall plant-based diets and healthy plant-based diets had 26% (HR, 0.74 [95% CI, 0.62-0.88], P trend<0.001) and 21% (HR, 0.79 [95% CI, 0.66-0.95], P trend=0.03) lower risks of all-cause mortality, respectively. Each 10-point higher score of unhealthy plant-based diets was modestly associated with a higher risk of CKD progression (HR, 1.14 [95% CI, 1.03-1.25) and all-cause mortality (HR, 1.11 [95% CI, 1.00-1.23). LIMITATIONS: Self-reported diet may be subject to measurement error. CONCLUSIONS: Adherence to an overall plant-based diet and a healthy plant-based diet is associated with a reduced risk of all-cause mortality among individuals with CKD. An unhealthy plant-based was associated with an elevated risk of CKD progression and all-cause mortality. PLAIN-LANGUAGE SUMMARY: Plant-based diets are healthful dietary patterns that have been linked to a lower risk of chronic diseases. However, the impact of plant-based diets on clinical outcomes in patients with chronic kidney disease (CKD) is not well established. In 2,539 individuals with CKD, we examined the associations of adherence to 3 different types of plant-based diets with the risks of CKD progression and all-cause mortality. We found that following an overall plant-based diet and a healthy plant-based diet was associated with a lower risk of all-cause mortality. By contrast, following an unhealthy plant-based diet was associated with a higher risk of CKD progression and all-cause mortality. These results suggest that the quality of plant-based diets may be important for CKD management.

Educación alimentaria en pacientes en dialisis / Nutritional education in dialysis patients

La enfermedad renal crónica terminal aumenta el riesgo cardiovascular y puede ocasionar defectos en la mineralización ósea. Para prevenir esto, se debe mantener el fósforo plasmático normal, que depende de la diálisis, los quelantes y la ingesta de fósforo, principalmente de origen inorgánico, incorporado mediante aditivos alimentarios. Las intervenciones nutricionales son pilares en el tratamiento de estos pacientes. El objetivo es facilitar estrategias alimentarias a un grupo de pacientes pediátricos en diálisis, mediante educación alimentaria nutricional, para aumentar el consumo de alimentos naturales, disminuyendo la ingesta de fósforo inorgánico especialmente de los productos cárnicos procesados. Materiales y métodos: se estudió una población pediátrica en diálisis. Se preparó un programa educativo con atención personalizada, instrucción alimentaria y seguimiento mensual, seguido de un taller. Resultados: n: 17 pacientes, edad decimal media de 12,3, 53% sexo masculino, 88% en hemodiálisis. Previo a la intervención el 64,7% consumía productos cárnicos procesados. Luego del taller el 58,8% disminuyó su consumo, el 41,2% aumentó la ingesta de preparaciones caseras, el 53% incorporó nuevos condimentos, de los cuales el 89% presentó al incorporarlos, mejor aceptación a las preparaciones. Conclusiones: la hiperfosfatemia está presente en alrededor del 50% de los pacientes en diálisis asociándose a un incremento entre 20% al 40% del riesgo de mortalidad. La presencia de fósforo oculto en los alimentos y la falta de adherencia hacen prioritario trabajar en programas educativos que favorezcan el aprendizaje colaborativo, centralizados en prácticas culinarias, para brindar herramientas que faciliten una alimentación natural, disminuyendo el consumo de ultraprocesados (AU)

Chronic end-stage renal disease increases the risk of cardiovascular disease and may lead to defects in bone mineralization. In order to prevent these risks, normal plasma phosphorus levels should be maintained. Achieving this goal depends on dialysis, chelators, and phosphorus intake, mainly of inorganic origin, incorporated through food supplements. Nutritional interventions are crucial in the treatment of these patients. The objective is to facilitate nutritional strategies to a group of pediatric dialysis patients, through food education, to increase the consumption of natural foods, decreasing the intake of inorganic phosphorus, especially from processed meat products. Materials and methods: a pediatric population undergoing dialysis was studied. An educational program was prepared with personalized care, nutritional instruction, and monthly follow-up visits, followed by a workshop. Results: n: 17 patients, mean age 12.3 years, 53% male, 88% on hemodialysis. Prior to the intervention, 64.7% consumed processed meat products. After the workshop, 58.8% decreased their consumption, 41.2% increased the intake of homemade food, 53% incorporated new seasonings, of whom 89% reported better acceptance of the preparations when they were incorporated. Conclusions: hyperphosphatemia is observed in around 50% of patients undergoing dialysis and is associated with a 20% to 40% increased risk of mortality. The presence of hidden phosphorus in food and the lack of adherence point to the need for the development of educational programs that promote collaborative learning, focusing on food-preparation practices. These programs should provide tools that facilitate a natural diet, reducing the consumption of ultra-processed food (AU)

Low-protein diet supplemented with inulin lowers protein-bound toxin levels in patients with stage 3b-5 chronic kidney disease: a randomized controlled study / La dieta baja en proteínas suplementada con inulina reduce los niveles de toxinas unidas a proteínas en pacientes con enfermedad renal crónica en estadio 3b-5: un estudio controlado aleatorio

Objective: this study aimed to evaluate whether low-salt low-protein diet (LPD) supplemented with 10 g of inulin could lower serum toxin levels in patients with chronic kidney disease (CKD), thereby providing evidence for adjusting dietary prescriptions of inhospital patients and outpatient nutrition consultants. Methods: we randomized 54 patients with CKD into two groups. Dietary protein intake compliance was evaluated using a 3-day dietary diary and 24-h urine nitrogen levels. The primary outcomes were indoxyl sulfate (IS) and p-cresyl sulfate (PCS), and secondary outcomes included inflammation marker levels, nutritional status, and renal function. We assessed 89 patients for eligibility, and a total of 45 patients completed the study, including 23 and 22 in the inulin-added and control groups, respectively. Results: PCS values decreased in both groups after intervention: inulin-added group, ∆PCS -1.33 (-4.88, -0.63) μg/mL vs. LPD group, -4.7 (-3.78, 3.69) μg/mL (p = 0.058). PCS values reduced from 7.52 to 4.02 μg/mL (p < 0.001) in the inulin-added group (p < 0.001). Moreover, IS decreased from 3.42 (2.53, 6.01) μg/mL to 2.83 (1.67, 4.74) μg/mL after adding inulin; ∆IS was -0.64 (-1.48, 0.00) μg/mL, and a significant difference was observed compared with the control group (p = 0.004). The inflammation index decreased after intervention. Conclusion: dietary fiber supplementation may reduce serum IS and PCS levels and modulate their inflammatory status in predialysis CKD patients.(AU)

Objetivo: este ensayo aleatorizado doble ciego comparó el efecto de una dieta baja en proteínas (LPD) con o sin suplementos orales de 10 gde inulina en los niveles de PBUT en pacientes con ERC en prediálisis durante 12 semanas.Métodos: clasificamos aleatoriamente a 54 pacientes con ERC en dos grupos. El cumplimiento de la ingesta dietética de proteínas se evaluóutilizando un diario dietético de 3 días y nitrógeno en orina de 24 horas. Los resultados primarios fueron IS y PCS y los resultados secundariosincluyeron niveles de marcadores de inflamación, estado nutricional y función renal. Evaluamos la elegibilidad de 89 pacientes y 45 completaronla intervención, incluidos 23 y 22 en los grupos de inulina añadida y de control, respectivamente.Resultados: el sodio urinario promedio de 24 horas fue de 86 mmol/día y la ingesta promedio de proteínas fue de ~0,7 g/kg/día. Los valores dePCS exhibieron una tendencia decreciente en ambos grupos después de la intervención: grupo con inulina añadida, ∆PCS -1.33 (-4.88, -0.63)μg/mL vs. grupo LPD, -4.7 (-3.78, 3.69) μg/mL) (p =0,058). Los valores de PCS se redujeron de 7,52 a 4,02 μg/mL (p < 0,001) con inulina(p < 0,001). Además, IS disminuyó de 3,42 (2,53, 6,01) μg/mL a 2,83 (1,67, 4,74) μg/mL después de agregar inulina; El ∆IS fue -0,64 (-1,48;0,00) μg/mL y se observó una diferencia significativa en comparación con el grupo control (p =0,004).Conclusión: la suplementación con fibra dietética puede reducir las toxinas de unión a proteínas séricas en pacientes con ERC en prediálisisy modular su estado inflamatorio.(AU)

Physical activity and nutrition in chronic kidney disease.

PURPOSE OF REVIEW: Lifestyle intervention is considered a cornerstone in chronic kidney disease management and has been recommended in different international or regional clinical practice guidelines in chronic kidney disease. However, evidence was largely based on the general population. Here we summarized the latest evidence supporting lifestyle intervention in chronic kidney disease. RECENT FINDINGS: Both observational cohort studies as well as randomized controlled trials have demonstrated health benefits with more physical activity in chronic kidney disease. There are compelling observational data supporting different health and kidney benefits with a healthy dietary pattern rich in fruits and vegetables, whole grains, plant-based foods and low in salt, low in sugar, saturated fat, red meat and ultraprocessed foods, a plant-based diet or Mediterranean diet in chronic kidney disease population. Clinical and epidemiologic studies also showed that higher 24 h urine potassium excretion (as proxy of higher dietary potassium intake) may be associated with lower blood pressure, better kidney outcomes and lower mortality in chronic kidney disease population. Randomized controlled trials also suggested that salt substitutes improved blood pressure control, reduced all-cause death and cardiovascular event risk in the general population compared with regular salt. SUMMARY: Accumulating evidence supports the current recommendation of encouraging physical activity and promoting a healthy dietary pattern in chronic kidney disease patients. Whether potassium needs restriction in chronic kidney disease diet requires further review. The safety versus benefits of salt substitutes in patients with moderate and advanced chronic kidney disease warrants further investigation.

Estimated Benefits and Risks of Using a Reduced-Sodium, Potassium-Enriched Salt Substitute in India: A Modeling Study.

BACKGROUND: Salt substitution (ie, replacement of table and cooking salt with potassium-enriched salt substitutes) is a promising strategy to reduce blood pressure and prevent cardiovascular disease, particularly in countries like India where there is high sodium intake, mainly from discretionary salt, and low potassium intake. Life-threatening hyperkalemia from increased potassium intake is a postulated concern for individuals with chronic kidney disease. METHODS: We used comparative risk assessment models to estimate the number of (1) cardiovascular deaths averted due to blood pressure reductions; (2) potential hyperkalemia-related deaths from increased potassium intake in individuals with advanced chronic kidney disease; and (3) net averted deaths from nationwide salt substitution in India. We evaluated a conservative scenario, based on a large, long-term pragmatic trial in rural China; and an optimistic scenario informed by our recent trial in India. Sensitivity analyses were conducted to assess the robustness of the findings. RESULTS: In the conservative scenario, a nationwide salt substitution intervention was estimated to result in ≈214 000 (95% uncertainty interval, 92 764-353 054) averted deaths from blood pressure reduction in the total population and ≈52 000 (22 961-80 211) in 28 million individuals with advanced chronic kidney disease, while ≈22 000 (15 221-31 840) hyperkalemia-deaths might be caused by the intervention. The corresponding estimates for the optimistic scenario were ≈351 000 (130 470-546 255), ≈66 000 (24 925-105 851), and ≈9000 (4251-14 599). Net benefits were consistent across sensitivity analyses. CONCLUSIONS: Modeling nationwide salt substitution in India consistently estimated substantial net benefits, preventing around 8% to 14% of annual cardiovascular deaths. Even allowing for potential hyperkalemia risks there were net benefits estimated for individuals with chronic kidney disease.

Acceptability of Plant-Based Diets for People with Chronic Kidney Disease: Perspectives of Renal Dietitians.

The purpose of this study was to explore the perspective of renal dietitians regarding plant-based diets for chronic kidney disease (CKD) management and evaluate the acceptability of a hypothetical plant-based dietary prescription aiming for the consumption of 30 unique plant foods per week. This study used an exploratory mixed methods design. Forty-six renal dietitians participated in either an online survey (n = 35) or an in-depth interview (n = 11). Dietitians perceived that plant-based diets could address multiple clinical concerns relevant to CKD. Forty percent of survey respondents reported the hypothetical dietary prescription was realistic for people with CKD, 34.3% were unsure, and 25.7% perceived it as unrealistic. Strengths of the hypothetical prescription included shifting the focus to whole foods and using practical resources like recipes. Limited staffing, time, and follow-up opportunities with patients, as well as differing nutrition philosophies were the most commonly reported challenges to implementation; while a supportive multidisciplinary team was identified as an important enabler. To increase patient acceptance of plant-based dietary approaches, education about plant food benefits was recommended, as was implementing small, incremental dietary changes. Successful implementation of plant-based diets is perceived to require frequent patient contact and ongoing education and support by a dietitian. Buy-in from the multidisciplinary team was also considered imperative.

A ketogenic diet attenuates acute and chronic ischemic kidney injury and reduces markers of oxidative stress and inflammation.

BACKGROUND: Ischemic kidney injury is a common clinical condition resulting from transient interruption of the kidney's normal blood flow, leading to oxidative stress, inflammation, and kidney dysfunction. The ketogenic diet (KD), a low-carbohydrate, high-fat diet that stimulates endogenous ketone body production, has potent antioxidant and anti-inflammatory effects in distinct tissues and might thus protect the kidney against ischemia and reperfusion (IR) injury. MAIN METHODS: Male Wistar rats were fed a KD or a control diet (CD) for three days before analyzing metabolic parameters or testing nephroprotection. We used two different models of kidney IR injury and conducted biochemical, histological, and Western blot analyses at 24 h and two weeks after surgery. KEY FINDINGS: Acute KD feeding caused protein acetylation, liver AMPK activation, and increased resistance to IR-induced kidney injury. At 24 h after IR, rats on KD presented reduced tubular damage and improved kidney functioning compared to rats fed with a CD. KD attenuated oxidative damage (protein nitration, 4-HNE adducts, and 8-OHdG), increased antioxidant defenses (GPx and SOD activity), and reduced inflammatory intermediates (IL6, TNFα, MCP1), p50 NF-κB expression, and cellular infiltration. Also, KD prevented interstitial fibrosis development at two weeks, up-regulation of HSP70, and chronic Klotho deficiency. SIGNIFICANCE: Our findings demonstrate for the first time that short-term KD increases tolerance to experimental kidney ischemia, opening the opportunity for future therapeutic exploration of a dietary preconditioning strategy to convey kidney protection in the clinic.

Effects of Sodium-Specific Medical Nutrition Therapy from a Registered Dietitian Nutritionist in Individuals with Chronic Kidney Disease: An Evidence Analysis Center Systematic Review and Meta-Analysis.

Dietary sodium intake can increase risk of hypertension, a leading cause of kidney failure in individuals with chronic kidney disease. The objective of this systematic review was to examine the effect of sodium-specific medical nutrition therapy provided by a registered dietitian nutritionist or international equivalent on blood pressure and urinary sodium excretion in individuals with chronic kidney disease, stages 2 through 5, receiving maintenance dialysis and posttransplant. Medline, the Cumulative Index to Nursing and Allied Health Literature, Cochrane Cochrane Central Register of Controlled Trials, and other databases were searched to identify eligible controlled trials published in the English language from January 2000 until June 2020 that addressed the research question. Risk of bias was assessed using the RoB 2.0 tool and quality of evidence was examined by outcome using the Grading of Recommendations Assessment, Development, and Evaluation method. Of the 5,642 articles identified, eight studies were included in the final analyses. Six studies targeted clients who were not dialyzed, including one with clients who were posttransplantation, and two studies with clients receiving maintenance hemodialysis. Sodium-specific medical nutrition therapy from a registered dietitian nutritionist significantly reduced clinic systolic blood pressure (mean difference -6.7, 95% CI -11.0 to -2.4 mm Hg; I2 = 51%) and diastolic blood pressure (mean difference -4.8, 95% CI, -7.1 to -2.4 mm Hg; I2 = 23%) as well as urinary sodium excretion (mean difference -67.6, 95% CI -91.6 to -43.6 mmol/day; I2 = 84.1%). Efficacy was limited to individuals who were not dialyzed, including posttransplantation, but the intervention did not significantly improve blood pressure in individuals receiving maintenance hemodialysis. Adults with chronic kidney disease should begin to work with registered dietitian nutritionist early in the course of disease to receive individualized, effective counseling to improve risk factors and, ultimately, health outcomes.

The Impact of RDNs on Non-Communicable Diseases: Proceedings from The State of Food and Nutrition Series Forum.

In the United States, nutrition-related morbidities are rising steadily at rates corresponding to increasing overweight and obesity in the population. Such morbidities take huge tolls on personal health and impose high costs on health care systems. In 2019, the Academy of Nutrition and Dietetics (Academy) and the Academy of Nutrition and Dietetics Foundation (Academy Foundation) embarked on a new project titled "The State of Food and Nutrition Series" to demonstrate the value of nutrition interventions led by registered dietitian nutritionists for individuals with the following 3 high-priority non-communicable diseases that affect many in the United States and globally: type 2 diabetes mellitus, chronic kidney disease, and hypertension. Poor nutritional status contributes to disease onset and progression in these non-communicable diseases, and appropriate medical nutrition therapy can prevent or delay worsening and ameliorate poor health outcomes. However, many people who have these conditions do not have access to an registered dietitian nutritionist, and consequently do not receive the nutrition care they need. On February 19-20, 2020 in Arlington, VA, as the first stage in The State of Food and Nutrition Series, the Academy and the Academy Foundation gathered health care policymakers, clinicians, and researchers from across the country for the State of Food and Nutrition Series Forum, where Academy leaders sought input to build a comprehensive research strategy that will quantify the impact of patient access to registered dietitian nutritionist-led nutrition interventions for type 2 diabetes mellitus, chronic kidney disease, and hypertension. This article summarizes the findings of that forum.

Influence of Polyunsaturated Fatty Acid Intake on Kidney Functions of Rats with Chronic Renal Failure.

Arachidonic acid (ARA), an omega-6 (ω-6) polyunsaturated fatty acid (PUFA), is involved in the development and maintenance of renal functions, whereas docosahexaenoic acid (DHA) is an omega-3 (ω-3) PUFA that has anti-inflammatory effects and attenuates nephropathy. However, their effects on the progression of chronic kidney disease (CKD) remain unknown. The aim of this study was to assess the effects of feeding ARA, DHA, and ARA and DHA-containing diets on rats with 5/6 nephrectomized kidneys. Urine and feces were collected every 4 weeks, and the kidneys were collected at 16 weeks after surgery. Urinary albumin (U-ALB) excretion increased gradually with nephrectomy, but the U-ALB excretion was attenuated by feeding the rats with an ARA + DHA-containing diet. Reactive oxygen species (ROS) levels in the kidneys were lower in the ARA + DHA group than in the other groups. At 4 weeks after surgery, the lipid peroxide (LPO) levels in the plasma of the ARA + DHA groups decreased significantly after surgery compared to the control CKD group, but this did not happen at 16 weeks post-surgery. There was a significant negative correlation between LPO levels in the plasma at 4 weeks and creatinine clearance, and a positive correlation with urinary albumin levels. These results suggest that the combination of ARA and DHA inhibit the progress of early stage CKD.

Spontaneously Low Protein Intake in Elderly CKD Patients: Myth or Reality? Analysis of Baseline Protein Intake in a Large Cohort of Patients with Advanced CKD.

The recent guidelines on nutritional management of chronic kidney disease (CKD) advise a reduction in protein intake as early as CKD stage 3, regardless of age, to slow kidney function impairment. However, since elderly patients are usually considered as having a spontaneously reduced protein intake, nutritional interventions to reduce protein intake are often considered futile. This study aimed to assess the baseline protein intake of elderly CKD patients referred for nephrology care, and explore the need for dietary evaluations, focusing on the current recommendations for protein restriction in CKD. This is an observational study of CKD patients followed in the unit dedicated to advanced CKD patients in Le Mans, France. Patients with stages 3 to 5 not on dialysis were included. All patients were evaluated by an expert dietician to assess their baseline protein intake, whenever possible on the basis of a 7-days diet journal; when this was not available, dietary recall or analysis of delivered meals was employed. Demographic characteristics, underlying kidney disease, Charlson Comorbidity Index (CCI), Malnutrition-Inflammation Score (MIS), Subjective Global Assessment (SGA) and clinical and laboratory data were recorded. Between 15 November 2017 and 31 December 2020, 436 patients were evaluated in the unit. Their age distribution was as follows: "young": <60 (n = 62), "young-old": 60-69 (n = 74), "old": 70-79 (n = 108), "old-old": 80-89 (n = 140) and "oldest-old": ≥90 (n = 54). The prevalence of vascular nephropathies was higher in patients older than 70 years compared to younger ones, as did CCI and MIS (p < 0.001). Moderate nutritional impairment (SGA: B) was higher in elderly patients, reaching 53.7% at ≥90, while less than 3% of patients in the overall cohort were classified as SGA C (p < 0.001). The median protein intake was higher than the recommended one of 0.8 g/kg/day in all age groups; it was 1.2 g/kg/day in younger patients and 1.0 thereafter (p < 0.001). Patient survival depended significantly on age (p < 0.001) but not on baseline protein intake (p = 0.63), and younger patients were more likely to start dialysis during follow-up (p < 0.001). Over half of the patients, including the old-old and oldest-old, were still on follow-up two years after referral and it was found that survival was only significantly associated with age and comorbidity and was not affected by baseline protein intake. Our study shows that most elderly patients, including old-old and extremely old CKD patients, are spontaneously on diets whose protein content is higher than recommended, and indicates there is a need for nutritional care for this population.

Effects of Low Protein Diet on Modulating Gut Microbiota in Patients with Chronic Kidney Disease: A Systematic Review and Meta-analysis of International Studies.

Background: Although associations between low protein diet (LPD) and changes of gut microbiota have been reported; however, systematic discernment of the effects of LPD on diet-microbiome-host interaction in patients with chronic kidney disease (CKD) is lacking. Methods: We searched PUBMED and EMBASE for articles published on changes of gut microbiota associated with implementation of LPD in CKD patients until July 2021. Independent researchers extracted data and assessed risks of bias. We conducted meta-analyses of combine p-value, mean differences and random effects for gut microbiota and related metabolites. Study heterogeneity was measured by Tau2 and I2 statistic. This study followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Results: Five articles met inclusion criteria. The meta-analyses of gut microbiota exhibited enrichments of Lactobacillaceae (meta-p= 0.010), Bacteroidaceae (meta-p= 0.048) and Streptococcus anginosus (meta-p< 0.001), but revealed depletion of Bacteroides eggerthii (p=0.017) and Roseburia faecis (meta-p=0.019) in LPD patients compared to patients undergoing normal protein diet. The serum IS levels (mean difference: 0.68 ug/mL, 95% CI: -8.38-9.68, p= 0.89) and pCS levels (mean difference: -3.85 ug/mL, 95% CI: -15.49-7.78, p < 0.52) did not change between groups. We did not find significant differences on renal function associated with change of microbiota between groups (eGFR, mean difference: -7.21 mL/min/1.73 m2, 95% CI: -33.2-18.79, p= 0.59; blood urea nitrogen, mean difference: -6.8 mg/dL, 95% CI: -46.42-32.82, p= 0.74). Other clinical (sodium, potassium, phosphate, albumin, fasting sugar, uric acid, total cholesterol, triglycerides, C-reactive protein and hemoglobin) and anthropometric estimates (body mass index, systolic blood pressure and diastolic blood pressure) did not differ between the two groups. Conclusions: This systematic review and meta-analysis suggested that the effects of LPD on the microbiota were observed predominantly at the families and species levels but minimal on microbial diversity or richness. In the absence of global compositional microbiota shifts, the species-level changes appear insufficient to alter metabolic or clinical outputs.

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.

Nutritional Adequacy of Animal-Based and Plant-Based Asian Diets for Chronic Kidney Disease Patients: A Modeling Study.

Plant-based low protein diets (LPDs) have gained popularity for managing chronic kidney disease (CKD) patients. The nutritional adequacy of these and other LPDs prescribed for CKD patients have not been carefully examined. This study assessed the nutrient composition of such LPDs and moderately high protein diets (MHPDs) that might be prescribed for patients in the Asia Pacific region with CKD who are not dialyzed or undergoing maintenance dialysis. Conventional diets containing at least 50% animal-based proteins and plant-based diets were also planned with protein prescriptions of 0.5 to 0.8 g/kg/day and MHPDs with protein prescriptions of 1.0 to 1.2 g/kg/day. Plant-based, lacto-, ovo-, and lacto-ovo-vegetarian and vegan LPDs and MHPDs were planned by replacing some or all of the animal proteins from the conventional diet. With 0.5 g protein/kg/day, all diets were below the Recommended Dietary Allowances (RDA) for at least one essential amino acid (EAA). At a protein prescription of 0.6 g/kg/day, only the conventional LPD met the RDA for all EAAs. This deficiency with the plant-based LPDs persisted even with several plant food substitutions. With a protein prescription ≥0.7 g/kg/day, all the plant-based and vegetarian LPDs provided the RDA for all EAA. The plant-based and vegetarian diets also contained relatively greater potassium, phosphorus, and calcium content but lower long-chain n-3 polyunsaturated fatty acids and vitamin B-12 than the conventional diet. Other essential micronutrients were commonly below the RDA even at higher protein intakes. The low contents of some essential micronutrients were found in both animal-based and plant-based diets. Prescription of all LPDs for CKD patients, especially plant-based and vegetarian LPDs, requires careful planning to ensure the adequacy of all nutrients, particularly essential amino acids. Consideration should be given to supplementing all animal-based and plant-based LPDs and MHPDs with multivitamins and certain trace elements.

A low aromatic amino-acid diet improves renal function and prevent kidney fibrosis in mice with chronic kidney disease.

Despite decades of use of low protein diets (LPD) in the management of chronic kidney disease (CKD), their mechanisms of action are unclear. A reduced production of uremic toxins could contribute to the benefits of LPDs. Aromatic amino-acids (AA) are precursors of major uremic toxins such as p-cresyl sulfate (PCS) and indoxyl sulfate (IS). We hypothesize that a low aromatic amino acid diet (LA-AAD, namely a low intake of tyrosine, tryptophan and phenylalanine) while being normoproteic, could be as effective as a LPD, through the decreased production of uremic toxins. Kidney failure was chemically induced in mice with a diet containing 0.25% (w/w) of adenine. Mice received three different diets for six weeks: normoproteic diet (NPD: 14.7% proteins, aromatic AAs 0.019%), LPD (5% proteins, aromatic AAs 0.007%) and LA-AAD (14% proteins, aromatic AAs 0.007%). Both LPD and LA-AAD significantly reduced proteinuria, kidney fibrosis and inflammation. While LPD only slightly decreased plasma free PCS and free IS compared to NPD; free fractions of both compounds were significantly decreased by LA-AAD. These results suggest that a LA-AAD confers similar benefits of a LPD in delaying the progression of CKD through a reduction in some key uremic toxins production (such as PCS and IS), with a lower risk of malnutrition.

Dietary Lipids and Dyslipidemia in Chronic Kidney Disease.

The progression of chronic kidney disease (CKD) leads to altered lipid metabolism. CKD patients exhibit high blood triglyceride (TG) levels, reduced concentrations and functionality of high-density lipoproteins (HDL), and elevated levels of atherogenic small, dense, low-density lipoproteins (sdLDL). Disorders of lipid metabolism and other metabolic disturbances place CKD patients at high risk for cardiovascular disease (CVD). Extensive evidence supports the cardioprotective effects of unsaturated fatty acids, including their beneficial effect on serum cholesterol and TG levels. Dietary lipids might therefore be especially important in the nutritional management of CKD. We review current dietary recommendations for fat intake by CKD patients and suggest potential nutritional interventions by emphasizing dietary lipids that might improve the blood lipid profile and reduce cardiovascular risk in CKD.

Chronic Kidney Disease: Role of Diet for a Reduction in the Severity of the Disease.

Chronic kidney disease affects ~37 million adults in the US, and it is often undiagnosed due to a lack of apparent symptoms in early stages. Chronic kidney disease (CKD) interferes with the body's physiological and biological mechanisms, such as fluid electrolyte and pH balance, blood pressure regulation, excretion of toxins and waste, vitamin D metabolism, and hormonal regulation. Many CKD patients are at risk of hyperkalemia, hyperphosphatemia, chronic metabolic acidosis, bone deterioration, blood pressure abnormalities, and edema. These risks may be minimized, and the disease's progression may be slowed through careful monitoring of protein, phosphorus, potassium, sodium, and calcium, relieving symptoms experienced by CKD patients. In this review, the current Kidney Disease Outcomes Quality Initiative (KDOQI) recommendations are highlighted, reflecting the 2020 update, including explanations for the pathophysiology behind the recommendations. The Dietary Approaches to Stop Hypertension, the Mediterranean diet, and the whole foods plant-based diet are currently being examined for their potential role in delaying CKD progression. Biological explanations for why the whole foods plant-based diet may benefit CKD patients compared to diets that include animal products are examined. Strong evidence continues to support the importance of diet meeting the daily requirement in the prevention and progression of kidney disease, and medical nutrition therapy with a registered dietitian is a critical aspect in medical intervention for CKD.