Alkaline Diet and Metabolic Acidosis: Practical Approaches to the Nutritional Management of Chronic Kidney Disease

Association between dietary protein intake and risk of chronic kidney disease: a systematic review and meta-analysis

Objective

There is suggestive data indicating a correlation among dietary protein intake and the progression of chronic kidney disease (CKD). Nonetheless, the exact associations between dietary protein intake and the incidence of CKD have remained uncertain. We performed the first meta-analysis to explore the correlation among total protein, plant protein, animal protein intake and CKD risk.

Methods

The study conformed the PRISMA statement guidelines. We comprehensively searched PubMed, Web of Science, and Embase until to December 2023. The retrieved studies underwent rigorous evaluation for eligibility, and relevant data were meticulously extracted. The Newcastle-Ottawa Scale (NOS) tool was applied to evaluate the risk of bias. Subsequently, relevant data were extracted and pooled to evaluate the relations among dietary protein intake and CKD incidence.

Results

Totally, 6,191 articles were identified, six studies were eligible. A total of 148,051 participants with 8,746 CKD cases were included. All studies had a low overall risk of bias. Higher total, plant and animal protein intake were all correlated with decreased CKD incidence, pooled risk ratios (RRs) and 95% confidence intervals (CIs) were as follows: (RR = 0.82, 95% CI = 0.71-0.94, p = 0.005; I2 = 38%, p = 0.17); (RR = 0.77, 95% CI = 0.61-0.97, p = 0.03; I2 = 77%, p = 0.001); (RR = 0.86, 95% CI = 0.76-0.97, p = 0.02; I2 = 0%, p = 0.59), respectively. For fish and seafood within animal protein: RR = 0.84, 95% CI = 0.74-0.94. Subgroup analysis showed that geographical region, sample size, follow-up time, not assessing protein by food frequency questionnaire, using %energy as the measurement index, not adjusting for several covariates may be the sources of heterogeneity for plant protein. A significant non-linear relation among plant protein and incident CKD was observed by dose-response analysis.

Conclusion

The data showed a lower CKD risk significantly associated higher-level dietary total, plant or animal protein (especially for fish and seafood) intake. Further prospective studies demonstrating the correlations of precise sources, intake and duration of dietary protein and incident CKD are warranted.

A Therapeutic Approach in the Management of Chronic Kidney Disease: Plant-Based Dietary Models and Associated Parameters

PURPOSE OF REVIEW

Chronic kidney disease is one of the leading causes of death worldwide today. Nutrition and nutrition-related factors have a very important role in both the prevention and management of the disease. Plant-based dietary practices are one of the promising approaches to chronic kidney disease. This review aims to examine the potential benefits and risks of plant-based diet models on symptoms and indices used in diet quality in chronic kidney disease.

RECENT FINDINGS

Recently, a growing body of evidence has shown that, unlike animal-based diets, diets rich in plant-based nutrients may play an active role in the incidence of chronic kidney disease in many ways and the management of common symptoms, such as metabolic acidosis, uremic toxicity, and hyperphosphatemia. Implementation of existing plant-based dietary patterns in patients with chronic kidney disease may increase the efficacy of the diet and improve patients' quality of life by expanding their food choices. While there are concerns about creatine deficiency, dietary adequacy, and accessibility regarding plant-based diets, available information is limited.

Relationship between dietary fiber and all-cause mortality, cardiovascular mortality, and cardiovascular disease in patients with chronic kidney disease: a systematic review and meta-analysis

BACKGROUND

The potential protective effects of dietary fiber against all-cause mortality, cardiovascular mortality, and cardiovascular disease in patients with chronic kidney disease have not been definitively established. To verify this relationship, a systematic review and a meta-analysis were undertaken.

METHODS

PubMed, The Cochrane Library, Web of Science, Embase, ProQuest, and CINAHL were used to systematically search for prospective cohort studies that investigate the association between dietary fiber and all-cause mortality, cardiovascular mortality, and cardiovascular disease in individuals with chronic kidney disease (CKD). This search was conducted up to and including March 2023.

RESULTS

The analysis included 10 cohort studies, with a total of 19,843 patients who were followed up for 1.5-10.1 y. The results indicated a significant negative correlation between dietary fiber and all-cause mortality among patients with CKD (HR 0.80, 95% CI 0.58-0.97, P < 0.001). Subgroup analysis further revealed that the study population and exposure factors were significantly associated with all-cause mortality (P < 0.001). Increased dietary fiber intake was associated with a reduced risk of cardiovascular mortality (HR 0.78; 95% CI 0.67-0.90) and a reduced incidence of cardiovascular disease (HR 0.87; 95% CI 0.80-0.95) among patients with CKD.

CONCLUSIONS

The pooled results of our meta-analysis indicated an inverse association between dietary fiber intake and all-cause mortality, cardiovascular mortality, and cardiovascular disease.

Association of Plant Protein Intake With Risk of Incident CKD: A UK Biobank Study

RATIONALE & OBJECTIVE

Data suggest that various dietary interventions slow kidney disease progression and improve clinical outcomes for those with chronic kidney disease (CKD). However, the association between plant protein intake and incident CKD has been uncertain.

STUDY DESIGN

Prospective cohort study.

SETTING & PARTICIPANTS

117,809 participants who completed at least 1 dietary questionnaire and had an estimated glomerular filtration rate (eGFR) ≥ 60mL/min/1.73m2, a urinary albumin-creatinine ratio (UACR)<30mg/g, and no history of CKD.

EXPOSURE

Daily plant protein intake in g/kg/day.

OUTCOME

Incident CKD based on the International Classification of Diseases, 10th Revision (ICD-10) or the Office of Population Censuses and Surveys Classification of Interventions and Procedures, version 4 (OPCS-4) codes.

ANALYTICAL APPROACH

A cause-specific proportional hazards analysis incorporating competing risks that treated death occurring before incident CKD as a competing event.

RESULTS

During a median follow-up period of 9.9 years, incident CKD occurred in 3,745 participants (3.2%; incidence rate, 3.2 per 1,000 person-years). In a multivariable model, the adjusted hazard ratio (AHR) for the second, third, and highest quartiles of plant protein intake was 0.90 (95% CI, 0.82-0.99), 0.83 (95% CI, 0.75-0.92), and 0.82 (95% CI, 0.73-0.93), respectively, compared with the lowest quartile. Modeled as a continuous variable, the AHR per 0.1g/kg/day plant protein intake increase was 0.96 (95% CI, 0.93-0.99). This beneficial association was also consistent in secondary analyses for which CKD was defined based on codes or 2 consecutive measures of eGFR<60mL/min/1.73m2 or UACR>30mg/g. Various sensitivity analyses demonstrated consistent findings.

LIMITATIONS

Potential incomplete dietary assessments; limited generalizability due to the characteristics of participants in the UK Biobank Study.

CONCLUSIONS

In this large, prospective cohort study, greater dietary plant protein intake was associated with a lower risk of incident CKD. Further interventional studies demonstrating the kidney-protective benefits of plant protein intake are warranted.

PLAIN-LANGUAGE SUMMARY

Plant-based diets confer various health benefits, including lowering the risk of cardiovascular disease and certain cancers. However, the relationship between plant protein intake and the risk of chronic kidney disease (CKD) remains unclear. Our study investigated the association between plant protein intake and the development of CKD. Using the UK Biobank Study data, we found that participants with a higher plant protein intake had a lower risk of developing CKD. Our finding suggests that a higher dietary intake of plant-based protein may be beneficial for kidney health and provides insight into dietary interventions to prevent CKD in primary care settings.

The 1995 potential renal acid load (PRAL) values may no longer adequately reflect the actual acid-base impact of certain foods: A hypothesis

Background: In 1995, Remer and Manz reported potential renal acid load (PRAL) values of various foods, quantifying their estimated impact on acid-base balance. Their estimation considered ionic dissociation, sulphur metabolism and intestinal absorption rates for several micronutrients and proteins. Notably, PRAL values are based on food content data from the early 1990s and may nowadays no longer adequately reflect accurate estimates. Some foods' macronutrient and mineral content has declined over the past three decades due to changes in soil mineral health. Aim: We hypothesize that the 1995 PRAL values no longer adequately reflect reliable estimates of the current acid-base impact of some foods. Methods: Based on specific examples, we argue that these values overestimate the alkalizing effects of various fruits and vegetables. Conclusion: Discussing evidence in favour of (and against) our hypothesis, we conclude that the 1995 PRAL estimates should nowadays rather be used as a relative guidance and reviewed carefully.

Reducing Dietary Acid With Fruit and Vegetables Versus Oral Alkali in People With Chronic Kidney Disease (ReDACKD): A Clinical Research Protocol

Background

Individuals with chronic kidney disease (CKD) can develop metabolic acidosis which, in turn, is associated with faster progression of CKD and an increased need for dialysis. Oral sodium bicarbonate (the current standard of care therapy for metabolic acidosis) is poorly tolerated leading to low adherence. Base-producing or alkalizing Fruit and vegetables have potential as an alternative treatment for metabolic acidosis as they have been shown to reduce acid load arising from the diet.

Objective

This trial will evaluate the feasibility of providing base-producing fruit and vegetables as a dietary treatment for metabolic acidosis, compared with oral sodium bicarbonate.

Design

A 2-arm, open-label, dual-center, randomized controlled feasibility trial.

Setting

Two Canadian sites: a nephrology clinic in Winnipeg, Manitoba, and a nephrology clinic in Halifax, Nova Scotia.

Participants

Adult participants with G3-G5 CKD and metabolic acidosis.

Measurements

Participants will undergo baseline measurements and attend 5 study visits over 12 months at which they will have a measurement of feasibility criteria as well as blood pressure, blood and urine biochemistry, 5-repetition chair stand test (STS5), and questionnaires to assess quality of life and symptoms. Furthermore, participants fill out Automated Self-Administered 24-hour recalls (ASA-24) in the beginning, middle, and end of trial.

Methods

A total of 40 eligible participants will be randomized 1:1 to either base-producing fruit and vegetables (experimental) group or sodium bicarbonate (control) group, beginning from a daily dose of 1500 mg.

Limitations

Using self-administered dietary assessments, lack of supervision over the consumption of study treatments and the possible disappointment of the control group for not receiving fruit and vegetables would be considered as limitations for this study. However, we are planning to undertake proper practices to overcome the possible limitations. These practices are discussed throughout the article in detail.

Conclusions

This study will generate data on base-producing fruit and vegetables consumption as a dietary treatment for metabolic acidosis in CKD. The data will be used to design a future multi-center trial looking at slowing CKD progression in people with metabolic acidosis.

Trial Registration

This study is registered on clinicaltrials.gov with the identifier NCT05113641.

Dietary acid load and its interaction with CETP TaqB1 polymorphisms on lipid profile among patients with Type 2 diabetes mellitus

OBJECTIVE

Gene-diet interaction plays a key role in the inter-individual differences in lipid abnormalities as a major risk factor for cardiovascular diseases (CVDs). Thus, we explored the interaction between CETP TaqB1 polymorphism with dietary acid load (DAL) on lipid profile among type 2 diabetes mellitus (T2DM).

METHOD

This cross-sectional study conducted on 220 Iranian patients with T2DM. Dietary acid load (PRAL and NEAP) was calculated via a validated food-frequency questionnaire (FFQ). The polymerase chain reaction (PCR) used for genotyping Taq1B polymorphism. Biochemical markers were measured by standard protocol. The interaction between CETP Taq1B polymorphism and DAL (PRAL and NEAP) on lipid profile was performed by a generalized linear regression model (GLM).

RESULTS

The overall prevalence of rs708272 genotypes was 8.6%, 72.7% and 18.6% for B1B1, B1B2 and B2B2 genotype respectively. This study showed that people with the B1B1 genotype had greater LDL, TC, LDL/HDL, and TG when they consumed diets that scored higher on the NEAP and PRAL indexes than those with the B1B2 and B2B2 genotypes. Besides, carriers of the B1B1 allele who were in the highest tertile of NEAP, had lower HDL (P Interaction < 0.05).

CONCLUSIONS

In summary, the lipid profile might be improved in B1B1 homozygotes by less adherence to DAL indexes, however, the findings should be validated in high-quality interventional studies.

The association of dietary acid load (DAL) with estimated skeletal muscle mass and bone mineral content: a cross-sectional study

BACKGROUND & AIMS

Dietary patterns that promote mild metabolic acidosis may have a negative effect on bone and muscle, and a high dietary acid load (DAL) may be detrimental to skeletal muscle mass and bone mineral content. However, the association between skeletal muscle mass and bone mineral content with dietary acid load has not been consistently reported in previous studies. The objective of the study was to evaluate the association of potential renal net acid load (PRAL) and net endogenous acid production (NEAP) with bone mineral content and skeletal muscle mass in pre-menopause women with overweight or obesity in Iran.

METHOD

Three hundred and ninety women with a body mass index (BMI) of 25 were included in this cross-sectional study. We used a validated 147-item semi-quantitative food frequency questionnaire (FFQ) for evaluating the dietary intake. Based on the dietary data, potential renal net acid load (PRAL) and net endogenous acid production (NEAP) were calculated. Muscle mass and bone mineral content were estimated by a bioelectrical impedance analyzer (BIA).

RESULTS

After controlling for potential confounders, we discovered a significant linear relationship between PRAL (β = -0.027, 95%CI = -0.049 to -0.004, P = 0.02) and NEAP (β = -0.05, 95%CI = -0.097 to -0.003, P = 0.03) and skeletal muscle mass index. However, there was no significant difference between SMM and BMC across PRAL and NEAP tertiles.

CONCLUSION

PRAL and NEAP were found to be inversely related to skeletal muscle mass index among overweight/obese women. Further research is required to establish whether this relationship is important for musculoskeletal health in these populations.

How Well Do Low-PRAL Diets Fare in Comparison to the 2020-2025 Dietary Guidelines for Americans?

The regular consumption of net acid-producing diets can produce "acid stress" detrimental to human health. Alkalizing diets characterized by a negative potential renal acid load (also called low-PRAL diets (LPD)) enjoy uninterrupted popularity. However, the nutritional adequacy of said diets has rarely been assessed in large populations. Using data from the National Health and Nutrition Examination Surveys, we estimated nutrient intake in individuals consuming an LPD and contrasted the results in an age- and sex-specific manner to individuals on an acidifying diet (high-PRAL diet, HPD). Both groups were compared with the daily nutritional goals (DNG) specified in the 2020-2025 Dietary Guidelines for Americans (DGA). Our analysis included 29,683 individuals, including 7234 participants on an LPD and 22,449 participants on an HPD. Individuals on an LPD numerically met more nutritional goals than individuals on an HPD, yet both failed to meet the goals for several nutrients of public health concern (vitamin D and calcium). As opposed to individuals on an HPD, LPD consumers met the DGA recommendations for saturated fat and potassium. Individuals on an LPD consumed significantly more fiber than individuals on an HPD, as well as yielded a more favorable potassium-to-sodium intake ratio.

Long-term dietary acid load is associated with depression in multiple sclerosis, but less evidence was found with fatigue and anxiety

BACKGROUND

Diet-dependent acid-base load has been associated with worsening in mental health, but to date no study has examined this in people with multiple sclerosis (PwMS). We examined the association between potential renal acid load (PRAL) and net endogenous acid production (NEAP) scores and depression, anxiety, and fatigue in PwMS.

METHODS

Participants with a first clinical diagnosis of CNS demyelination were followed prospectively as part of the AusLong Study (aged 18-59 years at cohort entry). At baseline, 5- and 10-year reviews, PRAL and NEAP scores were calculated using dietary intake in the preceding 12 months calculated from a food frequency questionnaire. At 5- and 10-year reviews, the Hospital Anxiety and Depression Scale was used to assess depression and anxiety, and the Fatigue Severity Scale assessed fatigue.

RESULTS

Higher PRAL and NEAP scores were associated with increased subsequent absolute value and change in HADS depression scores over five years' follow-up (e.g., highest vs lowest PRAL quartile, 5-year change in HADS-D score: β=+3.01, 95%CI= 1.54, 4.48, p<0.001). The level of depression at the 10-year review was determined by both the baseline dietary acid scores and baseline-5-year changes in dietary acid scores (e.g., PRAL change from baseline to 5-year review, 10-year review HADS-D score: β=+0.09, 95%CI= 0.03, 0.15, p<0.001, NEAP change from baseline to 5-year review, 10-year review HADS-D score: β=+0.07, 95%CI= 0.01, 0.14, p=0.03). Some associations were observed with anxiety and fatigue but were much weaker and less consistent.

CONCLUSION

Our findings indicate that a higher dietary acid load potentially has a long-term influence on the level of depression in PwMS. The evidence is less convincing for anxiety and fatigue.

Ultraprocessed food consumption and kidney function decline in a population-based cohort in the Netherlands

BACKGROUND

Ultraprocessing makes food products more convenient, appealing, and profitable. Recent studies show that high ultraprocessed food (UPF) intake is associated with cardiometabolic diseases.

OBJECTIVES

The aim of this study is to investigate the association between UPF consumption and risks of kidney function decline in the general population.

METHODS

In a prospective, general population-based Lifelines cohort from Northern Netherlands, 78,346 participants free of chronic kidney disease (CKD) at baseline responded to a 110-item FFQ. We used a multivariable regression analysis to study the associations of the proportion (in grams/day) of UPFs in the total diet with a composite kidney outcome [incident CKD or a ≥30% estimated glomerular filtration rate (eGFR) decline relative to baseline] and annual change in eGFR.

RESULTS

On average, 37.7% of total food intake came from UPFs. After 3.6 ± 0.9 years of follow-up, 2470 participants (3.2%) reached the composite kidney outcome. Participants in the highest quartile of UPF consumption were associated with a higher risk of the composite kidney outcome (OR, 1.27; 95% CI, 1.09-1.47; P = 0.003) compared with those in the lowest quartile, regardless of their macro- or micronutrient intake or diet quality. Participants in the highest quartile had a more rapid eGFR decline (β, -0.17; 95% CI, -0.23 to -0.11; P < 0.001) compared with those in the lowest quartile. Associations were generally consistent across different subgroups.

CONCLUSIONS

Higher UPF consumption was associated with a higher risk of a composite kidney outcome (incident CKD or ≥30% eGFR decline) and a more rapid eGFR decline in the general population, independent of confounders and other dietary indices.

Comparison of dietary acid load score between celiac patients and healthy population

Background and aims

In the present study, we assessed the dietary acid load in adult celiac patients and compared it with that of the healthy population to provide more specific dietary recommendations for celiac patients.

Methods

This study was a cross-sectional study that included 130 celiac patients and 462 Non-celiac participants. The 80-item semi-quantitative food frequency questionnaire was used to obtain dietary data. Based on the dietary data, the dietary acid load (DAL), Potential renal net acid load (PRAL), and net endogenous acid production (NEAP) were calculated.

Results

The mean PRAL value is negative in the celiac group but positive in the general population. There was a significant difference in the PRAL score between celiac patients and the general population (p < 0.001). The mean NEAP and DAL score were significantly lower in the celiac group compared with the healthy population (P < 0.001). There were no significant differences between gluten-free diet adherents and non-adherents regarding the PRAL, NEAP, and DAL values (P > 0.05).

Conclusion

We showed that the patients with celiac disease had a significantly less acidogenic diet compared with that of the general population. So, following dies low in gluten may be associated with less acid production spacially in populations at risk of acid/base imbalance.

Medical nutrition therapy using plant-focused low-protein meal plans for management of chronic kidney disease in diabetes

PURPOSE OF REVIEW

Nearly half of all Americans with chronic kidney disease (CKD) also have type-2-diabetes (T2D). Whereas traditional and emerging pharmacotherapies are increasingly frequently used for the management of CKD in diabetes (CKD/DM), the role of integrated or multimodal interventions including the potentially synergistic and additive effect of diet and lifestyle modifications in addition to pharmacotherapy has not been well examined, in sharp contrast to the well-known integrated approaches to heart disease.

RECENT FINDINGS

Low-carbohydrate low-fat diets are often recommended in T2D, whereas low-protein diets (LPD) are recommended by guidelines for nondiabetic CKD with increasing emphasis on plant-based protein sources. High-protein diets with greater animal protein lead to glomerular hyperfiltration, especially in patients with T2D, and faster decline in renal function. Guidelines provide differing recommendations regarding the amount (low vs high) and source (plant vs animal) of dietary protein intake (DPI) in CKD/DM. Some such as KDIGO recommend 0.8 g/kg/day based on insufficient evidence for DPI restriction in CKD/DM, whereas KDOQI and ISRNM recommend a DPI of 0.6 to <0.8 g/kg/day. A patient-centered plant-focused LPD for the nutritional management of CKD/DM (PLAFOND), a type of PLADO diet comprising DPI of 0.6 to <0.8 g/kg/day with >50% plant-based sources, high dietary fiber, low glycemic index, and 25-35 Cal/kg/day energy, can be implemented by renal dietitians under Medical Nutrition Therapy.

SUMMARY

Potential risks vs benefits of high vs low protein intake in CKD/DM is unknown, for which expert recommendations remain opinion based. Randomized controlled studies are needed to examine safety, acceptability and efficacy of PLAFOND.

Dietary Acid Load and Relationship with Albuminuria and Glomerular Filtration Rate in Individuals with Chronic Kidney Disease at Predialysis State

The Western diet, characterized by excessive consumption of animal protein and reduced intake of vegetables and fruits, is also rich in sulfur, chlorine, and organic acids, which are the main sources of dietary acid load. A relationship between dietary acid load, renal function, and progression of chronic kidney disease has been demonstrated. Dietary modifications seem to contribute to a reduction in dietary acid load, and are associated with improved outcomes in individuals with chronic kidney disease (CKD). The aim of this paper was to review the existing evidence concerning the association between dietary acid load and renal function in nondialyzed individuals with CKD. A systematic review was conducted by gathering articles in electronic databases (MEDLINE/PubMed, Scopus, and Web of Science) from January 2018 to May 2021. Dietary acid load and GFR and/or albuminuria were analyzed. A total of 1078 articles were extracted, of which 5 met the inclusion criteria. Only one study found no statistically significant associations between the study variables. The remaining showed a negative association between dietary acid load and renal function. This systematic review confirmed the existence of an association between dietary acid load and renal function, with a high dietary acid load contributing to a decreased renal function.

Nutritional Approaches for the Management of Metabolic Acidosis in Chronic Kidney Disease

Metabolic acidosis is a severe complication of chronic kidney disease (CKD) which is associated with nefarious impairments such as bone demineralization, muscle wasting, and hormonal alterations, for example, insulin resistance. Whilst it is possible to control this condition with alkali treatment, consisting in the oral administration of sodium citrate or sodium bicarbonate, this type of intervention is not free from side effects. On the contrary, opting for the implementation of a targeted dietetic-nutritional treatment for the control of CKD metabolic acidosis also comes with a range of additional benefits such as lipid profile control, increased vitamins, and antioxidants intake. In our review, we evaluated the main dietary-nutritional regimens useful to counteract metabolic acidosis, such as the Mediterranean diet, the alkaline diet, the low-protein diet, and the vegan low-protein diet, analyzing the potentialities and limits of every dietary-nutritional treatment. Literature data suggest that the Mediterranean and alkaline diets represent a valid nutritional approach in the prevention and correction of metabolic acidosis in CKD early stages, while the low-protein diet and the vegan low-protein diet are more effective in CKD advanced stages. In conclusion, we propose that tailored nutritional approaches should represent a valid therapeutic alternative to counteract metabolic acidosis.

A Narrative Review of Dietary Approaches for Kidney Transplant Patients

A healthy eating pattern has proven to lower the risk of metabolic and cardiovascular diseases. However, there are sparse dietary recommendations for kidney transplant recipients, and the ones available focus only on single nutrients intake, such as sodium, potassium, and proteins, and not on the overall eating pattern. Considering that individuals do not typically consume nutrients in isolation, but as part of a complete dietary pattern, it is challenging for the average transplanted patient to understand and implement specific dietary recommendations. Also, single-nutrient interventions demonstrate largely inconclusive effects, and it seems improbable that they could have a strong enough impact on transplant outcomes. Dietary trends such as plant-based diets, intermittent fasting, low-carb diet/keto-diet, and juicing, have gained major attention from the media. Herein, we review the potential risks and benefits of these diets in kidney transplant recipients and provide an updated dietary recommendation for this population with consideration of current nutritional trends. Overall, the Mediterranean and DASH diets have demonstrated to be the most beneficial dietary patterns to the post kidney transplant population by focusing on less meat and processed foods, while increasing the intake of fresh foods and plant-based choices. We believe that to maintain a healthy lifestyle posttransplant, patients should be educated about the scientific evidence of different diets and choose a dietary pattern that is sustainable long-term.

Plant-Dominant Low-Protein Diet for Conservative Management of Chronic Kidney Disease

Chronic kidney disease (CKD) affects >10% of the adult population. Each year, approximately 120,000 Americans develop end-stage kidney disease and initiate dialysis, which is costly and associated with functional impairments, worse health-related quality of life, and high early-mortality rates, exceeding 20% in the first year. Recent declarations by the World Kidney Day and the U.S. Government Executive Order seek to implement strategies that reduce the burden of kidney failure by slowing CKD progression and controlling uremia without dialysis. Pragmatic dietary interventions may have a role in improving CKD outcomes and preventing or delaying dialysis initiation. Evidence suggests that a patient-centered plant-dominant low-protein diet (PLADO) of 0.6–0.8 g/kg/day composed of >50% plant-based sources, administered by dietitians trained in non-dialysis CKD care, is promising and consistent with the precision nutrition. The scientific premise of the PLADO stems from the observations that high protein diets with high meat intake not only result in higher cardiovascular disease risk but also higher CKD incidence and faster CKD progression due to increased intraglomerular pressure and glomerular hyperfiltration. Meat intake increases production of nitrogenous end-products, worsens uremia, and may increase the risk of constipation with resulting hyperkalemia from the typical low fiber intake. A plant-dominant, fiber-rich, low-protein diet may lead to favorable alterations in the gut microbiome, which can modulate uremic toxin generation and slow CKD progression, along with reducing cardiovascular risk. PLADO is a heart-healthy, safe, flexible, and feasible diet that could be the centerpiece of a conservative and preservative CKD-management strategy that challenges the prevailing dialysis-centered paradigm.

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.

Design of polymer-based antimicrobial hydrogels through physico-chemical transition

The antimicrobial activity represents a cornerstone in the development of biomaterials: it is a leading request in many areas, including biology, medicine, environment and industry. Over the years, different polymeric scaffolds are proposed as solutions, based on the encapsulation of metal ions/particles, antibacterial agents or antibiotics. However, the compliance with the biocompatibility criteria and the concentration of the active principles to avoid under- and over-dosing are being debated. In this work, we propose the synthesis of a versatile hydrogel using branched polyacrylic acid (carbomer 974P) and aliphatic polyetherdiamine (elastamine®) through physico-chemical transition, able to show its ability to counteract the bacterial growth and infections thanks to the polymers used, that are not subjected to further chemical modifications. In particular, the antimicrobial activity is clearly demonstrated against Staphyloccoccus aureus and Candida albicans, two well-known opportunistic pathogens. Moreover, we discuss the hydrogel use as drug carrier to design a unique device able to combine the antibacterial/antimicrobial properties to the controlled drug delivery, as a promising tool for a wide range of biomedical applications.

[Dietary control of metabolic acidosis in chronic kidney disease]

Metabolic acidosis is a frequent complication of chronic kidney disease. Although it is known to appear at advanced stages, many studies suggest a state of "global protonic retention" starting at early stages of the disease, responsible of tissue damage, particularly musculoskeletal, alteration of protidic metabolism and endocrine disorders, promoting malnutrition and chronic inflammation, and finally increasing mortality. The majority of international recommandations suggest of supplementation by alkali, most of the time by sodium bicarbonate, to struggle against this complication. An interesting alternative to correct acidosis would consist on the modulation of the endogenous production of acid by playing with the alimentary incomes. In fact, it has been demonstrated that some different types of food produce or consume protons during their metabolism. Low protein diet and rich fresh fruits and vegetables diet would manage to correct at least as well as the supplementation by sodium bicarbonate the metabolic acidosis, and to struggle against its complications, noteworthy by slowing the decline of glomerular filtration rate by limiting the toxic adaptative fibrotic mechanisms, demonstrated by the decrease of urinary tubulo-interstitial suffering markers. Of the condition of being well led, those diets do not seem to expose patients to an over-risk of malnutrition or hyperkaliemia. They therefore appear to be an attractive alternative, efficiency and safe, to fight against chronic kidney disease metabolic acidosis and its complications.

Potassium-sparing effects of furosemide in mice on high-potassium diets

In individuals on a regular "Western" diet, furosemide induces a kaliuresis and reduction in plasma K concentration by inhibiting Na reabsorption in the thick ascending limb of Henle's loop, enhancing delivery of Na to the aldosterone-sensitive distal nephron. In the aldosterone-sensitive distal nephron, the increased Na delivery stimulates K wasting due to an exaggerated exchange of epithelial Na channel-mediated Na reabsorption of secreted K. The effects of furosemide are different in mice fed a high-K, alkaline (HK) diet: the large-conductance Ca-activated K (BK) channel, in conjunction with the BK β₄-subunit (BK-α/β₄), mediates K secretion from intercalated cells (IC) of the connecting tubule and collecting ducts. The urinary alkaline load is necessary for BK-α/β₄-mediated K secretion in HK diet-fed mice. However, furosemide acidifies the urine by increasing vacuolar ATPase expression and acid secretion from IC, thereby inhibiting BK-α/β₄-mediated K secretion and sparing K. In mice fed a low-Na, high-K (LNaHK) diet, furosemide causes a greater increase in plasma K concentration and reduction in K excretion than in HK diet-fed mice. Micropuncture of the early distal tubule of mice fed a LNaHK diet, but not a regular or a HK diet, reveals K secretion in the thick ascending limb of Henle's loop. The sites of action of K secretion in individuals consuming a high-K diet should be taken into account when diuretic agents known to waste K with low or moderate K intakes are prescribed.