Dietary Sodium and Other Nutrient Intakes among Patients Undergoing Hemodialysis in New Zealand

How to Limit Interdialytic Weight Gain in Patients on Maintenance Hemodialysis: State of the Art and Perspectives

Background: Interdialytic weight gain (IDWG), defined as the accumulation of salt and water intake between dialysis sessions, is a critical parameter of fluid management and a marker of adherence to dietary and fluid restrictions in hemodialysis patients. Excessive IDWG has been strongly associated with increased cardiovascular risk, including left ventricular hypertrophy, cardiac dysfunction, and cerebrovascular complications. Additionally, it necessitates more aggressive ultrafiltration, potentially compromising hemodynamic stability, impairing quality of life, and escalating healthcare costs. Despite international guidelines recommending an IDWG target of <4-4.5% of body weight, many patients struggle to achieve this due to barriers in adhering to dietary and fluid restrictions. This review explores the current state-of-the-art strategies to mitigate IDWG and evaluates emerging diagnostic and therapeutic perspectives to improve fluid management in dialysis patients. Methods: A literature search was conducted in PubMed/MEDLINE, Scopus, and Web of Science to identify studies on IDWG in hemodialysis. Keywords and MeSH terms were used to retrieve peer-reviewed articles, observational studies, RCTs, meta-analyses, and systematic reviews. Non-English articles, case reports, and conference abstracts were excluded. Study selection followed PRISMA guidelines, with independent screening of titles, abstracts, and full texts. Data extraction focused on IDWG definitions, risk factors, clinical outcomes, and management strategies. Due to study heterogeneity, a narrative synthesis was performed. Relevant data were synthesized thematically to evaluate both established strategies and emerging perspectives. Results: The current literature identifies three principal strategies for IDWG control: cognitive-behavioral interventions, dietary sodium restriction, and dialysis prescription adjustments. While educational programs and behavioral counseling improve adherence, their long-term effectiveness remains constrained by patient compliance and logistical challenges. Similarly, low-sodium diets, despite reducing thirst, face barriers to adherence and potential nutritional concerns. Adjustments in dialysate sodium concentration have yielded conflicting results, with concerns regarding hemodynamic instability and intradialytic hypotension. Given these limitations, alternative approaches are emerging. Thirst modulation strategies, including chewing gum to stimulate salivation and acupuncture for autonomic regulation, offer potential benefits in reducing excessive fluid intake. Additionally, technological innovations, such as mobile applications and telemonitoring, enhance self-management by providing real-time feedback on fluid intake. Biofeedback-driven dialysis systems enable dynamic ultrafiltration adjustments, improving fluid removal efficiency while minimizing hemodynamic instability. Artificial intelligence (AI) is advancing predictive analytics by integrating wearable bioimpedance sensors and dialysis data to anticipate fluid overload and refine individualized dialysis prescriptions, driving precision-based volume management. Finally, optimizing dialysis frequency and duration has shown promise in achieving better fluid balance and cardiovascular stability, suggesting that a personalized, multimodal approach is essential for effective IDWG management. Conclusions: Despite decades of research, IDWG remains a persistent challenge in hemodialysis, requiring a multifaceted, patient-centered approach. While traditional interventions provide partial solutions, integrating thirst modulation strategies, real-time monitoring, biofeedback dialysis adjustments, and AI-driven predictive tools represent the next frontier in fluid management. Future research should focus on long-term feasibility, patient adherence, and clinical efficacy, ensuring these innovations translate into tangible improvements in quality of life and cardiovascular health for dialysis patients.

Interdialytic weight gain and low-salt diet in patients on chronic hemodialysis: A systematic review and meta-analysis

OBJECTIVE

The present systematic review and meta-analysis aims to determine the difference in the interdialytic weight gain (IDWG) between low salt intake diet and normal/high salt intake diet or between nutritional counseling aimed at reducing diet salt intake and no nutritional counseling in patients on chronic hemodialysis.

METHODS

Medline, PubMed, Web of Science, and the Cochrane Library were searched. Randomized, crossover or parallel studies and observational studies were considered for inclusion and: 1) included adult patients on chronic hemodialysis since at least 6 months; 2) compared normal salt intake diet with low salt intake diet on IDWG; 3) compared nutritional counseling aimed at reducing diet salt intake with no intervention on IDWG; 4) reported on IDWG.

RESULTS

Eight articles (783 patients) were fully assessed for eligibility and included in the investigation. Meta-analysis showed frequencies of patients that increased their weight after dialysis more than 2.5 Kg (events) over total enrolled subjects for each group (control and experimental). As no significant heterogeneity was observed (I2 = 8%; p = 0.36), the pooled analysis was performed using a fixed-effect model. Funnel plot was generated and no obvious asymmetry was observed. The Overall Odds Ratio to get an event in the experimental group, in respect to controls, is 0.57 (0.33-0.97) (p = 0.04] with single studies OR ranging between 0.11 and 1.08.

CONCLUSION

The present systematic review and meta-analysis suggest that the use of a low salt diet sodium or a nutritional counseling aimed at reducing diet salt intake is associated with a statistically significant reduction of the IDWG in patients on chronic hemodialysis.

Prevalence and factors associated with malnutrition among hemodialysis patients in a single hemodialysis center in Vietnam: A cross-sectional study

Malnutrition is a common problem among hemodialysis patients that increases morbidity and mortality and decreases the quality of life. This study aimed to assess the prevalence of malnutrition and associated factors and survey the consumption of energy and several nutrients among hemodialysis patients. A prospective observational study with a cross-sectional design was conducted on 76 patients on hemodialysis therapy at Nguyen Tri Phuong Hospital, Ho Chi Minh City, Vietnam, for 2 months (from May to July 2022). Dialysis malnutrition score was used to determine patients' nutritional status. Data about their biochemical parameters were retrieved from records with the newest results. Among the 76 patients, 38 (50.0%) were female. The mean age of the patients was 55.0 ± 13.5 years. Based on the dialysis malnutrition score, 56 (73.7%) patients had mild to moderate malnutrition, while 2 (2.6%) had severe malnutrition. The average energy intake was 21.5 kcal/kg/day, with only 3.9% meeting the recommended intake. The average protein intake was 1.0 g/kg/day, and about 10.5% of participants complied with the recommended protein level. In addition, the majority of patients did not reach the recommendations for sodium (56.6%), potassium (88.2%), phosphate (75.0%), and calcium (82.9%). We found a significant association between patients' occupation (P < .05), dialysis vintage (P < .001), and malnutrition status. Malnutrition is widespread among Vietnamese hemodialysis patients, which necessitates regular assessment and monitoring. We recommend paying more attention to the nutritional status of patients who are unemployed, retired, or stopped working and those with ≥ 5 years of hemodialysis.

Impact of dietary sodium restriction on falls among middle-aged and older adults: Results of an 8-year longitudinal study

AIM

This study aimed to understand the relationship between dietary sodium restriction (DSR) and falling experiences in middle-aged and older adults.

METHODS

The 8-year follow-up data from the Taiwan Longitudinal Study on Aging, covering 5131 individuals aged ≥50 years, were analyzed using random-effects panel logit models. Participants were asked to indicate whether they were told by a physician to reduce or avoid sodium intake from food and whether they had had fall experiences during the past year. We modelled falling experiences as a function of DSR (independent variable), involuntary body weight loss and walking difficulty (mediators), and chronic diseases (moderator), adjusting for individual-level characteristics.

RESULTS

Individuals with DSR were at a higher risk of falls compared with those with no DSR (adjusted odds ratio [AOR] = 1.30, 95% confidence interval [CI] = 1.11-1.53). This effect was more prevalent in individuals with a history of stroke (AOR = 1.85, 95% CI = 1.19-2.87). Those told to reduce sodium intake by a physician were likely to lose weight involuntarily (AOR = 1.20, 95% CI = 1.05-1.36) and had difficulty walking up two or three flights of stairs alone (AOR = 2.38, 95% CI = 1.73-3.27), which mediated the effect of DSR on increased fall risk (AOR = 1.15, 95% CI = 0.95-1.38). We found a temporal effect: participant reactions to short- and mid-term DSR were significant.

CONCLUSIONS

DSR was associated with a greater likelihood of falls among middle-aged and older adults, particularly those with a history of stroke. Geriatr Gerontol Int 2024; 24: 292-299.

Dietary Sodium Restriction and Frailty among Middle-Aged and Older Adults: An 8-Year Longitudinal Study

Frailty is a common geriatric syndrome. However, there is little information about the relationship between dietary sodium restriction (DSR) and frailty in later life. This study aimed to elucidate the relationship between DSR and frailty in middle-aged and older adults. The 8-year follow-up data from the Taiwan Longitudinal Study on Aging, including 5131 individuals aged ≥50 years, were analyzed using random-effects panel logit models. DSR was evaluated by assessing whether the participants were told by a physician to reduce or avoid sodium intake from food. Three indices were used to measure frailty: the Study of Osteoporotic Fractures (SOF) index, the Fried index, and the Fatigue, Resistance, Ambulation, Illness, and Loss of weight (FRAIL) index. Individuals with DSR were more likely to report frailty compared with those with non-DSR (SOF: adjusted odds ratio [AOR] = 1.82, 95% confidence interval [CI] = 1.46-2.27; Fried: AOR = 2.55, 95% CI = 1.64-3.98; FRAIL: AOR = 2.66, 95% CI = 1.89-3.74). DSR was associated with a higher likelihood of SBF (AOR = 2.61, 95% CI = 1.61-4.22). We identified a temporal trajectory in our study, noting significant participant reactions to both short- and mid-term DSR. Future research should address the balance between frailty risk and cardiovascular risk related to DSR.

Potential modulating effects of Allium mongolicum regel ethanol extract on rumen fermentation and biohydrogenation bacteria of dairy cows in vitro

The objective of this study was to evaluate the potential modulating effects of Allium mongolicum regel ethanol extract (AME) on rumen fermentation and biohydrogenation (BH) bacteria in vitro. Four Holstein cows were used as donors for the rumen fluid used in this study. In experiment 1, five treatments (supplemented with 0 mg/g, 1 mg/g, 2 mg/g, 3 mg/g, and 4 mg/g of AME based on fermentation substrate, respectively) were conducted to evaluate the effects of different levels of AME on fermentation status in vitro. The results showed that after 24 h of fermentation, MCP was reduced with AME supplementation (p < 0.05), and the multiple combinations of different combinations index (MFAEI) value was the highest with 3 mg/g of AME. In experiment 2, six treatments were constructed which contained: control group (A1); the unsaturated fatty acid (UFA) mixture at 3% concentration (A2); the mixture of A2 and 3 mg/g of AME (A3); 3 mg/g of AME (A4); the UFA mixture at 1.5% concentration (A5); the mixture of A5 and 3 mg/g of AME (A6). The abundance of bacterial species involved in BH was measured to evaluate the potential modulating effect of AME on rumen BH in vitro. Compared with the A1 group, the A3, A4, and A6 groups both showed significant decreases in the abundance of rumen BH microbial flora including Butyrivibrio proteoclasticus, Butyrivibrio fibrisolvens, Ruminococcus albus and Clostridium aminophilum (p < 0.01). The A3 group was less inhibitory than A4 in the abundance of B. proteoclasticus, B. fibrisolvens, and R. albus, and the inhibitory effect of the A6 group was higher than that of A4. In conclusion, the supplementation with 3 mg/g of AME could modulate the rumen fermentation and affect BH key bacteria, which suggests that AME may have the potential to inhibit the rumen BH of dairy cows.

Results of Salt Intake Restriction Monitored with the New Sodium Control Biosensor

INTRODUCTION

Adherence to a low-sodium (Na) diet is crucial in patients under hemodialysis, as it improves cardiovascular outcomes and reduces thirst and interdialytic weight gain. Recommended salt intake is lower than 5 g/day. The new 6008 CAREsystem monitors incorporate a Na module that offers the advantage of estimating patients' salt intake. The objective of this study was to evaluate the effect of dietary Na restriction for 1 week, monitored with the Na biosensor.

METHODS

A prospective study was conducted in 48 patients who maintained their usual dialysis parameters and were dialyzed with a 6008 CAREsystem monitor with activation of the Na module. Total Na balance, pre-/post-dialysis weight, serum Na (sNa), changes in pre- to post-dialysis sNa (ΔsNa), diffusive balance, and systolic and diastolic blood pressure were compared twice, once after 1 week of patients' usual Na diet and again after another week with more restricted Na intake.

RESULTS

Restricted Na intake increased the percentage of patients on a low-Na diet (<85 Na mmol/day) from 8% to 44%. Average daily Na intake decreased from 149 ± 54 to 95 ± 49 mmol, and interdialytic weight gain was reduced by 460 ± 484 g per session. More restricted Na intake also decreased pre-dialysis sNa and increased both intradialytic diffusive balance and ΔsNa. In hypertensive patients, reducing daily Na by more than 3 g Na/day lowered their systolic blood pressure.

CONCLUSIONS

The new Na module allowed objective monitoring of Na intake, which in turn could permit more precise personalized dietary recommendations in patients under hemodialysis.

Dietary Intake Correlated to Waist-To-Hip Ratio in Patients on Maintenance Hemodialysis

OBJECTIVE

Individuals with end-stage kidney disease (ESKD) receiving maintenance hemodialysis (MHD) are at risk for protein-energy wasting (PEW). Inadequate dietary intake and altered anthropometrics are two criteria of the PEW diagnosis. This study explored whether individuals with ESKD on MHD meet the National Kidney Foundation Kidney Disease Outcome Quality Initiative (NKF-KDOQI) 2020 guidelines for nutritional adequacy on a dialysis treatment day (DD) and explored the relationship between dietary energy [DEI] and protein [DPI] intake and anthropometrics.

METHODS

This was a secondary analysis of clinical and demographic data for 142 adults from the Rutgers Nutrition and Kidney Disease database. The study assessed the relationships between DEI, DPI, and anthropometrics, including body mass index (BMI), BMI category, waist circumference, and waist-to-hip ratio (WHR) using Pearson's or Spearman's correlation and one-way ANOVA.

RESULTS

The sample had a median age of 55.7 years; 58% were male, 83.8% were Black/African American, with a median dialysis vintage of 42.0 months (e.g., 3.5 years). Seventy-five percent of the data sample were overweight or obese. The WHR was 1.0 ± 0.8 cm for males and 0.9 ± 0.1 for females. DEI and DPI on a DD did not meet the NKF-KDOQI 2020 guidelines. Median DEI was 17.6 ± 8.4 kcal/kg and DPI was 0.7 ± 0.4 g/kg. In the total sample, significant positive correlations were found between DEI (r = 0.74, P = 0.03) and DPI (r = 0.18, P = 0.037) and WHR. In females, a significant positive correlation was identified between DPI and WHR (r = 0.26, P = 0.046).

CONCLUSIONS

These findings suggest that the nutritional intake of individuals with ESKD receiving MHD is inadequate to meet NKF-KDOQI 2020 guidelines on a DD. WHR may be a useful tool to assess alterations in anthropometrics related to DEI or DPI in this population, but more research is warranted.

Association between salt intake and long-term mortality in hemodialysis patients: A retrospective cohort study

Background

The association between salt intake and clinical outcomes in hemodialysis patients has been controversial. This study aimed to clarify the association between salt intake and mortality in hemodialysis patients.

Method

The present study included patients who underwent hemodialysis from June 1st 2016 to May 31st 2020. Corrected salt intake by ideal body weight was the main predictor of outcomes. Ideal body weight was calculated assuming that the ideal body mass index is 22 kg/m² for the Japanese population. The multivariate Cox proportional hazards model was used to determine the association between corrected salt intake and mortality, adjusting for potential confounders. The outcomes considered were all-cause mortality and cumulative incidence of cardiovascular events at year 4.

Result

A total of 492 adult patients were enrolled in the study. The mean daily salt intake and corrected salt intake at baseline were 9.5 g/day and 0.17 g/kg/day, respectively. The low corrected salt intake group (< 0.13 g/kg/day) demonstrated the highest 4-year all-cause mortality. No association was observed between corrected salt intake and the cumulative incidence of cardiovascular events. In multivariate Cox proportional hazards analysis, only the group with corrected salt intake of 0.16–0.20 g/kg/day was associated with a decreased hazard risk for all-cause death compared with the low corrected salt intake group.

Conclusion

The present study found that a low salt intake was associated with high all-cause mortality in hemodialysis patients. Reduced long-term survival may be attributed to malnutrition resulting from excessive salt restriction.

Experiences of New Zealand Haemodialysis Patients in Relation to Food and Nutrition Management: A Qualitative Study

People receiving haemodialysis have considerable and complex dietary and healthcare needs, including co-morbidities. A recent New Zealand study has shown that few patients on haemodialysis are able to meet nutritional requirements for haemodialysis. This study aims to describe the perspectives and experiences of dietary management among patients on haemodialysis in New Zealand. This exploratory qualitative study used in-depth semi-structured interviews. Purposive sampling was used to recruit participants from different ethnic groups. Forty interviews were conducted, audio-recorded and transcribed verbatim. An inductive approach was taken using thematic analysis. Forty participants were interviewed. Participants spoke of major disruption to their lives as a result of their chronic kidney disease and being on haemodialysis, including loss of employment, financial challenges, loss of independence, social isolation and increased reliance on extended family. Most had received adequate dietary information, although some felt that more culturally appropriate support would have enabled a healthier diet. These findings show that further support to make the recommended dietary changes while on haemodialysis should focus on socio-cultural factors, in addition to the information already provided.

The Association Between Handgrip Strength and Predialysis Serum Sodium Level in Patients With Chronic Kidney Disease Stage 5D

Purpose: Handgrip strength (HGS) is a useful tool for the systematic assessment of muscle function related to nutritional status. Reduced HGS has been associated with adverse clinical outcomes in chronic kidney disease (CKD) stage 5D patients. In the same patients, predialysis low serum sodium (sNa) has been associated with malnutrition and mortality. Here, we investigated the role of predialysis sNa on muscle function in CKD-5D patients.

Methods: We evaluated 45 patients on hemodialysis (HD) and 28 patients on peritoneal dialysis (PD) with HGS measurement, bioimpedance analysis, anthropometric measures, and malnutrition inflammation score (MIS). According to established diagnostic criteria, reduced HGS was defined as strength below 30 and 20 Kg in men and women, respectively. Predialysis sNa values were defined as the mean of all predialysis measurements during the preceding 6 months. Data analysis was performed separately for each of the HD and PD groups.

Results: The proportions of reduced HGS did not differ between the HD (66%) and PD (54%) groups, respectively. Patients in the HD group as compared to those in the PD group had higher serum albumin and potassium and mid-arm muscle circumference and lower residual renal function (RRF) and residual urine volume. Multivariate logistic analysis, after controlling for muscle mass, nutritional biomarkers, MIS, fluid overload and RRF, showed that for every 1 mmol/l increase of sNa the odds of reduced HGS was decreased by 60% (OR = 0.40, 95% CI: 0.16–0.99) and 42% (OR = 0.58, 95% CI: 0.36–0.93) in HD and PD patients, respectively. However, stratified analysis indicated that lower sNa levels predicted reduced HGS in individuals with a background of malnutrition, inflammation, overhydration and less preserved RRF, representing unfavorable conditions strongly related to muscle wasting in the dialysis setting.

Conclusions: Predialysis sNa is a strong and independent determinant of HGS, a reliable nutritional marker in CKD-5D stage patients. However, according to our findings, lower sNa levels appear to be a marker of underlying unfavorable conditions that are heavily associated with reduced HGS, rather than a causal determinant of reduced HGS. Whether optimizing sNa levels improves patient muscle performance requires further investigations.

Dietary Daily Sodium Intake Lower than 1500 mg Is Associated with Inadequately Low Intake of Calorie, Protein, Iron, Zinc and Vitamin B1 in Patients on Chronic Hemodialysis

Background: To measure daily sodium intake in patients on chronic hemodialysis and to compare the intake of nutrients, minerals, trace elements, and vitamins in patients who had a daily sodium intake below or above the value of 1500 mg recommended by the American Heart Association. Methods: Dietary intake was recorded for 3 days by means of 3-day diet diaries in prevalent patients on chronic hemodialysis. Each patient was instructed by a dietitian on how to fill the diary, which was subsequently signed by a next of kin. Results: We studied 127 patients. Mean sodium intake (mg) was 1295.9 ± 812.3. Eighty-seven (68.5%) patients had a daily sodium intake <1500 mg (group 1) and 40 (31.5%) ≥ 1500 mg (group 2). Correlation between daily sodium intake and daily calorie intake was significant (r = 0.474 [0.327 to 0.599]; p < 0.0001). Daily calorie intake (kcal/kg/day) was lower in group 1 (21.1 ± 6.6; p = 0.0001) than in group 2 (27.1 ± 10.4). Correlation between daily sodium intake and daily protein intake was significant (r = 0.530 [0.392 to 0.644]; p < 0.0001). The daily protein intake (grams/kg/day) was lower in group 1 (0.823 ± 0.275; p = 0.0003) than in group 2 (1.061 ± 0.419). Daily intake of magnesium, copper, iron, zinc, and selenium was significantly lower in group 1 than in group 2. Daily intake of vitamin A, B2, B3, and C did not differ significantly between group 1 and group 2. Daily intake of vitamin B1 was significantly lower in group 1 than in group 2. Significantly lower was, in group 1 than in group 2, the percentage of patients within the target value with regard to intake of calories (11.5% vs. 37.5%; p = 0.001) and proteins (9.2% vs. 27.5%; p = 0.015) as well as of iron (23% vs. 45%; p = 0.020), zinc (13.8% vs. 53.8%; p = 0.008) and vitamin B1 (8.1% vs. 50%; p < 0.001). Conclusion: A low daily intake of sodium is associated with an inadequately low intake of calorie, proteins, minerals, trace elements, and vitamin B1. Nutritional counselling aimed to reduce the intake of sodium in patients on chronic hemodialysis should not disregard an adequate intake of macro- and micronutrients, otherwise the risk of malnutrition is high.