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

Nutrition Education Models for Patients With Chronic Kidney Disease

Nutrition is an integral component in the management of chronic kidney disease (CKD), and kidney health professionals play a crucial role in educating patients on dietary interventions for CKD. Several dietary modifications are indicated for CKD that require frequent adaptations with CKD progression and with underlying metabolic disturbances. However, poor adherence to dietary interventions is not uncommon among patients with CKD. An effective education program on nutrition intervention consists of providing knowledge and developing skills that are necessary to support behavioral change. The application of theoretical models of behavioral change such as social cognitive theory and the transtheoretical model in nutrition intervention has been reported to be effective in promoting changes in dietary habits. This review summarizes the evidence supporting the application of theoretical models as strategies to enhance nutrition education for patients with CKD. In addition, digital technologies are gaining interest in empowering patients and facilitating nutrition management in patients with CKD. This review also examines the applications of the latest digital technologies guided by behavioral theory in facilitating patients' changes in dietary intake patterns and lifestyle habits.

Caring for Patients With Advanced Chronic Kidney Disease: Dietary Options and Conservative Care Instead of Maintenance Dialysis

An expert advisory board discussed the prevention and treatment of chronic kidney disease (CKD), with a focus on dietary options. This is timely, given the uptake of value based models for kidney care in the United States. Timing of dialysis start is influenced by patients' clinical status and complex patient-clinician interactions. Patients value personal freedom and quality of life and may want to delay dialysis, whilst physicians are sometimes more concerned with clinical outcomes. Kidney-preserving therapy can prolong the dialysis-free period and preserve residual kidney function, thus patients are asked to adjust their lifestyle and diet, to follow a low- or very low-protein diet, with or without ketoacid analogues. Multi-modal approaches include pharmacotherapies, management of symptoms, and a gradual, individualized dialysis transition. Patient empowerment is vital, including CKD education and involvement in decision making. These ideas may help patients, their families, and clinical teams to improve the management of CKD.

Impact of SARS-CoV-2 Pandemic on food Security in Patients With chronic Kidney Disease

OBJECTIVE

The present study aims to determine the degree of Food Insecurity (FI) in adult patients with CKD during the COVID-19 pandemic, as well as the association between FI and food consumption.

METHODS

A cross-sectional study was conducted on patients with chronic kidney disease (CKD), with and without substitutive treatment, and older than 18 years of age. Food security was measured using the Mexican Food Security Scale (MFSS). Sociodemographic data and a food frequency questionnaire were obtained. Multinomial logistic regression was performed using the 4 categories of food security (food security as reference); principal component analysis was also performed to assess the relationship between food consumption patterns and sociodemographic characteristics.

RESULTS

The prevalence of FI in patients with CKD was 71.6%, the most prevalent degree of FI was moderate. As FI increased, a greater amount of beans, eggs, sweets/desserts, soft drinks, and artificial juices (P < .001) was consumed. The risk factors of FI were diabetes, hypertension, unpaid occupation, living in the country's capital, having children at home, or a decrease in income due to the pandemic. Four main components were identified that were associated with the different degrees of FI.

CONCLUSION

The present study allowed us to conclude that more than 70% of CKD patients in the study cohort had some type of FI, which makes it difficult to adhere to treatment and may increase the risk of advanced CKD. A less healthy food pattern is associated with greater FI.

Nutritional and Hydration Status and Adherence to Dietary Recommendations in Dalmatian Dialysis Patients

Protein-energy wasting (PEW) is considered one of the major complications of chronic kidney disease (CKD), particularly in dialysis patients. Insufficient energy and protein intake, together with clinical complications, may contribute to the onset and severity of PEW. Therefore, the aim of the study was to analyze the differences in nutritional and hydration status and dietary intake among Dalmatian dialysis patients. Fifty-five hemodialysis (HD) and twenty peritoneal dialysis (PD) participants were included. For each study participant, data about body composition, anthropometric, laboratory, and clinical parameters were obtained. The Malnutrition Inflammation Score (MIS) and two separate 24-h dietary recalls were used to assess nutritional status and dietary intake. The Nutrient Adequacy Ratio (NAR) and Mean Adequacy Ratio (MAR) were calculated to compare actual dietary intake with recommended intake. Additionally, the estimated 10-year survival was calculated using the Charlson Comorbidity Index. The prevalence of malnutrition according to MIS was 47.3% in HD and 45% in PD participants. Significant differences in fat tissue parameters were found between HD and PD participants, whereas significant differences in hydration status and muscle mass parameters were not found. A significant difference in NAR between HD and PD participants was noticed for potassium and phosphorus intake, but not for MAR. MIS correlated negatively with anthropometric parameters, fat mass, visceral fat level and trunk fat mass, and iron and uric acid in HD participants, whereas no significant correlations were found in PD participants. The estimated 10-year survival correlated with several parameters of nutritional status in HD and PD participants, as well as nutrient intake in HD participants. These results indicate a high prevalence of malnutrition and inadequate dietary intake in the Dalmatian dialysis population which, furthermore, highlights the urgent need for individualized and structural nutritional support.

New approaches in the nutritional treatment of advanced chronic kidney disease

INTRODUCTION

Patients with advanced chronic kidney disease (ACKD) have a high prevalence of malnutrition. The dietary restrictions that we usually apply in terms of macro and micronutrients force our patients to follow dietary guidelines that deviate from healthy patterns.

OBJETIVES

To determine if a personalized nutritional intervention program, minimizing the usual restrictions would be justified in case it improved the evolution of kidney disease compared to standard treatment.

SECUNDARY OBJETIVES

To determine changes in nutrient intakes and in anthropometric and biochemical parameters, as well as quantify episodes of hyperkalemia.

MATERIAL AND METHODS

A single-center, randomized and controlled educational intervention clinical trial was conduct in patients from the ERCA outpatients clinic at the Complejo Hospitalario Universitario de Albacete. 75 patients were included, assigning 35 to a Control group and 40 to the Intervention group with 1-year follow-up. The nutritional status was determined using anthropometric data, body composition by Bioimpedance, blood and urine biochemical parameters and a 24-h recall questionnaire. The nutritional intervention was carried out in three different ways: individual, collective and telephone recall.

RESULTS

At the beginning of the study, the BMI showed a situation of weight excess with a mean of 28.83 kg/m² (5.4) in men and 26.96 kg/m² (4.09) in women. 70% of our patients had overweight. The abdominal circumference was 105.3 cm (10.2) and 92.3 cm (13.7) for men and women respectively without significant changes throughout the study. The percentage of fat mass (FM) was high in both groups for men and women throughout the study. We did not find biochemical parameters of malnutrition and only significant differences were observed in glomerular filtration rate (GFR), which increased in the intervention group. No patient presented any episodes of hyperkalemia during the study. The energy intake in both groups showed an inadequate distribution of macronutrients with a poor intake of carbohydrates (CH) that was supplemented with an excess of fat. In the case of micronutrients, we did observe an increase in potassium and fiber intakes with a decrease in sodium and phosphorus in the intervention group.

CONCLUSIONS

Malnutrition is not exclusively an intake defficit and encompasses both the problems derived from a deficit and an excess of nutrients intake. Un to 70% of our patients showed weight excess and a fat mass higher than desirable. The implementation of an individualized nutritional education program, including a vegetables and fiber rich diet, less atherogenic, not only did not cause electrolyte alterations but also slowed the progression of kidney disease.

Diet in the management of non-dialysis dependent chronic kidney disease: perceptions and practices of health professionals

Background

Therapeutic strategies, including dietary intervention, to target non-dialysis dependent Chronic Kidney Disease (CKD) progression have been at the forefront of recent renal research. Nephrologists and other renal health professionals are key stakeholders in the dietary management of patients with non-dialysis dependent CKD and referrals to dietetic services. The aims of this study were to explore (i) health professional perceptions regarding the role of diet in managing non-dialysis dependent CKD, and (ii) health professional practices regarding the provision of dietary advice and referrals to dietetic services.

Methods

A 31-item online survey was emailed to members of professional renal networks and associations in Australia and New Zealand. Data was analysed descriptively. Categorical variables were assessed to determine associations between referral frequency, demographic variables, health professional role (non-dietetic versus dietetic) and perceptions of the role of diet.

Results

Overall, 189 health professionals completed the survey. Nephrologists (42%), renal nurses (29%) and renal dietitians (24%) were the most common respondents. Non-dietetic health professionals rated the importance of diet in the management of non-dialysis dependent CKD significantly lower than renal dietitians (73% versus 98% ranked as very-extremely important, p = 0.002). Fifty percent of non-dietetic health professionals referred patients to renal dietetic services never or 0–25% of the time. Reasons for not referring included perceptions there is a lack of evidence that diet reduces CKD progression, perceptions that patients will not adhere to dietary recommendations, and a desire to reduce visit burden for patients. Barriers to accessing dietetic services were perceived to be significant and include lengthy wait times and inadequate dietetic staffing.

Conclusion

Inconsistencies exist between non-dietetic health professionals and dietitians regarding the importance of diet in non-dialysis dependent CKD. Referral practices appear to be influenced by beliefs about the evidence base and perceptions regarding the ability of dietitians to meet referral demand. Raising awareness for non-dietetic health professionals working in nephrology regarding the evidence on diet and CKD progression is needed. An improved understanding of this evidence base may improve knowledge and referral patterns. Further, an increase in renal dietetic staffing is recommended to enhance patient access to services.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-022-02790-y.

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.

Dietary strategies for gut-derived protein-bound uremic toxins and cardio-metabolic risk factors in chronic kidney disease: A focus on dietary fibers

Chronic kidney disease (CKD) is associated with altered composition and function of gut microbiota. The cause of gut dysbiosis in CKD is multifactorial and encompasses the following: uremic state, metabolic acidosis, slow colonic transit, dietary restrictions of plant-based fiber-rich foods, and pharmacological therapies. Dietary restriction of potassium-rich fruits and vegetables, which are common sources of fermentable dietary fibers, inhibits the conversion of dietary fibers to short-chain fatty acids (SCFA), which are the primary nutrient source for the symbiotic gut microbiota. Reduced consumption of fermentable dietary fibers limits the population of SCFA-forming bacteria and causes dysbiosis of gut microbiota. Gut dysbiosis induces colonic fermentation of protein and formation of gut-derived uremic toxins. In this review, we discuss the roles and benefits of dietary fiber on gut-derived protein-bound uremic toxins and plant-based dietary patterns that could be recommended to decrease uremic toxin formation in CKD patients. Recent studies have indicated that dietary fiber supplementation may be useful to decrease gut-derived uremic toxin formation and slow CKD progression. However, research on associations between adherence of healthy dietary patterns and gut-derived uremic toxins formation in patients with CKD is lacking.

New approaches in the nutritional treatment of advanced chronic kidney disease

INTRODUCTION

Patients with advanced chronic kidney disease (ACKD) have a high prevalence of malnutrition. The dietary restrictions that we usually apply in terms of macro and micronutrients force our patients to follow dietary guidelines that deviate from healthy patterns.

OBJECTIVES

To determine if a personalized nutritional intervention program, minimizing the usual restrictions would be justified in case it improved the evolution of kidney disease compared to standard treatment.

SECONDARY OBJECTIVES

To determine changes in nutrient intakes and in anthropometric and biochemical parameters, as well as quantify episodes of hyperkalemia.

MATERIAL AND METHODS

A single-center, randomized and controlled educational intervention clinical trial was conduct in patients from the ERCA outpatients clinic at the Complejo Hospitalario Universitario de Albacete. 75 patients were included, assigning 35 to a Control group and 40 to the Intervention group with 1-year follow-up. The nutritional status was determined using anthropometric data, body composition by Bioimpedance, blood and urine biochemical parameters and a 24-h recall questionnaire. The nutritional intervention was carried out in three different ways: individual, collective and telephone recall.

RESULTS

At the beginning of the study, the BMI showed a situation of weight excess with a mean of 28.83 kg/m2 (5.4) in men and 26.96 kg/m2 (4.09) in women. 70% of our patients had overweight. The abdominal circumference was 105.3 cm (10.2) and 92.3 cm (13.7) for men and women respectively without significant changes throughout the study. The percentage of fat mass (FM) was high in both groups for men and women throughout the study. We did not find biochemical parameters of malnutrition and only significant differences were observed in glomerular filtration rate (GFR), which increased in the intervention group. No patient presented any episodes of hyperkalemia during the study. The energy intake in both groups showed an inadequate distribution of macronutrients with a poor intake of carbohydrates (CH) that was supplemented with an excess of fat. In the case of micronutrients, we did observe an increase in potassium and fiber intakes with a decrease in sodium and phosphorus in the intervention group.

CONCLUSIONS

Malnutrition is not exclusively an intake deficit and encompasses both the problems derived from a deficit and an excess of nutrients intake. Un to 70% of our patients showed weight excess and a fat mass higher than desirable. The implementation of an individualized nutritional education program, including a vegetables and fiber rich diet, less atherogenic, not only did not cause electrolyte alterations but also slowed the progression of kidney disease.

Optimizing Diet to Slow CKD Progression

Due to the unique role of the kidney in the metabolism of nutrients, patients with chronic kidney disease (CKD) lose the ability to excrete solutes and maintain homeostasis. Nutrient intake modifications and monitoring of nutritional status in this population becomes critical, since it can affect important health outcomes, including progression to kidney failure, quality of life, morbidity, and mortality. Although there are multiple hemodynamic and metabolic factors involved in the progression and prognosis of CKD, nutritional interventions are a central component of the care of patients with non-dialysis CKD (ND-CKD) and of the prevention of overweight and possible protein energy-wasting. Here, we review the reno-protective effects of diet in adults with ND-CKD stages 3-5, including transplant patients.

Nutritional status, hyperkalaemia and attainment of energy/protein intake targets in haemodialysis patients following plant-based diets: a longitudinal cohort study

Background

Patients undergoing haemodialysis (HD) are often discouraged from eating fruits and vegetables because of fears of hyperkalaemia and undernutrition, yet evidence to support these claims is scarce. We here explore the association between adherence to a healthy plant-based diet with serum potassium, surrogates of nutritional status and attainment of energy/protein intake targets in HD patients.

Methods

We performed an observational single-centre study of stable patients undergoing HD with repeated dietary assessment every 3 months. Patients were provided with personalized nutritional counselling according to current guidelines. The diet was evaluated by 3-day food records and characterized by a healthy plant-based diet score (HPDS), which scores positively the intake of plant foods and negatively animal foods and sugar. The malnutrition inflammation score (MIS) and serum potassium were also assessed at each visit. We used mixed-effects models to evaluate the association of the HPDS with markers of nutritional status, serum potassium levels and attainment of energy/protein intake targets.

Results

After applying inclusion and exclusion criteria, a total of 150 patients contributing to 470 trimestral observations were included. Their mean age was 42 years [standard deviation (SD) 18] and 59% were women. In multivariable models, a higher HPDS was not associated with serum potassium levels or odds of hyperkalaemia {potassium >5.5 mEq/L; odds ratio [OR] 1.00 [95% confidence interval (CI) 0.94–1.07] per HPDS unit higher}. Patients with a higher HPDS did not differ in terms of energy intake [OR for consuming <30 kcal/kg day 1.05 (95% CI 0.97–1.13)] but were at risk of low protein intake [OR for consuming <1.1 g of protein/kg/day 1.11 (95% CI 1.04–1.19)]. A higher HPDS was associated with a lower MIS, indicating better nutritional status.

Conclusions

In patients undergoing HD, adherence to a healthy plant-based diet was not associated with serum potassium, hyperkalaemia or differences in energy intake. Although these patients were less likely to reach daily protein intake targets, they appeared to associate with better nutritional status over time.

Quality or Quantity of Proteins in the Diet for CKD Patients: Does "Junk Food" Make a Difference? Lessons from a High-Risk Pregnancy

BACKGROUND

How to manage patients with severe kidney disease in pregnancy is still a matter of discussion, and deciding if and when to start dialysis is based on the specialist's experience and dialysis availability. The effect of toxic substances usually cleared by the kidney may be more severe and readily evident. The review, and related case, underlines the importance of considering the presence of additives in food in delicate conditions, such as CKD pregnancy. The Case: A 39-year-old indigenous woman from a low-resourced area in Mexico was referred to the obstetric nephrology at 25 gestational weeks because of serum creatinine at 3.6 mg/dL, hypertension on low-dose alpha-methyl-dopa, and nephrotic-range proteinuria. Kidney ultrasounds showed small poorly differentiated kidneys; foetal ultrasounds detected a female foetus, normal for gestational age. The patient's baseline protein intake, which was estimated at 1.2-1.3 g/kg/day, was mostly of animal-origin (>70%) poor-quality food ("junk food"). In the proposed diet, protein intake was only slightly reduced (1.0-1.2 g/kg/day), but the source of proteins was changed (only 30% of animal origin) with attention to food quality. A remarkable decrease in BUN was observed, in concomitance with adequate dietary follow-up, with rapid rise of BUN when the patient switched temporarily back to previous habits. A healthy female baby weighing 2,460 g (11th centile for gestational age) was delivered at 37 gestational weeks. Discussion and Literature Review: While data on patients with chronic kidney disease are scant, the long list of contaminants present in food, especially if of low quality, should lead us to reflect on their potential negative effect on kidney function and make us realize that eating healthy, unprocessed "organic" food should be encouraged, in delicate conditions such as pregnancy and breastfeeding and for young children, in particular when kidney function is failing. The case herein described gave us the opportunity to reflect on the importance of diet quality and on the potential risks linked to food additives, many of which, including phosphates and potassium, are not declared on food labels, while others, including dyes, antioxidants, thickeners, emulsifiers, and preservatives, are qualitatively, but not quantitatively, reported.

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.

Patients with chronic kidney disease are not well adhered to dietary recommendations: a cross-sectional study

Background

Nutrition and dietary patterns are modifiable factors that can be utilized to prevent or slow the progression of Chronic kidney disease (CKD). Adherence to current dietary recommendations can reduce the incidence, or slow the progression of CKD and reduce mortality. The objectives of this study was to compare the dietary nutrient intake of CKD patients (CKD above stage 3 including hemodialysis) to dietary recommendations and to assess the correlations of those dietary nutrient intakes with each other and with chosen laboratory measurements.

Methods

A hospital-based cross-sectional study was conducted among 100 patients with CKD. A consecutive 7 days dietary record supplemented with interviews for data completion was used to assess dietary intake. Recent clinical laboratory measurements were obtained from patients’ medical records. The obtained dietary data were analyzed by the Ethiopian food composition database and the nutrisurvey software. Dietary energy and nutrients intake were compared with recommendations for CKD patients.

Results

The dietary energy intake (DEI) of almost all patients was below recommended levels. The average Dietary protein intake (DPI) was above the recommended levels (0.95 ± 0.27 g/kg/day) for about 60% of the respondents. Besides, 38% and only two of the respondents had their dietary phosphorus and potassium intakes above recommended levels, respectively. Estimated Glomerular filtration rate (eGFR) was positively correlated with both total and animal protein intakes while blood levels of creatinine and urea were negatively correlated with animal protein intake.

Conclusion

Patients with CKD are not well adhered to dietary recommendations and some nutrients showed correlation with chosen clinical laboratory measurements. Besides, DEI and DPI were below and above recommended levels, respectively, for most patients. Besides, more than one-third of the participants had phosphorus intakes above recommendation. These non-optimal dietary nutrient intakes may contribute to fast clinical deterioration and mortality.

Ameliorating Chronic Kidney Disease Using a Whole Food Plant-Based Diet

Novel approaches to ameliorating chronic kidney disease (CKD) are warranted as most patients are undiagnosed until they begin displaying symptoms of kidney failure. There is increasing evidence that a whole food plant-based (WFPB) diet may offer benefits that slow the progression of CKD, decrease the incidence cardiovascular disease, decrease rates of diabetes and obesity, and reduce inflammation and cholesterol, which in turn can delay kidney failure and the initiation of dialysis. While animal-based protein ingestion promotes an acidic environment, inflammation and renal hyperfiltration, study authors report plant-based protein can be alkaline-producing and anti-inflammatory and can contain renoprotective properties. Although there may be benefits to adopting a WFPB diet, macronutrient and micronutrient content should be carefully considered and adjusted to avoid malnutrition in CKD patients. Further research needs to be done in order to establish the biological plausibility and feasibility of a WFPB in individuals with diagnosed CKD.

The association between dietetic consultation and time to dialysis for patients attending a pre-dialysis clinic: A retrospective cohort study

AIM

A multidisciplinary approach, including dietetics, is considered the optimal model of care for dialysis preparation. Dietetic consultation (DC) focuses on symptom management and dietary changes to delay time to dialysis. Evidence of the effectiveness of DC on time to dialysis is limited. This study aimed to investigate the impact of DC on time to dialysis for patients attending a pre-dialysis clinic.

METHODS

A retrospective cohort study was designed to include all patients attending outpatient pre-dialysis clinics at a large metropolitan renal service between January 2014 and March 2018. Time to dialysis (days) was compared between patients that received DC and those who did not. Cox proportional hazards analysis allowing for adjustment of differences and confounders was undertaken.

RESULTS

A cohort of 246 patients was identified. Median estimated glomerular filtration rate was 16mL/min per 1.73 m² (interquartile range = 13-20) at initial pre-dialysis clinic visit and 63% commenced dialysis during the study period. Only 41% of patients received dietetic consultation. Significantly fewer patients needed to commence dialysis in the DC group compared to the no-DC group (hazards ratio 0.63; 95% confidence interval (CI) 0.45-0.89; P = 0.008 Cox proportion hazard). The DC group commenced dialysis significantly later than the no-DC group; 933 days (95% CI 832-1034) versus 710 days (95% CI 630-790) respectively, after the initial pre-dialysis clinic visit; log-rank 0.005.

CONCLUSION

DC provided to patients attending a pre-dialysis clinic was associated with a delayed time to dialysis. Standardised referral pathways to improve patient access to renal dietetic services are recommended to optimise care.

Dietary intake of non-dialysis chronic kidney disease patients: the PROGREDIR study. A cross-sectional study

BACKGROUND

Despite evidence that diet is very important in relation to chronic kidney disease (CKD) progression, studies in this field are scarce and have focused only on some specific nutrients. We evaluated the energy, macronutrient and micronutrient intakes and dietary patterns of non-dialysis CKD participants in the PROGREDIR study.

DESIGN AND SETTING

Cross-sectional study; CKD cohort, São Paulo, Brazil.

METHODS

Baseline data on 454 participants in the PROGREDIR study were analyzed. Dietary intake was evaluated through a food frequency questionnaire. Dietary patterns were derived through principal component analysis. Energy and protein intakes were compared with National Kidney Foundation recommendations. Linear regression analysis was performed between energy and nutrient intakes and estimated glomerular filtration rate (eGFR), and between sociodemographic and clinical variables and dietary patterns.

RESULTS

Median energy and protein intakes were 25.0 kcal/kg and 1.1 g/kg, respectively. In linear regression, protein intake (β = -3.67; P = 0.07) was related to eGFR. Three dietary patterns (snack, mixed and traditional) were retained. The snack pattern was directly associated with male gender (β = 0.27; P = 0.006) and inversely with diabetes (β = -0.23; P = 0.02). The traditional pattern was directly associated with male gender (β = 0.27; P = 0.007) and schooling (β = 0.40; P < 0.001) and inversely with age (β = -0.01; P = 0.001) and hypertension (β = -0.34; P = 0.05).

CONCLUSIONS

We identified low energy and high protein intake in this population. Protein intake was inversely related to eGFR. Dietary patterns were associated with age, gender, schooling level, hypertension and diabetes.

The Effect of Polyphenol-Rich Interventions on Cardiovascular Risk Factors in Haemodialysis: A Systematic Review and Meta-Analysis

End-stage kidney disease is a strong risk factor for cardiovascular-specific mortality. Polyphenol-rich interventions may attenuate cardiovascular disease risk factors; however, this has not been systematically evaluated in the hemodialysis population. Using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, the following databases were searched: Cochrane Library (http://www.cochranelibrary.com/), MEDLINE (https://health.ebsco.com/products/medline-with-full-text), Embase (https://www.elsevier.com/solutions/embase-biomedical-research), and CINAHL (https://www.ebscohost.com/nursing/products/cinahl-databases/cinahl-complete). Meta-analyses were conducted for measures of lipid profile, inflammation, oxidative stress, and blood pressure. Risk of bias was assessed using the Cochrane Collaboration Risk of Bias tool and quality of the body of evidence was assessed by the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) methodology. Twelve studies were included for review. Polyphenol-rich interventions included soy, cocoa, pomegranate, grape, and turmeric. Polyphenol-rich interventions significantly improved diastolic blood pressure (Mean Difference (MD) −5.62 mmHg (95% Confidence Interval (CI) −8.47, −2.78); I² = 2%; p = 0.0001), triglyceride levels (MD −26.52 mg/dL (95% CI −47.22, −5.83); I² = 57%; p = 0.01), and myeloperoxidase (MD −90.10 (95% CI −135.84, −44.36); I² = 0%; p = 0.0001). Included studies generally had low or unclear risks of bias. The results of this review provide preliminary support for the use of polyphenol-rich interventions for improving cardiovascular risk markers in haemodialysis patients. Due to the limited number of studies for individual polyphenol interventions, further studies are required to provide recommendations regarding individual polyphenol intervention and dose.

Dietary Metabolites and Chronic Kidney Disease

Dietary contents and their metabolites are closely related to chronic kidney disease (CKD) progression. Advanced glycated end products (AGEs) are a type of uremic toxin produced by glycation. AGE accumulation is not only the result of elevated glucose levels or reduced renal clearance capacity, but it also promotes CKD progression. Indoxyl sulfate, another uremic toxin derived from amino acid metabolism, accumulates as CKD progresses and induces tubulointerstitial fibrosis and glomerular sclerosis. Specific types of amino acids (d-serine) or fatty acids (palmitate) are reported to be closely associated with CKD progression. Promising therapeutic targets associated with nutrition include uremic toxin absorbents and inhibitors of AGEs or the receptor for AGEs (RAGE). Probiotics and prebiotics maintain gut flora balance and also prevent CKD progression by enhancing gut barriers and reducing uremic toxin formation. Nrf2 signaling not only ameliorates oxidative stress but also reduces elevated AGE levels. Bardoxolone methyl, an Nrf2 activator and NF-κB suppressor, has been tested as a therapeutic agent, but the phase 3 clinical trial was terminated owing to the high rate of cardiovascular events. However, a phase 2 trial has been initiated in Japan, and the preliminary analysis reveals promising results without an increase in cardiovascular events.