A proinflammatory diet is associated with systemic inflammation and reduced kidney function in elderly adults

Dietary inflammatory index, mediating biomarkers and incident frailty in Chinese community-dwelling older adults

OBJECTIVES

Diet can modulate systemic inflammation, while inflammation is a critical contributory factor of frailty. However, longitudinal data on the association between dietary inflammatory index (DII) and frailty are limited, and the intermediate mechanisms remain unclear. This study aimed to examine the association between DII and incident frailty and the potential mediating roles of frailty-related biomarkers.

DESIGN

Prospective cohort study.

SETTING

The Mr. OS and Ms. OS (Hong Kong) study.

PARTICIPANTS

A total of 3,035 community-dwelling men and women aged above 65 years without frailty at baseline were included.

MEASUREMENTS

DII scores were calculated using the locally validated food frequency questionnaire. Incident frailty at year four was defined using the Fried frailty phenotype. Logistic regression was used to examine the association between DII and frailty onset. Mediation analysis was used to explore the mediating roles of frailty-related biomarkers in the DII-frailty association.

RESULTS

During four years of follow-up, 208 individuals developed frailty. Compared with the lowest tertile of DII, the highest tertile was associated with an increased risk of incident frailty (OR: 1.82; 95% CI: 1.17-2.82; p = 0.008) after adjustment for relevant confounders. The DII-frailty association was significant in men but not in women. Furthermore, increasing serum homocysteine, decreasing serum folate, and reducing estimated glomerular filtration rate (eGFR) mediated 11.6%, 7.1%, and 9.6 % of the total relation between DII and frailty onset, respectively.

CONCLUSION

In this cohort study, a pro-inflammatory diet was associated with a higher risk of frailty onset, mediated by homocysteine, folate, and renal function.

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 Chronic Kidney Disease With Dietary Inflammatory Index in Adults Aged 50 Years and Older: Dose-Response Analysis of a Nationally Representative Population-Based Study

OBJECTIVE

Dietary inflammatory index (DII) is associated with systemic inflammatory markers, which have been linked to the development of chronic kidney disease (CKD). However, epidemiological studies on the association of DII scores with CKD are sparse. This study aimed to quantitatively assess the dose-response relationship of DII scores with the prevalence of CKD.

METHODS

Adults (≥50 years) from the 2007 to 2018 National Health and Nutrition Examination Survey (N = 12,090) were included. DII scores were calculated based on 27 nutritional parameters. The outcome of interest is the prevalence of CKD 3-5 stages, which is defined as an estimated glomerular filtration rate <60 mL/min/1.73 m2. The nonlinear dose-response relationship of DII scores with the prevalence of CKD stages 3-5 was assessed with restricted cubic splines. Stratified analyses were conducted by age, sex, and race/ethnicity. Covariates included age, sex, body mass index, race/ethnicity, education, ratio of family income to poverty, smoking, physical activity, hypertension, diabetes, and daily intakes of total plain water, sodium, and energy.

RESULTS

The weighted prevalence of CKD stages 3-5 was 14.77%. The relationship of DII scores with CKD stages 3-5 was linear, and the odds ratios (95% confidence intervals) of CKD stages 3-5 were 0.68 (0.51-0.84) for -2 (DII score), 0.83 (0.74-0.93) for -1, 1.00 for 0 (reference value), 1.20 (1.07-1.32) for 1, 1.41 (1.16-1.66) for 2, 1.63 (1.28-1.98) for 3, 1.84 (1.34-2.34) for 4, and 2.08 (1.30-2.86) for 5. The linear relationship pattern of DII scores with CKD stages 3-5 was observed in stratified analyses by age, sex, and race/ethnicity, respectively.

CONCLUSIONS

Higher DII scores were independently and linearly associated with the odds of CKD stages 3-5, which deserves to be confirmed in further prospective cohort studies.

Association of Dietary Inflammatory Index with CKD progression and estimated glomerular filtration rate in the American CKD population: A cross-sectional study

PURPOSE

The number of CKD patients is on the rise worldwide, and diet has become an essential aspect influencing the treatment and prognosis of CKD. However, limited research has explored the association of the Dietary Inflammatory Index (DII) with CKD progression and the essential kidney function indicator, eGFR, in CKD patients. This study aimed to analyze the association between DII and CKD progression and eGFR in the US CKD population using data from the National Health and Nutrition Examination Survey (NHANES).

METHODS

This study utilized data obtained from the National Health and Nutrition Examination Survey (NHANES) spanning from 2007 to 2018, with a total sample size of 2,488 individuals. Study used multiple imputation, based on 5 replications and a chained equation approach method in the R MI procedure, to account for missing data. Weighted multiple logistic regression was used to analyze the relationship between DII and the risk of higher CKD stage and a weighted multiple regression analysis was used to assess the relationship between DII and eGFR. Weighted Generalized Additive Models and smoothed curve fitting were applied to detect potential non-linear relationships in this association.

RESULTS

In all three models, it was found that DII was positively associated with the risk of higher CKD stage (P < 0.0001), and an increase in DII was associated with a decrease in eGFR (P < 0.0001). The trend across quartiles of DII remained statistically significant, revealing a gradual elevation in higher CKD stage risk and reduction in eGFR levels for the second, third, and fourth quartiles compared to the lowest quartile (P for trend < 0.0001). Upon adjusting for age, gender, race, education level, poverty income ratio (PIR), marital status, body mass index (BMI), metabolic equivalent (MET) score, drinking, smoking, history of hypertension, history of diabetes, cotinine, systolic blood pressure, diastolic blood pressure, total triglycerides, and total cholesterol, we found a positive correlation between DII and the risk of higher CKD stage (OR = 1.26, 95% CI: 1.14-1.40). Further investigation revealed that an increase in DII was associated with a decrease in eGFR (β = -1.29, 95% CI: -1.75, -0.83). Smooth curves illustrated a non-linear positive correlation between DII and CKD risk, while a non-linear negative correlation was observed between DII and eGFR.

CONCLUSIONS

Our study results indicate that an increase in DII is associated with an increased risk of higher CKD stage and a decrease in eGFR in all three models. In the fully adjusted model, the risk of higher CKD stage increased by 26% and the eGFR decreased by 1.29 ml/min/1.73 m2 for each unit increase in DII. This finding suggests that in patients with CKD in the US, improved diet and lower DII values may help slow the decline in eGFR and delay the progression of CKD.

Elevated Inflammation and Poor Diet Quality Associated with Lower eGFR in United States Adults: An NHANES 2015-2018 Analysis

Chronic kidney disease is prevalent within the United States likely due to dietary habits. The purpose of this study was to examine the relationship between the high-sensitivity c-reactive protein (hs-CRP) and diet quality (DQ) and their effect on the eGFR. A cross-sectional secondary data analysis study was conducted among adults (n = 6230) using NHANES 2015-2018 data. DQ was determined by the Healthy Eating Index-2015 (HEI-2015). Multivariable linear regressions were conducted based on eGFR (≥90 or <60 mL/min/1.73 m2) after adjustments for age, race/ethnicity, hypertension, diabetes mellitus, cardiovascular disease, and kidney disease awareness. All analyses were performed in SAS version 9.4 with a statistical significance of p < 0.05. Results showed that participants who had an eGFR of <60 mL/min/1.73 m2 were older and had a higher prevalence of hypertension and diabetes and had higher hs-CRP compared to participants with an eGFR ≥ 90 (p < 0.005). Of participants with an eGFR < 60, 27% reported that they were aware they had kidney disease. Regardless of the eGFR at baseline, there was a negative interaction effect on the DQ scores and hs-CRP on the eGFR (p < 0.05). Independently, for participants with an eGFR < 60, their DQ scores had a positive significant relationship on their eGFR (p = 0.03), whereas their hs-CRP had a negative significant relationship on thier eGFR (p < 0.001). For participants with an eGFR < 60, age, hypertension, and kidney disease awareness influenced this relationship (p < 0.001). Overall, low DQ and elevated hs-CRP contributed to a reduction in kidney function. Efforts to improve dietary intake and strategies to reduce inflammation and improve kidney function are necessary.

The relationship between dietary inflammatory index and osteoporosis among chronic kidney disease population

Dietary inflammation index (DII) is an epidemiological survey tool to evaluate dietary inflammation potential. Osteoporosis, whose development is deeply affected by inflammation, may be also affected by dietary inflammatory patterns. However, the relationship between DII and osteoporosis is unclear for chronic kidney disease (CKD) population. Our study involved 526 CKD patients from the US National Health and Nutrition Examination Survey (NHANES). DII levels were stratified into four quantile groups. Multivariable regression models were used to examine the association between DII and osteoporosis. Restricted cubic splines and subgroup analysis were additionally adopted. Results showed that the overall prevalence of osteoporosis among CKD patients was 25.3%. After fully adjusted, OR (95% confidence interval) for Q4 group compared with Q3 (reference group) in total and female population were 2.09 (1.05, 4.23) and 2.80 (1.14, 7.08), respectively. Subgroup analysis indicated that these results had no interaction with age, gender, body mass index (BMI), renal function, urinary protein, calcium, phosphorus and total 25-hydroxyvitamin D. DII was negatively correlated with lumbar spine bone mineral density (BMD) in CKD population (P < 0.05). Therefore, in CKD patients, higher DII was associated with higher osteoporosis risk and lower BMD of lumber spine, especially in female. Anti-inflammatory diet patterns may be a protective intervention for some CKD-related osteoporosis.

The association of dietary patterns with incident chronic kidney disease and kidney function decline among middle-aged Korean adults: a cohort study

OBJECTIVES

This study assessed the association of dietary patterns with the incidence of chronic kidney disease (CKD) and kidney function decline among Korean adults.

METHODS

Data were collected from the records of 20,147 men and 39,857 women who participated in the Health Examinees study. Principal component analysis was used to identify 3 dietary patterns (prudent, flour-based food and meat, and white rice-based), and CKD risk was defined using the Epidemiology Collaboration equation for estimated glomerular filtration rate: (eGFR) <60 mL/min/1.73 m2. A kidney function decline was defined as a >25% decrease in eGFR from baseline.

RESULTS

During the 4.2-year follow-up, 978 participants developed CKD and 971 had a 25% decline in kidney function. After adjusting for potential impact variables, compared with the lowest quartile of the prudent dietary pattern, participants in the highest quartile had a 37% lower risk of kidney function decline among men (hazard ratio [HR], 0.63; 95% confidence interval [CI], 0.47 to 0.85); while higher adherence to the flour-based food and meat dietary pattern was associated with an increased risk of CKD in both men (HR, 1.63; 95% CI, 1.22 to 2.19) and women (HR, 1.47; 95% CI, 1.05 to 2.05) as well as a decline in kidney function in both men (HR, 1.49; 95% CI, 1.07 to 2.07) and women (HR, 1.77; 95% CI, 1.33 to 2.35).

CONCLUSIONS

Although a higher adherence to the prudent dietary pattern was inversely associated with the risk of kidney function decline in men, there was no association with CKD risk. In addition, a higher adherence to the flour-based food and meat dietary pattern increased the risk of CKD and kidney function decline. Further clinical trials are needed to confirm these associations.

Dose-response relationship between dietary inflammatory index and diabetic kidney disease in US adults

OBJECTIVE

The impact of the dietary potential inflammatory effect on diabetic kidney disease (DKD) has not been adequately investigated. The present study aimed to explore the association between dietary inflammatory index (DII) and DKD in US adults.

DESIGN

This is a cross-sectional study.

SETTING

Data from the National Health and Nutrition Examination Survey (2007-2016) were used. DII was calculated from 24-h dietary recall interviews. DKD was defined as diabetes with albuminuria, impaired glomerular filtration rate or both. Logistic regression and restricted cubic spline models were adopted to evaluate the associations.

PARTICIPANTS

Data from the National Health and Nutrition Examination Survey (2007-2016) were used, which can provide the information of participants.

RESULTS

Four thousand two-hundred and sixty-four participants were included in this study. The adjusted OR of DKD was 1·04 (95 % CI 0·81, 1·36) for quartile 2, 1·24 (95 % CI 0·97, 1·59) for quartile 3 and 1·64 (95 % CI 1·24, 2·17) for quartile 4, respectively, compared with the quartile 1 of DII. A linear dose-response pattern was observed between DII and DKD (Pnonlinearity = 0·73). In the stratified analyses, the OR for quartile 4 of DII were significant among adults with higher educational level (OR 1·83, 95 % CI 1·26, 2·66) and overweight or obese participants (OR 1·67, 95 % CI 1·23, 2·28), but not among the corresponding another subgroup. The interaction effects between DII and stratified factors on DKD were not statistically significant (all P values for interactions were >0·05).

CONCLUSIONS

Our findings suggest that a pro-inflammatory diet, shown by a higher DII score, is associated with increased odd of DKD.

Turmeric supplementation with piperine is more effective than turmeric alone in attenuating oxidative stress and inflammation in hemodialysis patients: A randomized, double-blind clinical trial

PURPOSE

Turmeric has renop rotective effects that can act to reduce oxidative stress and inflammation in hemodialysis (HD) patients. Piperine has been indicated as a bioavailability enhancer of turmeric and consequently of its biological effects. However, data on the efficacy of the turmeric/piperine combination in HD patients are limited. We aimed to verify whether turmeric supplementation in combination with piperine has a superior effect to turmeric alone in increasing antioxidant capacity and reducing oxidative stress and inflammation in HD patients.

METHODS

This randomized, double-blind clinical trial was conducted in HD patients (age 20-75 years). Patients were supplemented with turmeric (3 g/day) or turmeric/piperine (3 g turmeric + 2 mg piperine/day) for 12 weeks. Malondialdehyde (MDA), antioxidant enzymes catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), high-sensitivity C-reactive protein (hs-CRP), and ferritin were evaluated at baseline and the end of the study.

RESULTS

There was a reduction in the MDA and ferritin levels in the turmeric/piperine group and in the comparison between groups at the end of the study [MDA: -0.08(-0.14/0.01) nmol/mL versus -0.003(-0.10/0.26) nmol/mL, p = 0.003; ferritin: -193.80 ± 157.29 mg/mL versus 51.99 ± 293.25 mg/mL, p = 0.018]. In addition, GPx activity reduced in the turmeric group (p = 0.029). No changes were observed for CAT, GR, and hs-CRP.

CONCLUSION

Turmeric plus piperine was superior to turmeric alone in decreasing MDA and ferritin levels. The use of a combination of turmeric and piperine as a dietary intervention may be beneficial for modulating the status oxidative and inflammation in HD patients.

BRAZILIAN REGISTRY OF CLINICAL TRIALS NUMBER

RBR-2t5zpd; Registration Date: May 2, 2018.

Association of dietary inflammatory index with chronic kidney disease and kidney stones in Iranian adults: A cross-sectional study within the Ravansar non-communicable diseases cohort

Chronic inflammation plays a central role in the pathogenesis of chronic kidney disease (CKD). The association of dietary inflammatory index (DII) with CKD remains underexplored. Thus, the present study aimed to determine the association between the DII, risk of CKD, and kidney stone formation using the data from the Ravansar non-communicable diseases (RaNCD) cohort study conducted in Kermanshah, Iran. The cross-sectional study was conducted using the recruitment phase data of the RaNCD cohort study comprising 9,824 individuals with an age range of 35–65 years. Food frequency questionnaires (FFQ) were used to evaluate the association between diet and DII scores. Renal function was assessed using estimated glomerular filtration rate (eGFR), blood urea nitrogen (BUN), and serum creatinine (Cr) level. CKD was defined based on eGFR. The prevalence of kidney stones was evaluated by participants’ self-report. A total of 1,791 participants (18.24%) had kidney stones, while a majority were in the first quartile (27.69%). Out of 9,824 subjects, 1,747 subjects (eGFR: 18.50 ml/min per 1.73 m2; 95% CI: 17.72–19.30) had CKD. A significant trend for eGFR across all quartiles (Qs) of DII was observed. The odds ratio of CKD in the fourth quartile (pro-inflammatory diet) was 4.38-times higher than in the first quartile (anti-inflammatory diet) of DII (95% CI = 3.58–5.36). Women were found to be more likely to have less eGFR than men in the DII Qs. Collectively, the findings indicated that consumption of a pro-inflammatory diet was associated with a high occurrence of CKD. As a matter of interest, the results also revealed that a pro-inflammatory diet had no significant correlation with kidney stone development.

Proinflammatory Diets and Risk of ESKD in US Adults with CKD

Background

Inflammation may affect long-term kidney function. Diet may play a role in chronic inflammation. We hypothesized that proinflammatory diets increase the risk of progression to kidney failure with replacement therapy (KFRT), and systemic inflammation is a mediator of the effect of diet on progression to KFRT.

Methods

In the 1988-1994 National Health and Nutrition Examination Survey linked to the national ESKD registry, in adults with CKD (eGFR 15-59 ml/min per 1.73 m²), aged ≥20 years, we calculated the Adapted Dietary Inflammatory Index (ADII) at baseline from a 24-hour dietary recall and an inflammation score (IS) using average of z scores of four inflammation biomarkers. We explored the association of the ADII and IS with risk of incident KFRT using Cox proportional model, adjusting for sociodemographics, physical activity, Framingham risk score, eGFR, and urinary ACR. We evaluated whether, and to what extent, IS mediated the effect of the ADII on KFRT incidence, using causal mediation analysis.

Results

Of 1084 adults with CKD, 109 (10%) developed KFRT. The ADII was associated with increased risk of KFRT (relative hazard [RH] per SD increase (2.56): 1.4 [1.04-1.78]). IS was also associated with KFRT (RH: 1.12; 95% CI, 1.02 to 1.25). Approximately 36% of the association between the ADII and KFRT was explained by IS.

Conclusions

Among adults with CKD, a proinflammatory diet was associated with risk of KFRT, and that association was partially explained by an increase in inflammatory markers. Dietary interventions that reduce inflammation may offer an approach for preventing KFRT.

Energy-Adjusted Dietary Inflammatory Index Is Associated With 5-Year All Cause and Cardiovascular Mortality Among Chronic Kidney Disease Patients

Background

Diet management is a pivotal intervention for chronic kidney disease (CKD) patients. Dietary inflammation index (DII) is developed to evaluate the integral inflammatory potential of a diet pattern. However, research about the association between DII and mortality in CKD is limited.

Objective

We conducted a cohort study to investigate the relationship between energy-adjusted DII (E-DII) and the 5-year all-cause and cardiovascular mortality in CKD population.

Materials and Methods

CKD participants with complete E-DII data and death status from National Health and Nutrition Examination Survey (1999–2014) were involved in this study. E-DII was calculated based on dietary recall interviews. Smooth curve fitting, Kaplan–Meier survival analysis, and Cox proportional hazards models were used to evaluate the association between E-DII and the 5-year all cause and cardiovascular mortality. Subgroup analysis was also performed.

Results

A total of 7,207 participants were included (55.46% elderly and 46.54% male) in this study. The 5-year all-cause and cardiovascular mortality were 16.86 and 4.32%, respectively. Smooth curve fitting showed a “J” shape and near linear relationship between the E-DII score and the 5-year all-cause and cardiovascular mortality, respectively. In multivariate Cox proportional hazards models, the hazard ratios (95% confidence intervals [CI]) for the highest tertile of the E-DII were 1.33 (1.15, 1.54) for all-cause mortality, and 1.54 (1.15, 2.07) for cardiovascular mortality when compared with the lowest tertile of the E-DII. The subgroup analyses revealed relatively stronger associations between the E-DII and the mortality among CKD patients with other death risk factors.

Conclusions

Energy-adjusted dietary inflammatory index is independently related with the 5-year all-cause and cardiovascular mortality among CKD patients. Therefore, anti-inflammatory diet patterns should be recommended for CKD patients.

Dietary Inflammatory Potential Is Associated With Sarcopenia Among Chronic Kidney Disease Population

Background

Sarcopenia, characterized by impaired muscle mass and function, is a common complication and the main reason for bad life quality and high mortality in chronic kidney disease (CKD). Limiting systemic inflammation is a potable intervention for sarcopenia. Dietary inflammatory potential can influence systemic inflammation. However, research about the association between dietary inflammatory potential and sarcopenia in CKD is limited.

Aim

To investigate the association between dietary inflammatory potential and sarcopenia in the CKD population.

Methods

We conducted a cross-section study based on the public database of the National Health and Nutrition Examination Survey (NHANES). In total, 2,569 adult CKD participants who had complete data for dietary inflammatory potential and sarcopenia were included. The dietary inflammatory potential was calculated by the dietary inflammation index (DII) score based on dietary recall interviews. We assessed sarcopenia via low skeletal muscle mass measured by dual-energy X-ray absorptiometry. Smooth curve fitting and a generalized linear mixed model were used to evaluate the relationship between DII and sarcopenia. Moreover, subgroup and sensitivity analyses were performed.

Results

The overall prevalence of sarcopenia among patients with CKD is 19.11%. Smooth curve fitting results displayed that the DII score is near-linear positively associated with sarcopenia. Logistic regression confirmed sarcopenia is independently related to DII scores (odds ratio [OR], 1.17; 95% CI, 1.06–1.29). Subgroup analyses revealed relatively stronger associations between DII and sarcopenia among patients with CKD with other sarcopenia risk factors, such as hypoalbuminemia, low energy intake, low protein intake, and comorbidities.

Conclusion

The dietary inflammatory potential is independently related to sarcopenia among patients with CKD. Anti-inflammatory diet patterns may be a protective intervention for CKD-associated sarcopenia.

Diet Quality and Dietary Inflammatory Index in Dutch Inflammatory Bowel Disease and Irritable Bowel Syndrome Patients

Inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS) share common culprit foods and potential pathophysiological factors. However, how diet may contribute to disease course and whether this differs between both entities is unclear. We therefore investigated the association of dietary indices with intestinal inflammation and gastrointestinal symptoms in both IBD and IBS patients. Food frequency questionnaires from 238 IBD, 261 IBS and 195 healthy controls (HC) were available to calculate the overall diet quality by the Dutch Healthy Diet-Index 2015 (DHD-2015) and its inflammatory potential by the Adapted Dietary Inflammatory Index (ADII). Intestinal inflammation and symptoms were evaluated by faecal calprotectin and the Gastrointestinal Symptom Rating Scale, respectively. The DHD-2015 was lower in IBD and IBS versus HC (p < 0.001), being associated with calprotectin levels in IBD (b = −4.009, p = 0.006), and with abdominal pain (b = −0.012, p = 0.023) and reflux syndrome (b = −0.016, p = 0.004) in IBS. ADII scores were comparable between groups and were only associated with abdominal pain in IBD (b = 0.194, p = 0.004). In this side-by-side comparison, we found a lower diet quality that was differentially associated with disease characteristics in IBD versus IBS patients. Longitudinal studies are needed to further investigate the role of dietary factors in the development of flares and predominant symptoms.

Dietary Inflammatory Index in relation to Type 2 Diabetes: A Meta-Analysis

Background and Aims

Epidemiologic studies show a strong association between chronic inflammation and type 2 diabetes (T2D). Diet may also affect the risk of T2D by modulating inflammation. This meta-analysis aimed to assess the relation of dietary inflammatory index (DII) and risk of T2D.

Methods

PubMed and Scopus were systematically searched from their inception to September 2020 to identify relevant studies. Relative risks, hazard ratios, or odds ratios (OR), with their corresponding 95% confidence intervals (95% CI), were calculated and pooled using a random-effects model.

Results

A total of 48 different studies, with a total sample size of 1,687,424 participants, were eligible to be included in this meta-analysis. In the overall analysis, no significant association was observed between DII and risk of T2D (OR = 1.03, 95% CI: 0.91 to 1.15), with significant evidence for heterogeneity (I 2  = 96.5%, P < 0.001); however, higher DII was identified as being significantly related to increased risk of T2D in high quality studies (OR = 1.58, 95% CI: 1.15 to 2.17). In the stratified analysis by the dietary assessment tool, background disease, and sex of participants, DII showed no significant association with T2D.

Conclusions

Higher DII might be associated with an increased risk of T2D. Additional well-designed studies are required to confirm this finding.

Higher dietary inflammatory index is associated with increased all-cause mortality in adults with chronic kidney disease

BACKGROUND

Diet property grounded on inflammatory potential, evaluated by the dietary inflammatory index (DII), has been proven to be connected with mortality, while studies of adults with chronic kidney disease (CKD) are scarce.

OBJECTIVE

The purpose of this research was to evaluate the interrelationships between DII and all-cause mortality among adults with CKD.

METHODS

In the National Health and Nutrition Examination Survey (NHANES) 2001-2006, we identified and evaluated data of 4,554 adults with CKD. DII scores were calculated from 24 h of dietary consumption at baseline. Vital status was followed through 31 December 2015. The association of all-cause mortality with DII score was assessed using the Kaplan-Meier curve and the Cox regression analysis.

RESULTS

After an average follow-up of 132.103 months, a total of 1,246 (27.36%) deaths were recorded. The death rates in the DII tertile categories were 24.04, 26.81, and 31.23%, respectively. The Kaplan-Meier curve showed increased death risks for the high DII tertile as compared with the low DII tertile. After we adjusted for a broad range of possible confounders, the estimation between extreme tertiles of DII scores presented a positive and significant association with all-cause mortality [hazard ratio (HR): 1.21, 95% CI: 1.05-1.39].

CONCLUSION

Our results confirm the hypothesis that proinflammatory diets contribute to the increased all-cause mortality in adults with CKD.

The dietary inflammatory index is inversely associated with depression, which is minimally mediated by C-reactive protein

Depression affects 8% of adults in America and is one of the leading causes of disability in Western countries. The dietary inflammatory index (DII) has previously been reported to be associated with inflammation and depression. However, no study to date has looked at the potential mediating effect of inflammation on the association of DII and depression. We hypothesized that the association of DII and depression would be both statistically and clinically mediated substantially by inflammation. We assessed these associations using the cross-sectional National Health and Nutrition Examination Survey (NHANES) 2005-2010 database. Our analysis included 10,022 participants aged 20 years and older. Inflammation was assessed with C-reactive protein (CRP) levels. Diet was measured using two 24 hour dietary recalls. Depression was assessed using the 9-item Patient Health Questionnaire (PHQ-9), which has a score range of 0 to 27, with the higher score showing more severe depressive symptoms. Comparing the highest to lowest DII quartiles, the mean score difference for depression was 0.47 units (95% CI 0.24-0.70, P-trend <.001) in the multivariable adjusted model. In the sex-stratified models, the results remained significant only among females, with the mean score difference of 0.72 (95% CI 0.34-1.10, P-trend <.001). CRP mediated 3.6% of the association between DII and depression in the total population in the fully adjusted model, which was statistically significant (P-trend <.001) but not clinically significant. No mediation association was found in the sex-stratified models. Further studies are needed to assess the associations with various inflammatory biomarkers in larger and more diverse populations.

Greater adherence to the dietary approaches to stop hypertension dietary pattern is associated with preserved muscle strength in patients with autosomal dominant polycystic kidney disease: a single-center cross-sectional study

The present study aimed to determine whether certain diets lower the risk of low muscle strength in patients with autosomal dominant polycystic kidney disease (ADPKD). In this cross-sectional study, outpatient ADPKD patients were enrolled from a tertiary care hospital. Muscle strength was assessed on the basis of handgrip strength (HGS), and dietary pattern indices were calculated using dietary intake data. Among the 68 participants included in this study, 19 (27.9%) had low HGS. Cystatin C concentrations were significantly higher in all participants, and in women in the low compared to the normal HGS group in the unadjusted analyses (P = 0.004). Among analyzed dietary pattern indices, the Dietary Approaches to Stop Hypertension (DASH) score was lower, for all participants and men, in the low compared to the normal HGS group (P < 0.05). Especially, the component score for whole grains of the DASH score was significantly lower in men in the low compared to the normal HGS group in unadjusted analyses. The DASH score was positively correlated with HGS in men (r = 0.387, P = 0.046). In addition, logistic regression analysis showed that the DASH score was negatively associated with low HGS, for all participants (odds ratio = 0.851, P = 0.049) and men (odds ratio = 0.716, P = 0.043), after adjusting for age, sex, and body weight. These findings suggest that the DASH dietary pattern may promote the preservation of muscle strength in ADPKD patients. The DASH diet can be considered as a nutritional strategy to maintain muscle strength and prevent sarcopenia in ADPKD patients.

Dietary inflammatory index and cardiorenal function in women with diabetes and prediabetes

BACKGROUND AND AIMS

Previous studies had shed a new light on the importance of multiple inflammatory mechanisms in the pathogenesis of arterial stiffness. The dietary inflammatory index (DII®) is a new tool for estimating the overall inflammatory potential of the diet. The aim of this study is to assess the association of the inflammatory potential of diet with peripheral arterial stiffness and renal function in women with diabetes and prediabetes.

METHODS AND RESULTS

This is an observational cross-sectional study. A total of 2644 females aged 45-75 years were included for the study. Dietary intake in the past 12 months was assessed by a validated China National Nutrition and Health Survey 2002 (CNHS2002) food-frequency questionnaire. Energy-adjusted DII (E-DII) scores were calculated from daily dietary information. In a multivariable linear regression analysis adjusted for potential confounders, E-DII was positively associated with brachial ankle pulse wave velocity (baPWV) in participants with diabetes (β = 12.820; 95% CI = 2.565, 23.076; P = 0.014) and prediabetes (β = 29.025; 95% CI = 1.110, 56.940; P = 0.042), but not in females with normal glucose homeostasis. In addition, per unit increase of E-DII was significantly associated with lower eGFR (β = -1.363; 95% CI = -2.335, -0.392; P = 0.006) in patients with diabetes.

CONCLUSION

We identified a direct association between E-DII and arterial stiffness, decreasedeGFR in middle-aged and elderly women with diabetes or prediabetes. Future studies are needed to verify and clarify the role of E-DII as an intervention target for cardiorenal complications of chronic hyperglycemia.

Dietary Factors and Prevention: Risk of End-Stage Kidney Disease by Fruit and Vegetable Consumption

BACKGROUND

The association between fruit and vegetable (FV) intake and the risk of end-stage kidney disease (ESKD) has not been examined in the general population and fully explored in chronic kidney disease (CKD). We prospectively evaluated this relationship in US representative sample of adults and evaluated consistency by the presence or absence, and severity, of CKD.

METHODS

We used data from the Third National Health and Nutrition Examination Survey (1988-1994) linked with the US Renal Data System, including 14,725 adults aged ≥20 years and with follow-up for ESKD through 2008. Daily FV intake was ascertained using a food frequency questionnaire. We examined the association between selected categories of FV intake and ESKD using a Fine Gray competing risk model adjusting for sociodemographics, lifestyle, clinical and nutritional factors, estimated glomerular filtration rate, and albuminuria. We evaluated whether risk varied in individuals with severe versus any CKD.

RESULTS

230 participants (1.5%) developed ESKD during follow-up. In the adjusted model, compared to highest intake, those in lowest categories of FV intake had a higher risk of ESKD, for <2 times/day (1.45 [1.24-1.68], 2 to <3 times/day (1.40 [1.18-1.61]), 3 to <4 times/day (1.25 [1.04-1.46]), and 4 to <6 times/day (1.14 [0.97-1.31]). There was suggestion of heterogeneity (p for interaction = 0.03) with possible stronger inverse association in patients with CKD than those without CKD. After stratification, we obtained similar strong inverse association when we examined ESKD incidence across intake of FVs in participants with CKD stages 1-4 (n = 5,346) and specifically in those with CKD stages 3-4 (n = 1,084).

CONCLUSIONS

Low intake of FVs was associated with higher risk of ESKD in US adults with and without CKD, supporting an emerging body of literature on the potential benefits of plant-rich diets for prevention of ESKD.

Dietary patterns and chronic kidney disease outcomes: A systematic review

Chronic kidney disease (CKD) is a serious public health problem and its prevalence is growing in many countries, often related to issues resulting from the lifestyle in growing economies and the population's life expectancy. Nutritional therapy is a beneficial but still neglected strategy for preventing CKD and delaying disease progression. The aim of this study was to assess the association of dietary patterns with CKD development and progression. Observational studies conducted in adult humans and the correlation between the adopted dietary pattern and prevalent and incident cases of CKD were assessed. A significant association was observed between unhealthy dietary patterns and an increased risk of developing or worsening CKD, as well as an adverse effect. Whereas healthy eating patterns characterized by the consumption of fruit, vegetables and dietary fibre showed nephroprotective outcomes.

Dietary patterns and associations with biomarkers of inflammation in adults: a systematic review of observational studies

Background

Evidence indicates that low-grade inflammation is involved in manychronic diseases of ageing. Modifiable lifestyle factors including dietcan affect low-grade inflammation. Dietary patterns allow assessment of the complex interactions of food nutrients and health and may be associated with inflammatory status.

This systematic review aimed to summarises current evidence from observational studies for associations between dietary patterns and inflammatory biomarkers in the general adult population. This review followed the PRISMA guidelines.

Methods

We conducted a systematic search in Embase, CINAHL Complete, Global Health and MEDLINE complete databases. Search terms included terms for diet (“dietary patterns”, “diet scores”) and inflammation (“inflammation“, “c-reactive protein“, “interleukin“).

Results

The search produced 7161 records. Duplicates were removed leaving 3164 for screening. There were 69 studies included (60 cross-sectional, 9 longitudinal). Papers included studies that were: 1) observational studies; 2) conducted in community-dwelling adults over 18 years of age; 3) assessed dietary patterns; 4) measured specified biomarkers of inflammation and 5) published in English. Dietary patterns were assessed using diet scores (n = 45), data-driven approaches (n = 22), both a data-driven approach and diet score (n = 2). The most frequently assessed biomarkers were CRP (n = 64) and/or IL-6 (n = 22). Cross-sectionally the majority of analyses reported an association between higher diet scores (mostly Mediterranean and anti-inflammatory diet scores) and lower inflammatory markers with 82 significant associations from 133 analyses. Only 22 of 145 cross-sectional analyses using data-driven approaches reported an association between a dietary patterns and lower inflammatory markers; the majority reported no association. Evidence of an association between dietary patterns and inflammatory markers longitudinally is limited, with the majority reporting no association.

Conclusions

Adherence to healthy, Mediterranean and anti-inflammatory dietary scores, appear to be associated with lower inflammatory status cross-sectionally. Future research could focus on longitudinal studies using a potential outcomes approach in the data analysis.

Trial registration

PROSPERO Registration Number CRD42019114501.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12937-021-00674-9.

The association of dietary inflammatory index with urinary risk factors of kidney stones formation in men with nephrolithiasis

Objective

Inflammation plays a leading role in the pathogenesis of nephrolithiasis. The association of the dietary inflammatory index (DII) with urinary lithogenic factors is unclear. This study aimed to evaluate the relation of DII to urinary risk factors of kidney stones formation.

Results

Of 264 participants, 61.4% (n = 162), 72% (n = 190), 74.6% (n = 197), 68.6% (n = 181), and 80.3% (n = 212) had hyperoxaluria, hypercreatininuria, hypercalciuria, hyperuricosuria, hypocitraturia, respectively. There was a significant increasing trajectory in urinary calcium, uric acid, and creatinine as well as a decreasing trend in urinary citrate across tertiles of DII score (all P = ≤0.001). After multivariate adjustment for energy intake, age, physical activity and body mass index, high DII scores were associated with elevated odds of having hypercreatininuria (OR = 2.80, 95%CI: 1.10–7.12, P_trend = 0.04), hypercalciuria (OR = 7.44, 95%CI: 2.62–21.14, P_trend ≤ 0.001), hyperuricosuria (OR = 2.22, 95%CI: 1.001–4.95, P_trend = 0.05), and hypocitraturia (OR = 5.84, 95%CI: 2.14–15.91, P_trend ≤ 0.001). No association was identified between DII and hyperoxaluria.

Plant-based diets, insulin sensitivity and inflammation in elderly men with chronic kidney disease

BACKGROUND

In persons with CKD, adherence to plant-based diets is associated with lower risk of CKD progression and death, but underlying mechanisms are poorly characterized. We here explore associations between adherence to plant-based diets and measures of insulin sensitivity and inflammation in men with CKD stages 3-5.

METHODS

Cross-sectional study including 418 men free from diabetes, aged 70-71 years and with cystatin-C estimated glomerular filtration rate (eGFR) <60 mL/min/1.73m² and not receiving kidney-specific dietetic advice. Information from 7-day food records was used to evaluate the adherence to a plant-based diet index (PBDi), which scores positively the intake of plant-foods and negatively animal-foods. Insulin sensitivity and glucose disposal rate were assessed with the gold-standard hyperinsulinemic euglycemic glucose clamp technique. Inflammation was evaluated by serum concentrations of C-reactive protein (CRP) and interleukin (IL)-6. Associations were explored through linear regression and restricted cubic splines.

RESULTS

The majority of men had CKD stage 3a. Hypertension and cardiovascular disease were the most common comorbidities. The median PBDi was 38 (range 14-55). Across higher quintiles of PBDi (i.e. higher adherence), participants were less often smokers, consumed less alcohol, had lower BMI and higher eGFR (P for trend <0.05 for all). Across higher PBDi quintiles, patients exhibited higher insulin sensitivity and lower inflammation (P for trend <0.05). After adjustment for eGFR, lifestyle factors, BMI, comorbidities and energy intake, a higher PBDi score remained associated with higher glucose disposal rate and insulin sensitivity as well as with lower levels of IL-6 and CRP.

CONCLUSION

In elderly men with non-dialysis CKD stages 3-5, adherence to a plant-based diet was associated with higher insulin sensitivity and lower inflammation, supporting a possible role of plant-based diets in the prevention of metabolic complications of CKD.

Dietary inflammatory index and the aging kidney in older women: a 10-year prospective cohort study

PURPOSE

Chronic inflammation plays a role in the pathogenesis of age-related renal disease and the diet can moderate systemic inflammation. The primary objective of this study was to examine the associations between a dietary inflammatory index (DII^®) score and renal function, the trajectory of renal function decline, and renal disease-related hospitalizations and/or mortality over 10 years.

METHODS

The study was conducted in 1422 Western Australian women without prevalent chronic kidney disease and aged ≥ 70 years. Baseline dietary data, obtained from a validated food frequency questionnaire, were used to calculate a DII score for each individual.

RESULTS

In this cohort, the mean [range] DII score was 0.19 [- 6.14 to 6.39]. A higher DII score was associated with poorer renal function at baseline and a greater renal function decline over 10 years; after multivariable adjustments, a one-unit higher DII score was associated with a 0.55 mL/min/1.73 m² lower eGFR at baseline (p = 0.01) and a 0.06 mL/min/1.73 m² greater annual decline in eGFR over 10 years (p = 0.05). Restricted cubic splines provide evidence of a non-linear association between baseline DII score and risk of a renal disease-related event. Compared to participants in the lowest quintile, those in the highest quintile of DII score were at a higher risk of experiencing a renal disease-related event (adjusted HR 2.06, 95% CI 0.97, 4.37).

CONCLUSION

Recommending an increased consumption of foods with a higher anti-inflammatory potential could form part of a multifaceted approach to reduce the risk of renal disease through diet and lifestyle changes.

Influence of Dietary Ingredients on Lean Body Percent, Uremic Toxin Concentrations, and Kidney Function in Senior-Adult Cats

The goal of this study was to determine if modification of currently available maintenance foods with alternative ingredients, botanicals (fruit and vegetables), and increased amounts of functional lipids (fish oil) would delay the age-associated decline in glomerular filtration rate (GFR) and lean body mass (LBM) in senior-adult cats. Forty-four healthy cats (mean age, 12.2 years; range 10.7 to 14.0 years) were fed one of three foods (n = 14 or 15 per group) for six months: control food with 32.6% protein (as fed), or control food supplemented with increasing amounts of functional food bioactives: fish oil, fruit and vegetables, different protein sources, and <32.0% protein [functional foods one (FF1) and two (FF2)]. Senior-adult cats were compared before and after the feeding trial with 20 young-adult cats (mean age, 3.5 years; range 2.1 to 4.9 years). Compared with younger cats, older cats had decreased lean-body percent and serum albumin concentrations. Feeding FF1 and FF2 for six months increased lean-body percent, maintained serum albumin concentrations, increased GFR, decreased serum symmetric dimethylarginine (SDMA) concentrations, and decreased concentrations of the uremic toxin 3-indoxyl sulfate. These dietary changes may assist in offsetting sarcopenia and the chronic inflammation associated with aging in senior-adult cats.

Greater Dietary Inflammatory Index score is associated with higher likelihood of chronic kidney disease

Chronic kidney disease (CKD) is described as a progressive alteration of kidney function, resulting from multiple factors, including behaviours. We investigated the association of the Dietary Inflammatory Index (DII®) with prevalent CKD in adult Americans. National Health and Nutrition Examination Survey participants with measured data on kidney function markers from 2005 to 2012 were included in this study. Prevalent CKD was based on an estimated glomerular filtration rate (eGFR) <60 ml/min per 1·73 m2 or urinary albumin/creatinine≥30 mg/g. Energy-adjusted DII (E-DIITM) scores were calculated from 24-h dietary recalls. Statistical analyses accounted for the survey design and sample weights. We included 21 649 participants, with 1634 (6·8 %) having prevalent CKD. Participants with high E-DII scores had greater BMI, fasting blood glucose and systolic blood pressure, and were more likely to be diabetic or hypertensive (all P<0·001) compared with those with lower E-DII scores. In regression models adjusted for age, sex, race, fasting blood glucose, blood pressure, BMI, hypertension and diabetes status, mean eGFR significantly decreased across increasing quartiles of E-DII, whereas serum uric acid level and log urinary albumin:creatinine ratio significantly increased (all P<0·001). Prevalent CKD increased from 5·3 % in the lowest to 9·3 % in the highest E-DII quartile (P=0·02). In multivariable-adjusted logistic regression models, the odds of prevalent CKD were 29 % higher in the highest compared with the lowest E-DII quartile. Pro-inflammatory diet is associated with declining kidney function and high prevalence of CKD. Dietary changes that reduce inflammation have a potential to prevent CKD.

Dietary Patterns and Renal Health Outcomes in the General Population: A Review Focusing on Prospective Studies

Healthy dietary patterns may promote kidney health and prevent adverse renal outcomes. Although reviews have summarized the findings from studies on dietary patterns for chronic kidney disease (CKD) management, less is known about dietary patterns for maintaining kidney health prior to CKD development. The current review summarized the results from observational studies from March 2009 to March 2019 investigating associations between dietary patterns and renal outcomes in the general population. The main renal outcome assessed was CKD (estimated glomerular filtration rate < 60 mL/min/1.73 m2). A total of twenty-six research articles met the inclusion criteria. Adherence to the Dietary Approaches to Stop Hypertension (DASH) and Mediterranean diets were significantly associated with a decreased risk of CKD in the majority of the studies. Furthermore, a posteriori "unhealthy" dietary patterns were associated with an increased risk of CKD. In conclusion, the findings from this review suggest that adherence to DASH and Mediterranean dietary patterns may be useful in promoting kidney health and preventing CKD in the general population. More studies, in particular among minorities, are warranted to investigate the role of diet, a potentially modifiable factor, in promoting kidney health.

The Inflammatory Potential of the Diet is Directly Associated with Incident Depressive Symptoms Among French Adults

BACKGROUND

Low-grade chronic inflammation has been suggested to play a substantial role in the etiology of depression; however, studies on the prospective association between the inflammatory potential of the diet and depression are limited.

OBJECTIVE

The aim of this study was to investigate the association between the inflammatory potential of the diet (measured using the Alternate Dietary Inflammatory Index, ADII) and incident depressive symptoms. We also tested the potential modulating effect of sex, age, BMI, and lifestyle indicators.

METHODS

The study sample consisted of 26,730 participants (aged 18-86 y) from the NutriNet-Santé study. Baseline ADII was computed using repeated 24-h dietary records collected during the first 2 y of the follow-up. Incident cases of depressive symptoms were defined by a Center for Epidemiologic Studies Depression scale ≥17 for men and ≥23 for women at least once during follow-up. HR and 95% CI were estimated using multivariable Cox proportional hazards models.

RESULTS

A total of 2221 incident cases of depressive symptoms were identified over a mean follow-up of 5.4 y. After accounting for a wide range of potential confounders, the highest quartile of the ADII was associated with a 15% (95% CI: 2, 31) increase in the risk of depressive symptoms compared with the lowest quartile. In the stratified analyses, associations were statistically significant only among women (HRquartile4 vs. quartile1: 1.19; 95% CI: 1.02, 1.37), middle-age adults (HRquartile4 vs. quartile1: 1.16; 95% CI: 1.00, 1.35), and participants with a BMI ≥25 (HRquartile4 vs. quartile1: 1.29; 95% CI: 1.04, 1.60).

CONCLUSIONS

Overall, a proinflammatory diet was associated with a higher risk of depressive symptoms, especially among women, middle-age adults, and participants with overweight or obesity. These findings contribute to the increasing scientific evidence showing a detrimental role of the proinflammatory diet. The NutriNet-Santé study is registered at clinicaltrials.gov as NCT03335644.

Dietary Inflammatory Index, Pre-Frailty and Frailty among Older US Adults: Evidence from the National Health and Nutrition Examination Survey, 2007-2014

OBJECTIVE

This study aimed to investigate the association between dietary inflammation, pre-frailty and frailty among older US adults. Additionally, effect modification of gender on the association between dietary inflammation and frailty was assessed.

DESIGN

Study data came from the National Health and Nutrition Examination Survey (2007-2014) - a nationally representative, cross-sectional study of adults.

PARTICIPANTS

The analytic sample included adults ≥60 years (n=7,182).

MEASUREMENTS

Dietary Inflammatory Index (DII®) scores were calculated from 24-hour dietary recalls; DII was categorized into quintiles from Quintile 1 (Q1) (least inflammatory) to Q5 (most inflammatory). Frailty was assessed by four criteria: exhaustion, weakness, low body mass, and low physical activity. Individuals were then categorized into robust (0 criteria), pre-frail (1-2 criteria), or frail (3-4 criteria). Multinomial logistic regression was used to examine the odds of frailty categories (pre-frail vs. robust; frail vs. robust).

RESULTS

After adjusting for potential confounders, individuals in DII quintile 5 (vs Q1) were more likely to be pre-frail (OR = 1.71; 95% CI: 1.36-2.15) and frail (OR = 1.70; 95% CI: 1.02-2.85). Individuals in Q4 had greater odds of frailty only (OR = 1.82; 95% CI: 1.13, 2.93). No evidence of effect modification by gender on the association of DII and frailty was found.

CONCLUSION

This study expands upon previous evidence of a relationship between dietary inflammation and frailty. When designing nutrition-based frailty interventions, inflammatory properties of diets should be considered.

Empirically developed dietary inflammatory potential (EDIP) in patients candidate for coronary artery bypass grafting surgery (CABG): Association with metabolic parameters, dietary antioxidant quality score and dietary phytochemical index

AIMS

It has been suggested that empirically developed dietary inflammatory potential (EDIP) is a diagnostic tool for assessment of inflammatory potential of diet in prediction of risk factors related to chronic disease. In the current work, we examined the association between EDIP with cardio-metabolic risk factors, dietary antioxidant quality score (DAQs), dietary phytochemical index (DPI) and Mediterranean dietary quality index (MEDQI) in patients candidate for CABG.

MATERIALS AND METHODS

In the current cross-sectional study, the data obtained from Tehran- Heart Center-Coronary Outcome Measurement (THC-COM) study from 454 patients candidate for the CABG were used. Laboratory measurements including hemoglobin (Hb)-A1C, serum lipids, creatinine, blood urea nitrogen (BUN), hematocrit, Lp(a), telomerase activity, serum vitamin D and c-reactive protein (CRP) were measured with commercial laboratory methods. Dietary indices were measured according to the data obtained from with semi-quantitative FFQ.

RESULTS

In the current work, patients in top quintile of EDIP had higher BMI and higher prevalence of hyperlipidemia compared with patients in lowest quintile (BMI: 28.08 ±3.68 vs 26.69 ± 3.67 and hyperlipidemia: 77.8 vs 65.5%; P < 0.05). Moreover, lower EDIP scores were accompanied with higher vitamin E (0.48 vs 0.4) and total dietary antioxidant scores (4.40 VS 4.28), higher dietary phytochemical scores (69.79 vs 58.29) and lower dietary Mediterranean quality scores (P < 0.05 and P < 0.01 respectively). In male patients, being at highest quintiles of EDIP make patients 2-5% more likely to have higher concentrations of serum cholesterol, BUN and Lp (a), and 6 to 8 times more likely to have higher creatinine and 66% more likely to have lower albumin concentrations compared with male patients in lowest quintiles. In female patients, lower HCT, higher creatinine, higher CRP concentrations and higher telomerase activity were also achieved by higher EDIP scores (P < 0.05).

CONCLUSION

According to our finding, EDIP was associated with obesity, high prevalence of dyslipidemia and cardio-metabolic risk factors. Moreover, EDIP was in an inverse association with dietary antioxidant quality score and dietary phytochemical index. Therefore, EDIP could be assumed as a precise tool for estimating the CVD related risk factors among patients candidate for CABG.

A higher ratio of refined grain to whole grain is associated with a greater likelihood of chronic kidney disease: a population-based study

A growing number of studies suggest that diet and renal function are related. However, little is known about the link between both whole grain (WG) and refined grain (RG) consumption and kidney function parameters. Thus, we investigated the association of WG and RG with urinary albumin to creatinine ratio (ACR) and prevalent chronic kidney disease (CKD). Data from participants of the National Health and Nutrition Examination Surveys (NHANES) from 2005 to 2010 were collected. Estimated glomerular filtration rate (eGFR) was calculated by the CKD Epidemiology Collaboration equation. Survey design and sample weights were taken into consideration for statistical analyses. Finally, we included 16 325 participants from NHANES, 6·9 % of whom had prevalent CKD. In models adjusted for age, sex, race, fasting blood glucose, blood pressure, adiposity, hypertension and diabetes status, mean eGFR significantly increased across increasing quartiles of WG (Q1: 88·2 v. Q4: 95·4 ml/min per 1·73 m2, P&lt;0·001), whereas it significantly decreased across increasing quartiles of RG (Q1: 97·2 v. Q4: 88·4 ml/min per 1·73 m2, P&lt;0·001). Furthermore, serum uric acid levels and ACR significantly decreased across quartiles of WG (both P&lt;0·001). In multivariable-adjusted logistic regression models, the likelihood of prevalent CKD was 21 % lower in the highest WG quartile compared with the lowest one. In conclusion, our results shed light on the beneficial impact of WG on kidney function and CKD, whereas RG is adversely associated with eGFR.

Dietary Pattern and Macronutrients Profile on the Variation of Inflammatory Biomarkers: Scientific Update

It is known that the dietary pattern and macronutrients profile may influence the expression and secretion of inflammatory biomarkers, and the low-grade inflammation is associated with the manifestation of noncommunicable chronic diseases. Therefore, this review aimed to present and discuss the role of dietary patterns and macronutrients on the variation of inflammatory markers related to NCD risk. Scientific evidences within the last five years based on clinical trials, case-controls, cohorts, and cross-sectional studies indicate that normocaloric, carbohydrate-moderated, low-glycemic index, protein-moderated, monounsaturated and polyunsaturated fatty acid-rich, omega-3, and low-saturated fat diets display positive effects on the inflammatory state, both in healthy individuals and in those with cardiovascular risk, although the second group seems to benefit more from changes in the dietary profile.

Dietary inflammatory index: a potent association with cardiovascular risk factors among patients candidate for coronary artery bypass grafting (CABG) surgery

BACKGROUND

Recently, the clinical importance of dietary inflammatory index (DII) in predicting the inflammatory potential of diet and its role in pathogenesis of several chronic disease including some types of cancers, osteoporosis, cardiovascular disease and renal disease has been proposed. However, its association with the disease severity and progression and cardio-metabolic risk factors among patients candidate for coronary artery bypass graft surgery (CABG) has not been evaluated yet. In the current study, the association of DII with cardiovascular risk factors among patients candidate for CABG has been investigated.

METHODS

In the current cross-sectional study, 454 patients aged 35-80 years as candidates of CABG and hospitalized in Tehran Heart Center were enrolled. Anthropometric and demographic characteristics were obtained from all of the participants. Dietary intakes were evaluated with a semi-quantitative food-frequency questionnaire (FFQ) and DII was calculated. Biochemical parameters including hemoglobin (Hb) A1C, serum lipids, albumin, creatinine and high-sensitive C-reactive protein (hs-CRP), lipoprotein (a), creatinine, blood urea nitrogen (BUN), albumin and hematocrit (HCT) were also assessed by commercial laboratory methods. Left ventricular ejection- fraction, number of diseased vessels, New York Heart Association (NYHA) functional class and the European system for cardiac operative risk evaluation (EuroSCORE) were estimated for clinical assessment. One way analysis of variance and chi square tests were used for comparison of demographic parameters between groups. Beta estimates and 95% confidence intervals (CI) for the association between DII and clinical parameters were estimated using linear regression adjusted for the confounders.

RESULTS

According to our findings, high DII scores were associated with higher age, lower body mass index (BMI), higher prevalence of diabetes and myocardial infarction (MI) and lower educational attainment (P < 0.05). Male patients in 4th and 3rd quartile of DII had significantly higher total cholesterol (TC), triglyceride (TG), albumin, creatinine, BUN and hs-CRP concentrations and lower high density lipoprotein cholesterol (HDL) concentrations compared with male patients in lower quartiles (P < 0.05). While in female patients, only lipoprotein (a) concentrations and hematocrit (HCT) percentage in the 4th and 2nd quartile were significantly higher than lower quartiles. EuroSCORE was also significantly higher in top quartiles of DII (P = 0.006).

CONCLUSION

As shown in our results, DII was in a positive association with several cardiovascular risk factors. The higher inflammatory potential of diet denoted higher values of serum lipids, CRP and kidney function tests and higher EuroSCORE as a predictor of post-operative mortality. Therefore, DII can be demonstrated as a target of nutritional interventions for ameliorating the CVD risk factors among patients candidate for CABG especially in male patients.

Dietary fibre intake in relation to the risk of incident chronic kidney disease

The purpose of this study was primarily to evaluate the association of total fibre intake with the risk of incident chronic kidney disease (CKD). We also evaluated the association of dietary fibre from fruits, vegetables, cereals and legumes with the incidence of CKD in a population-based prospective study. We followed up 1630 participants of the Tehran Lipid and Glucose Study for 6·1 years, who were initially free of CKD. Baseline diet was assessed by a valid and reliable FFQ. Estimated glomerular filtration rate (eGFR) was calculated, using the Modification of Diet in Renal Disease Study equation, and CKD was defined as eGFR <60 ml/min per 1·73 m2. OR using multivariable logistic regression was reported for the association of incident CKD with tertiles of dietary fibre intake. After adjustment for age, sex, smoking, total energy intake, physical activity, diabetes and using angiotensin-converting-enzyme inhibitor, the OR for subjects in the highest compared with the lowest tertile of total fibre intake was 0·47 (95 % CI 0·27, 0·86). In addition, for every 5 g/d increase in total fibre intake, the risk of incident CKD decreased by 11 %. After adjusting for potential confounders, OR for participants in the highest compared with the lowest tertile of fibre from vegetables was 0·63 (95 % CI 0·43, 0·93) and from legumes it was 0·68 (95 % CI 0·47, 0·98). We observed inverse associations between total fibre intake and risk of incident CKD, which demonstrate that high fibre intake, mainly from legumes and vegetables, may reduce the occurrence of CKD.

Elderly patients on hemodialysis have worse dietary quality and higher consumption of ultraprocessed food than elderly without chronic kidney disease

OBJECTIVES

The multiple dietary restrictions recommended to patients on hemodialysis (HD), coupled with conditions imposed by aging, may lead to poor dietary quality in these patients. The aim of this study was to investigate the dietary quality and consumption of ultraprocessed food by elderly patients on HD and those without chronic kidney disease (CKD). Additionally, diets on the day of dialysis and on nondialysis days were evaluated.

METHODS

This was a cross-sectional study conducted with 153 noninstitutionalized elderly patients on HD (Elder-HD) and 47 non-CKD elderly (Elder-Healthy) aged ≥60 y. From a 3-d food record, the dietary quality was assessed using the Brazilian Healthy Eating Index Revised (BHEI-R) and the energy contribution of food-processing groups.

RESULTS

Compared with the Elder-Healthy group, the Elder-HD group showed a lower total BHEI-R score (P < 0.05). On the weekdays, the Elder-HD group showed lower scores (P < 0.05) of whole fruit, dark green vegetables and legumes, meat, eggs, and legumes, whereas total cereals showed a higher score (P < 0.05). When furthering the analysis on the Elder-HD group, although the total BHEI-R score did not differ among the days assessed, the components whole fruit, dark green vegetables, and legumes had lower scores (P < 0.05) on the day of dialysis, and the opposite was observed for milk and dairy products. Moreover, the Elder-HD showed a higher (P < 0.05) contribution of processed and ultraprocessed foods and lower (P < 0.05) contribution of natural or minimally processed foods.

CONCLUSION

The Elder-HD group showed poorer dietary quality and higher consumption of processed and ultraprocessed foods than the Elder-Healthy group. Moreover, when compared with the nondialysis day, these patients exhibited worse dietary quality, on the day of dialysis.

A longitudinal study on the acceptance and effects of a therapeutic renal food in pet dogs with IRIS-Stage 1 chronic kidney disease

Currently, nutritional management is recommended when serum creatinine (Cr) exceeds 1.4 mg/dl in dogs with IRIS-Stage 2 chronic kidney disease (CKD) to slow progressive loss of kidney function, reduce clinical and biochemical consequences of CKD, and maintain adequate nutrition. It is unknown if dietary interventions benefit non-azotemic dogs at earlier stages. A prospective 12-month feeding trial was performed in client-owned dogs with IRIS-Stage 1 CKD (n = 36; 20 had persistently dilute urine with urine specific gravity (USG) <1.020 without identifiable non-renal cause; six had persistent proteinuria of renal origin with urine protein creatinine (UPC) ratio >0.5; 10 had both). Ease of transition to therapeutic renal food and effects on renal biomarkers and quality of life attributes were assessed. Dogs were transitioned over 1 week from grocery-branded foods to renal food. At 0, 3, 6, 9, and 12-months a questionnaire to assess owner's perception of their pet's acceptance of renal food and quality of life was completed. Renal biomarkers, including serum Cr, blood urea nitrogen (BUN), and symmetric dimethylarginine (SDMA), and USG and UPC ratio were measured. Of 36 dogs initially enrolled, 35 (97%) dogs were transitioned to therapeutic renal food. Dogs moderately or extremely liked the food 88% of the time, ate most or all of the food 84% of the time, and were moderately or extremely enthusiastic while eating 76% of the time. All renal biomarkers (Cr, BUN, and SDMA) were decreased (p ≤ .05) from baseline at 3-months, and remained decreased from baseline at 12-months in dogs completing the study (n = 20). Proteinuria was reduced in 12 of 16 dogs (p = .045) with proteinuria. Owners reported improvement in overall health and quality of life attributes, and hair and coat quality (all p < .01). In summary, dogs with IRIS-Stage 1 CKD readily transition to renal food. Decreasing serum biomarker concentrations and reduction in proteinuria suggest stabilized kidney function.

Susceptibility to chronic inflammation: an update

Chronic inflammation is defined by the persistence of inflammatory processes beyond their physiological function, resulting in tissue destruction. Chronic inflammation is implicated in the progression of many chronic diseases and plays a central role in chronic inflammatory and autoimmune disease. As such, this review aims to collate some of the latest research in relation to genetic and environmental susceptibilities to chronic inflammation. In the genetic section, we discuss some of the updates in cytokine research and current treatments that are being developed. We also discuss newly identified canonical and non-canonical genes associated with chronic inflammation. In the environmental section, we highlight some of the latest updates and evidence in relation to the role that infection, diet and stress play in promoting inflammation. The aim of this review is to provide an overview of the latest research to build on our current understanding of chronic inflammation. It highlights the complexity associated with chronic inflammation, as well as provides insights into potential new targets for therapies that could be used to treat chronic inflammation and consequently prevent disease progression.

Positive Impact of Nutritional Interventions on Serum Symmetric Dimethylarginine and Creatinine Concentrations in Client-Owned Geriatric Dogs

A prospective study was conducted in client-owned geriatric dogs to evaluate the short-term effects of a test food on serum symmetric dimethylarginine (SDMA) and creatinine (Cr) concentrations. Test food contained functional lipids (fish oil), antioxidants (lipoic acid, vitamins C and E), L-carnitine, botanicals (fruits and vegetables), controlled sodium concentration, and high quality protein sources (high bioavailability and an ideal amino acid composition). Dogs (n = 210) were fed either test food or owner's-choice foods (non-nutritionally controlled cohort). Dogs were included based on age and body weight: small (6.8 to 11.4 kg) and medium dogs (11.5 to 22.7 kg) were ≥ 9 years, whereas dogs >22.7 kg were ≥ 7 years at baseline. At baseline, all dogs had to have serum Cr concentrations within the reference interval and be free of chronic disease. Renal function biomarkers and urinalysis results at baseline, and after consuming test food or owner's-choice foods for 3 and 6 months, were evaluated. Only dogs consuming test food showed significant decreases in serum SDMA and Cr concentrations (both P ≤ 0.05) across time. At baseline or during the 6-month feeding trial, 18 dogs (8.6%) had increased serum SDMA, but normal serum Cr, consistent with IRIS Stage 1 chronic kidney disease. This included 9 dogs fed test food and 9 dogs fed owner's-choice foods. Compared with baseline, after feeding 9 dogs test food for 6 months, serum SDMA decreased in 8 dogs and increased in 1 dog. After feeding 9 dogs owner's-choice foods for 6 months, serum SDMA decreased in 4 dogs and increased in 4 dogs (remained stable in 1 dog). The decreases in serum SDMA and Cr concentrations were significant (both P = 0.03) only for dogs fed test food. These results suggest that nonazotemic dogs with elevated serum SDMA (early renal insufficiency) when fed a test food designed to promote healthy aging are more likely to demonstrate improved renal function compared with dogs fed owner's-choice foods.

Positive Impact of Nutritional Interventions on Serum Symmetric Dimethylarginine and Creatinine Concentrations in Client-Owned Geriatric Cats

A prospective study was conducted in client-owned geriatric cats to evaluate the short- term effects of a test food on serum symmetric dimethylarginine (SDMA) and creatinine (Cr) concentrations. Test food contained functional lipids (fish oil), antioxidants (vitamins C and E), L-carnitine, botanicals (vegetables), highly bioavailable protein, and amino acid supplements. Cats (n = 80) were fed either test food or owner's-choice foods (non-nutritionally controlled cohort). Cats were included based on age (≥ 9 years), indoor only, neutered, and free of chronic disease. At baseline, all cats had serum Cr concentrations within the reference interval. Renal function biomarkers and urinalysis results at baseline and after consuming test food or owner's-choice foods for 3 and 6 months were evaluated. Cats consuming test food showed significant decreases in serum Cr and BUN concentrations across time. Overall, cats consuming owner's-choice foods showed significant increases in serum SDMA concentrations at 3 and 6 months compared with baseline (P ≤ 0.05), whereas in cats consuming test food serum SDMA concentrations did not change. At baseline or during the 6-month feeding trial, 23 (28.8%) cats had increased serum SDMA, but normal serum Cr consistent with IRIS Stage 1 chronic kidney disease. This included 6 cats fed test food and 17 cats fed owner's-choice foods. In the 6 cats fed test food, serum SDMA decreased in 3 cats and remained stable in 1 cat, whereas in the 17 cats fed owner's-choice foods, serum SDMA increased in 13 cats and decreased or remained stable in 4 cats. The increase in serum SDMA concentration was significant (P = 0.02) only for cats fed owner's-choice foods. These results suggest that nonazotemic cats with elevated serum SDMA (early renal insufficiency) when fed a food designed to promote healthy aging are more likely to demonstrate stable renal function compared with cats fed owner's-choice foods. Cats fed owner's-choice foods were more likely to demonstrate progressive renal insufficiency.

Nutritional Interventions that Slow the Age-Associated Decline in Renal Function in a Canine Geriatric Model for Elderly Humans

OBJECTIVE

To determine the effects of feeding traditional and renal protective foods (RPF) supplemented with functional food bioactives on glomerular filtration rate (GFR), lean body percent (LB%), and selected circulating biomarker and metabolite concentrations in a geriatric dog model.

DESIGN

Randomized block design and cross-sectional study.

SETTING

Hill's Pet Nutrition, Inc. dog colony.

PARTICIPANTS

Eighty-one geriatric dogs (mean age, 10.4; range, 7.9-14.2 years) and 30 mature-adult dogs (mean age, 5.0; range, 3.3-6.9 years).

INTERVENTION

Geriatric dogs were fed one of three foods (n = 27 per group) for 6 months: a traditional RPF (control) that was energy dense and mildly protein-restricted, or control food supplemented with increasing amounts of functional food bioactives: fish oil, lipoic acid, fruits and vegetables, and higher quality protein sources [functional foods one (FF1) and two (FF2)]. Geriatric dogs were compared before and after the feeding trial with mature adult dogs.

MEASUREMENTS

Renal function was assessed by GFR, LB% was determined by dual energy x-ray absorptiometry, and circulating biomarkers and metabolites were measured in blood.

RESULTS

Before the feeding trial, GFR (+28.2%), LB% (+18.6%), and serum total protein (+10.0%) were higher in mature versus healthy geriatric dogs (all P<0.001). Geriatric dogs consuming all three foods increased (P<0.001) GFR over time; group averages ranged from 13.0-16.9%. Dogs fed the highest supplemented level of bioactives (FF2) had lower (P<0.001) symmetric dimethylarginine (SDMA) concentrations (-14.3%). Feeding functional foods did not alter body weight, but increased (P<0.001) serum protein concentration (+6.7%).

CONCLUSION

Supplementation with functional food bioactives can temporarily reverse the age-associated decline in renal function and serum total protein.

Therapeutics targeting persistent inflammation in chronic kidney disease

Systemic inflammation is a condition intrinsically linked to chronic kidney disease (CKD) and its other typical sequelae, such as acquired immune dysfunction, protein-energy wasting (PEW), and accelerated vascular aging that promote premature cardiovascular disease (CVD) and infections, the two leading causes of death in CKD patients. Inflammation is a major contributor to complications in CKD, and inflammatory markers, such as C-reactive protein and pro- and anti-inflammatory cytokines, correlate with underlying causes and consequences of the inflamed uremic phenotype, such as oxidative stress, endothelial dysfunction, CVD, PEW, and infections, and are sensitive and independent predictors of outcome in CKD. Therefore, inflammation appears to be a logical target for potential preventive and therapeutic interventions in patients with CKD. Putative anti-inflammatory therapy strategies aiming at preventing complications and improving outcomes in CKD span over several areas: (1) dealing with the source of inflammation (such as cardiovascular, gastrointestinal or periodontal disease and depression); (2) providing nonspecific immune modulatory effects by promoting healthy dietary habits and other lifestyle changes; (3) promoting increased use of recognized pharmacologic interventions that have pleiotropic effects; and, (4) introducing novel targeted anticytokine interventions. This review provides a brief update on inflammatory biomarkers and possible therapeutic approaches targeting inflammation and the uremic inflammatory milieu in patients with CKD.

Significance of Neutrophil Gelatinase-Associated Lipocalin Level-to-Serum Creatinine Ratio for Assessing Severity of Inflammation in Patients with Renal Dysfunction

The aim of this study was to assess the significance of the neutrophil gelatinase-associated lipocalin/serum creatinine ratio (NGAL/sCr ratio) in patients with renal dysfunction. The percent difference between plasma NGAL level and the NGAL/sCr ratio was 36.7% (95% CI, 18.4–83.7%) in patients with sCr level ≥ 1.2 mg/dL. In a multivariate analysis, high sensitivity C-reactive protein (hsCRP) was significantly associated with the NGAL/sCr ratio and plasma NGAL level (r = 0.526 and r = 0.453, resp., P < 0.001). In a receiver operating characteristics curve, the diagnostic ability of the NGAL/sCr ratio to identify hsCRP > 4.0 mg/dL was superior to that of NGAL [0.783 (95% CI, 0.674–0.892) versus 0.733 (95% CI, 0.615–0.852), P = 0.032]. The area under the curve of the NGAL/sCr ratio was larger than that of hsCRP to detect corrected erythrocyte sedimentation rate > 25 mm/h and the neutrophil-to-lymphocyte ratio >4.5 in renal dysfunction. In short, the NGAL/sCr ratio may offer useful information when screening patients with both systemic inflammation and renal dysfunction.

Cellular and Molecular Mechanisms of Chronic Kidney Disease with Diabetes Mellitus and Cardiovascular Diseases as Its Comorbidities

Chronic kidney disease (CKD), diabetes mellitus (DM), and cardiovascular diseases (CVD) are complex disorders of partly unknown genesis and mostly known progression factors. CVD and DM are the risk factors of CKD and are strongly intertwined since DM can lead to both CKD and/or CVD, and CVD can lead to kidney disease. In recent years, our knowledge of CKD, DM, and CVD has been expanded and several important experimental, clinical, and epidemiological associations have been reported. The tight cellular and molecular interactions between the renal, diabetic, and cardiovascular systems in acute or chronic disease settings are becoming increasingly evident. However, the (patho-) physiological basis of the interactions of CKD, DM, and CVD with involvement of multiple endogenous and environmental factors is highly complex and our knowledge is still at its infancy. Not only single pathways and mediators of progression of these diseases have to be considered in these processes but also the mutual interactions of these factors are essential. The recent advances in proteomics and integrative analysis technologies have allowed rapid progress in analyzing complex disorders and clearly show the opportunity for new efficient and specific therapies. More than a dozen pathways have been identified so far, including hyperactivity of the renin–angiotensin (RAS)–aldosterone system, osmotic sodium retention, endothelial dysfunction, dyslipidemia, RAS/RAF/extracellular-signal-regulated kinase pathway, modification of the purinergic system, phosphatidylinositol 3-kinase (PI 3-kinase)-dependent signaling pathways, and inflammation, all leading to histomorphological alterations of the kidney and vessels of diabetic and non-diabetic patients. Since a better understanding of the common cellular and molecular mechanisms of these diseases may be a key to successful identification of new therapeutic targets, we review in this paper the current literature about cellular and molecular mechanisms of CKD.