Effects of soy consumption on oxidative stress, blood homocysteine, coagulation factors, and phosphorus in peritoneal dialysis patients

Effect of Egg-White Protein Alone or Combined With Niacin on Nutritional Status, and Phosphorus Control in Maintenance Hemodialysis Patients: A Randomized Controlled Trial

OBJECTIVE

Niacin is reported to decrease phosphorus concentration in maintenance hemodialysis (MHD) patients. Egg white is one of the main substitutable proteins in MHD patients due to its low phosphorus content. Therefore, we aimed to evaluate the effects of combined egg white and niacin supplementation on dialysis patients' serum phosphorus and nutritional biomarkers.

DESIGN AND METHODS

In this randomized controlled clinical trial, 98 patients on MHD were randomly allocated to four groups for 8 weeks: 24 g egg white (n = 25), 600 g niacin daily (n = 24), egg white combined with niacin (n = 24), and control (n = 24). Calcium, phosphorus, fibroblast growth factor-23, and other nutritional markers were assessed.

RESULTS

There was a significant difference among the groups only in phosphorus at the end of the trial, which was significantly lower in the niacin group (4.38 + 0.812 mg/dL) than in both the egg white (5.07 + 0.49 mg/dL) and egg white with niacin supplementation (5.41 + 0.662 mg/dL) groups. In this regard, albumin increased in egg white and egg white with niacin supplementation, while albumin did not change significantly in the niacin group. Urea reduction ratio and Kt/V rose only in the egg-white group, while aspartate aminotransferase increased only in the niacin and control groups.

CONCLUSION

Niacin decreases serum phosphorus concentration more than egg-white protein or a combined intervention. Egg white protein supplementation has beneficial effects on some nutritional statuses other than phosphorus control without the side effects of niacin.

Chronic Kidney Disease Diets for Kidney Failure Prevention: Insights from the IL-11 Paradigm

Nearly every fifth adult in the United States and many older adults worldwide are affected by chronic kidney disease (CKD), which can progress to kidney failure requiring invasive kidney replacement therapy. In this review, we briefly examine the pathophysiology of CKD and discuss emerging mechanisms involving the physiological resolution of kidney injury by transforming growth factor beta 1 (TGFβ1) and interleukin-11 (IL-11), as well as the pathological consequences of IL-11 overproduction, which misguides repair processes, ultimately culminating in CKD. Taking these mechanisms into account, we offer an overview of the efficacy of plant-dominant dietary patterns in preventing and managing CKD, while also addressing their limitations in terms of restoring kidney function or preventing kidney failure. In conclusion, this paper outlines novel regeneration strategies aimed at developing a reno-regenerative diet to inhibit IL-11 and promote repair mechanisms in kidneys affected by CKD.

Effects of oral nutritional supplements on the nutritional status and inflammatory markers in patients on maintenance dialysis: a systematic review and meta-analysis of randomized clinical trials

Background and aims

Patients on hemodialysis (HD) or peritoneal dialysis (PD) often have insufficient energy and protein intake, resulting in poor nutritional status and adverse outcomes. Oral nutritional supplements (ONSs) are the most commonly used to increase such patients' energy and protein intakes.

Methods

In this systematic review and meta-analysis, we analyzed studies on nutritional status, inflammatory markers, and electrolyte levels in patients on dialysis receiving ONSs. We searched four electronic databases from inception until 31 December 2022, for randomized controlled trials comparing ONS treatment versus placebo or routine care.

Results

22 studies with 1185 patients on dialysis were included in our meta-analysis. Compared with the control group, the ONS group exhibited significantly increased serum albumin levels [1.26 g/l (95%CI, 0.50-2.02, P < 0.0001; I2 = 80.4%)], body mass indexes (BMIs) [0.30 kg/m2 (95%CI, 0.09-0.52, P = 0.005; I2 = 41.4%)], and handgrip strength (HGS) [0.96 kg (95%CI, 0.07-1.84, P = 0.034; I2 = 41.4%)] from baseline to the end of intervention. No significant differences were observed between the groups in lean body mass, phase angle, C-reactive protein, and serum phosphorus and potassium levels. In terms of improving albumin, the subgroup analyses show that ONS use seems to be more inclined to three variations: HD patients, short-term use, and non-intradialytic supplementation.

Conclusion

In conclusion, ONS use can improve the nutritional status of patients on dialysis in terms of their serum albumin, BMI, and HGS without significant effects on serum phosphorus, potassium, and C-reactive protein levels. However, it remains uncertain whether these results translate to improvement in clinically relevant outcomes. Large-scale high-quality studies are still required in this population.

The impact of protein source on serum potassium and phosphate levels in adults living with advanced kidney disease

BACKGROUND AND AIMS

Plant proteins may be restricted on low potassium/phosphorus diets. The primary objective was to investigate the impact of protein source on serum potassium and phosphate levels in adults with stage 4-5 chronic kidney disease (CKD), including hemodialysis (HD).

METHODS AND RESULTS

Using a cross-sectional design, 24-h recalls or food frequency questionnaires were used to assess dietary intake. Serum values were obtained from medical records. Quartiles (Q1-4) of plant:animal protein serving ratios was considered to investigate outcomes, with Q1 having high animal and low plant serving intake and those in Q4 having high plant and low animal servings. 216 participants were enrolled, 135 on HD and 81 stage 4/5 CKD. For both HD and CKD, there was no difference in either serum potassium or phosphate levels between those in Q4 consuming high plant:animal vs Q1 low plant:animal (for HD: potassium 4.6 mmol/L vs 4.6 mmol/L; phosphate 1.8 mmol/L vs 1.6 mmol/L, respectively; for CKD: potassium 4.7 mmol/L vs 4.6 mmol/L; phosphate 1.4 mmol/L vs 1.4 mmol/L; all p > 0.05). Those in Q4 consuming high plant:animal consumed 7.5 g (62%) more fibre than those in Q1 (low plant:animal). For diet quality, Q4 (high plant:animal) had a 12.8 point (24%) higher healthy eating index score than Q1 (low plant:animal). There was no relationship between plant:animal and serum albumin or hospital admissions (all p > 0.05).

CONCLUSIONS

Consumption of higher proportions of plant protein was not associated with higher serum potassium or phosphate levels but was associated with higher fibre and diet quality.

Review of Isoflavones and Their Potential Clinical Impacts on Cardiovascular and Bone Metabolism Markers in Peritoneal Dialysis Patients

Cardiovascular disease is the most important cause of mortality in patients with chronic kidney disease, including patients undergoing peritoneal dialysis. Oxidative stress, systemic and vascular inflammation, and lipid abnormalities are important causes of cardiovascular disease in these patients. Bone disorders are also a common complication in dialysis patients and can lead to bone fractures, decreased quality of life, vascular calcification, cardiovascular disease, and increased mortality. Studies in non-uremic populations have shown that soy isoflavones have beneficial effects on oxidative stress, inflammation, lipid abnormalities, and markers of bone metabolism; however, very few studies in this field have been conducted with peritoneal dialysis patients. This paper reviews the key data regarding the effects of soy isoflavones on cardiovascular disease and bone markers and discusses the role of this nutraceutical in preventing and managing the complications of peritoneal dialysis.

The Impact of Protein Type on Phosphorus Intake, Serum Phosphate Concentrations, and Nutrition Status in Adults with Chronic Kidney Disease: A Critical Review

Lower phosphorus intake to prevent hyperphosphatemia for those with chronic kidney disease (CKD) is often recommended. Plant proteins are frequently restricted for their high phosphorus content despite having lower bioavailability. To summarize the evidence on protein type and dietary phosphorus intake, serum phosphate concentrations, and nutritional adequacy in adults with CKD, a search in MEDLINE via Ovid was conducted. Citation lists were reviewed to identify any additional articles. Sixteen articles were included-7 intervention (n = 290) and 9 observational (n = 4933). All intervention trials reported high-plant-protein diets provided adequate protein and adhered to low phosphorus diet guidelines. All intervention trials reported higher plant-protein intake was associated with lower serum phosphate; however, only 2 achieved statistical significance. For observational studies, 2 reported that higher proportions of plant to animal protein resulted in lower phosphorus intake but equivalent serum phosphate concentrations. Two reported that plant protein and animal protein had equivalent correlation values to phosphorus intake and no correlation to serum phosphate concentrations. One trial reported lower total phosphorus and protein intake among those who consumed more plant proteins but did not examine serum concentrations. Four reported lower serum phosphate concentrations among those who consumed more plant proteins but did not report dietary phosphorus intake. Of the observational studies that reported on protein intake, all reported lower protein intake among those with higher versus lower plant-protein intake. BMI tended to be lower among those consuming more plant protein. There was not a consistent relation between protein type and albumin concentrations. Routine restriction of plant-protein foods to prevent hyperphosphatemia in CKD would likely benefit from re-evaluation, as evidence does not suggest that higher plant-protein intake leads to higher serum phosphate concentrations or worse nutritional status, although longer-duration intervention trials with larger sample sizes appear to be warranted.

The Effects of Medicinal Plants and Bioactive Natural Compounds on Homocysteine

Background: Among non-communicable diseases, cardiovascular diseases (CVDs) are the leading cause of mortality and morbidity in global communities. By 2030, CVD-related deaths are projected to reach a global rise of 25 million. Obesity, smoking, alcohol, hyperlipidemia, hypertension, and hyperhomocysteinemia are several known risk factors for CVDs. Elevated homocysteine is tightly related to CVDs through multiple mechanisms, including inflammation of the vascular endothelium. The strategies for appropriate management of CVDs are constantly evolving; medicinal plants have received remarkable attention in recent researches, since these natural products have promising effects on the prevention and treatment of various chronic diseases. The effects of nutraceuticals and herbal products on CVD/dyslipidemia have been previously studied. However, to our knowledge, the association between herbal bioactive compounds and homocysteine has not been reviewed in details. Thus, the main objective of this study is to review the efficacy of bioactive natural compounds on homocysteine levels according to clinical trials and animal studies. Results: Based on animal studies, black and green tea, cinnamon, resveratrol, curcumin, garlic extract, ginger, and soy significantly reduced the homocysteine levels. According to the clinical trials, curcumin and resveratrol showed favorable effects on serum homocysteine. In conclusion, this review highlighted the beneficial effects of medicinal plants as natural, inexpensive, and accessible agents on homocysteine levels based on animal studies. Nevertheless, the results of the clinical trials were not uniform, suggesting that more well-designed trials are warranted.

Revising Dietary Phosphorus Advice in Chronic Kidney Disease G3-5D

We summarize how practicing dietitians combined available evidence with clinical experience, to define revised dietary recommendations for phosphorus in chronic kidney disease G3-5D. As well as a review of the evidence base, 4 priority topics were reviewed. These were translated into 3 nutrient level recommendations: the introduction of some plant protein where phosphorus is largely bound by phytate; consideration of protein intake in terms of phosphorus load and the phosphorus to protein ratio; and an increased focus on avoiding phosphate additives. This review summarizes and interprets the available evidence in order to support the development of practical food-based advice for patients with chronic kidney disease.

Effects of soy isoflavones on serum systemic and vascular inflammation markers and oxidative stress in peritoneal dialysis patients: A randomized controlled trial

Cardiovascular disease (CVD) is common in peritoneal dialysis (PD) patients. This study was designed to investigate the effects of isoflavones on systemic and vascular inflammation markers and oxidative stress in PD patients. In this randomized clinical trial, 40 PD patients were randomly assigned to either the isoflavone or the placebo group. The isoflavone group received 100 mg soy isoflavones daily for 8 weeks, whereas the placebo group received corresponding placebos. At baseline and the end of eighth week, serum high sensitive C-reactive protein (hs-CRP), intercellular adhesion molecule type 1 (ICAM-1), vascular cell adhesion molecule type 1 (VCAM-1), E-selectin, and malondialdehyde were measured. Serum VCAM-1 decreased significantly in the isoflavone group at the end of Week 8 compared to baseline (p = .01), whereas no significant change was observed in the placebo group. Serum ICAM-1 decreased significantly in the isoflavone (p = .01) and placebo (p = .01) group compared to baseline. However, the reduction of ICAM-1 was significantly higher in the isoflavone group than in the placebo group (p = .02). There were no significant differences between the two groups in mean changes of serum E-selectin, malondialdehyde, and hs-CRP. This study indicates that isoflavones reduce serum VCAM-1 and ICAM-1, which are two CVD risk factors, in PD patients.

Prevalence of dynapenic obesity and sarcopenic obesity and their associations with cardiovascular disease risk factors in peritoneal dialysis patients

Background

Dynapenic obesity and sarcopenic obesity increase cardiovascular disease (CVD) and mortality in nonuremic patients. The present study was designed to determine the prevalence of dynapenic obesity and sarcopenic obesity and their associations with CVD risk factors in peritoneal dialysis (PD) patients.

Methods

All eligible PD patients in Tehran peritoneal dialysis centers were included in this cross-sectional study. Skeletal muscle mass and fat mass were assessed using bioelectrical impedance analysis. Muscle strength and physical performance were determined using hand grip strength and a 4-meter walk gait speed test, respectively. In addition, a 5-mL blood sample was obtained from each patient.

Results

The prevalence of dynapenic obesity and sarcopenic obesity were 11.4% and 3.8% in PD patients, respectively. Serum high-sensitive C-reactive protein (hs-CRP), soluble intercellular adhesion molecule type 1, triglyceride, total cholesterol, and low-density lipoprotein cholesterol were significantly higher in PD patients with dynapenic obesity than in dynapenic nonobese and nondynapenic nonobese patients. Similarly, serum concentrations of CVD risk factors in PD patients with sarcopenic obesity were higher than in nonsarcopenic nonobese patients, but these differences were statistically significant only for serum hs-CRP and triglyceride. In addition, muscle strength and skeletal muscle mass percentage were negatively associated with markers of inflammation and dyslipidemia, whereas body fat percentage was positively associated with these CVD risk factors.

Conclusion

This study indicates that although the prevalence of dynapenic obesity and sarcopenic obesity are relatively low in PD patients, these disorders may be associated with CVD risk factors.

The effects of oral nutritional supplements in patients with maintenance dialysis therapy: A systematic review and meta-analysis of randomized clinical trials

Background/objective

This systematic review aims to determine the potential effects of oral nutritional supplements (ONS) in patients receiving maintenance dialysis therapy (MDT).

Methods

Electronic databases were searched without language limits through to July 2018. Randomized controlled trials (RCTs) that involved comparisons of ONS versus placebo or routine care are included in this meta-analysis. RevMan 5.3 statistical software was used for meta-analysis.

Results

15 articles with 589 subjects were included in our study. There are insufficient comparable data of randomized trials to allow meta-analysis of mortality. Albumin levels may be improved by the macronutrient blends or protein/amino acid supplements in MDT patients. Compared with the control group, serum albumin levels and BMI in the ONS group were increased by 1.58 g/L (95% CI, 0.52–2.63, P = 0.003; I² = 85%) and 0.40 kg/m² (95% CI, 0.10–0.71, P = 0.01; I² = 49%), respectively. In the subgroup analysis of patients receiving hemodialysis, albumin levels in ONS group were increased by 2.17 g/L (95% CI, 0.89–3.45, P<0.001; I² = 90%). ONS may not influence serum phosphorus and potassium levels.

Conclusions

Very low-quality evidence suggests that Short-term oral energy or protein/amino acid supplements may improve nutritional status by increasing serum albumin levels and BMI in MDT patients, without influence on serum potassium levels. High-quality and large RCTs, particularly regarding the effects of ONS on mortality and quality of life, are needed to further validate our findings.

Systemic Redox Imbalance in Chronic Kidney Disease: A Systematic Review

Patients with chronic kidney disease (CKD) experience imbalance between oxygen reactive species (ROS) production and antioxidant defenses leading to cell and tissue damage. However, it remains unclear at which stage of renal insufficiency the redox imbalance becomes more profound. The aim of this systematic review was to provide an update on recent advances in our understanding of how the redox status changes in the progression of renal disease from predialysis stages 1 to 4 to end stage 5 and whether the various treatments and dialysis modalities influence the redox balance. A systematic review was conducted searching PubMed and Scopus by using the Cochrane and PRISMA guidelines. In total, thirty-nine studies met the inclusion criteria and were reviewed. Even from an early stage, imbalance in redox status is evident and as the kidney function worsens it becomes more profound. Hemodialysis therapy per se seems to negatively influence the redox status by the elevation of lipid peroxidation markers, protein carbonylation, and impairing erythrocyte antioxidant defense. However, other dialysis modalities do not so far appear to confer advantages. Supplementation with antioxidants might assist and should be considered as an early intervention to halt premature atherogenesis development at an early stage of CKD.

Interventions for lowering plasma homocysteine levels in dialysis patients

BACKGROUND

People with end-stage kidney disease (ESKD) have high rates of cardiovascular events. Randomised controlled trials (RCTs) of homocysteine-lowering therapies have not shown reductions in cardiovascular event rates in the general population. However, people with kidney disease have higher levels of homocysteine and may have different mechanisms of cardiovascular disease. We performed a systematic review of the effect of homocysteine-lowering therapies in people with ESKD.

OBJECTIVES

To evaluate the benefits and harms of established homocysteine lowering therapy (folic acid, vitamin B6, vitamin B12) on all-cause mortality and cardiovascular event rates in patients with ESKD.

SEARCH METHODS

We searched Cochrane Kidney and Transplant's Specialised Register to 25 January 2016 through contact with the Information Specialist using search terms relevant to this review.

SELECTION CRITERIA

Studies conducted in people with ESKD that reported at least 100 patient-years of follow-up and assessed the effect of therapies that are known to have homocysteine-lowering properties were included.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data using a standardised form. The primary outcome was cardiovascular mortality. Secondary outcomes included all-cause mortality, incident cardiovascular disease (fatal and nonfatal myocardial infarction and coronary revascularisation), cerebrovascular disease (stroke and cerebrovascular revascularisation), peripheral vascular disease (lower limb amputation), venous thromboembolic disease (deep vein thrombosis and pulmonary embolism), thrombosis of dialysis access, and adverse events. The effects of homocysteine-lowering therapies on outcomes were assessed with meta-analyses using random-effects models. Prespecified subgroup and sensitivity analyses were conducted.

MAIN RESULTS

We included six studies that reported data on 2452 participants with ESKD. Interventions investigated were folic acid with or without other vitamins (vitamin B6, vitamin B12). Participants' mean age was 48 to 65 years, and proportions of male participants ranged from 50% to 98%.Homocysteine-lowering therapy probably leads to little or no effect on cardiovascular mortality (4 studies, 1186 participants: RR 0.93, 95% CI 0.70 to 1.22). There was no evidence of heterogeneity among the included studies (I² = 0%). Homocysteine-lowering therapy had little or no effect on all-cause mortality or any other of this review's secondary outcomes. All prespecified subgroup and sensitivity analyses demonstrated little or no difference. Reported adverse events were mild and there was no increase in the incidence of adverse events from homocysteine-lowering therapies (3 studies, 1248 participants: RR 1.12, 95% CI 0.51 to 2.47; I(2) = 0%). Overall, studies were assessed as being at low risk of bias and there was no evidence of publication bias.

AUTHORS' CONCLUSIONS

Homocysteine-lowering therapies were not found to reduce mortality (cardiovascular and all-cause) or cardiovascular events among people with ESKD.

The effect of soy or isoflavones on homocysteine levels: a meta-analysis of randomised controlled trials

BACKGROUND

The present study aimed to evaluate the effect of soy or isoflavones on blood homocysteine levels via a systematic review and meta-analysis.

METHODS

Pubmed, Embase, Web of Science and the Cochrane Library (up to 16 December 2015) were used for the literature review. Only randomised controlled trials were included. The primary outcome was the standard mean difference (SMD) of blood homocysteine levels between the experimental and control groups.

RESULTS

Nineteen randomised controlled studies were included for qualitative analysis. Eighteen studies were included in the data synthesis. Soy or isoflavones were found to have no effect on homocysteine levels, with a SMD of -0.21 (95% confidence interval = -0.43 to 0.00, I² =67.7%, random effect model). No publication bias was found among those studies (P = 0.296 for Egger's test, and P = 0.198 for Begg's test).

CONCLUSIONS

Soy or isoflavones were not found to be associated with a reduction in homocysteine levels. Further studies might still be needed in carefully selected populations.

Soy-based renoprotection

Chronic kidney disease (CKD) is a significant public health problem as risk factors such as advanced age, obesity, hypertension and diabetes rise in the global population. Currently there are no effective pharmacologic treatments for this disease. The role of diet is important for slowing the progression of CKD and managing symptoms in later stages of renal insufficiency. While low protein diets are generally recommended, maintaining adequate levels of intake is critical for health. There is an increasing appreciation that the source of protein may also be important. Soybean protein has been the most extensively studied plant-based protein in subjects with kidney disease and has demonstrated renal protective properties in a number of clinical studies. Soy protein consumption has been shown to slow the decline in estimated glomerular filtration rate and significantly improve proteinuria in diabetic and non-diabetic patients with nephropathy. Soy’s beneficial effects on renal function may also result from its impact on certain physiological risk factors for CKD such as dyslipidemia, hypertension and hyperglycemia. Soy intake is also associated with improvements in antioxidant status and systemic inflammation in early and late stage CKD patients. Studies conducted in animal models have helped to identify the underlying molecular mechanisms that may play a role in the positive effects of soy protein on renal parameters in polycystic kidney disease, metabolically-induced kidney dysfunction and age-associated progressive nephropathy. Despite the established relationship between soy and renoprotection, further studies are needed for a clear understanding of the role of the cellular and molecular target(s) of soy protein in maintaining renal function.

Soy milk consumption, inflammation, coagulation, and oxidative stress among type 2 diabetic patients with nephropathy

OBJECTIVE

To determine the effects of soy milk consumption compared with cow's milk on inflammation, coagulation, and oxidative stress among patients with diabetic nephropathy.

RESEARCH DESIGN AND METHODS

This randomized, crossover clinical trial was conducted on 25 type 2 diabetic patients with nephropathy. This study had two trial phases, each for 4 weeks and one washout period for 2 weeks. Patients were randomly assigned to consume a diet containing soy milk or a diet containing cow's milk.

RESULTS

Soy milk consumption resulted in a significant reduction in d-dimer level (percent change: -3.77 vs. 16.13%; P < 0.05). This significant effect remained even after adjusting for confounding factor (carbohydrate intake). However, soy milk consumption had no significant effects on tumor necrosis factor-α, interleukin-6, high-sensitivity C-reactive protein (hs-CRP), and malondialdehyde levels. The result was near to significance regarding the effect of soy milk consumption on hs-CRP (percent change: -35.45 vs. 36.76%; P = 0.05). However, this effect was not significant after adjusting for the confounding variable (carbohydrate intake).

CONCLUSIONS

Soy milk consumption could decrease serum d-dimer level among type 2 diabetic patients with nephropathy. However, markers of inflammation and oxidative stress did not change following soy milk intake among these patients.

The role of soy in vegetarian diets

Soyfoods have long been prized among vegetarians for both their high protein content and versatility. Soybeans differ markedly in macronutrient content from other legumes, being much higher in fat and protein, and lower in carbohydrate. In recent years however, soyfoods and specific soybean constituents, especially isoflavones, have been the subject of an impressive amount of research. Nearly 2,000 soy-related papers are published annually. This research has focused primarily on the benefits that soyfoods may provide independent of their nutrient content. There is particular interest in the role that soyfoods have in reducing risk of heart disease, osteoporosis and certain forms of cancer. However, the estrogen-like effects of isoflavones observed in animal studies have also raised concerns about potential harmful effects of soyfood consumption. This review addresses questions related to soy and chronic disease risk, provides recommendations for optimal intakes, and discusses potential contraindications. As reviewed, the evidence indicates that, with the exception of those individuals allergic to soy protein, soyfoods can play a beneficial role in the diets of vegetarians. Concerns about adverse effects are not supported by the clinical or epidemiologic literature. Based on the soy intake associated with health benefits in the epidemiologic studies and the benefits noted in clinical trials, optimal adult soy intake would appear to be between two and four servings per day.