Dietary patterns and chronic kidney disease outcomes: A systematic review

Is resveratrol really effective in kidney disease?: A different perspective than ever before

BACKGROUND

Chronic kidney disease (CKD) is a global health problem and it is stated that the use of resveratrol supplement contributes to the protection of kidney health. In this study, it was aimed to evaluate the effect of resveratrol supplementation on kidney function, inflammation and histopathological findings in rats with experimental adenine-induced kidney damage.

METHODS

Three different groups of 10 randomly selected rats were formed. The first group was the negative control group, the second group was the uremic control group (KDG), and the third group was the group in which uremia was created and resveratrol was applied (RG). Kidney damage was induced by administration of 200 mg/kg adenine. Resveratrol supplementation was administered at 20 mg/kg after kidney damage. Serum urea, creatinine, indoxyl sulfate (IS), p-cresol, glomerular filtration rate, C-reactive protein (CRP); interleukin (IL)-6 and tumor necrosis factor (TNF)-α gene expression levels and histopathological findings were evaluated.

RESULTS

It was determined that resveratrol supplement applied after the formation of connective tissue in renal failure didn't have an improvement effect on the urine amount, kidney function and inflammatory parameters and histopathological changes (p > 0.05). Just, the increase in the CRP value of KDG (p < 0.05) was not observed in RG.

CONCLUSION

The findings suggest that resveratrol administered after kidney damage with adenine has no effect on kidney disease.

Dietary inflammatory index and lower glomerular filtration rate in Mexican adults

We hypothesized that higher scores on the dietary inflammatory index (DII) would be associated with a lower glomerular filtration rate (GFR). This cross-sectional study included 2098 participants from Mexican Teachers Cohort Study, the Health Workers Cohort Study, and the Comitán Study belonging to the RenMex consortium. Energy-adjusted DII scores were estimated using a semi-quantitative food frequency questionnaire (FFQ). eGFR was estimated by the CKD Epidemiology Collaboration equation. Quantile regression models and ordered regression models were estimated to assess the associations of interest. Median age of study participants was 47 years, median eGFR was 102.9 mL/min/1.73m2, and the median energy-adjusted DII was 0.89 (range, -2.25, +4.86). The median eGFR was lower in participants in the highest percentile of DII compared to those in the lowest percentile (103.8 vs 101.4). We found that continuous and categorical energy-adjusted DII scores were associated with lower eGFR, especially at the lower percentiles. In adjusted ordered logistic regression, we found that the highest DII category was associated with 1.80 times the odds of belonging to the mildly decreased eGFR category or moderately decreased eGFR category compared lowest DII category (OR: 1.80, 95%CI 1.35, 2.40). A high DII score was associated with a lower eGFR among the Mexican population. Additional studies are crucial to validate these findings and explore potential strategies to reduce the consumption of pro-inflammatory foods as a preventive approach for chronic kidney disease (CKD).

Association of cardiovascular health metrics with all-cause and cardiovascular disease mortality in chronic kidney disease: A cohort study

BACKGROUND AND AIMS

Since the global burden of chronic kidney disease (CKD) is rising rapidly, the study aimed to assess the association of cardiovascular health (CVH) metrics with all-cause and cardiovascular disease (CVD) mortality among individuals with CKD.

METHODS AND RESULTS

The cohort study included 5834 participants with CKD from the National Health and Nutrition Examination Survey 1999-2018. A composite CVH score was calculated based on smoking status, physical activity, body mass index, blood pressure, total cholesterol, diet quality, and glucose control. Primary outcomes were all-cause and CVD mortality as of December 31, 2019. Multivariable-adjusted Cox proportional hazards models were used to estimate the association between CVH metrics and deaths in CKD patients. During a median follow-up of 7.2 years, 2178 all-cause deaths and 779 CVD deaths were documented. Compared to participants with ideal CVH, individuals with intermediate CVH exhibited a 46.0% increase in all-cause mortality (hazard ratio, 1.46; 95% confidence interval: 1.17, 1.83), while those with poor CVH demonstrated a 101.0% increase (2.01; 1.54, 2.62). For CVD mortality, individuals with intermediate CVH experienced a 56.0% increase (1.56; 1.02, 2.39), and those with poor CVH demonstrated a 143.0% increase (2.43; 1.51, 3.91). Linear trends were noted for the associations of CVH with both all-cause mortality (P for trend <0.001) and CVD mortality (P for trend = 0.02).

CONCLUSIONS

Lower CVH levels were associated with higher all-cause and CVD mortality in individuals with CKD, which highlights the importance of maintaining good CVH in CKD patients.

Food insecurity and kidney disease: a systematic review

BACKGROUND

The risk of developing and worsening chronic kidney disease (CKD) is associated with unhealthy dietary patterns. Food insecurity is defined by a limited or uncertain availability of nutritionally adequate and safe food; it is also associated with several chronic medical conditions. The aim of this systematic review is to investigate the current knowledge about the relationship between food insecurity and renal disease.

METHODS

We selected the pertinent publications by searching on the PubMed, Scopus, and the Web of Science databases, without any temporal limitations being imposed. The searching and selecting processes were carried out through pinpointed inclusion and exclusion criteria and in accordance with the Prisma statement.

RESULTS

Out of the 26,548 items that were first identified, only 9 studies were included in the systemic review. Eight out of the nine investigations were conducted in the US, and one was conducted in Iran. The studies evaluated the relationship between food insecurity and (i) kidney disease in children, (ii) kidney stones, (iii) CKD, (iv) cardiorenal syndrome, and (v) end stage renal disease (ESRD). In total, the different research groups enrolled 49,533 subjects, and food insecurity was reported to be a risk factor for hospitalization, kidney stones, CKD, ESRD, and mortality.

CONCLUSIONS

The relationship between food insecurity and renal disease has been underestimated. Food insecurity is a serious risk factor for health problems in both wealthy and poor populations; however, the true prevalence of the condition is unknown. Healthcare professionals need to take action to prevent the dramatic effect of food insecurity on CKD and on other chronic clinical conditions.

COVID-19 and Nutrition: Focus on Chronic Kidney Disease

Some chronic diseases, including chronic kidney disease (CKD), may be associated with poor outcomes, including a high rate of hospitalization and death after COVID-19 infection. In addition to the vaccination program, diet intervention is essential for boosting immunity and preventing complications. A healthy diet containing bioactive compounds may help mitigate inflammatory responses and oxidative stress caused by COVID-19. In this review, we discuss dietary interventions for mitigating COVID-19 complications, including in persons with CKD, which can worsen COVID-19 symptoms and its clinical outcomes, while diet may help patients with CKD to resist the ravages of COVID-19 by improving the immune system, modulating gut dysbiosis, mitigating COVID-19 complications, and reducing hospitalization and mortality. The concept of food as medicine, also known as culinary medicine, for patients with CKD can be extrapolated to COVID-19 infection because healthy foods and nutraceuticals have the potential to exert an important antiviral, anti-inflammatory, and antioxidant role.

Scientific evidence supporting the newly developed one-health labeling tool "Med-Index": an umbrella systematic review on health benefits of mediterranean diet principles and adherence in a planeterranean perspective

BACKGROUND

Med-Index is a one-health front-of-pack (FOP) label, based on Mediterranean diet (MedDiet) principles, developed to summarize information about the nutritional properties and related-health benefits of any food as well as its sustainable production processes, and the associated food company's social responsibility parameters in a new "Planeterranean" perspective. Thus, Med-Index can be adopted in and by any European region and authority as well as worldwide; this is achieved by consumption and cooking of locally available and sourced foods that respect MedDiet principles, both in terms of healthy nutrition and sustainable production. The huge body of scientific evidence about the health benefits of the MedDiet model and principles requires a comprehensive framework to encompass the scientific reliability and robustness of this tool. A systematic review was carried out to examine the association between human health and adherence to MedDiet patterns upon which the "Med-Index" tool was subsequently developed.

METHODS

MEDLINE and PubMed databases were searched for eligible publications from 1990 to April 2023. Systematic literature reviews, with or without meta-analysis, of clinical trials and observational studies were screened by two independent investigators for eligibility, data extraction, and quality assessment. English language and the time interval 1990-2023 were applied. A registry code CRD42023464807 was generated on PROSPERO and approved for this search protocol. The corrected covered area (CCA), calculated to quantify the degree of overlap between reviews, gave a slight overlap (CCA = 4%).

RESULTS

A total of 84 systematic reviews out of 6681 screened records were selected. Eligible reviews included studies with predominantly observational designs (61/84, 72.6%%), of which 26/61 referenced studies of mixed observational and RCT designs, while 23/84 (27.4%) were RCT-only systematic reviews. Seventy-nine different entries were identified for health outcomes, clustered into 10 macro-categories, each reporting a statistically significant association with exposure to the MedDiet. Adherence to MedDiet was found to strongly benefit age-related chronic diseases (21.5%), neurological disorders (19%), and obesity-related metabolic features (12.65), followed by CVDs (11.4%), cancer (10.1%), diabetes (7.5%), liver health (6.3%), inflammation (5%), mortality (5%), and renal health (1.2%). The quality of the studies was moderate to high.

CONCLUSION

In the context of a "Planeterranean" framework and perspective that can be adopted in any European region and worldwide, MedDiet represents a healthy and sustainable lifestyle model, able to prevent several diseases and reduce premature mortality. In addition, the availability of a FOP, such as Med-Index, might foster more conscious food choices among consumers, paying attention both to human and planetary health.

Sustainable Development Goals: Challenges and the Role of the International Society of Nephrology in Improving Global Kidney Health

The United Nations 2030 agenda for sustainable development includes 17 sustainable development goals (SDGs) that represent a universal call to end poverty and protect the planet, and are intended to guide government and private sector policies for international cooperation and optimal mobilization of resources. At the core of their achievement is reducing mortality by improving the global burden of noncommunicable diseases (NCDs), the leading causes of death and disability worldwide. CKD is the only NCD with a consistently rising age-adjusted mortality rate and is rising steadily up the list of the causes of lives lost globally. Kidney disease is strongly affected by social determinants of health, with a strong interplay between CKD incidence and progression and other NCDs and SDGs. Tackling the shared CKD and NCD risk factors will help with progress toward the SDGs and vice versa . Challenges to global kidney health include both preexisting socioeconomic factors and natural and human-induced disasters, many of which are intended to be addressed through actions proposed in the sustainable development agenda. Opportunities to address these challenges include public health policies focused on integrated kidney care, kidney disease surveillance, building strategic partnerships, building workforce capacity, harnessing technology and virtual platforms, advocacy/public awareness campaigns, translational and implementation research, and environmentally sustainable kidney care.

Transgenerational and intergenerational effects of early childhood famine exposure in the cohort of offspring of Leningrad Siege survivors

Famine exposure during early life development can affect disease risk in late-life period, yet, transmission of phenotypic features from famine-exposed individuals to the next generations has not been well characterized. The purpose of our case-control study was to investigate the association of parental starvation in the perinatal period and the period of early childhood with the phenotypic features observed in two generations of descendants of Leningrad siege survivors. We examined 54 children and 30 grandchildren of 58 besieged Leningrad residents who suffered from starvation in early childhood and prenatal age during the Second World War. Controls from the population-based national epidemiological ESSE-RF study (n = 175) were matched on sex, age and body mass index (BMI). Phenotypes of controls and descendants (both generations, children and grandchildren separately) were compared, taking into account multiple testing. Comparison of two generations descendants with corresponding control groups revealed significantly higher creatinine and lower glomerular filtration rate (GFR), both in meta-analysis and in independent analyses. The mean values of GFR for all groups were within the normal range (GFR less than 60 mL/min/1.73 m² was recorded in 2 controls and no one in DLSS). Additionally, independent of the creatinine level, differences in the eating pattern were detected: insufficient fish and excessive red meat consumption were significantly more frequent in the children of the Leningrad siege survivors compared with controls. Blood pressure, blood lipids and glucose did not differ between the groups. Parental famine exposure in early childhood may contribute to a decrease in kidney filtration capacity and altered eating pattern in the offspring of famine-exposed individuals.

Dietary protein and muscle wasting in chronic kidney disease: new insights

PURPOSE OF REVIEW

Muscle wasting is an important health problem in chronic kidney disease (CKD) patients. Protein restriction in the diet can be one of the main causes of muscle wasting in this population. In this review, we aimed to investigate the relationship between dietary protein intake and muscle wasting in CKD patients according to recent literature.

RECENT FINDINGS

The one of the main mechanisms responsible for the muscle wasting is the disturbances in skeletal muscle protein turnover. Muscle wasting primarily occurs when the rates of muscle protein breakdown exceed the muscle protein synthesis. Dietary protein intake represents an important role by causing a potent anabolic stimulus resulting a positive muscle protein balance. Compared to studies made in healthy populations, there are very limited studies in the literature about the relationship between dietary protein intake and muscle wasting in the CKD population. Majority of the studies showed that a more liberal protein intake is beneficial for muscle wasting in especially advanced CKD and hemodialysis population.

SUMMARY

Although evaluating muscle wasting in CKD patients, the amount of protein in the diet of patients should also be reviewed. Although excessive protein intake has some negative consequences on this patient group, a more liberated dietary protein intake should be taken into account in this patient group with muscle wasting and especially in dialysis patients.

The Intake of Ultra-Processed Foods and Prevalence of Chronic Kidney Disease: The Health Examinees Study

Emerging evidence links several health outcomes to the consumption of ultra-processed food (UPF), but few studies have investigated the association between UPF intake and kidney function. This cross-sectional study investigated the prevalence of chronic kidney disease (CKD) in relation to UPF intake in Korea. Data were obtained from the 2004−2013 Health Examinees (HEXA) study. The intake of UPF was assessed using a 106-item food frequency questionnaire and evaluated using the NOVA classification. The prevalence of CKD was defined as an estimated glomerular filtration rate (eGFR) of <60 mL/min/m2. Poisson regression models were used to compute the prevalence ratios (PR) of CKD according to quartiles of the proportion of UPF intake (% food weight). A total of 134,544 (66.4% women) with a mean age of 52.0 years and an eGFR of 92.7 mL/min/m2 were analysed. The median proportion of UPF in the diet was 5.6%. After adjusting for potential confounders, the highest quartile of UPF intake was associated with the highest prevalence of CKD (PR 1.16, 95% CI 1.07−1.25), and every IQR (6.6%) increase in the proportion of UPF in the diet was associated with a 6% higher prevalence of CKD (PR 1.06, 95% CI 1.03−1.09). Furthermore, the highest consumption of UPF was inversely associated with eGFR (Q4 vs. Q1: β −1.07, 95% CI −1.35, −0.79; per IQR increment: (β −0.45, 95% CI −0.58, −0.32). The intake of UPF was associated with a high prevalence of CKD and a reduced eGFR. Longitudinal studies in the Korean population are needed to corroborate existing findings in other populations.

Living Well With Kidney Disease and Effective Symptom Management: Consensus Conference Proceedings

Chronic kidney disease (CKD) confers a high burden of uremic symptoms that may be underrecognized, underdiagnosed, and undertreated. Unpleasant symptoms, such as CKD-associated pruritus and emotional/psychological distress, often occur within symptom clusters, and treating 1 symptom may potentially alleviate other symptoms in that cluster. The Living Well with Kidney Disease and Effective Symptom Management Consensus Conference convened health experts and leaders of kidney advocacy groups and kidney networks worldwide to discuss the effects of unpleasant symptoms related to CKD on the health and well-being of those affected, and to consider strategies for optimal symptom management. Optimizing symptom management is a cornerstone of conservative and preservative management which aim to prevent or delay dialysis initiation. In persons with kidney dysfunction requiring dialysis (KDRD), incremental transition to dialysis and home dialysis modalities offer personalized approaches. KDRD is proposed as the preferred term given the negative connotations of "failure" as a kidney descriptor, and the success stories in CKD journeys. Engaging persons with CKD to identify and prioritize their personal values and individual needs must be central to ensure their active participation in CKD management, including KDRD. Person-centered communication and care are required to ensure diversity, equity, and inclusion; education/awareness that considers the health literacy of persons with CKD; and shared decision-making among the person with CKD, care partners, and providers. By putting the needs of people with CKD, including effective symptom management, at the center of their treatment, CKD can be optimally treated in a way that aligns with their goals.

Health-Related Quality of Life in Relation to Fruit and Vegetable Intake among Polish Pharmacists

A direct association between health-related quality of life (HQoL) and nutrition remains unclear, although lifestyle habits are known to impact on human health. Thus, the aim of this study was to estimate an association between dietary habits, such as vegetable and fruit consumption, in particular, and HQoL. SF-36 (RAND-SF-36) and the Dietary Habits and Nutrition Beliefs Questionnaire (KomPAN) were addressed to Polish pharmacists with a valid professional license. After the preliminary verification, 667 pharmacists were included into the study, and altogether, 11 questions from the KomPAN questionnaire and all RAND-SF-36 multiple choice questions were processed for statistical analysis. All HQoL scores, excluding physical functioning and role-physical, were significantly higher in the group declaring fruit consumption ≥1 time per day (p < 0.005), while physical functioning (p = 0.008) and general health (p = 0.03) were significantly higher in the group declaring vegetable consumption ≥1 time per day. Thus, there is indeed a positive association between vegetable and fruit consumption and HQoL. Increased fruit intake could certainly impact on the health-related quality of life of Polish pharmacists, primarily in terms of mental functioning, while increased vegetable intake could impact in terms of physical functioning.

A Prospective Cohort Study of Racial/Ethnic Variation in the Association between Change in Cystatin C and Dietary Quality in Older Americans

Using a sample of U.S. adults aged 65 and older, we examined the role of dietary quality in cystatin C change over 4 years and whether this association varied by race/ethnicity. The Health and Retirement Study provided observations with biomarkers collected in 2012 and 2016, participant attributes measured in 2012, and dietary intake assessed in 2013. The sample was restricted to respondents who were non-Hispanic/Latino White (n = 789), non-Hispanic/Latino Black (n = 108), or Hispanic/Latino (n = 61). Serum cystatin C was constructed to be equivalent to the 1999-2002 NHANES scale. Dietary intake was assessed by a semi-quantitative food frequency questionnaire (FFQ) with diet quality measured using an energy-adjusted form of the Alternative Healthy Eating Index-2010 (AHEI-2010). Statistical analyses were conducted using autoregressive linear modeling adjusting for covariates and complex sampling design. Cystatin C slightly increased from 1.2 mg/L to 1.3 mg/L over the observational period. Greater energy-adjusted AHEI-2010 scores were associated with slower increase in cystatin C from 2012-2016. Among respondents reporting moderately low to low dietary quality, Hispanic/Latinos had significantly slower increases in cystatin C than their non-Hispanic/Latino White counterparts. Our results speak to the importance of considering racial/ethnic determinants of dietary intake and subsequent changes in health in aging populations. Further work is needed to address measurement issues including further validation of dietary intake questionnaires in diverse samples of older adults.

Prospective associations between a priori dietary patterns adherence and kidney function in an elderly Mediterranean population at high cardiovascular risk

Purpose

To assess the association between three different a priori dietary patterns adherence (17-item energy reduced-Mediterranean Diet (MedDiet), Trichopoulou-MedDiet and Dietary Approach to Stop Hypertension (DASH)), as well as the Protein Diet Score and kidney function decline after one year of follow-up in elderly individuals with overweight/obesity and metabolic syndrome (MetS).

Methods

We prospectively analyzed 5675 participants (55–75 years) from the PREDIMED-Plus study. At baseline and at one year, we evaluated the creatinine-based estimated glomerular filtration rate (eGFR) and food-frequency questionnaires-derived dietary scores. Associations between four categories (decrease/maintenance and tertiles of increase) of each dietary pattern and changes in eGFR (ml/min/1.73m²) or ≥ 10% eGFR decline were assessed by fitting multivariable linear or logistic regression models, as appropriate.

Results

Participants in the highest tertile of increase in 17-item erMedDiet Score showed higher upward changes in eGFR (β: 1.87 ml/min/1.73m²; 95% CI: 1.00–2.73) and had lower odds of ≥ 10% eGFR decline (OR: 0.62; 95% CI: 0.47–0.82) compared to individuals in the decrease/maintenance category, while Trichopoulou-MedDiet and DASH Scores were not associated with any renal outcomes. Those in the highest tertile of increase in Protein Diet Score had greater downward changes in eGFR (β: − 0.87 ml/min/1.73m²; 95% CI: − 1.73 to − 0.01) and 32% higher odds of eGFR decline (OR: 1.32; 95% CI: 1.00–1.75).

Conclusions

Among elderly individuals with overweight/obesity and MetS, only higher upward change in the 17-item erMedDiet score adherence was associated with better kidney function after one year. However, increasing Protein Diet Score appeared to have an adverse impact on kidney health. Trial Registration Number: ISRCTN89898870 (Data of registration: 2014).

Supplementary Information

The online version contains supplementary material available at 10.1007/s00394-022-02838-7.

High-fat diet caused renal damage in ApoE-/- mice via the activation of RAGE-mediated inflammation

High-fat diet (HFD) is the primary cause of metabolic syndrome associated chronic kidney disease. This study aimed to investigate the pathogenesis of HFD-induced kidney injury. ApoE^-/- mice were fed with HFD and kidney damage was examined. In addition, HK-2 human renal proximal tubular epithelial cells were treated with fructose and receptor of advanced glycation end products (RAGE) siRNA. The results showed that HFD increased body weight, blood glucose and insulin resistance in ApoE^-/- mice. The kidney damage was associated with increased oxidative stress and strong staining of RAGE and NF-κB in kidney tissues, as well as high serum levels of TNF-α, IL-1β and IL-6. Western-blot analysis showed that HFD increased the levels of RAGE, p-IκBα, p-NF-κB, bax, caspase-3 and caspase-9 but decreased the levels of Bcl-2 in kidney tissues. In HK-2 cells, fructose promoted the secretion of TNF-α, IL-1β and IL-6 and increased the levels of RAGE, p-IκBα, p-NF-κB, bax, caspase-3 and caspase-9, but decreased the levels of Bcl-2. Moreover, RAGE siRNA could attenuate increased levels of p-IκBα, p-NF-κB, bax, caspase-3 and caspase-9 while restore decreased levels of Bcl-2 in fructose-treated HK-2 cells. In conclusion, HFD causes kidney injury by promoting oxidative stress, inflammation and apoptosis possibly through the activation of RAGE/NF-κB pathway.