Nutrition Interventions in Chronic Kidney Disease

A kidney-specific fasting-mimicking diet induces podocyte reprogramming and restores renal function in glomerulopathy

Cycles of a fasting-mimicking diet (FMD) promote regeneration and reduce damage in the pancreases, blood, guts, and nervous systems of mice, but their effect on kidney disease is unknown. In addition, a FMD has not been tested in rats. Here, we show that cycles of a newly developed low-salt FMD (LS-FMD) restored normal proteinuria and nephron structure and function in rats with puromycin-induced nephrosis compared with that in animals with renal damage that did not receive the dietary intervention. LS-FMD induced modulation of a nephrogenic gene program, resembling renal developmental processes in multiple kidney structures. LS-FMD also activated podocyte-lineage reprogramming pathways and promoted a quiescent state in mature podocytes in the rat kidney damage model. In a pilot clinical study in patients with chronic kidney disease, FMD cycles of 5 days each month for 3 months promoted renoprotection, including reduction of proteinuria and improved endothelial function, compared with that in patients who did not receive the FMD cycles. These results show that FMD cycles, which promote the reprogramming of multiple renal cell types and lead to glomerular damage reversal in rats, should be tested further for the treatment of progressive kidney diseases.

Association between Dietary Intake, Profibrotic Markers, and Blood Pressure in Patients with Chronic Kidney Disease

Background

Among profibrotic and oxidant factors, matrix metalloproteinases (MMPs) and advanced glycation end products (AGEs) have a major impact on the progression of chronic kidney disease (CKD). However, very limited studies evaluated the relationships between nutrient intake and the mentioned factors in patients with CKD. Therefore, the present study aimed to investigate the correlation between dietary intake and the levels of MMPs, AGEs, and blood pressure (BP) in these patients.

Materials and Methods

This cross-sectional study was performed on 90 patients with CKD (stages 2-5). To evaluate the dietary intake of patients, three days of 24-hour food recall were completed through face-to-face and telephone interviews. Measurement of MMP-2 and MMP-9 concentration was done by enzyme-linked immunosorbent assay. The fluorimetric technique was used to measure the total serum AGEs.

Results

The patients' average dietary intake of sodium, potassium, phosphorus, energy, and protein was 725 mg/day, 1600 mg/day, 703 mg/day, 1825 kcal/day, and 64.83 g/day, respectively. After adjustment of confounding variables, a significant inverse relationship was observed between dietary intake of insoluble fiber and serum levels of MMP-2 (β = -0.218, P = 0.05). In addition, a significant positive relationship was found between molybdenum (Mo) intake and diastolic BP (β =0.229, P = 0.036).

Conclusion

A higher intake of insoluble fiber might be associated with lower serum levels of MMP-2. Also, a higher Mo intake can be correlated to a higher DBP in patients with CKD. It is suggested to conduct future studies with longitudinal designs and among various populations to better elucidate the observed relationships.

Development and assessment of a nutrition literacy scale for patients with end-stage kidney disease undergoing dialysis and its correlation with quality of life

OBJECTIVES

To construct a valid and reliable Nutritional Literacy Scale for patients with end-stage kidney disease (ESKD) receiving dialysis and evaluate associations between nutrition literacy and quality of life.

METHODS

A total of 208 ESKD patients receiving dialysis were selected for this study. Nutrition literacy evaluation items were drafted based on dietary guidelines for chronic kidney disease (CKD), Literature reviews and expert consultation. Scale reliability and validity were then assessed. Factors influencing nutrition literacy and the associations among nutrition literacy, nutritional status, and quality of life were evaluated.

RESULTS

The scale consists of 28 items with a scale-level content validity index of 0.91 and item-level content validity indices ranging from 0.83 to 1.00. Factor analysis identified 4 common factors (dimensions) named nutrition knowledge, cognitive attitude, behavioral practice, and information acquisition ability that collectively explained 56.31% of literacy score variation. The overall Cronbach's α coefficient of the scale was 0.83, the dimensional Cronbach's α coefficients ranged from 0.79 to 0.87, and the retest reliability was r = 0.73 (p < 0.05). Age, education level, residence (urban vs. Rural) , occupational status and dialysis modalities were significant factors influencing nutrition literacy. Nutrition literacy score was negatively correlated with SGA score and positively correlated with serum albumin and prealbumin concen- trations, and with SF-36 quality of life score (all p < 0.05).

CONCLUSIONS

This new Nutrition Literacy Scale demonstrates high reliability and validity for Chinese ESKD patients undergoing dialysis. The nutrition literacy is influenced by age, education level, residence, occupational status and dialysis modalities, associated not only with nutritional status but also with quality of life.

Association of Zinc Status with Matrix Metalloproteinases, Advanced Glycation End-Products, and Blood Pressure in Patients with Chronic Kidney Disease

Inflammation, oxidative stress, and hypertension trigger the development of chronic kidney disease (CKD). Zinc is known to have antioxidant and anti-inflammatory properties and a possible role in regulating blood pressure. The aim of this study was to investigate the correlation of serum zinc with matrix metalloproteinase-2 and-9 (MMP-2, MMP-9), advanced glycation end products (AGEs), and blood pressure in patients with CKD. This cross-sectional study included 90 patients with CKD. Serum zinc and the levels of MMP-2, MMP-9, AGEs, and creatinine were measured using validated biochemical methods. Three 24-h food recalls were completed to evaluate dietary zinc intake. Systolic and diastolic blood pressure (SBP, DBP) were measured using a digital sphygmomanometer. Participants' mean age was 60.68 ± 8.81 years. The prevalence of zinc deficiency in our participants was 10%. Serum zinc was negatively correlated with MMP-9 (r =  - 0.231, p = 0.032) and creatinine (r =  - 0.304, p = 0.004). However, after adjusting for confounding variables, the association between serum zinc and MMP-9 was near the significance level (β =  - 0.174, p = 0.09) and zinc remained in the model as one of the predictors. Serum zinc was positively correlated with the dietary intake of zinc (r = 0.241, p = 0.025) and estimated glomerular filtration rate (eGFR) (r = 0.259, p = 0.015). In conclusion, our results showed that serum zinc might be one of the predictors of serum MMP-9 in patients with CKD. In addition, serum zinc was positively associated with its dietary intake and eGFR. Future longitudinal studies or clinical trials are required to reveal any causal association between zinc status and profibrotic or inflammatory biomarkers among patients with CKD.

Association of malnutrition with renal dysfunction and clinical outcome in patients with heart failure

Malnutrition, glomerular damage (GD), and renal tubular damage (RTD) are common morbidities associated with poor clinical outcomes in heart failure (HF) patients. However, the association between malnutrition and renal dysfunction and its impact on clinical outcomes in HF patients have not yet been fully elucidated. We assessed the nutritional status and renal function of 1061 consecutive HF patients. Malnutrition, GD, and RTD were defined as a controlling nutritional status (CONUT) score of ≥ 5, reduced eGFR or microalbuminuria, and levels of N-acetyl-beta-d-glucosamidase of > 14.2 U/gCr according to previous reports, respectively. Patients with RTD had a higher CONUT score and a lower prognostic nutritional index and geriatric nutritional risk index than those without. Multivariate logistic analysis demonstrated that RTD, but not GD, was significantly associated with malnutrition. There were 360 cardiac events during the median follow-up period of 688 days. Multivariate Cox proportional hazard regression analysis demonstrated that comorbid malnutrition and renal dysfunction, rather than simple malnutrition, were significantly associated with cardiac events in HF patients. We found a close relationship between malnutrition and renal dysfunction in HF patients. Comorbid malnutrition and renal dysfunction were risk factors for cardiac events in HF patients, suggesting the importance of managing and treating these.

Effect of vegetarian diets on renal function in patients with chronic kidney disease under non-dialysis treatment: A scoping review

ABSTRACT Vegetable protein diets (VPDs) in chronic kidney disease (CKD) patients may be related to beneficial biological actions and possibly clinical impact. This is a scoping review that merge studies that evaluated the effect of a vegetarian diet on kidney function in adults with CKD under non-dialysis treatment. The evaluated outcome was the impact in renal function assessed by eGFR or creatinine clearance. MEDLINE (accessed by PubMed) was searched up to September 8, 2020. Data were extracted by two independent reviewers, who also assessed the quality of the studies. Of 341 retrieved articles, 4 studies assessing 324 patients were included in the analysis. One study showed that a very low-protein ketoanalogue-supplemented vegetarian diet had benefits in relation to a conventional low-protein diet, while the other three studies demonstrated no difference in kidney function between the evaluated diets. Additional studies are needed to assess the benefits of vegetarian diets for further recommendations in CKD management.

Neuroimmunoendocrine Link Between Chronic Kidney Disease and Olfactory Deficits

Chronic kidney disease (CKD) is a multifactorial pathology that progressively leads to the deterioration of metabolic functions and results from deficient glomerular filtration and electrolyte imbalance. Its economic impact on public health is challenging. Mexico has a high prevalence of CKD that is strongly associated with some of the most common metabolic disorders like diabetes and hypertension. The gradual loss of kidney functions provokes an inflammatory state and endocrine alterations affecting several systems. High serum levels of prolactin have been associated with CKD progression, inflammation, and olfactory function. Also, the nutritional status is altered due to impaired renal function. The decrease in calorie and protein intake is often accompanied by malnutrition, which can be severe at advanced stages of the disease. Nutrition and olfactory functioning are closely interconnected, and CKD patients often complain of olfactory deficits, which ultimately can lead to deficient food intake. CKD patients present a wide range of deficits in olfaction like odor discrimination, identification, and detection threshold. The chronic inflammatory status in CKD damages the olfactory epithelium leading to deficiencies in the chemical detection of odor molecules. Additionally, the decline in cognitive functioning impairs the capacity of odor differentiation. It is not clear whether peritoneal dialysis and hemodialysis improve the olfactory deficits, but renal transplants have a strong positive effect. In the present review, we discuss whether the olfactory deficiencies caused by CKD are the result of the induced inflammatory state, the hyperprolactinemia, or a combination of both.

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.

Comprehensive lifestyle modification as complementary therapy to prevent and manage post-transplant diabetes mellitus*

Post-transplant diabetes mellitus (PTDM) is one from the most common metabolic complications after kidney transplantation. PTDM develops in the early period after transplantation. The risk factors of PTDM are carbohydrate imbalances occurring in the patient prior to transplantation, surgery and the inclusion of immunosuppressive treatment. Kidney transplant patients tend to gain weight, which is associated with an increased risk of post-transplant diabetes, cardiovascular diseases and abnormal transplanted kidney function. Patients after kidney transplantation should be advised to adopt a lifestyle based on a proper diet, exercise, weight control and smoking cessation. The strategy to reduce the risk factors for PTDM development should start before transplantation and continue after kidney transplantation. A targeted, non-pharmacological approach to patients already during the dialysis period may have a significant impact on reducing post-transplantation diabetes. Lifestyle interventions can effectively reduce the risk of development and inhibit the progression of post-transplantation diabetes. The article describes elements of comprehensive non-pharmacological management based on available knowledge of rehabilitation, dietetics and psychology.

Effects of honey supplementation on renal dysfunction and metabolic acidosis in rats with high-fat diet-induced chronic kidney disease

Background Metabolic diseases are associated with impaired renal function which accelerates chronic kidney disease (CKD) progression. The aim of this study was to investigate the effects of 16-week honey supplementation on renal function, metabolic acidosis and renal abnormalities in Wistar rats fed a high-fat diet (HFD). Methods Wistar rats were fed a HFD and sucrose (30%) solution and randomly grouped and treated. Group 1 was fed rat chow and treated with drinking water while groups 2, 3, 4 and 5 were fed a HFD and treated with drinking water, 1, 2 and 3 g/kg body weight (BW) of honey, respectively, once daily for 16 weeks. After the rats were sacrificed, the serum samples were obtained and used for the analysis of total cholesterol, urea, creatinine, sodium, potassium, calcium, bicarbonates and chloride ions. Histopathological examinations of the kidneys were performed. Results The serum creatinine and anion gap levels were significantly (p < 0.01) higher while the levels of serum total calcium and ionized fraction were significantly (p < 0.01) lower in HFD-fed control rats than in chow-fed rats. The kidney of HFD-fed control rats was characterized by tubular necrosis, glomerular atrophy, hemorrhage and severe focal aggregate inflammatory (FAIC) cells. Honey treatment (1, 2 or 3 g/kg BW) prevented elevations in serum creatinine while it restored serum levels of total calcium and ionized calcium towards those in rats fed chow only. All the three doses of honey also significantly (p < 0.01) reduced anion gap and ameliorated renal lesions. Honey treatment (2 g/kg BW) significantly (p < 0.05) increased bicarbonate and chloride ion in HFD-fed rats compared with HFD-fed control rats. Conclusions Sixteen-week honey supplementation ameliorates renal dysfunction, metabolic acidosis and renal morphological abnormalities in HFD-fed Wistar rats.

Neighborhood Food Outlet Access and Dietary Intake among Adults with Chronic Kidney Disease: Results from the Chronic Renal Insufficiency Cohort Study

BACKGROUND

Healthy diet is essential in the management of chronic kidney disease (CKD) and preventing related comorbidities. Food outlet access has been studied in the general population; however, the influence of the local food environment on dietary intake among people with CKD has not been evaluated.

OBJECTIVES

This study examined the associations of food outlet density and type of outlets with dietary intake in a multicenter cohort of racially and ethnically diverse patients with CKD.

METHODS

The Chronic Renal Insufficiency Cohort Study is a multicenter prospective study of patients with CKD that used a validated food frequency questionnaire to capture dietary intake at the baseline visit. This is a cross-sectional analysis of 2,484 participants recruited in 2003-2006 from seven Chronic Renal Insufficiency Cohort Study centers. Food outlet data were used to construct a count of the number of fast-food restaurants, convenience stores, and grocery stores per 10,000 population for each geocoded census block group. Multivariable linear and logistic regression models were used to evaluate the associations between measures of food outlet availability and dietary factors.

RESULTS

The proportion of participants living in zero-, low-, and high-food outlet density areas differed by gender, race or ethnicity, and income level. Among male subjects, living in areas with zero or the highest number of outlets was associated with having the highest caloric intakes in multivariable models. Male subjects living in areas with zero outlets consumed the highest levels of sodium and phosphorous. Female subjects living in areas with zero outlets had the lowest average intake of calories, sodium, and phosphorous. Among low-income female subjects, close proximity to more outlets was associated with higher calorie consumption. Among all participants, access to fast-food restaurants was not associated with an unhealthy diet score, and access to grocery stores was not associated with a healthy diet score.

CONCLUSIONS

Average caloric and nutrient intakes differed by outlet availability; however, there were no strong associations with type of food outlet. This should be considered when developing food-focused public health policies.

Dietary Patterns of Patients with Chronic Kidney Disease: The Influence of Treatment Modality

BACKGROUND

We analyzed the dietary patterns of Brazilian individuals with a self-declared diagnosis of chronic kidney disease (CKD) and explored associations with treatment modality.

METHODS

Weekly consumption of 14 food intake markers was analyzed in 839 individuals from the 2013 Brazil National Health Survey with a self-declared diagnosis of CKD undergoing nondialysis (n = 480), dialysis (n = 48), or renal transplant (n = 17) treatment or no CKD treatment (n = 294). Dietary patterns were derived by exploratory factor analysis of food intake groups. Multiple linear regression models, adjusted by sociodemographic and geographical variables, were used to evaluate possible differences in dietary pattern scores between different CKD treatment groups.

RESULTS

Two food patterns were identified: an "Unhealthy" pattern (red meat, sweet sugar beverages, alcoholic beverages, and sweets and a negative loading of chicken, excessive salt, and fish) and a "Healthy" pattern (raw and cooked vegetables, fruits, fresh fruit juice, and milk). The Unhealthy pattern was inversely associated with nondialysis and dialysis treatment (β: -0.20 (95% CI: -0.33; -0.06) and β: -0.80 (-1.16; -0.45), respectively) and the Healthy pattern was positively associated with renal transplant treatment (β: 0.32 (0.03; 0.62)).

CONCLUSIONS

Two dietary patterns were identified in Brazilian CKD individuals and these patterns were linked to CKD treatment modality.

Number of existing permanent teeth is associated with chronic kidney disease in the elderly Korean population

BACKGROUND/AIMS

The aim of this study was to assess the association between the number of existing permanent teeth and chronic kidney disease (CKD) in a representative sample of the elderly Korean population.

METHODS

A total of 2,519 subjects who participated in the Korean National Health and Nutrition Examination Survey were cross-sectionally examined. The number of existing permanent teeth was evaluated by clinical oral examination. CKD was defined based on definition and classification by Kidney Disease: Improving Global Outcomes (KDIGO) 2012 guidelines. Multivariable logistic regression analyses were performed controlling for age, gender, income, education, tooth-brushing frequency, periodontitis, state of dentition, smoking, alcohol consumption, hypertension, obesity, diabetes mellitus, and hypercholesterolemia. Subgroup analyses by age and gender were also performed.

RESULTS

The number of teeth was significantly associated with CKD after controlling for all potential confounders (adjusted odds ratio [AOR], 1.67; 95% confidence interval [CI], 1.04 to 2.70 for lower number of teeth; AOR, 1.59; 95% CI, 1.14 to 2.23 for moderate number of teeth). In the subgroup analyses, the association was highlighted in females aged 75 years over (AOR, 2.55; 95% CI, 1.05 to 6.20 for lower number of teeth; AOR, 1.95; 95% CI, 1.01 to 3.80 for moderate number of teeth).

CONCLUSION

Our findings suggest that the number of existing permanent teeth may be associated with CKD among Korean elderly.

Daily Intake of Grape Powder Prevents the Progression of Kidney Disease in Obese Type 2 Diabetic ZSF1 Rats

Individuals living with metabolic syndrome (MetS) such as diabetes and obesity are at high risk for developing chronic kidney disease (CKD). This study investigated the beneficial effect of whole grape powder (WGP) diet on MetS-associated CKD. Obese diabetic ZSF1 rats, a kidney disease model with MetS, were fed WGP (5%, w/w) diet for six months. Kidney disease was determined using blood and urine chemical analyses, and histology. When compared to Vehicle controls, WGP intake did not change the rat bodyweight, but lowered their kidney, liver and spleen weight, which were in parallel with the lower serum glucose and the higher albumin or albumin/globin ratio. More importantly, WGP intake improved the renal function as urination and proteinuria decreased, or it prevented kidney tissue damage in these diabetic rats. The renal protection of WGP diet was associated with up-regulation of antioxidants (Dhcr24, Gstk1, Prdx2, Sod2, Gpx1 and Gpx4) and downregulation of Txnip (for ROS production) in the kidneys. Furthermore, addition of grape extract reduced H₂O₂-induced cell death of cultured podocytes. In conclusion, daily intake of WGP reduces the progression of kidney disease in obese diabetic rats, suggesting a protective function of antioxidant-rich grape diet against CKD in the setting of MetS.