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Special Issue "Nutrition and Chronic Kidney Disease"

A special issue of Nutrients (ISSN 2072-6643).

Deadline for manuscript submissions: closed (28 February 2017)

Special Issue Editors

Guest Editor
Dr. Bengt Lindholm

Division of Renal Medicine, Department of Clinical Science, Intervention and Technology Karolinska Institutet, Karolinska University Hospital Huddinge, Stockholm
Website | E-Mail
Interests: identification; prevention and treatment of nutritional; metabolic; hormonal; cardiovascular and other alterations in chronic kidney disease patients that contribute to premature aging and increased morbimortality
Guest Editor
Dr. Peter Stenvinkel

Division of Renal Medicine, Department of Clinical Science, Intervention and Technology Karolinska Institutet, Karolinska University Hospital Huddinge, Stockholm
Website | E-Mail
Interests: identification; prevention and treatment of nutritional; metabolic; hormonal; cardiovascular and other alterations in chronic kidney disease patients that contribute to premature aging and increased morbimortality

Special Issue Information

Dear Colleagues,

Nutritional and metabolic disorders may promote initiation and progression of chronic kidney disease (CKD), a metabolic disease affecting virtually all aspects of nutrition and metabolism, especially when CKD progresses to end-stage renal disease (ESRD). Changes in intake (and losses) of essential and non-essential nutrients and disturbances of metabolic and hormonal pathways promote catabolism and alter the requirements of nutrients in CKD, resulting in poor nutritional status characterized by protein-energy wasting (PEW), inflammation and other disorders. Poor nutritional status and specific nutrient abnormalities (deficiencies or abnormal abundance of, e.g., electrolytes and water) together with other highly prevalent conditions in CKD, such as inflammation, CKD-mineral bone disorders, and the uremic milieu contribute to sarcopenia, frailty, immune dysfunction, premature vascular ageing, cardiovascular disease, and other mortality-predictive conditions.

Although the literature in this field is expanding rapidly, our knowledge about the underlying mechanisms, and appropriate methods for diagnosis, prevention and treatment of nutritional disorders in CKD, are far from complete and further studies are highly warranted. You are invited to submit proposals for manuscripts that fit the objectives of this Special Issue.

The objective of this proposed Special Issue on “Nutrition in Chronic Kidney Disease” is to publish selected papers detailing specific aspects of nutrition in chronic kidney disease, such as the analyses of nutritional issues in CKD, such as contributions addressing exploring pathways of nutritional disorders, characterization of nutritional disorders, nutrient intake and losses, implications of nutritional disorders, and other issues affecting nutrition in patients with CKD.

Thus, the key idea is to accomplish, through this Special Issue, a sample of some of the nutritional challenges in patients with chronic kidney disease in order to improve the diagnosis, treatment or prevention of nutritional disorders in this group of patients.

Dr. Peter Stenvinkel
Dr. Bengt Lindholm
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Nutrients is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2000 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Chronic kidney disease
  • Dialysis
  • Nutritional status
  • Nutrients
  • Protein and Energy Intake

Published Papers (34 papers)

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Open AccessArticle
Body Composition Analysis Allows the Prediction of Urinary Creatinine Excretion and of Renal Function in Chronic Kidney Disease Patients
Nutrients 2017, 9(6), 553; https://doi.org/10.3390/nu9060553
Received: 20 February 2017 / Revised: 9 May 2017 / Accepted: 23 May 2017 / Published: 28 May 2017
Cited by 4 | PDF Full-text (1154 KB) | HTML Full-text | XML Full-text
Abstract
The aim of this study was to predict urinary creatinine excretion (UCr), creatinine clearance (CCr) and the glomerular filtration rate (GFR) from body composition analysis. Body cell mass (BCM) is the compartment which contains muscle mass, which is where creatinine is generated. BCM [...] Read more.
The aim of this study was to predict urinary creatinine excretion (UCr), creatinine clearance (CCr) and the glomerular filtration rate (GFR) from body composition analysis. Body cell mass (BCM) is the compartment which contains muscle mass, which is where creatinine is generated. BCM was measured with body impedance analysis in 165 chronic kidney disease (CKD) adult patients (72 women) with serum creatinine (SCr) 0.6–14.4 mg/dL. The GFR was measured (99mTc-DTPA) and was predicted using the Modification of Diet in Renal Disease (MDRD) formula. The other examined parameters were SCr, 24-h UCr and measured 24-h CCr (mCCr). A strict linear correlation was found between 24-h UCr and BCM (r = 0.772). Multiple linear regression (MR) indicated that UCr was positively correlated with BCM, body weight and male gender, and negatively correlated with age and SCr. UCr predicted using the MR equation (MR-UCr) was quite similar to 24-h UCr. CCr predicted from MR-UCr and SCr (MR-BCM-CCr) was very similar to mCCr with a high correlation (r = 0.950), concordance and a low prediction error (8.9 mL/min/1.73 m2). From the relationship between the GFR and the BCM/SCr ratio, we predicted the GFR (BCM GFR). The BCM GFR was very similar to the GFR with a high correlation (r = 0.906), concordance and a low prediction error (12.4 mL/min/1.73 m2). In CKD patients, UCr, CCr and the GFR can be predicted from body composition analysis. Full article
(This article belongs to the Special Issue Nutrition and Chronic Kidney Disease)
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Open AccessArticle
Green Tea Polyphenols, Mimicking the Effects of Dietary Restriction, Ameliorate High-Fat Diet-Induced Kidney Injury via Regulating Autophagy Flux
Nutrients 2017, 9(5), 497; https://doi.org/10.3390/nu9050497
Received: 27 February 2017 / Revised: 25 April 2017 / Accepted: 9 May 2017 / Published: 14 May 2017
Cited by 5 | PDF Full-text (2652 KB) | HTML Full-text | XML Full-text
Abstract
Epidemiological and experimental studies reveal that Western dietary patterns contribute to chronic kidney disease, whereas dietary restriction (DR) or dietary polyphenols such as green tea polyphenols (GTPs) can ameliorate the progression of kidney injury. This study aimed to investigate the renal protective effects [...] Read more.
Epidemiological and experimental studies reveal that Western dietary patterns contribute to chronic kidney disease, whereas dietary restriction (DR) or dietary polyphenols such as green tea polyphenols (GTPs) can ameliorate the progression of kidney injury. This study aimed to investigate the renal protective effects of GTPs and explore the underlying mechanisms. Sixty Wistar rats were randomly divided into 6 groups: standard diet (STD), DR, high-fat diet (HFD), and three diets plus 200 mg/kg(bw)/day GTPs, respectively. After 18 weeks, HFD group exhibited renal injuries by increased serum cystatin C levels and urinary N-acetyl-β-d-glucosaminidase activity, which can be ameliorated by GTPs. Meanwhile, autophagy impairment as denoted by autophagy-lysosome related proteins, including LC3-II, Beclin-1, p62, cathepsin B, cathepsin D and LAMP-1, was observed in HFD group, whereas DR or GTPs promoted renal autophagy activities and GTPs ameliorated HFD-induced autophagy impairment. In vitro, autophagy flux suppression was detected in palmitic acid (PA)-treated human proximal tubular epithelial cells (HK-2), which was ameliorated by epigallocatechin-3-gallate (EGCG). Furthermore, GTPs (or EGCG) elevated phosphorylation of AMP-activated protein kinase in the kidneys of HFD-treated rats and in PA-treated HK-2 cells. These findings revealed that GTPs mimic the effects of DR to induce autophagy and exert a renal protective effect by alleviating HFD-induced autophagy suppression. Full article
(This article belongs to the Special Issue Nutrition and Chronic Kidney Disease)
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Open AccessArticle
Non-Traditional Aspects of Renal Diets: Focus on Fiber, Alkali and Vitamin K1 Intake
Nutrients 2017, 9(5), 444; https://doi.org/10.3390/nu9050444
Received: 27 February 2017 / Revised: 16 April 2017 / Accepted: 20 April 2017 / Published: 29 April 2017
Cited by 11 | PDF Full-text (729 KB) | HTML Full-text | XML Full-text
Abstract
Renal diets for advanced chronic kidney disease (CKD) are structured to achieve a lower protein, phosphate and sodium intake, while supplying adequate energy. The aim of this nutritional intervention is to prevent or correct signs, symptoms and complications of renal insufficiency, delaying the [...] Read more.
Renal diets for advanced chronic kidney disease (CKD) are structured to achieve a lower protein, phosphate and sodium intake, while supplying adequate energy. The aim of this nutritional intervention is to prevent or correct signs, symptoms and complications of renal insufficiency, delaying the start of dialysis and preserving nutritional status. This paper focuses on three additional aspects of renal diets that can play an important role in the management of CKD patients: the vitamin K1 and fiber content, and the alkalizing potential. We examined the energy and nutrients composition of four types of renal diets according to their protein content: normal diet (ND, 0.8 g protein/kg body weight (bw)), low protein diet (LPD, 0.6 g protein/kg bw), vegan diet (VD, 0.7 g protein/kg bw), very low protein diet (VLPD, 0.3 g protein/kg bw). Fiber content is much higher in the VD and in the VLPD than in the ND or LPD. Vitamin K1 content seems to follow the same trend, but vitamin K2 content, which could not be investigated, might have a different pattern. The net endogenous acid production (NEAP) value decreases from the ND and LPD to the vegetarian diets, namely VD and VLPD; the same finding occurred for the potential renal acid load (PRAL). In conclusion, renal diets may provide additional benefits, and this is the case of vegetarian diets. Namely, VD and VLPD also provide high amounts of fibers and Vitamin K1, with a very low acid load. These features may have favorable effects on Vitamin K1 status, intestinal microbiota and acid-base balance. Hence, we can speculate as to the potential beneficial effects on vascular calcification and bone disease, on protein metabolism, on colonic environment and circulating levels of microbial-derived uremic toxins. In the case of vegetarian diets, attention must be paid to serum potassium levels. Full article
(This article belongs to the Special Issue Nutrition and Chronic Kidney Disease)
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Open AccessArticle
Factors Associated with Decreased Lean Tissue Index in Patients with Chronic Kidney Disease
Nutrients 2017, 9(5), 434; https://doi.org/10.3390/nu9050434
Received: 24 February 2017 / Revised: 3 April 2017 / Accepted: 25 April 2017 / Published: 27 April 2017
Cited by 22 | PDF Full-text (985 KB) | HTML Full-text | XML Full-text
Abstract
Muscle wasting is common and is associated with increased morbidity and mortality in patients with chronic kidney disease (CKD). However, factors associated with decreased muscle mass in CKD patients are seldom reported. We performed a cross-sectional study of 326 patients (age 65.8 ± [...] Read more.
Muscle wasting is common and is associated with increased morbidity and mortality in patients with chronic kidney disease (CKD). However, factors associated with decreased muscle mass in CKD patients are seldom reported. We performed a cross-sectional study of 326 patients (age 65.8 ± 13.3 years) with stage 3–5 CKD who were not yet on dialysis. Muscle mass was determined using the Body Composition Monitor (BCM), a multifrequency bioimpedance spectroscopy device, and was expressed as the lean tissue index (LTI, lean tissue mass/height2). An LTI of less than 10% of the normal value (low LTI) indicates muscle wasting. Patients with low LTI (n = 40) tended to be diabetic, had significantly higher fat tissue index, urine protein creatinine ratio, and interleukin-6 and tumor necrosis factor-α levels, but had significantly lower serum albumin and hemoglobin levels compared with those with normal LTI. In multivariate linear regression analysis, age, sex, cardiovascular disease, and interleukin-6 were independently associated with LTI. Additionally, diabetes mellitus remained an independent predictor of muscle wasting according to low LTI by multivariate logistic regression analysis. We conclude that LTI has important clinical correlations. Determination of LTI may aid in clinical assessment by helping to identify muscle wasting among patients with stage 3–5 CKD. Full article
(This article belongs to the Special Issue Nutrition and Chronic Kidney Disease)
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Open AccessArticle
The Association of Ankle Brachial Index, Protein-Energy Wasting, and Inflammation Status with Cardiovascular Mortality in Patients on Chronic Hemodialysis
Nutrients 2017, 9(4), 416; https://doi.org/10.3390/nu9040416
Received: 27 February 2017 / Revised: 17 April 2017 / Accepted: 18 April 2017 / Published: 21 April 2017
Cited by 11 | PDF Full-text (1226 KB) | HTML Full-text | XML Full-text
Abstract
Protein-energy wasting (PEW) is highly prevalent in hemodialysis (HD) patients. We investigated the association of abnormal ankle brachial index (ABI), PEW, and chronic inflammation status with clinical prognosis in HD patients. A total of 973 HD patients were enrolled and were followed-up for [...] Read more.
Protein-energy wasting (PEW) is highly prevalent in hemodialysis (HD) patients. We investigated the association of abnormal ankle brachial index (ABI), PEW, and chronic inflammation status with clinical prognosis in HD patients. A total of 973 HD patients were enrolled and were followed-up for 8 years. As a marker of the PEW, geriatric nutritional risk index (GNRI) was used. Cut-off levels were 91.2 for GNRI defined from previous studies and 1.9 mg/L for C-reactive protein (CRP) as median value, respectively. Abnormal ABI was seen in 332 (34.1%) patients. Declined GNRI and elevated CRP levels were independently associated with abnormal ABI (odds ratio (OR) 0.97, 95% confidence interval (CI) 0.96–0.99, p = 0.0009 and OR 1.40, 95% CI 1.07–1.83, p = 0.013, respectively). GNRI levels were also independently correlated with CRP levels (β = −0.126, p < 0.0001). During follow-up period, 283 (29.1%) patients died, including 123 (12.6%) due to cardiovascular disease (CVD). Abnormal ABI (adjusted hazard ratio (HR) 1.62, 95% CI 1.13–2.32, p = 0.0096), GNRI < 91.2 (adjusted HR 1.57, 95% CI 1.06–2.33, p = 0.023) and CRP > 1.9 mg/L (adjusted HR 1.89, 95% CI 1.31–2.77, p = 0.0007) independently predicted mortality due to CVD, respectively. In conclusion, abnormal ABI, GNRI, and CRP levels were closely associated with each other, and the combination of these variables increase their predictive values for the risk of mortality due to CVD and all-cause mortality in HD patients. Full article
(This article belongs to the Special Issue Nutrition and Chronic Kidney Disease)
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Open AccessArticle
Nutritional Status Predicts 10-Year Mortality in Patients with End-Stage Renal Disease on Hemodialysis
Nutrients 2017, 9(4), 399; https://doi.org/10.3390/nu9040399
Received: 6 February 2017 / Revised: 12 April 2017 / Accepted: 15 April 2017 / Published: 18 April 2017
Cited by 17 | PDF Full-text (595 KB) | HTML Full-text | XML Full-text
Abstract
Protein-energy wasting (PEW) is associated with mortality in patients with end-stage renal disease (ESRD) on maintenance hemodialysis. The correct diagnosis of PEW is extremely important in order to predict clinical outcomes. However, it is unclear which parameters should be used to diagnose PEW. [...] Read more.
Protein-energy wasting (PEW) is associated with mortality in patients with end-stage renal disease (ESRD) on maintenance hemodialysis. The correct diagnosis of PEW is extremely important in order to predict clinical outcomes. However, it is unclear which parameters should be used to diagnose PEW. Therefore, this retrospective observational study investigated the relationship between mortality and nutritional parameters in ESRD patients on maintenance hemodialysis. A total of 144 patients were enrolled. Nutritional parameters, including body mass index, serum albumin, dietary intake, normalized protein catabolic rate (nPCR), and malnutrition inflammation score (MIS), were measured at baseline. Fifty-three patients died during the study. Survivors had significantly higher nPCR (1.10 ± 0.24 g/kg/day vs. 1.01 ± 0.21 g/kg/day; p = 0.048), energy intake (26.7 ± 5.8 kcal/kg vs. 24.3 ± 4.2 kcal/kg; p = 0.009) and protein intake (0.91 ± 0.21 g/kg vs. 0.82 ± 0.24 g/kg; p = 0.020), and lower MIS (5.2 ± 2.3 vs. 6.1 ± 2.1, p = 0.039). In multivariable analysis, energy intake <25 kcal/kg (HR 1.860, 95% CI 1.018–3.399; p = 0.044) and MIS > 5 (HR 2.146, 95% CI 1.173–3.928; p = 0.013) were independent variables associated with all-cause mortality. These results suggest that higher MIS and lower energy intake are harmful to ESRD patients on maintenance hemodialysis. Optimal energy intake could reduce mortality in these patients. Full article
(This article belongs to the Special Issue Nutrition and Chronic Kidney Disease)
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Open AccessArticle
Intake of Marine-Derived Omega-3 Polyunsaturated Fatty Acids and Mortality in Renal Transplant Recipients
Nutrients 2017, 9(4), 363; https://doi.org/10.3390/nu9040363
Received: 28 February 2017 / Revised: 27 March 2017 / Accepted: 30 March 2017 / Published: 5 April 2017
Cited by 3 | PDF Full-text (730 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
The effect of marine-derived omega-3 polyunsaturated fatty acids (n-3 PUFA) on long-term outcome in renal transplant recipients (RTR) remains unclear. We investigated whether marine-derived n-3 PUFA intake is associated with all-cause and cardiovascular (CV) mortality in RTR. Intake of eicosapentaenoic [...] Read more.
The effect of marine-derived omega-3 polyunsaturated fatty acids (n-3 PUFA) on long-term outcome in renal transplant recipients (RTR) remains unclear. We investigated whether marine-derived n-3 PUFA intake is associated with all-cause and cardiovascular (CV) mortality in RTR. Intake of eicosapentaenoic acid plus docosahexaenoic acid (EPA-DHA) was assessed using a validated Food Frequency Questionnaire. Cox regression analyses were performed to evaluate the associations of EPA-DHA intake with all-cause and CV mortality. We included 627 RTR (age 53 ± 13 years). EPA-DHA intake was 102 (42–215) mg/day. During median follow-up of 5.4 years, 130 (21%) RTR died, with 52 (8.3%) due to CV causes. EPA-DHA intake was associated with lower risk of all-cause mortality (Hazard Ratio (HR) 0.85; 95% confidence interval (95% CI) 0.75–0.97). Age (p = 0.03) and smoking status (p = 0.01) significantly modified this association, with lower risk of all-cause and CV mortality particularly in older (HR 0.75, 95% CI 0.61–0.92; HR 0.68, 95% CI 0.48–0.95) and non-smoking RTR (HR 0.80, 95% CI 0.68–0.93; HR 0.74, 95% CI 0.56–0.98). In conclusion, marine-derived n-3 PUFA intake is inversely associated with risk of all-cause and CV mortality in RTR. The strongest associations were present in subgroups of patients, which adds further evidence to the plea for EPA-DHA supplementation, particularly in elderly and non-smoking RTR. Full article
(This article belongs to the Special Issue Nutrition and Chronic Kidney Disease)
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Open AccessArticle
Analysis of Outcomes of the NRS 2002 in Patients Hospitalized in Nephrology Wards
Nutrients 2017, 9(3), 287; https://doi.org/10.3390/nu9030287
Received: 30 December 2016 / Revised: 25 February 2017 / Accepted: 6 March 2017 / Published: 16 March 2017
Cited by 6 | PDF Full-text (595 KB) | HTML Full-text | XML Full-text
Abstract
Introduction: Malnutrition is a common problem among hospitalized patients. In chronic kidney disease, it affects up to 50% of the population. Undernourishment has an adverse effect on prognosis and prolongs convalescence. The aim of the study was to test the effectiveness of NRS [...] Read more.
Introduction: Malnutrition is a common problem among hospitalized patients. In chronic kidney disease, it affects up to 50% of the population. Undernourishment has an adverse effect on prognosis and prolongs convalescence. The aim of the study was to test the effectiveness of NRS (Nutrition Risk Screening) -2002 in the assessment of risk of malnutrition for patients hospitalized in nephrology wards. The aim was to develop clinical characteristics of malnourished patients and to assess the relationship between nutritional status and patient outcome. Methods: The analysis included 292 patients, consecutively admitted to nephrology wards. NRS-2002 was assessed in comparison to subjective global assessment. Associations with patient characteristics and outcome were evaluated. Results: Out of all the respondents, 119 patients (40%) suffered from malnutrition. The NRS-2002 showed a very strong relationship with Subjective Global Assessment (SGA) (p < 0.0001). Malnourished patients were older, were characterized by a significantly lower body mass index (BMI), and had a much longer hospitalization duration. In multiple regression analysis, the presence of malnutrition proved to be an independent predictor of the duration of hospital stay. CONCLUSIONS: Malnutrition is highly prevalent among patients hospitalized in nephrology wards, and it affects the length of hospitalization. Identification of malnourished patients and patients at serious risk of malnutrition progression allows the implementation of appropriate nutritional intervention. Full article
(This article belongs to the Special Issue Nutrition and Chronic Kidney Disease)
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Open AccessArticle
Diabetes Mellitus and Younger Age Are Risk Factors for Hyperphosphatemia in Peritoneal Dialysis Patients
Nutrients 2017, 9(2), 152; https://doi.org/10.3390/nu9020152
Received: 23 October 2016 / Revised: 27 January 2017 / Accepted: 13 February 2017 / Published: 17 February 2017
Cited by 1 | PDF Full-text (241 KB) | HTML Full-text | XML Full-text
Abstract
Hyperphosphatemia has been associated with adverse outcomes in patients with end stage kidney disease (ESKD). The purpose of this study was to determine risk factors for hyperphosphatemia in ESKD patients treated with peritoneal dialysis (PD). This information will be used to develop a [...] Read more.
Hyperphosphatemia has been associated with adverse outcomes in patients with end stage kidney disease (ESKD). The purpose of this study was to determine risk factors for hyperphosphatemia in ESKD patients treated with peritoneal dialysis (PD). This information will be used to develop a patient specific phosphate binder application to facilitate patient self-management of serum phosphate. Adult PD patients documented their food, beverage, and phosphate binder intake for three days using a dietitian developed food journal. Phosphate content of meals was calculated using the ESHA Food Processor SQL Software (ESHA Research, Salem, UT, USA). Clinic biochemistry tests and an adequacy assessment (Baxter Adequest program) were done. Univariate logistic regression was used to determine predictors of serum phosphate >1.78 mmol/L. A multivariable logistic regression model was then fit including those variables that achieved a significance level of p < 0.20 in univariate analyses. Sixty patients (38 men, 22 women) completed the protocol; they were 60 ± 17 years old, 50% had a history of diabetes mellitus (DM) and 33% had hyperphosphatemia (PO4 > 1.78 mmol/L). In univariate analysis, the variables associated with an increased risk of hyperphosphatemia with a p-value < 0.2 were male gender (p = 0.13), younger age (0.07), presence of DM (0.005), higher dose of calcium carbonate (0.08), higher parathyroid serum concentration (0.08), lower phosphate intake (0.03), lower measured glomerular filtration rate (0.15), higher phosphate excretion (0.11), and a higher body mass index (0.15). After multivariable logistic regression analysis, younger age (odds ratio (OR) 0.023 per decade, 95% confidence interval (CI) 0.00065 to 0.455; p = 0.012), presence of diabetes (OR 11.40, 95 CI 2.82 to 61.55; p = 0.0003), and measured GFR (OR 0.052 per mL/min decrease; 95% CI 0.0025 to 0.66) were associated with hyperphosphatemia. Our results support that younger age and diabetes mellitus are significant risk factors for hyperphosphatemia. These findings warrant further investigation to determine the potential mechanisms that predispose younger patients and those with DM to hyperphosphatemia. Full article
(This article belongs to the Special Issue Nutrition and Chronic Kidney Disease)
Open AccessArticle
Very Low-Protein Diet (VLPD) Reduces Metabolic Acidosis in Subjects with Chronic Kidney Disease: The “Nutritional Light Signal” of the Renal Acid Load
Nutrients 2017, 9(1), 69; https://doi.org/10.3390/nu9010069
Received: 5 October 2016 / Revised: 4 January 2017 / Accepted: 9 January 2017 / Published: 17 January 2017
Cited by 19 | PDF Full-text (735 KB) | HTML Full-text | XML Full-text
Abstract
Background: Metabolic acidosis is a common complication of chronic kidney disease; current guidelines recommend treatment with alkali if bicarbonate levels are lower than 22 mMol/L. In fact, recent studies have shown that an early administration of alkali reduces progression of CKD. The aim [...] Read more.
Background: Metabolic acidosis is a common complication of chronic kidney disease; current guidelines recommend treatment with alkali if bicarbonate levels are lower than 22 mMol/L. In fact, recent studies have shown that an early administration of alkali reduces progression of CKD. The aim of the study is to evaluate the effect of fruit and vegetables to reduce the acid load in CKD. Methods: We conducted a case-control study in 146 patients who received sodium bicarbonate. Of these, 54 patients assumed very low-protein diet (VLPD) and 92 were controls (ratio 1:2). We calculated every three months the potential renal acid load (PRAL) and the net endogenous acid production (NEAP), inversely correlated with serum bicarbonate levels and representing the non-volatile acid load derived from nutrition. Un-paired T-test and Chi-square test were used to assess differences between study groups at baseline and study completion. Two-tailed probability values ≤0.05 were considered statistically significant. Results: At baseline, there were no statistical differences between the two groups regarding systolic blood pressure (SBP), diastolic blood pressure (DBP), protein and phosphate intake, urinary sodium, potassium, phosphate and urea nitrogen, NEAP, and PRAL. VLPD patients showed at 6 and 12 months a significant reduction of SBP (p < 0.0001), DBP (p < 0.001), plasma urea (p < 0.0001) protein intake (p < 0.0001), calcemia (p < 0.0001), phosphatemia (p < 0.0001), phosphate intake (p < 0.0001), urinary sodium (p < 0.0001), urinary potassium (p < 0.002), and urinary phosphate (p < 0.0001). NEAP and PRAL were significantly reduced in VLPD during follow-up. Conclusion: VLPD reduces intake of acids; nutritional therapy of CKD, that has always taken into consideration a lower protein, salt, and phosphate intake, should be adopted to correct metabolic acidosis, an important target in the treatment of CKD patients. We provide useful indications regarding acid load of food and drinks—the “acid load dietary traffic light”. Full article
(This article belongs to the Special Issue Nutrition and Chronic Kidney Disease)
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Open AccessArticle
Comparative Study on Trace Element Excretions between Nonanuric and Anuric Patients Undergoing Continuous Ambulatory Peritoneal Dialysis
Nutrients 2016, 8(12), 826; https://doi.org/10.3390/nu8120826
Received: 28 October 2016 / Revised: 26 November 2016 / Accepted: 15 December 2016 / Published: 20 December 2016
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Abstract
Few studies have been reported on alterations of trace elements (TE) in peritoneal dialysis patients. Our objective was to investigate and assess the characteristics of daily TE excretions in continuous ambulatory peritoneal dialysis (CAPD) patients. This cross-sectional study included 61 CAPD patients (nonanuric/anuric: [...] Read more.
Few studies have been reported on alterations of trace elements (TE) in peritoneal dialysis patients. Our objective was to investigate and assess the characteristics of daily TE excretions in continuous ambulatory peritoneal dialysis (CAPD) patients. This cross-sectional study included 61 CAPD patients (nonanuric/anuric: 45/16) and 11 healthy subjects in Wuhan, China between 2013 and 2014. The dialysate and urine of patients and urine of healthy subjects were collected. The concentrations of copper (Cu), zinc (Zn), selenium (Se), molybdenum (Mo), and arsenic (As) in dialysate and urine were determined using inductively coupled plasma mass spectrometer (ICP-MS). Various clinical variables were obtained from automatic biochemical analyzer. Daily Cu, Zn, Se, and Mo excretions in nonanuric patients were higher than healthy subjects, while arsenic excretion in anuric patients was lower. A strong and positive correlation was observed between Se and Mo excretion in both dialysate (β = 0.869, p < 0.010) and urine (β = 0.968, p < 0.010). Furthermore, the clinical variables associated with Se excretion were found to be correlated with Mo excretion. Our findings indicated that nonanuric CAPD patients may suffer from deficiency of some essential TEs, while anuric patients are at risk of arsenic accumulation. A close association between Se and Mo excretion was also found. Full article
(This article belongs to the Special Issue Nutrition and Chronic Kidney Disease)
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Open AccessArticle
Patient Survival and Costs on Moderately Restricted Low-Protein Diets in Advanced CKD: Equivalent Survival at Lower Costs?
Nutrients 2016, 8(12), 758; https://doi.org/10.3390/nu8120758
Received: 8 August 2016 / Revised: 23 October 2016 / Accepted: 16 November 2016 / Published: 25 November 2016
Cited by 6 | PDF Full-text (481 KB) | HTML Full-text | XML Full-text
Abstract
The indications for delaying the start of dialysis have revived interest in low-protein diets (LPDs). In this observational prospective study, we enrolled all patients with chronic kidney disease (CKD) who followed a moderately restricted LPD in 2007–2015 in a nephrology unit in Italy: [...] Read more.
The indications for delaying the start of dialysis have revived interest in low-protein diets (LPDs). In this observational prospective study, we enrolled all patients with chronic kidney disease (CKD) who followed a moderately restricted LPD in 2007–2015 in a nephrology unit in Italy: 449 patients, 847 years of observation. At the start of the diet, the median glomerular filtration rate (GFR) was 20 mL/min, the median age was 70, the median Charlson Index was 7. Standardized mortality rates for the “on-diet” population were significantly lower than for patients on dialysis (United States Renal Data System (USRDS): 0.44 (0.36–0.54); Italian Dialysis Registry: 0.73 (0.59–0.88); French Dialysis Registry 0.70 (0.57–0.85)). Considering only the follow-up at low GFR (≤15 mL/min), survival remained significantly higher than in the USRDS, and was equivalent to the Italian and French registries, with an advantage in younger patients. Below the e-GFR of 15 mL/min, 50% of the patients reached a dialysis-free follow-up of ≥2 years; 25% have been dialysis-free for five years. Considering an average yearly cost of about 50,000 Euros for dialysis and 1200 Euros for the diet, and different hypotheses of “spared” dialysis years, treating 100 patients on a moderately restricted LPD would allow saving one to four million Euros. Therefore, our study suggests that in patients with advanced CKD, moderately restricted LPDs may allow prolonging dialysis-free follow-up with comparable survival to dialysis at a lower cost. Full article
(This article belongs to the Special Issue Nutrition and Chronic Kidney Disease)
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Open AccessArticle
Cholecalciferol Additively Reduces Serum Parathyroid Hormone and Increases Vitamin D and Cathelicidin Levels in Paricalcitol-Treated Secondary Hyperparathyroid Hemodialysis Patients
Nutrients 2016, 8(11), 708; https://doi.org/10.3390/nu8110708
Received: 12 August 2016 / Revised: 10 October 2016 / Accepted: 1 November 2016 / Published: 5 November 2016
Cited by 22 | PDF Full-text (1497 KB) | HTML Full-text | XML Full-text
Abstract
Background: Active Vitamin D analogues are used clinically for prevention and treatment of secondary hyperparathyroidism (SHPT) in hemodialysis (HD) patients. Nutritional vitamin D supplementation is used for additional local parathyroid (PTH) suppression, with lower incidence of hypercalcemia and hyperphosphatemia. This study evaluates the [...] Read more.
Background: Active Vitamin D analogues are used clinically for prevention and treatment of secondary hyperparathyroidism (SHPT) in hemodialysis (HD) patients. Nutritional vitamin D supplementation is used for additional local parathyroid (PTH) suppression, with lower incidence of hypercalcemia and hyperphosphatemia. This study evaluates the possible beneficial effects of combined vitamin D treatment (paricalcitol and cholecalciferol). Methods: Sixty HD patients with serum parathyroid hormone (iPTH) >300 pg/mL were enrolled. All patients administered 2 mcg/day of paricalcitol and were randomly allocated into control group (placebo) or study group (cholecalciferol) for 16 weeks. Serum 25(OH)D3, iPTH and human cathelicidin (hCAP-18) were measured at baseline and during follow-up. Results: iPTH levels decreased in the study group appropriately and were more significantly decreased at 16 weeks. Study group had significantly increased 25(OH)D3 levels. In addition, the study group had significantly increased serum hCAP-18 levels compared with control group. Correlation analysis showed a significant correlation between the percentage increase in serum hCAP-18 and 25(OH)D3 levels. Conclusions: Cholecalciferol, in combination with paricalcitol, additively lowers the iPTH levels in a significant number of patients after 16 weeks of supplementation. A dose of 5000 IU/week of cholecalciferol could maintain serum 25(OH)D3 levels above 30 ng/dL as early as 8 weeks after beginning supplementation. Doubling of serum cathelicidin levels were noted after 16 weeks of cholecalciferol supplementation in 40% of study patients. Full article
(This article belongs to the Special Issue Nutrition and Chronic Kidney Disease)
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Open AccessArticle
Changes in Body Composition in the Two Years after Initiation of Haemodialysis: A Retrospective Cohort Study
Nutrients 2016, 8(11), 702; https://doi.org/10.3390/nu8110702
Received: 31 August 2016 / Revised: 20 October 2016 / Accepted: 1 November 2016 / Published: 4 November 2016
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Abstract
Malnutrition is common in haemodialysis (HD) and is linked to poor outcomes. This study aimed to describe changes in body composition after the initiation of HD and investigate whether any routinely collected parameters were associated with these changes. The study cohort came from [...] Read more.
Malnutrition is common in haemodialysis (HD) and is linked to poor outcomes. This study aimed to describe changes in body composition after the initiation of HD and investigate whether any routinely collected parameters were associated with these changes. The study cohort came from the HD population of a single centre between 2009 and 2014. Body composition measurements were obtained from a database of bioimpedance results using the Body Composition Monitor (BCM), while demographics and laboratory values came from the renal unit database. Primary outcomes were changes in normohydration weight, lean tissue mass and adipose tissue mass over the two years after HD initiation. A total of 299 patients were included in the primary analyses, showing an increase in adipose tissue, loss of lean tissue and no significant change in normohydration weight. None of the routinely collected parameters were associated with the lean tissue changes. Loss of lean tissue over the first year of dialysis was associated with increased mortality. The results showing loss of lean tissue that is not limited to those traditionally assumed to be at high risk supports interventions to maintain or improve lean tissue as soon as possible after the initiation of HD. It highlights the importance of monitoring nutrition and the potential for routine use of bioimpedance. Full article
(This article belongs to the Special Issue Nutrition and Chronic Kidney Disease)
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Open AccessArticle
Association between Low Dietary Protein Intake and Geriatric Nutrition Risk Index in Patients with Chronic Kidney Disease: A Retrospective Single-Center Cohort Study
Nutrients 2016, 8(10), 662; https://doi.org/10.3390/nu8100662
Received: 31 August 2016 / Revised: 7 October 2016 / Accepted: 14 October 2016 / Published: 23 October 2016
Cited by 6 | PDF Full-text (2140 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Reduced dietary protein intake in malnourished patients with chronic kidney disease (CKD) may be associated with adverse clinical outcomes, which may mask any efficacy of a low-protein diet. The study included 126 patients with CKD who attended a dedicated dietary counseling clinic in [...] Read more.
Reduced dietary protein intake in malnourished patients with chronic kidney disease (CKD) may be associated with adverse clinical outcomes, which may mask any efficacy of a low-protein diet. The study included 126 patients with CKD who attended a dedicated dietary counseling clinic in 2005–2009 and were systematically followed until January 2015. Of these patients, 20 (15.9%) had moderate or severe nutrition-related risk of geriatric nutritional risk index (GNRI) < 92; these patients were more likely to be older, have a greater proteinuria, and have lower body mass index and serum albumin concentration. Dietary protein intake was significantly lower in older patients (r = −0.33, p < 0.001) and those with lower glomerular filtration rate (r = 0.47, p < 0.001). The non-protein to nitrogen calorie ratio was independently associated with GNRI. Reduced GNRI was significantly associated with mortality (hazard ratio (HR) = 4.94; 95% confidence interval (CI) = 1.61–15.42, p = 0.012) and cardiovascular events (HR = 9.37; 95% CI = 2.49–37.34, p = 0.006), but not with adverse renal outcomes. Restricting protein intake may be harmful to patients with any nutrition-related risk, suggesting that improvement of nutritional status should be a high priority. Full article
(This article belongs to the Special Issue Nutrition and Chronic Kidney Disease)
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Open AccessArticle
Low-Protein Diets in Diabetic Chronic Kidney Disease (CKD) Patients: Are They Feasible and Worth the Effort?
Nutrients 2016, 8(10), 649; https://doi.org/10.3390/nu8100649
Received: 7 August 2016 / Revised: 11 September 2016 / Accepted: 3 October 2016 / Published: 21 October 2016
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Abstract
Low-protein diets (LPDs) are often considered as contraindicated in diabetic patients, and are seldom studied. The aim of this observational study was to provide new data on this issue. It involved 149 diabetic and 300 non-diabetic patients who followed a LPD, with a [...] Read more.
Low-protein diets (LPDs) are often considered as contraindicated in diabetic patients, and are seldom studied. The aim of this observational study was to provide new data on this issue. It involved 149 diabetic and 300 non-diabetic patients who followed a LPD, with a personalized approach aimed at moderate protein restriction (0.6 g/day). Survival analysis was performed according to Kaplan–Meier, and multivariate analysis with Cox model. Diabetic versus non-diabetic patients were of similar age (median 70 years) and creatinine levels at the start of the diet (2.78 mg/dL vs. 2.80 mg/dL). There was higher prevalence of nephrotic proteinuria in diabetic patients (27.52% vs. 13.67%, p = 0.002) as well as comorbidity (median Charlson index 8 vs. 6 p = 0.002). Patient survival was lower in diabetic patients, but differences levelled off considering only cases with Charlson index > 7, the only relevant covariate in Cox analysis. Dialysis-free survival was superimposable in the setting of good compliance (Mitch formula: 0.47 g/kg/day in both groups): about 50% of the cases remained dialysis-free 2 years after the first finding of e-GFR (estimated glomerular filtration rate) < 15 mL/min, and 1 year after reaching e-GFR < 10 mL/min. In patients with type 2 diabetes, higher proteinuria was associated with mortality and initiation of dialysis. In conclusion, moderately restricted LPDs allow similar results in diabetic and non non-diabetic patients with similar comorbidity. Full article
(This article belongs to the Special Issue Nutrition and Chronic Kidney Disease)
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Open AccessArticle
High Prevalence of Hyperhomocysteinemia and Its Association with Target Organ Damage in Chinese Patients with Chronic Kidney Disease
Nutrients 2016, 8(10), 645; https://doi.org/10.3390/nu8100645
Received: 14 August 2016 / Revised: 27 September 2016 / Accepted: 3 October 2016 / Published: 20 October 2016
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Abstract
Hyperhomocysteinemia (HHcy) is recognized as a risk factor for cardiovascular disease. However, the prevalence of HHcy and its role in association with target organ damage in patients with chronickidney disease (CKD) are not well understood. This cross-sectional study included 1042 CKD patients who [...] Read more.
Hyperhomocysteinemia (HHcy) is recognized as a risk factor for cardiovascular disease. However, the prevalence of HHcy and its role in association with target organ damage in patients with chronickidney disease (CKD) are not well understood. This cross-sectional study included 1042 CKD patients who were admitted to our hospital. Patients were divided into two groups: hyperhomocysteinemia and normohomocysteinemia. Multivariable linear regression analyses were used to evaluate the association between plasma homocysteine and renal/cardiovascular parameters. The prevalence of HHcy in patients with CKD was 52.78%, and the prevalence in CKD stage 1, stage 2, stage 3, stage 4 and stage 5 patients was 10.73%, 29.22%, 58.71%, 75.23% and 83.75%, respectively. Patients with HHcy had higher incidences of renal damage, left ventricular hypertrophy, left ventricular diastolic dysfunction and abnormal carotid intima-media thickness compared with patients with normohomocysteinemia (p < 0.05), while multivariable linear regression analyses showed plasma homocysteine was only associated with the estimated glomerular filtration rate (eGFR). eGFR, uric acid, albumin, gender, hemoglobin and calcium×phosphate were associated with levels of plasma homocysteine in these CKD patients. The prevalence of HHcy in Chinese patients with CKD was high, and serum homocysteine levels were associated with impaired renal function in these patients. Full article
(This article belongs to the Special Issue Nutrition and Chronic Kidney Disease)
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Open AccessArticle
Paternal High Fat Diet in Rats Leads to Renal Accumulation of Lipid and Tubular Changes in Adult Offspring
Nutrients 2016, 8(9), 521; https://doi.org/10.3390/nu8090521
Received: 26 July 2016 / Revised: 16 August 2016 / Accepted: 17 August 2016 / Published: 23 August 2016
Cited by 9 | PDF Full-text (768 KB) | HTML Full-text | XML Full-text
Abstract
Along with diabetes and obesity, chronic kidney disease (CKD) is increasing across the globe. Although some data support an effect of maternal obesity on offspring kidney, the impact of paternal obesity is unknown; thus, we have studied the effect of paternal obesity prior [...] Read more.
Along with diabetes and obesity, chronic kidney disease (CKD) is increasing across the globe. Although some data support an effect of maternal obesity on offspring kidney, the impact of paternal obesity is unknown; thus, we have studied the effect of paternal obesity prior to conception. Male Sprague Dawley rats were fed chow diet or high fat diet (HFD) for 13–14 weeks before mating with chow-fed females. Male offspring were weaned onto chow and killed at 27 weeks for renal gene expression and histology. Fathers on HFD were 30% heavier than Controls at mating. At 27 weeks of age offspring of obese fathers weighed 10% less; kidney triglyceride content was significantly increased (5.35 ± 0.84 vs. 2.99 ± 0.47 μg/mg, p < 0.05, n = 8 litters per group. Histological analysis of the kidney demonstrated signs of tubule damage, with significantly greater loss of brush border, and increased cell sloughing in offspring of obese compared to Control fathers. Acat1, involved in entry of fatty acid for beta-oxidation, was significantly upregulated, possibly to counteract increased triglyceride storage. However other genes involved in lipid metabolism, inflammation and kidney injury showed no changes. Paternal obesity was associated with renal triglyceride accumulation and histological changes in tubules, suggesting a mild renal insult in offspring, who may be at risk of developing CKD. Full article
(This article belongs to the Special Issue Nutrition and Chronic Kidney Disease)
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Open AccessReview
Dietary Approaches in the Management of Diabetic Patients with Kidney Disease
Nutrients 2017, 9(8), 824; https://doi.org/10.3390/nu9080824
Received: 5 July 2017 / Revised: 22 July 2017 / Accepted: 25 July 2017 / Published: 31 July 2017
Cited by 8 | PDF Full-text (594 KB) | HTML Full-text | XML Full-text
Abstract
Chronic kidney disease (CKD) is one of the most prevalent complications of diabetes, and patients with diabetic kidney disease (DKD) have a substantially higher risk of cardiovascular disease and death compared to their non-diabetic CKD counterparts. In addition to pharmacologic management strategies, nutritional [...] Read more.
Chronic kidney disease (CKD) is one of the most prevalent complications of diabetes, and patients with diabetic kidney disease (DKD) have a substantially higher risk of cardiovascular disease and death compared to their non-diabetic CKD counterparts. In addition to pharmacologic management strategies, nutritional and dietary interventions in DKD are an essential aspect of management with the potential for ameliorating kidney function decline and preventing the development of other end-organ complications. Among DKD patients with non-dialysis dependent CKD, expert panels recommend lower dietary protein intake of 0.8 g/kg of body weight/day, while higher dietary protein intake (>1.2 g/kg of body weight/day) is advised among diabetic end-stage renal disease patients receiving maintenance dialysis to counteract protein catabolism, dialysate amino acid and protein losses, and protein-energy wasting. Carbohydrates from sugars should be limited to less than 10% of energy intake, and it is also suggested that higher polyunsaturated and monounsaturated fat consumption in lieu of saturated fatty acids, trans-fat, and cholesterol are associated with more favorable outcomes. While guidelines recommend dietary sodium restriction to less than 1.5–2.3 g/day, excessively low sodium intake may be associated with hyponatremia as well as impaired glucose metabolism and insulin sensitivity. As patients with advanced DKD progressing to end-stage renal disease may be prone to the “burnt-out diabetes” phenomenon (i.e., spontaneous resolution of hypoglycemia and frequent hypoglycemic episodes), further studies in this population are particularly needed to determine the safety and efficacy of dietary restrictions in this population. Full article
(This article belongs to the Special Issue Nutrition and Chronic Kidney Disease)
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Open AccessReview
Nutritional Vitamin D in Renal Transplant Patients: Speculations and Reality
Nutrients 2017, 9(6), 550; https://doi.org/10.3390/nu9060550
Received: 8 March 2017 / Revised: 15 May 2017 / Accepted: 22 May 2017 / Published: 27 May 2017
Cited by 5 | PDF Full-text (953 KB) | HTML Full-text | XML Full-text
Abstract
Reduced levels of nutritional vitamin D are commonly observed in most chronic kidney disease (CKD) patients and particularly in patients who have received a kidney transplant (KTx). In the complex clinical scenario characterizing the recipients of a renal graft, nutritional vitamin D deficiency [...] Read more.
Reduced levels of nutritional vitamin D are commonly observed in most chronic kidney disease (CKD) patients and particularly in patients who have received a kidney transplant (KTx). In the complex clinical scenario characterizing the recipients of a renal graft, nutritional vitamin D deficiency has been put in relation not only to the changes of mineral and bone metabolism (MBM) after KTx, but also to most of the medical complications which burden KTx patients. In fact, referring to its alleged pleiotropic (non-MBM related) activities, vitamin D has been claimed to play some role in the occurrence of cardiovascular, metabolic, immunologic, neoplastic and infectious complications commonly observed in KTx recipients. Furthermore, low nutritional vitamin D levels have also been connected with graft dysfunction occurrence and progression. In this review, we will discuss the purported and the demonstrated effects of native vitamin D deficiency/insufficiency in most of the above mentioned fields, dealing separately with the MBM-related and the pleiotropic effects. Full article
(This article belongs to the Special Issue Nutrition and Chronic Kidney Disease)
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Open AccessReview
Dialysis Procedures Alter Metabolic Conditions
Nutrients 2017, 9(6), 548; https://doi.org/10.3390/nu9060548
Received: 7 March 2017 / Revised: 25 April 2017 / Accepted: 23 May 2017 / Published: 27 May 2017
Cited by 4 | PDF Full-text (210 KB) | HTML Full-text | XML Full-text
Abstract
A progressive chronic kidney disease results in retention of various substances that more or less contribute to dysfunction of various metabolic systems. The accumulated substances are denominated uremic toxins. Although many toxins remain undetected, numerous newly defined toxins participate in the disturbance of [...] Read more.
A progressive chronic kidney disease results in retention of various substances that more or less contribute to dysfunction of various metabolic systems. The accumulated substances are denominated uremic toxins. Although many toxins remain undetected, numerous newly defined toxins participate in the disturbance of food breakdown. In addition, toxic effects may downregulate other pathways, resulting in a reduced ability of free fatty acid breakdown by lipoprotein lipase (LPL) and hepatic lipase (HL). Dialysis may even worsen metabolic functions. For LPL and HL, the use of heparin and low molecular weight heparin as anticoagulation during hemodialysis (HD) initiate a loss of these enzymes from their binding sites and degradation, causing a temporary dysregulation in triglyceride breakdown. This lack of function will cause retention of the triglyceride containing lipids for at least 8 h. In parallel, the breakdown into free fatty acids is limited, as is the energy supply by them. This is repeated thrice a week for a normal HD patient. In addition, dialysis will cause a loss of amino acids and disturb glucose metabolism depending on the dialysates used. The addition of glucose in the dialysate may support oxidation of carbohydrate and the retention of Amadori products and subsequent tissue alterations. To avoid these effects, it seems necessary to further study the effects of anticoagulation in HD, the extent of use of glucose in the dialysate, and the supplementation of amino acids. Full article
(This article belongs to the Special Issue Nutrition and Chronic Kidney Disease)
Open AccessReview
The Effect of Diet on the Survival of Patients with Chronic Kidney Disease
Nutrients 2017, 9(5), 495; https://doi.org/10.3390/nu9050495
Received: 28 February 2017 / Revised: 14 April 2017 / Accepted: 10 May 2017 / Published: 13 May 2017
Cited by 10 | PDF Full-text (282 KB) | HTML Full-text | XML Full-text
Abstract
The prevalence of chronic kidney disease (CKD) is high and it is gradually increasing. Individuals with CKD should introduce appropriate measures to hamper the progression of kidney function deterioration as well as prevent the development or progression of CKD-related diseases. A kidney-friendly diet [...] Read more.
The prevalence of chronic kidney disease (CKD) is high and it is gradually increasing. Individuals with CKD should introduce appropriate measures to hamper the progression of kidney function deterioration as well as prevent the development or progression of CKD-related diseases. A kidney-friendly diet may help to protect kidneys from further damage. Patients with kidney damage should limit the intake of certain foods to reduce the accumulation of unexcreted metabolic products and also to protect against hypertension, proteinuria and other heart and bone health problems. Despite the fact that the influence of certain types of nutrients has been widely studied in relation to kidney function and overall health in CKD patients, there are few studies on the impact of a specific diet on their survival. Animal studies demonstrated prolonged survival of rats with CKD fed with protein-restricted diets. In humans, the results of studies are conflicting. Some of them indicate slowing down of the progression of kidney disease and reduction in proteinuria, but other underline significant worsening of patients’ nutritional state, which can be dangerous. A recent systemic study revealed that a healthy diet comprising many fruits and vegetables, fish, legumes, whole grains, and fibers and also the cutting down on red meat, sodium, and refined sugar intake was associated with lower mortality in people with kidney disease. The aim of this paper is to review the results of studies concerning the impact of diet on the survival of CKD patients. Full article
(This article belongs to the Special Issue Nutrition and Chronic Kidney Disease)
Open AccessReview
Nutrients Turned into Toxins: Microbiota Modulation of Nutrient Properties in Chronic Kidney Disease
Nutrients 2017, 9(5), 489; https://doi.org/10.3390/nu9050489
Received: 14 March 2017 / Revised: 22 April 2017 / Accepted: 9 May 2017 / Published: 12 May 2017
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Abstract
In chronic kidney disease (CKD), accumulation of uremic toxins is associated with an increased risk of death. Some uremic toxins are ingested with the diet, such as phosphate and star fruit-derived caramboxin. Others result from nutrient processing by gut microbiota, yielding precursors of [...] Read more.
In chronic kidney disease (CKD), accumulation of uremic toxins is associated with an increased risk of death. Some uremic toxins are ingested with the diet, such as phosphate and star fruit-derived caramboxin. Others result from nutrient processing by gut microbiota, yielding precursors of uremic toxins or uremic toxins themselves. These nutrients include l-carnitine, choline/phosphatidylcholine, tryptophan and tyrosine, which are also sold over-the-counter as nutritional supplements. Physicians and patients alike should be aware that, in CKD patients, the use of these supplements may lead to potentially toxic effects. Unfortunately, most patients with CKD are not aware of their condition. Some of the dietary components may modify the gut microbiota, increasing the number of bacteria that process them to yield uremic toxins, such as trimethylamine N-Oxide (TMAO), p-cresyl sulfate, indoxyl sulfate and indole-3 acetic acid. Circulating levels of nutrient-derived uremic toxins are associated to increased risk of death and cardiovascular disease and there is evidence that this association may be causal. Future developments may include maneuvers to modify gut processing or absorption of these nutrients or derivatives to improve CKD patient outcomes. Full article
(This article belongs to the Special Issue Nutrition and Chronic Kidney Disease)
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Open AccessReview
Vegetarian Diet in Chronic Kidney Disease—A Friend or Foe
Nutrients 2017, 9(4), 374; https://doi.org/10.3390/nu9040374
Received: 26 January 2017 / Revised: 10 March 2017 / Accepted: 5 April 2017 / Published: 10 April 2017
Cited by 11 | PDF Full-text (260 KB) | HTML Full-text | XML Full-text
Abstract
Healthy diet is highly important, especially in patients with chronic kidney disease (CKD). Proper nutrition provides the energy to perform everyday activities, prevents infection, builds muscle, and helps to prevent kidney disease from getting worse. However, what does a proper diet mean for [...] Read more.
Healthy diet is highly important, especially in patients with chronic kidney disease (CKD). Proper nutrition provides the energy to perform everyday activities, prevents infection, builds muscle, and helps to prevent kidney disease from getting worse. However, what does a proper diet mean for a CKD patient? Nutrition requirements differ depending on the level of kidney function and the presence of co-morbid conditions, including hypertension, diabetes, and cardiovascular disease. The diet of CKD patients should help to slow the rate of progression of kidney failure, reduce uremic toxicity, decrease proteinuria, maintain good nutritional status, and lower the risk of kidney disease-related secondary complications (cardiovascular disease, bone disease, and hypertension). It has been suggested that plant proteins may exert beneficial effects on blood pressure, proteinuria, and glomerular filtration rate, as well as results in milder renal tissue damage when compared to animal proteins. The National Kidney Foundation recommends vegetarianism, or part-time vegetarian diet as being beneficial to CKD patients. Their recommendations are supported by the results of studies demonstrating that a plant-based diet may hamper the development or progression of some complications of chronic kidney disease, such as heart disease, protein loss in urine, and the progression of kidney damage. However, there are sparse reports suggesting that a vegan diet is not appropriate for CKD patients and those undergoing dialysis due to the difficulty in consuming enough protein and in maintaining proper potassium and phosphorus levels. Therefore, this review will focus on the problem as to whether vegetarian diet and its modifications are suitable for chronic kidney disease patients. Full article
(This article belongs to the Special Issue Nutrition and Chronic Kidney Disease)
Open AccessReview
The Diet and Haemodialysis Dyad: Three Eras, Four Open Questions and Four Paradoxes. A Narrative Review, Towards a Personalized, Patient-Centered Approach
Nutrients 2017, 9(4), 372; https://doi.org/10.3390/nu9040372
Received: 4 February 2017 / Revised: 17 March 2017 / Accepted: 31 March 2017 / Published: 10 April 2017
Cited by 10 | PDF Full-text (2311 KB) | HTML Full-text | XML Full-text
Abstract
The history of dialysis and diet can be viewed as a series of battles waged against potential threats to patients’ lives. In the early years of dialysis, potassium was identified as “the killer”, and the lists patients were given of forbidden foods included [...] Read more.
The history of dialysis and diet can be viewed as a series of battles waged against potential threats to patients’ lives. In the early years of dialysis, potassium was identified as “the killer”, and the lists patients were given of forbidden foods included most plant-derived nourishment. As soon as dialysis became more efficient and survival increased, hyperphosphatemia, was identified as the enemy, generating an even longer list of banned aliments. Conversely, the “third era” finds us combating protein-energy wasting. This review discusses four questions and four paradoxes, regarding the diet-dialysis dyad: are the “magic numbers” of nutritional requirements (calories: 30–35 kcal/kg; proteins > 1.2 g/kg) still valid? Are the guidelines based on the metabolic needs of patients on “conventional” thrice-weekly bicarbonate dialysis applicable to different dialysis schedules, including daily dialysis or haemodiafiltration? The quantity of phosphate and potassium contained in processed and preserved foods may be significantly different from those in untreated foods: what are we eating? Is malnutrition one condition or a combination of conditions? The paradoxes: obesity is associated with higher survival in dialysis, losing weight is associated with mortality, but high BMI is a contraindication for kidney transplantation; it is difficult to limit phosphate intake when a patient is on a high-protein diet, such as the ones usually prescribed on dialysis; low serum albumin is associated with low dialysis efficiency and reduced survival, but on haemodiafiltration, high efficiency is coupled with albumin losses; banning plant derived food may limit consumption of “vascular healthy” food in a vulnerable population. Tailored approaches and agreed practices are needed so that we can identify attainable goals and pursue them in our fragile haemodialysis populations. Full article
(This article belongs to the Special Issue Nutrition and Chronic Kidney Disease)
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Open AccessReview
Dietary Metabolites and Chronic Kidney Disease
Nutrients 2017, 9(4), 358; https://doi.org/10.3390/nu9040358
Received: 23 February 2017 / Revised: 30 March 2017 / Accepted: 31 March 2017 / Published: 4 April 2017
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Abstract
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 [...] Read more.
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. Full article
(This article belongs to the Special Issue Nutrition and Chronic Kidney Disease)
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Open AccessReview
Vitamin D in Chronic Kidney Disease and Dialysis Patients
Nutrients 2017, 9(4), 328; https://doi.org/10.3390/nu9040328
Received: 2 February 2017 / Revised: 15 March 2017 / Accepted: 20 March 2017 / Published: 25 March 2017
Cited by 19 | PDF Full-text (260 KB) | HTML Full-text | XML Full-text
Abstract
Vitamin D deficiency (<20 ng/mL) and insufficiency (20–29 ng/mL) are common among patients with chronic kidney disease (CKD) or undergoing dialysis. In addition to nutritional and sunlight exposure deficits, factors that affect vitamin D deficiency include race, sex, age, obesity and impaired vitamin [...] Read more.
Vitamin D deficiency (<20 ng/mL) and insufficiency (20–29 ng/mL) are common among patients with chronic kidney disease (CKD) or undergoing dialysis. In addition to nutritional and sunlight exposure deficits, factors that affect vitamin D deficiency include race, sex, age, obesity and impaired vitamin D synthesis and metabolism. Serum 1,25(OH)2D levels also decrease progressively because of 25(OH)D deficiency, together with impaired availability of 25(OH)D by renal proximal tubular cells, high fibroblast growth factor (FGF)-23 and decreased functional renal tissue. As in the general population, this condition is associated with increased morbidity and poor outcomes. Together with the progressive decline of serum calcitriol, vitamin D deficiency leads to secondary hyperparathyroidism (SHPT) and its complications, tertiary hyperparathyroidism and hypercalcemia, which require surgical parathyroidectomy or calcimimetics. Kidney Disease Outcomes Quality Initiative (KDOQI) and Kidney Disease Improving Global Outcomes (KDIGO) experts have recognized that vitamin D insufficiency and deficiency should be avoided in CKD and dialysis patients by using supplementation to prevent SHPT. Many vitamin D supplementation regimens using either ergocalciferol or cholecalciferol daily, weekly or monthly have been reported. The benefit of native vitamin D supplementation remains debatable because observational studies suggest that vitamin D receptor activator (VDRA) use is associated with better outcomes and it is more efficient for decreasing the serum parathormone (PTH) levels. Vitamin D has pleiotropic effects on the immune, cardiovascular and neurological systems and on antineoplastic activity. Extra-renal organs possess the enzymatic capacity to convert 25(OH)D to 1,25(OH)2D. Despite many unanswered questions, much data support vitamin D use in renal patients. This article emphasizes the role of native vitamin D replacement during all-phases of CKD together with VDRA when SHPT persists. Full article
(This article belongs to the Special Issue Nutrition and Chronic Kidney Disease)
Open AccessReview
Vitamins and Microelement Bioavailability in Different Stages of Chronic Kidney Disease
Nutrients 2017, 9(3), 282; https://doi.org/10.3390/nu9030282
Received: 23 January 2017 / Revised: 8 March 2017 / Accepted: 10 March 2017 / Published: 15 March 2017
Cited by 7 | PDF Full-text (223 KB) | HTML Full-text | XML Full-text
Abstract
Chronic kidney disease (CKD) predisposes one to either deficiency or toxic excess of different micronutrients. The knowledge on micronutrients—specifically water-soluble vitamins and trace elements—in CKD is very limited. Consequently, current guidelines and recommendations are mostly based on expert opinions or poor-quality evidence. Abnormalities [...] Read more.
Chronic kidney disease (CKD) predisposes one to either deficiency or toxic excess of different micronutrients. The knowledge on micronutrients—specifically water-soluble vitamins and trace elements—in CKD is very limited. Consequently, current guidelines and recommendations are mostly based on expert opinions or poor-quality evidence. Abnormalities of micronutrient resources in CKD develop for several reasons. Dietary restrictions and anorexia lead to an insufficient micronutrient intake, while diuretics use and renal replacement therapy lead to their excessive losses. Absorption is unpredictable, and metabolism impaired. Better understanding of the micronutrient needs of CKD patients could have an impact on many complications linked to vitamin and trace element disorders, including high mortality, increased risk of atherosclerosis, inflammation, oxidative stress, anemia, polyneuropathy, encephalopathy, weakness and fragility, muscle cramps, bone disease, depression, or insomnia. Here, we summarize the up-to-date knowledge on micronutrient resources in different stages of CKD, and share our experience with the assessment of micronutrient status. Full article
(This article belongs to the Special Issue Nutrition and Chronic Kidney Disease)
Open AccessReview
Stirring the Pot: Can Dietary Modification Alleviate the Burden of CKD?
Nutrients 2017, 9(3), 265; https://doi.org/10.3390/nu9030265
Received: 23 January 2017 / Revised: 27 February 2017 / Accepted: 6 March 2017 / Published: 11 March 2017
Cited by 11 | PDF Full-text (895 KB) | HTML Full-text | XML Full-text
Abstract
Diet is one of the largest modifiable risk factors for chronic kidney disease (CKD)-related death and disability. CKD is largely a progressive disease; however, it is increasingly appreciated that hallmarks of chronic kidney disease such as albuminuria can regress over time. The factors [...] Read more.
Diet is one of the largest modifiable risk factors for chronic kidney disease (CKD)-related death and disability. CKD is largely a progressive disease; however, it is increasingly appreciated that hallmarks of chronic kidney disease such as albuminuria can regress over time. The factors driving albuminuria resolution remain elusive. Since albuminuria is a strong risk factor for GFR loss, modifiable lifestyle factors that lead to an improvement in albuminuria would likely reduce the burden of CKD in high-risk individuals, such as patients with diabetes. Dietary therapy such as protein and sodium restriction has historically been used in the management of CKD. Evidence is emerging to indicate that other nutrients may influence kidney health, either through metabolic or haemodynamic pathways or via the modification of gut homeostasis. This review focuses on the role of diet in the pathogenesis and progression of CKD and discusses the latest findings related to the mechanisms of diet-induced kidney disease. It is possible that optimizing diet quality or restricting dietary intake could be harnessed as an adjunct therapy for CKD prevention or progression in susceptible individuals, thereby reducing the burden of CKD. Full article
(This article belongs to the Special Issue Nutrition and Chronic Kidney Disease)
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Open AccessReview
Protein Nutrition and Malnutrition in CKD and ESRD
Nutrients 2017, 9(3), 208; https://doi.org/10.3390/nu9030208
Received: 14 December 2016 / Accepted: 23 February 2017 / Published: 27 February 2017
Cited by 19 | PDF Full-text (1155 KB) | HTML Full-text | XML Full-text
Abstract
Elevated protein catabolism and protein malnutrition are common in patients with chronic kidney disease (CKD) and end‐stage renal disease (ESRD). The underlying etiology includes, but is not limited to, metabolic acidosis intestinal dysbiosis; systemic inflammation with activation of complements, endothelin‐1 and renin‐angiotensin‐aldosterone (RAAS) [...] Read more.
Elevated protein catabolism and protein malnutrition are common in patients with chronic kidney disease (CKD) and end‐stage renal disease (ESRD). The underlying etiology includes, but is not limited to, metabolic acidosis intestinal dysbiosis; systemic inflammation with activation of complements, endothelin‐1 and renin‐angiotensin‐aldosterone (RAAS) axis; anabolic hormone resistance; energy expenditure elevation; and uremic toxin accumulation. All of these derangements can further worsen kidney function, leading to poor patient outcomes. Many of these CKD‐related derangements can be prevented and substantially reversed, representing an area of great potential to improve CKD and ESRD care. This review integrates known information and recent advances in the area of protein nutrition and malnutrition in CKD and ESRD. Management recommendations are summarized. Thorough understanding the pathogenesis and etiology of protein malnutrition in CKD and ESRD patients will undoubtedly facilitate the design and development of more effective strategies to optimize protein nutrition and improve outcomes. Full article
(This article belongs to the Special Issue Nutrition and Chronic Kidney Disease)
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Open AccessReview
Effects of Magnesium on the Phosphate Toxicity in Chronic Kidney Disease: Time for Intervention Studies
Nutrients 2017, 9(2), 112; https://doi.org/10.3390/nu9020112
Received: 11 December 2016 / Revised: 20 January 2017 / Accepted: 3 February 2017 / Published: 6 February 2017
Cited by 13 | PDF Full-text (481 KB) | HTML Full-text | XML Full-text
Abstract
Magnesium, an essential mineral for human health, plays a pivotal role in the cardiovascular system. Epidemiological studies in the general population have found an association between lower dietary magnesium intake and an elevated risk of cardiovascular events. In addition, magnesium supplementation was shown [...] Read more.
Magnesium, an essential mineral for human health, plays a pivotal role in the cardiovascular system. Epidemiological studies in the general population have found an association between lower dietary magnesium intake and an elevated risk of cardiovascular events. In addition, magnesium supplementation was shown to improve blood pressure control, insulin sensitivity, and endothelial function. The relationship between magnesium and cardiovascular prognosis among patients with chronic kidney disease (CKD) has been increasingly investigated as it is becoming evident that magnesium can inhibit vascular calcification, a prominent risk of cardiovascular events, which commonly occurs in CKD patients. Cohort studies in patients receiving dialysis have shown a lower serum magnesium level as a significant risk for cardiovascular mortality. Interestingly, the cardiovascular mortality risk associated with hyperphosphatemia is alleviated among those with high serum magnesium levels, consistent with in vitro evidence that magnesium inhibits high-phosphate induced calcification of vascular smooth muscle cells. Furthermore, a harmful effect of high phosphate on the progression of CKD is also attenuated among those with high serum magnesium levels. The potential usefulness of magnesium as a remedy for phosphate toxicity should be further explored by future intervention studies. Full article
(This article belongs to the Special Issue Nutrition and Chronic Kidney Disease)
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Open AccessCase Report
Pregnancy, Proteinuria, Plant-Based Supplemented Diets and Focal Segmental Glomerulosclerosis: A Report on Three Cases and Critical Appraisal of the Literature
Nutrients 2017, 9(7), 770; https://doi.org/10.3390/nu9070770
Received: 19 February 2017 / Revised: 6 July 2017 / Accepted: 10 July 2017 / Published: 19 July 2017
Cited by 6 | PDF Full-text (5594 KB) | HTML Full-text | XML Full-text
Abstract
Chronic kidney disease (CKD) is increasingly recognized in pregnant patients. Three characteristics are associated with a risk of preterm delivery or small for gestational age babies; kidney function reduction, hypertension, and proteinuria. In pregnancy, the anti-proteinuric agents (ACE–angiotensin converting enzyme-inhibitors or ARBS -angiotensin [...] Read more.
Chronic kidney disease (CKD) is increasingly recognized in pregnant patients. Three characteristics are associated with a risk of preterm delivery or small for gestational age babies; kidney function reduction, hypertension, and proteinuria. In pregnancy, the anti-proteinuric agents (ACE–angiotensin converting enzyme-inhibitors or ARBS -angiotensin receptor blockers) have to be discontinued for their potential teratogenicity, and there is no validated approach to control proteinuria. Furthermore, proteinuria usually increases as an effect of therapeutic changes and pregnancy-induced hyperfiltration. Based on a favourable effect of low-protein diets on proteinuria and advanced CKD, our group developed a moderately protein-restricted vegan-vegetarian diet tsupplemented with ketoacids and aminoacids for pregnant patients. This report describes the results obtained in three pregnant patients with normal renal function, nephrotic or sub-nephrotic proteinuria, and biopsy proven diagnosis of focal segmental glomerulosclerosis, a renal lesion in which hyperfiltration is considered of pivotal importance (case 1: GFR (glomerular filtration rate): 103 mL/min; proteinuria 2.1 g/day; albumin 3.2 g/dL; case 2: GFR 86 mL/min, proteinuria 3.03 g/day, albumin 3.4 g/dL; case 3: GFR 142 mL/min, proteinuria 6.3 g/day, albumin 3.23 g/dL). The moderately restricted diet allowed a stabilisation of proteinuria in two cases and a decrease in one. No significant changes in serum creatinine and serum albumin were observed. The three babies were born at term (38 weeks + 3 days, female, weight 3180 g-62th centile; 38 weeks + 2 days, female, weight 3300 g-75th centile; male, 38 weeks + 1 day; 2770 g-8th centile), thus reassuring us of the safety of the diet. In summary, based on these three cases studies and a review of the literature, we suggest that a moderately protein-restricted, supplemented, plant-based diet might contribute to controlling proteinuria in pregnant CKD women with focal segmental glomerulosclerosis. However further studies are warranted to confirm the potential value of such a treatment strategy. Full article
(This article belongs to the Special Issue Nutrition and Chronic Kidney Disease)
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Open AccessConcept Paper
Eating Like a Rainbow: The Development of a Visual Aid for Nutritional Treatment of CKD Patients. A South African Project
Nutrients 2017, 9(5), 435; https://doi.org/10.3390/nu9050435
Received: 26 February 2017 / Revised: 11 April 2017 / Accepted: 17 April 2017 / Published: 28 April 2017
Cited by 3 | PDF Full-text (9341 KB) | HTML Full-text | XML Full-text
Abstract
Providing nutritional education for chronic kidney disease (CKD) patients in South Africa is complicated by several conditions: the population is composed of diverse ethnic groups, each with its own culture and food preferences; eleven languages are spoken and illiteracy is common in the [...] Read more.
Providing nutritional education for chronic kidney disease (CKD) patients in South Africa is complicated by several conditions: the population is composed of diverse ethnic groups, each with its own culture and food preferences; eleven languages are spoken and illiteracy is common in the lower socio-economic groups. Food preparation and storage are affected by the lack of electricity and refrigeration, and this contributes to a monotonous diet. In traditional African culture, two meals per day are often shared “from the pot”, making portion control difficult. There is both under- and over-nutrition; late referral of CKD is common. Good quality protein intake is often insufficient and there are several misconceptions about protein sources. There is a low intake of vegetables and fruit, while daily sodium intake is high, averaging 10 g/day, mostly from discretionary sources. On this background, we would like to describe the development of a simplified, visual approach to the “renal diet”, principally addressed to illiterate/non-English speaking CKD patients in Southern Africa, using illustrations to replace writing. This tool “Five steps to improve renal diet compliance”, also called “Eating like a Rainbow”, was developed to try to increase patients’ understanding, and has so far only been informally validated by feedback from users. The interest of this study is based on underlining the feasibility of dietary education even in difficult populations, focusing attention on this fundamental issue of CKD care in particular in countries with limited access to chronic dialysis. Full article
(This article belongs to the Special Issue Nutrition and Chronic Kidney Disease)
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Open AccessConcept Paper
Tradeoff-in-the-Nephron: A Theory to Explain the Primacy of Phosphate in the Pathogenesis of Secondary Hyperparathyroidism
Nutrients 2017, 9(5), 427; https://doi.org/10.3390/nu9050427
Received: 27 February 2017 / Revised: 10 April 2017 / Accepted: 17 April 2017 / Published: 26 April 2017
Cited by 1 | PDF Full-text (670 KB) | HTML Full-text | XML Full-text
Abstract
Chronic kidney disease (CKD) causes secondary hyperparathyroidism (SHPT). The cardinal features of SHPT are persistence of normocalcemia as CKD progresses and dependence of the parathyroid hormone concentration ([PTH]) on phosphate influx (IP). The tradeoff-in-the-nephron hypothesis integrates these features. It states that [...] Read more.
Chronic kidney disease (CKD) causes secondary hyperparathyroidism (SHPT). The cardinal features of SHPT are persistence of normocalcemia as CKD progresses and dependence of the parathyroid hormone concentration ([PTH]) on phosphate influx (IP). The tradeoff-in-the-nephron hypothesis integrates these features. It states that as the glomerular filtration rate (GFR) falls, the phosphate concentration ([P]CDN) rises in the cortical distal nephron, the calcium concentration ([Ca]CDN) in that segment falls, and [PTH] rises to maintain normal calcium reabsorption per volume of filtrate (TRCa/GFR). In a clinical study, we set GFR equal to creatinine clearance (Ccr) and IP equal to the urinary excretion rate of phosphorus (EP). We employed EP/Ccr as a surrogate for [P]CDN. We showed that TRCa/Ccr was high in patients with primary hyperparathyroidism (PHPT) and normal in those with SHPT despite comparably increased [PTH] in each group. In subjects with SHPT, we examined regressions of [PTH] on EP/Ccr before and after treatment with sevelamer carbonate or a placebo. All regressions were significant, and ∆[PTH] correlated with ∆EP/Ccr in each treatment cohort. We concluded that [P]CDN determines [PTH] in CKD. This inference explains the cardinal features of SHPT, much of the evidence on which other pathogenic theories are based, and many ancillary observations. Full article
(This article belongs to the Special Issue Nutrition and Chronic Kidney Disease)
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