Efficacy of low-protein diet for diabetic nephropathy: a systematic review of randomized controlled trials

The safety and efficacy of a protein-free diet with ketoacid analogues in chronic kidney disease-affected diabetic rats

Background

Diabetic nephropathy (DN) is a common vascular complication of diabetes Miletus (DM) that require weight control and dietary restrictions, especially for protein. A protein-restricted diet with ketoacid analogs (KA) reduces the intake of nitrogen while avoiding the harmful consequences of inadequate dietary protein intake.

Objective

This study aimed to investigate the efficacy and safety of a protein-free diet with ketoacid analogs in chronic kidney disease (CKD)-affected diabetic rats.

Material and methods

Sixty adult male albino rats were grouped into six equal groups (G): G (1) Control group, G (2) Normal rats. Received low protein diet, G (3) Diabetic control rats. Received standard diet, G (4) Diabetic rats. Received low protein diet for 12 weeks, G (5) Diabetic received α-keto amino acids (KAA) with a low protein diet and G (6) Diabetic received α-keto amino acids with protein-free diet. Blood sample was used to assess blood glucose (mg/dl), insulin (pmol/L), urea (mg/dl), creatinine (mg/dl), total cholesterol (TC) (mg/dl), LDL (mg/dl), HDL (mg/dl), triglycerides (TG) (mg/dl), and albumin (mg/dl) levels.

Results

A significant decrease in blood glucose, serum total cholesterol, LDL, triglycerides, serum urea and creatinine were observed while insulin level, albumin, glomerular filtration rate (GFR), urine volume and HDL were significantly increased in group six.

Conclusion

A protein-free diet containing KAA improves renal function, lowers blood glucose levels, maintains body weight, and does not worsen nutritional status in DN over time.

Effects of a Low-Protein Diet on Kidney Function in Patients With Chronic Kidney Disease: An Umbrella Review of Systematic Reviews and Meta-analyses of Randomized Controlled Trials

CONTEXT

Chronic kidney disease (CKD) stands out as one of the most widespread diseases globally. Dietary interventions, such as adopting a low-protein diet (LPD), play a crucial role as a key approach in impeding the advancement of CKD.

OBJECTIVE

The objective of this umbrella review was to provide understanding into the effects of an LPD on kidney function among individuals with CKD, along with evaluating the certainty of the available evidence.

DATA SOURCES

Searches for relevant studies were conducted without limitations through databases such as PubMed, Scopus, Web of Science, and Google Scholar, encompassing findings up to June 2023.

DATA EXTRACTION

The effect sizes for each meta-analysis were recalibrated using a random-effects model. The certainty of the evidence was evaluated using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach.

DATA ANALYSIS

Twenty-five meta-analyses including 47 randomized controlled trials were included in this study. Moderate certainty of the evidence suggests that LPDs may reduce glycated hemoglobin (HbA1c) and phosphorus levels, and the risk of progressing to end-stage renal disease in patients with CKD. Moreover, notable outcomes include increased glomerular filtration rate and decreased levels of serum albumin, blood urea nitrogen, and bicarbonate, although the certainty of evidence is low. In addition, LPDs can substantially decrease proteinuria, urine urea, and parathyroid hormone (PTH), although with very low certainty. The effects on serum creatinine, calcium, systolic blood pressure, and diastolic blood pressure are statistically nonsignificant, with the certainty of evidence ranging from low to moderate.

CONCLUSION

LPDs demonstrated beneficial effects on renal function in patients with CKD, which is supported by moderate to very low certainty evidence.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42023473647.

Common questions and misconceptions about protein supplementation: what does the scientific evidence really show?

Protein supplementation often refers to increasing the intake of this particular macronutrient through dietary supplements in the form of powders, ready-to-drink shakes, and bars. The primary purpose of protein supplementation is to augment dietary protein intake, aiding individuals in meeting their protein requirements, especially when it may be challenging to do so through regular food (i.e. chicken, beef, fish, pork, etc.) sources alone. A large body of evidence shows that protein has an important role in exercising and sedentary individuals. A PubMed search of "protein and exercise performance" reveals thousands of publications. Despite the considerable volume of evidence, it is somewhat surprising that several persistent questions and misconceptions about protein exist. The following are addressed: 1) Is protein harmful to your kidneys? 2) Does consuming "excess" protein increase fat mass? 3) Can dietary protein have a harmful effect on bone health? 4) Can vegans and vegetarians consume enough protein to support training adaptations? 5) Is cheese or peanut butter a good protein source? 6) Does consuming meat (i.e., animal protein) cause unfavorable health outcomes? 7) Do you need protein if you are not physically active? 8) Do you need to consume protein ≤ 1 hour following resistance training sessions to create an anabolic environment in skeletal muscle? 9) Do endurance athletes need additional protein? 10) Does one need protein supplements to meet the daily requirements of exercise-trained individuals? 11) Is there a limit to how much protein one can consume in a single meal? To address these questions, we have conducted a thorough scientific assessment of the literature concerning protein supplementation.

Effect of Low Protein Diet on Patients with Cardiovascular Disease: A Systematic Review and Meta-Analysis

Background

Low protein diet plays an important role in cardiovascular diseases. However, exact role is unclear so far. We aimed to find out the effect of low protein diet on patients with cardiovascular disease.

Methods

The PRISMA guidelines were followed throughout the research project until 10th Apr 2023. MeSH phrases and Boolean operators were used to search PubMed for suitable studies. The entire estimate was expressed as a 95% confidence interval around the mean difference. The model was picked because of the discrepancies found in the research. Choi's Q test and I2 statistics were used to determine the degree of variation between experiments. The funnel plot was used to qualitatively examine the publishing bias.

Results

Low-protein diets have a greater impact on waist circumference [-8.82 (-9.51, -8.13), P<0000.1] and high-density lipoprotein (HDL) [-0.05 (-0.07, -0.03), P<0000.1] alteration than non-LPD diets, as measured by the standard mean difference (SMD). Further, significant changes were observed in weight loss [1.51 (1.25, 1.77), P<0.00001], BMI, [0.46 (0.25, 0.67), P<0.0001], change systolic [2.48 (1.20, 3.77), P=0.0002] and diastolic blood pressure [1.49 (0.72, 2.26), P=0.0002], low density lipoprotein [0.09 (0.06, 0.12), P<0.00001], triglyceride [0.52 (0.49, 0.55), P<0.00001], in non-LPD group as compared to LPD group.

Conclusion

The results indicated the role of low protein diet on patients with cardiovascular disease.

Low-Protein Diets Could Be Effective and Safe in Elderly Patients with Advanced Diabetic Kidney Disease

Low-protein diets (LPDs) seem to improve metabolic complications of advanced CKD, thus postponing kidney replacement therapy (KRT) initiation. However, the nutritional safety of LPDs remains debatable in patients with diabetic kidney disease (DKD), especially in the elderly. This is a sub-analysis of a prospective unicentric interventional study which assessed the effects of LPD in patients with advanced DKD, focusing on the feasibility and safety of LPD in elderly patients. Ninety-two patients with DKD and stable CKD stage 4+, proteinuria >3 g/g creatininuria, good nutritional status, with confirmed compliance to protein restriction, were enrolled and received LPD (0.6 g mixed proteins/kg-day) supplemented with ketoanalogues of essential amino acids for 12 months. Of the total group, 42% were elderly with a median eGFR 12.6 mL/min and a median proteinuria 5.14 g/g creatininuria. In elderly patients, proteinuria decreased by 70% compared to baseline. The rate of kidney function decline was 0.1 versus 0.5 mL/min-month before enrolment. Vascular events occurred in 15% of cases, not related to nutritional intervention, but to the severity of CKD and higher MAP. LPDs seem to be safe and effective in postponing KRT in elderly patients with advanced DKD while preserving the nutritional status.

Chinese Guidelines for Medical Nutrition Therapy for Patients with Diabetes (2022 Edition)

Medical nutrition therapy (MNT) is the foundation of the comprehensive treatment of patients with diabetes. In 2010, the Chinese Clinical Nutritionist Center of the Chinese Medical Doctor Association developed the first Chinese guideline on MNT for patients with diabetes, and it was updated in 2015. Since then, new evidence has emerged in the field of MNT and metabolic therapy in patients with diabetes. The Nutrition and Metabolic Management Branch of the China International Exchange and Promotive Association for Medical and Health Care organized a team of experts from related institutions, including the Clinical Nutrition Branch of the Chinese Nutrition Society, Chinese Diabetes Society, Chinese Society for Parenteral and Enteral Nutri-tion, and Chinese Clinical Nutritionist Center of the Chinese Medical Doctor Association. Their task was to develop the Chinese Guidelines of Medical Nutrition Therapy in Diabetes (2022 Edition) in accordance with the requirements of the Guidelines for the Formulation/Revision of Clinical Guidelines in China (2022 Edition) by combining the questions raised and evidence gathered in clinical practices in China, to guide and standardize the clinical MNT.

Consumption of red, white, and processed meat and odds of developing kidney damage and diabetic nephropathy (DN) in women: a case control study

Diabetic nephropathy (DN) is one of the most prevalent and severe complications of diabetes mellitus (DM) and is associated with increased morbidity and mortality. We aimed to investigate the associations between red, processed, and white meat consumption and the odds of developing kidney damage and DN in women. We enrolled 105 eligible women with DN and 105 controls (30-65 years). A validated and reliable food frequency questionnaire (FFQ) was used to evaluate the consumption of red, processed, and white meat. Biochemical variables and anthropometric measurements were assessed for all patients using pre-defined protocols. Binary logistic regression was conducted to examine possible associations. The results of the present study showed that there was a direct significant association between high consumption of red meat and processed meats and odds of microalbuminuria (red meat 2.30, 95% CI 1.25, 4.22; P-value = 0.007, processed meat: OR 2.16, 95% CI 1.18, 3.95; P-value = 0.01), severe albuminuria (red meat OR 3.25, 95% CI 1.38, 7.46; P-value = 0.007, processed meat: OR 2.35, 95% CI 1.01, 5.49; P-value = 0.04), BUN levels (red meat: OR 2.56, 95% CI 1.10, 5.93; P-value = 0.02, processed meat: OR 2.42, 95% CI 1.04, 5.62; P-value = 0.03), and DN (red meat 2.53, 95% CI 1.45, 4.42; P-value = 0.001, processed meat: OR 2.21; 95% CI 1.27, 3.85; P-value = 0.005). In summary, our study suggests that higher consumption of red and processed meat sources may be associated with microalbuminuria, severe albuminuria, higher BUN level, and higher odds of DN.

Effects of dietary intervention on diabetic nephropathy: an umbrella review of systematic reviews and meta-analyses of randomized controlled trials

Objective

To evaluate the quality of evidence, potential biases, and validity of all available studies on dietary intervention and diabetic nephropathy (DN).

Methods

We conducted an umbrella review of existing meta-analyses of randomized controlled trials (RCTs) that focused on the effects of dietary intervention on DN incidence. The literature was searched via PubMed, Embase, Web of Science, and the Cochrane Database of Systematic Reviews. According to the Grading of Recommendations, Assessment, Development and Evaluation (GRADE), evidence of each outcome was evaluated and graded as "high", "moderate", "low" or "very low" quality to draw conclusions. Additionally, we classified evidence of outcomes into 4 categories.

Results

We identified 36 meta-analyses of RCTs and 55 clinical outcomes of DN from 395 unique articles. Moderate-quality evidence suggested that probiotic supplementation could significantly improve blood urea nitrogen (BUN), total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) levels in DN patients. Low-quality evidence indicated that probiotic supplementation significantly improved the serum creatinine concentration, urinary albumin-creatinine ratio (UACR), fasting blood glucose (FBG), HbA1c and high-density lipoprotein cholesterol (HDL-C) in DN patients. In addition, low-quality evidence suggested that a salt restriction diet could significantly improve the creatinine clearance rate (CrCl) in patients with DN. Low-quality evidence suggested that vitamin D supplementation could significantly improve the UACR in patients with DN. In addition, low-quality evidence has indicated that soy isoflavone supplementation could significantly improve BUN, FBG, total cholesterol (TC), triglyceride (TG) and LDL-C levels in patients with DN. Furthermore, low-quality evidence suggested that coenzyme Q10 supplementation could significantly improve HbA1c, TC and HDL-C in patients with DN, and dietary polyphenols also significantly improved HbA1c in patients with DN. Finally, low-quality evidence suggested that supplementation with antioxidant vitamins could significantly improve the serum creatinine concentration, systolic blood pressure, and HbA1c level in patients with DN. Given the small sample size, all significantly associated outcomes were evaluated as class IV evidence.

Conclusion

Moderate to low amounts of evidence suggest that supplementation with probiotics, vitamin D, soy isoflavones, coenzyme Q10, dietary polyphenols, antioxidant vitamins, or salt-restricted diets may significantly improve clinical outcomes in patients with DN.

Systematic Review Registration

https://www.crd.york.ac.uk/PROSPERO/, identifier CRD42024512670.

Does a Ketogenic Diet Have a Place Within Diabetes Clinical Practice? Review of Current Evidence and Controversies

Carbohydrate restriction has gained increasing popularity as an adjunctive nutritional therapy for diabetes management. However, controversy remains regarding the long-term suitability, safety, efficacy and potential superiority of a very low carbohydrate, ketogenic diet compared to current recommended nutritional approaches for diabetes management. Recommendations with respect to a ketogenic diet in clinical practice are often hindered by the lack of established definition, which prevents its capacity to be most appropriately prescribed as a therapeutic option for diabetes. Furthermore, with conflicted evidence, this has led to uncertainty amongst clinicians on how best to support and advise their patients. This review will explore whether a ketogenic diet has a place within clinical practice by reviewing current evidence and controversies.

The association between a low-carbohydrate diet score and the risk of diabetic nephropathy in women: A case-control study

OBJECTIVES

Because evidence linking carbohydrate consumption to diabetic nephropathy (DN) is scarce, and the association between a low-carbohydrate diet (LCD) and DN has not been investigated, we sought to investigate whether a higher LCD score is associated with DN among women.

METHODS

In a case-control study, 105 women with type 2 diabetes mellitus and DN and 105 controls with type 2 diabetes mellitus and without DN who attended Kowsar Diabetes Clinic in Semnan, Iran, were matched for age and diabetes duration. The data related to anthropometric and biochemical measures were collected and a food frequency questionnaire with 147 items was used to assess dietary intake. Based on the food frequency questionnaire, we calculated an LCD score for each study participant. Multivariate logistic regression was performed to examine the association between an LCD score and the odds of developing DN.

RESULTS

The results of the study demonstrated that the LCD score was not significantly associated with DN in the crude model (odds ratio = 0.39; 95% confidence interval, 0.14-1.07; P = 0.06). However, after adjusting for several confounders, subjects in the top quartile of the LCD score were associated with a 71% lower risk of DN (odds ratio [OR] = 0.29; 95% confidence interval, 0.10-0.86; P = 0.02). A significant trend toward decreased urinary albumin excretion was found with an increase in the LCD score (P = 0.005).

CONCLUSIONS

A diet low in carbohydrates was inversely associated with risk of DN. Further observational studies, and preferably randomized controlled trials, are needed to confirm the present results.

Diabetic nephropathy: Focusing on pathological signals, clinical treatment, and dietary regulation

Diabetic nephropathy (DN) is one of the most severe complications of diabetes. However, due to its complex pathological mechanisms, no effective therapeutic methods (other than ACEIs and ARBs) have been applied, which have been used for many years in clinical practice. Recent studies have shown that emerging therapeutics, including novel target-based pharmacotherapy, cell therapies, and dietary regulation, are leading to new hopes for DN management. This review aims to shed new light on the treatment of DN by describing the important pathological mechanisms of DN and by analysing recent advances in clinical treatment, including drug therapy, cell therapy, and dietary regulation. In pathological mechanisms, RAAS activation, AGE accumulation, and EMT are involved in inflammation, cellular stress, apoptosis, pyroptosis, and autophagy. In pharmacotherapy, several new therapeutics, including SGLT2 inhibitors, GLP-1 agonists, and MRAs, are receiving public attention. In addition, stem cell therapies and dietary regulation are also being emphasized. Herein, we highlight the importance of combining therapy and dietary regulation in the treatment of DN and anticipate more basic research or clinical trials to verify novel strategies.

Protein restriction for diabetic kidney disease

BACKGROUND

Diabetic kidney disease (DKD) continues to be the leading cause of kidney failure across the world. For decades dietary protein restriction has been proposed for patients with DKD with the aim to retard the progression of chronic kidney disease (CKD) towards kidney failure. However, the relative benefits and harms of dietary protein restriction for slowing the progression of DKD have not been addressed.

OBJECTIVES

To determine the efficacy and safety of low protein diets (LPD) (0.6 to 0.8 g/kg/day) in preventing the progression of CKD towards kidney failure and in reducing the incidence of kidney failure and death (any cause) in adult patients with DKD. Moreover, the effect of LPD on adverse events (e.g. malnutrition, hyperglycaemic events, or health-related quality of life (HRQoL)) and compliance were also evaluated.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Register of Studies up to 17 November 2022 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, EMBASE, conference proceedings, the International Clinical Trials Register (ICTRP) Search Portal and ClinicalTrials.gov.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) or quasi-RCTs in which adults with DKD not on dialysis were randomised to receive either a LPD (0.6 to 0.8 g/kg/day) or a usual or unrestricted protein diet (UPD) (≥ 1.0 g/kg/day) for at least 12 months.

DATA COLLECTION AND ANALYSIS

Two authors independently selected studies and extracted data. Summary estimates of effect were obtained using a random-effects model. Results were summarised as risk ratios (RR) with 95% confidence intervals (CI) for dichotomous outcomes and mean difference (MD) or standardised MD (SMD) with 95% CI for continuous outcomes. Confidence in the evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

MAIN RESULTS

We identified eight studies involving 486 participants with DKD. The prescribed protein intake in the intervention groups ranged from 0.6 to 0.8 g/kg/day. The prescribed protein intake in the control groups was ≥ 1.0 g/kg/day, or a calculated protein intake ≥ 1.0 g/kg/day if data on prescribed protein intake were not provided. The mean duration of the interventions was two years (ranging from one to five years). Risks of bias in most of the included studies were high or unclear, most notably for allocation concealment, performance and detection bias. All studies were considered to be at high risk for performance bias due to the nature of the interventions. Most studies were not designed to examine death or kidney failure. In low certainty evidence, a LPD may have little or no effect on death (5 studies, 358 participants: RR 0.38, 95% CI 0.10 to 1.44; I² = 0%), and the number of participants who reached kidney failure (4 studies, 287 participants: RR 1.16, 95% CI 0.38 to 3.59; I² = 0%). Compared to a usual or unrestricted protein intake, it remains uncertain whether a LPD slows the decline of glomerular filtration rate over time (7 studies, 367 participants: MD -0.73 mL/min/1.73 m²/year, 95% CI -2.3 to 0.83; I² = 53%; very low certainty evidence). It is also uncertain whether the restriction of dietary protein intake impacts on the annual decline in creatinine clearance (3 studies, 203 participants: MD -2.39 mL/min/year, 95% CI -5.87 to 1.08; I² = 53%). There was only one study reporting 24-hour urinary protein excretion. In very low certainty evidence, a LPD had uncertain effects on the annual change in proteinuria (1 study, 80 participants: MD 0.90 g/24 hours, 95% CI 0.49 to 1.31). There was no evidence of malnutrition in seven studies, while one study noted this condition in the LPD group. Participant compliance with a LPD was unsatisfactory in nearly half of the studies. One study reported LPD had no effect on HRQoL. No studies reported hyperglycaemic events.

AUTHORS' CONCLUSIONS

Dietary protein restriction has uncertain effects on changes in kidney function over time. However, it may make little difference to the risk of death and kidney failure. Questions remain about protein intake levels and compliance with protein-restricted diets. There are limited data on HRQoL and adverse effects such as nutritional measures and hyperglycaemic events. Large-scale pragmatic RCTs with sufficient follow-up are required for different stages of CKD.

Diet and Proteinuria: State of Art

Proteinuria is a broad term used to describe the pathological presence of proteins, including albumin, globulin, Bence-Jones protein, and mucoprotein in the urine. When persistent, proteinuria is a marker of kidney damage and represents a reliable predictor of the risk of progression of renal failure. Medical nutrition therapy is imperative for patients with proteinuria because it may slow the progression of renal disease. The aim of this review is to explore different nutritional approaches in the management of proteinuria and their influence on pathophysiological processes. As such, protein restriction is the main dietary intervention. Indeed, other management approaches are frequently used to reduce it regarding micro and macronutrients, but also the dietary style. Among these, the nutritional approach represents one of the most used and controversial interventions and the studies rarely take the form of randomized and controlled trials. With this work we aspire to analyze current clinical knowledge of how nutrition could influence proteinuria, potentially representing a useful tool in the management of proteinuric nephropathy.

Impact of low-protein diet on cardiovascular risk factors and kidney function in diabetic nephropathy: A systematic review and meta-analysis of randomized-controlled trials

AIM

To assess the efficacy of low-protein diets (LPD) on cardiovascular risk factors and kidney function in diabetic nephropathy (DN) based on randomized controlled trials (RCTs).

METHODS

A comprehensive systematic search was undertaken in PubMed/MEDLINE, Web of Science, SCOPUS and Embase databases from inception until January 2022 without using time or language restrictions. RCTs which reported the effects of LPD on cardiovascular risk factors and kidney function in DN were considered.

RESULTS

The results of the present study showed that a LPD significantly reduces urinary urea (WMD: -244.49 g/day, 95 % CI: -418.83, -70.16, P = 0.006) and HbA1c (WMD: -0.20, 95 % CI: -0.39, -0.01, P = 0.036) levels. However, the results did not show neither significant nor beneficial effect on other renal function and cardiovascular risk factors. Furthermore, the results of subgroup analysis showed LPD caused a further decrease in HbA1c during the follow-up period of ≤ 24 weeks, protein intake less than 0.8 g/kg/d and in individuals younger than 50 years. Albuminuria also showed a greater reduction in people under the age of 50 with type 1 diabetes (DMT1) following a LPD.

CONCLUSION

The results of the present study showed that LPD significantly reduces urinary urea and HbA1c.

Diabetic nephropathy ameliorated in patients with normal home blood pressure compared to those with isolated high home systolic blood pressure: A 5-year prospective cohort study among patients with type 2 diabetes mellitus

BACKGROUND

Using normal home blood pressure (home BP) as a reference, isolated high home systolic blood pressure (IH-home SBP) increases the risk of diabetic nephropathy. However, whether diabetic nephropathy would improve among diabetic patients without IH-home SBP has not been previously assessed.

METHODS

This prospective 5-year cohort study of 264 patients with moderate or severe albuminuria investigated the effect of IH-home SBP or normal home BP on the risk of diabetic nephropathy in patients with type 2 diabetes mellitus. Improvement of diabetic nephropathy was defined as remission or regression from moderate or severe albuminuria to normal or mildly increased albuminuria.

RESULTS

Improvement of diabetic nephropathy was shown in 59 out of 264 patients during 5 years. The adjusted odds ratio (95% confidence interval) of normal home BP for improving diabetic nephropathy was 2.52 (1.01-5.99, p = 0.05).

CONCLUSION

Normal home BP had relation to an improvement in diabetic nephropathy among type 2 diabetic patients with moderate and severe increased albuminuria in the observation period of 5 years. Good home BP control might be valuable to ameliorate diabetic nephropathy.

Beta vulgaris subsp. maritima: A Valuable Food with High Added Health Benefits

The present study was conducted to evaluate a natural extract, obtained from the Beta vulgaris plant, for its phytochemical composition and its beneficial health effects. Therefore, total phenolic and flavonoid contents, as well as identification and quantification of phenolic compounds by HPLC, were assessed in leaves’ extract. Moreover, antioxidant activities were investigated using free radical scavenging tests, (ABTS+ and DPPH+) and reducing power assay (FRAP) as well as ferrous ions’ (Fe2+) chelating activity. The Antiglycation effect was also evaluated, using the BSA-fructose model, and the antidiabetic effect was determined by inhibition of α-amylase and α-glucosidase enzymes. Additionally, the in vitro antitumor effect was quantified using the MTT assay, and the antibacterial activity was evaluated using the agar disc diffusion and broth microdilution methods. Both aqueous and methanolic extracts exhibited potential antioxidant capacity with a higher effect for the methanolic extract. Furthermore, the in vitro antitumor activity of the methanolic extracts exhibited potent cytotoxic effects against two breast cancer cell lines, MDA-MB-468 and MCF-7. Moreover, Beta vulgaris extracts inhibit not only α-amylase and α-glucosidase, but also advanced glycation end-products’ (AGEs) formation, which would prevent diabetes’ complications. Beta vulgaris methanolic extract revealed also a high antibacterial effect against Proteus mirabilis and Bacillus subtilis. Taken together, these results revealed that Beta vulgaris leaves’ extracts constitute a valuable food and natural source of bioactive molecules that could be used for the development of new, natural drugs against cancer and diabetes.

New progress in drugs treatment of diabetic kidney disease

Diabetic kidney disease (DKD) is not only one of the main complications of diabetes, but also the leading cause of the end-stage renal disease (ESRD). The occurrence and development of DKD have always been a serious clinical problem that leads to the increase of morbidity and mortality and the severe damage to the quality of life of human beings. Controlling blood glucose, blood pressure, blood lipids, and improving lifestyle can help slow the progress of DKD. In recent years, with the extensive research on the pathological mechanism and molecular mechanism of DKD, there are more and more new drugs based on this, such as new hypoglycemic drugs sodium-glucose cotransporter 2 (SGLT2) inhibitors, glucagon-like peptide-1 (GLP-1) inhibitors, and dipeptidyl peptidase-4 (DPP-4) inhibitors with good efficacy in clinical treatment. Besides, there are some newly developed drugs, including protein kinase C (PKC) inhibitors, advanced glycation end product (AGE) inhibitors, aldosterone receptor inhibitors, endothelin receptor (ETR) inhibitors, transforming growth factor-β (TGF-β) inhibitors, Rho kinase (ROCK) inhibitors and so on, which show positive effects in animal or clinical trials and bring hope for the treatment of DKD. In this review, we sort out the progress in the treatment of DKD in recent years, the research status of some emerging drugs, and the potential drugs for the treatment of DKD in the future, hoping to provide some directions for clinical treatment of DKD.

Impact of Isolated High Home Systolic Blood Pressure and Diabetic Nephropathy in Patients with Type 2 Diabetes Mellitus: A 5-Year Prospective Cohort Study

Background: A previous 2-year cohort study has shown that isolated high home systolic blood pressure (IH-HSBP) may increase the risk of diabetic nephropathy, using normal HBP as a reference. However, this association has not been previously assessed in the medium to long term. Methods: This prospective 5-year cohort study of 424 patients, with normal or mildly increased albuminuria, investigated the effect of IH-HSBP on the risk of diabetic nephropathy in patients with type 2 diabetes mellitus. Diabetic nephropathy was defined as an advancement from normal or mildly increased albuminuira to moderate or severely increased albuminuria. Results: Among 424 patients, 75 developed diabetic nephropathy during the study period. The adjusted odds ratio for developing diabetic nephropathy given IH-HSBP was 2.39 (95% confidence interval, 1.15–4.96, p = 0.02). The odds ratio for developing nephropathy in patients with IH-HSBP younger than 65 years was higher than that in patients with IH-HSBP older than 65 years. Conclusion: IH-HSBP was associated with an increased risk of diabetic nephropathy among type 2 diabetes mellitus patients with normal or mildly increased albuminuria in the medium to long term. The results support and strengthen previous reports. These findings suggest that IH-HSBP might be a useful marker in disease prognostication.

Nutrition in Chronic Kidney Disease-The Role of Proteins and Specific Diets

Chronic kidney disease (CKD) is a global public health burden, needing comprehensive management for preventing and delaying the progression to advanced CKD. The role of nutritional therapy as a strategy to slow CKD progression and uremia has been recommended for more than a century. Although a consistent body of evidence suggest a benefit of protein restriction therapy, patients' adherence and compliance have to be considered when prescribing nutritional therapy in advanced CKD patients. Therefore, these prescriptions need to be individualized since some patients may prefer to enjoy their food without restriction, despite knowing the potential importance of dietary therapy in reducing uremic manifestations, maintaining protein-energy status.

LINC00667 Sponges miR-4319 to Promote the Development of Nasopharyngeal Carcinoma by Increasing FOXQ1 Expression

Accumulating evidence has indicated that lncRNAs regulate various biological and pathological processes in diverse malignant tumors. The roles of LINC00667 in cancer development have been explored in glioma, hepatocellular carcinoma and non-small cell lung cancer, but not in nasopharyngeal carcinoma (NPC). In the present study, we characterize the role and molecular mechanism of LINC00667 in NPC progression. It was found that LINC00667 was overexpressed in NPC cells compared to normal cells. Silencing LINC00667 suppressed the proliferation, migration, invasion and epithelial mesenchymal transition (EMT) in NPC cells. In addition, bioinformatics analysis revealed that LINC00667 acted as a ceRNA to absorb miR-4319. Further investigations illustrated that miR-4319 had low expression in NPC cells and functioned as a tumor suppressor in the progression of NPC. Mechanistic study identified forkhead box Q1 (FOXQ1) as a functional target of miR-4319. The effect of LINC00667 in NPC development was mediated by the miR-4319/FOXQ1 axis. Analysis on tumorxenograft mouse model demonstrated that knockdown of LINC00667 repressed NPC tumor growth in vivo and confirmed the in vitro results. Our present study suggested that LINC00667 promoted the malignant phenotypes of NPC cells by competitively binding to miR-4319 to up-regulate FOXQ1 expression. Our results reveled that LINC00667 could be a diagnostic and therapeutic target for NPC patients.

Association between Low Protein Intake and Mortality in Patients with Type 2 Diabetes

The aim of this study was to investigate the association between protein intake and mortality risk in patients with type 2 diabetes. We analyzed a pooled data of 2494 diabetic patients from two prospective longitudinal studies. Nutritional intake was assessed using a Food Frequency Questionnaire at baseline. Protein intake per body weight (kg) per day was categorized into quartile groups. Adjusted hazard ratios (HRs) and 95% confidence interval (CI) were calculated using Cox regression analysis. During the six-year follow-up, there were 152 incidents of all-cause mortality. The HR for mortality in the lowest quartile of protein intake per body weight compared with the highest quartile was 2.26 (95% CI: 1.34–3.82, p = 0.002) after adjustment for covariates. Subgroup analyses revealed significant associations between low protein intake and mortality in patients aged over 75 years or under 65 years. After further adjustment of the total energy intake, a significant association between protein intake and mortality remained in patients aged ≥ 75 years, whereas the association was attenuated in those aged < 65 years. Our results suggest that adequate protein intake is necessary in older diabetic patients over 75 years, whereas with diabetes, whereas whole optimal total energy intake is required in younger patients with type 2 diabetes.

Isolated high home systolic blood pressure in patients with type 2 diabetes is a prognostic factor for the development of diabetic nephropathy: KAMOGAWA-HBP study

BACKGROUND

Isolated high home systolic blood pressure (IH-HSBP) has been revealed to be correlated with cardiovascular disease and diabetic nephropathy, however, the prognostic significance of IH-HSBP with the development of diabetic nephropathy is unclear.

METHODS

In this prospective 2-year cohort study of 477 patients with normoalbuminuria, we investigated the effect of IH-HSBP on the development of diabetic nephropathy defined by diabetic nephropathy advanced from normoalbuminuira to micro or macroalbuminuria.

RESULTS

Among 477 patients, 67 patients showed the development of diabetic nephropathy. In the multivariate logistic regression analyses, IH-HSBP was prognostic factor for the development of nephropathy after adjusting for sex, age, duration of diabetes mellitus, body mass index, total cholesterol, hemoglobin A1c, creatinine, smoking habits and use of renin-angiotensin-aldosterone system inhibitors (odds ratio: 2.53, 95% confidence interval: 1.16-5.56, p = 0.020).

CONCLUSION

IH-HSBP in patients with type 2 diabetes with normoalbuminuria was prognostic factor for the development of diabetic nephropathy. We should pay more attention to IH-HSBP to prevent the development of diabetic nephropathy.

Effects of dietary protein intake on renal outcome and mortality in patients with advanced diabetic nephropathy

BACKGROUND

The difficulty of adhering to a low-protein diet is a serious limitation of randomized controlled trials aimed at validating the efficacy of this therapy. In this observational study of patients with diabetic nephropathy, we examined the association of dietary protein intake (DPI) with renal outcome and mortality, taking into account the nutritional status.

METHODS

We conducted a single-center historical cohort study of 449 adult Japanese patients with type 2 diabetes and the urinary albumin-to-creatinine ratio of ≥ 300 mg/g or estimated glomerular filtration rate of < 30 mL/min/1.73 m². DPI was estimated with a formula using nitrogen levels in spot urine and body mass index. Malnutrition was defined as the Geriatric Nutritional Risk Index of ≤ 98. The primary and secondary endpoints were renal replacement therapy (RRT) initiation and mortality before RRT initiation, respectively. The Fine and Gray subdistribution hazard model was used to determine the relative effects of DPI on the respective endpoint.

RESULTS

Decreased DPI was associated with lower incidence of RRT with an adjusted hazard ratio of 0.81 (95% confidence interval: 0.72-0.92, p < 0.001). The interaction between DPI and nutritional status with respect to mortality was significant (p interaction = 0.047). Decreased DPI was a risk factor for mortality in patients with malnutrition (p = 0.009) but not in those without malnutrition (p = 0.559).

CONCLUSIONS

In patients with type 2 diabetic nephropathy, lower DPI was associated with lower incidence of RRT initiation, suggesting beneficial effects of a low-protein diet on kidneys. Conversely, lower DPI might lead to increased mortality in patients with malnutrition.

Identification of key lncRNAs contributing to diabetic nephropathy by gene co-expression network analysis

LncRNA is reported to have important role in diabetic nephropathy (DN). Here, we aim to identify key lncRNAs of DN using bioinformatics and systems biological methods. Method: Five microarray data sets from Gene Expression Omnibus (GEO) database were included. Probe sets were re-annotated. In the training set, differential expressed genes (DEGs) were identified. Weighted gene co-expression network analysis (WGCNA) was constructed to screen diabetic-related hub genes and reveal their potential biological function. Two more human data sets and mouse data sets were used as validation sets. Results: A total of 424 DEGs, including 10 lncRNAs, were filtered in the training data set. WGCNA and enrichment analysis of hub genes showed that inflammation and metabolic disorders are prominent in DN. Three key lncRNAs (NR_130134.1, NR_029395.1 and NR_038335.1) were identified. These lncRNAs are also differently expressed in another two human data sets. Functional enrichment of the mouse data sets showed consistent changes with that in human, indicating similar changes in gene expression pattern of DN and confirmed confidence of our analysis. Human podocytes and mesangial cells were culture in vitro. QPCR and fluorescence in situ hybridization were taken out to validate the expression and relationship of key lncRNAs and their related mRNAs. Results were also consistent with our analysis. Conclusions: Inflammation and metabolic disorders are prominent in DN. We identify three lncRNAs that are involved in these processes possibly by interacting with co-expressed mRNAs.

The Effects of a High-Protein Diet on Bone Mineral Density in Exercise-Trained Women: A 1-Year Investigation

The effects of long-term high-protein consumption (i.e., >2.2 g/kg/day) are unclear as it relates to bone mineral content. Thus, the primary endpoint of this investigation was to determine if consuming a high-protein diet for one year affected various parameters of body composition in exercise-trained women. This investigation is a follow-up to a prior 6-month study. Subjects were instructed to consume a high-protein diet (>2.2 g/kg/day) for one year. Body composition was assessed via dual-energy X-ray absorptiometry (DXA). Subjects were instructed to keep a food diary (i.e., log their food ~three days per week for a year) via the mobile app MyFitnessPal^®. Furthermore, a subset of subjects had their blood analyzed (i.e., basic metabolic panel). Subjects consumed a high-protein diet for one year (mean ± SD: 2.3 ± 1.1 grams per kilogram body weight daily [g/kg/day]). There were no significant changes for any measure of body composition over the course of the year (i.e., body weight, fat mass, lean body mass, percent fat, whole body bone mineral content, whole body T-score, whole body bone mineral density, lumbar bone mineral content, lumbar bone mineral density and lumbar T-score). In addition, we found no adverse effects on kidney function. Based on this 1-year within-subjects investigation, it is evident that a diet high in protein has no adverse effects on bone mineral density or kidney function.

High-protein diets in trained individuals

The United States (US) recommended dietary allowance (RDA) for protein is 0.8 grams per kilogram body weight per day (g/kg/d). The International Society of Sports Nutrition (ISSN) recently recommended an intake of 1.4-2.0 g/kg/d whereas the United States and Canadian Dietetic Association typically recommend a lower range of 1.2 to 1.7 g/kg/d. It is clear that the US RDA for protein is grossly inadequate for exercising individuals; thus, athletes are typically advised to consume twice the RDA. This falls within the range commonly recommended by academic societies. The effect of protein consumption that exceeds these aforementioned guidelines is not entirely known. This review examines the current literature as it pertains to the influence of very high protein intakes in trained individuals (i.e., humans). It is the scientific opinion of the author that athletes should consume at least 2.2 g/kg/d of protein.