Emma McMahon

A Randomized Trial of Dietary Sodium Restriction in CKD

There is a paucity of quality evidence regarding the effects of sodium restriction in patients with CKD, particularly in patients with pre-end stage CKD, where controlling modifiable risk factors may be especially important for delaying CKD progression and cardiovascular events. We conducted a double-blind placebo-controlled randomized crossover trial assessing the effects of high versus low sodium intake on ambulatory BP, 24-hour protein and albumin excretion, fluid status (body composition monitor), renin and aldosterone levels, and arterial stiffness (pulse wave velocity and augmentation index) in 20 adult patients with hypertensive stage 3-4 CKD as phase 1 of the LowSALT CKD study. Overall, salt restriction resulted in statistically significant and clinically important reductions in BP (mean reduction of systolic/diastolic BP, 10/4 mm Hg; 95% confidence interval, 5 to 15 /1 to 6 mm Hg), extracellular fluid volume, albuminuria, and proteinuria in patients with moderate-to-severe CKD. The magnitude of change was more pronounced than the magnitude reported in patients without CKD, suggesting that patients with CKD are particularly salt sensitive. Although studies with longer intervention times and larger sample sizes are needed to confirm these benefits, this study indicates that sodium restriction should be emphasized in the management of patients with CKD as a means to reduce cardiovascular risk and risk for CKD progression.

Achieving Salt Restriction in Chronic Kidney Disease

There is consistent evidence linking excessive dietary sodium intake to risk factors for cardiovascular disease and chronic kidney disease (CKD) progression in CKD patients; however, additional research is needed. In research trials and clinical practice, implementing and monitoring sodium intake present significant challenges. Epidemiological studies have shown that sodium intake remains high, and intervention studies have reported varied success with participant adherence to a sodium-restricted diet. Examining barriers to sodium restriction, as well as factors that predict adherence to a low sodium diet, can aid researchers and clinicians in implementing a sodium-restricted diet. In this paper, we critically review methods for measuring sodium intake with a specific focus on CKD patients, appraise dietary adherence, and factors that have optimized sodium restriction in key research trials and discuss barriers to sodium restriction and factors that must be considered when recommending a sodium-restricted diet.

Consumer acceptance of reformulated food products: A systematic review and meta-analysis of salt-reduced foods

ABSTRACT Food product reformulation is promoted as an effective strategy to reduce population salt intake and address the associated burden of chronic disease. Salt has a number of functions in food processing, including impacting upon physical and sensory properties. Manufacturers must ensure that reformulation of foods to reduce salt does not compromise consumer acceptability. The aim of this systematic review is to determine to what extent foods can be reduced in salt without detrimental effect on consumer acceptability. Fifty studies reported on salt reduction, replacement or compensation in processed meats, breads, cheeses, soups, and miscellaneous products. For each product category, levels of salt reduction were collapsed into four groups: <40%, 40–59%, 60–79% and ≥80%. Random effects meta-analyses conducted on salt-reduced products showed that salt could be reduced by approximately 40% in breads [mean change in acceptability for reduction <40% (−0.27, 95% confidence interval (CI) −0.62, 0.08; p = 0.13)] and approximately 70% in processed meats [mean change in acceptability for reductions 60–69% (−0.18, 95% CI −0.44, 0.07; p = 0.15)] without significantly impacting consumer acceptability. Results varied for other products. These results will support manufacturers to make greater reductions in salt when reformulating food products, which in turn will contribute to a healthier food supply.

Review of behaviour change interventions to reduce population salt intake.

BackgroundExcess salt intake is a major cause of raised blood pressure—the leading risk factor for death and disability worldwide. Although behaviour change interventions such as awareness campaigns and health education programs are implemented to reduce salt intake, their effectiveness is unclear. This global systematic review investigates the impact of population-level behaviour change interventions that aim to reduce salt intake.MethodsA search for published and grey literature was conducted using PubMed, Cochrane Library, Embase, Web of Science, Sage, Scopus, OpenGrey, Google Scholar and other relevant organizations’ websites. Studies were included if 1) published between 2005 and 2015; 2) the education or awareness-raising interventions were aimed at the population or sub-population and 3) salt intake and/or salt-related behaviours were outcome measures. Study and intervention characteristics were extracted for the descriptive synthesis and study quality was assessed.ResultsTwenty two studies involving 41,448 participants were included. Most were conducted in high income countries (n = 16), targeting adults (n = 21) in the general population (n = 16). Behaviour change interventions were categorised as health education interventions (n = 14), public awareness campaigns (n = 4) and multi-component interventions (including both health education and awareness campaigns, n = 4). 19 of the 22 studies demonstrated significant reductions in estimated salt intake and/or improvement in salt-related behaviours. All studies showed high risk of bias in one or more domains. Of the 10 higher quality studies, 5 found a significant effect on salt intake or salt behaviours based on the more objective outcome assessment method.ConclusionBased on moderate quality of evidence, population-level behaviour change interventions can improve salt-related behaviours and/or reduce salt intake. However, closer analysis of higher quality studies show inconsistent evidence of the effectiveness and limited effect sizes suggest the implementation of education and awareness-raising interventions alone are unlikely to be adequate in reducing population salt intake to the recommended levels. A framework which guides rigorous research and evaluation of population-level interventions in real-world settings would help understand and support more effective implementation of interventions to reduce salt intake.

The effect of lowering salt intake on ambulatory blood pressure to reduce cardiovascular risk in chronic kidney disease (LowSALT CKD study): protocol of a randomized trial

BackgroundDespite evidence implicating dietary sodium in the pathogenesis of cardiovascular disease (CVD) in chronic kidney disease (CKD), quality intervention trials in CKD patients are lacking. This study aims to investigate the effect of reducing sodium intake on blood pressure, risk factors for progression of CKD and other cardiovascular risk factors in CKD.Methods/designThe LowSALT CKD study is a six week randomized-crossover trial assessing the effect of a moderate (180 mmol/day) compared with a low (60 mmol/day) sodium intake on cardiovascular risk factors and risk factors for kidney function decline in mild-moderate CKD (stage III-IV). The primary outcome of interest is 24-hour ambulatory blood pressure, with secondary outcomes including arterial stiffness (pulse wave velocity), proteinuria and fluid status. The randomized crossover trial (Phase 1) is supported by an ancillary trial (Phase 2) of longitudinal-observational design to assess the longer term effectiveness of sodium restriction. Phase 2 will continue measurement of outcomes as per Phase 1, with the addition of patient-centered outcomes, such as dietary adherence to sodium restriction (degree of adherence and barriers/enablers), quality of life and taste assessment.DiscussionThe LowSALT CKD study is an investigator-initiated study specifically designed to assess the proof-of-concept and efficacy of sodium restriction in patients with established CKD. Phase 2 will assess the longer term effectiveness of sodium restriction in the same participants, enhancing the translation of Phase 1 results into practice. This trial will provide much-needed insight into sodium restriction as a treatment option to reduce risk of CVD and CKD progression in CKD patients.Trial registrationUniversal Trial Number: U1111-1125-2149. Australian New Zealand Clinical Trials Registry Number: ACTRN12611001097932

Store turnover as a predictor of food and beverage provider turnover and associated dietary intake estimates in very remote Indigenous communities

Objective: Determine how very‐remote Indigenous community (RIC) food and beverage (F&B) turnover quantities and associated dietary intake estimates derived from only stores, compare with values derived from all community F&B providers.

Taste perception in kidney disease and relationship to dietary sodium intake

Taste abnormalities are prevalent in Chronic Kidney Disease (CKD) potentially affecting food palatability and intake, and nutrition status. The TASTE CKD study aimed to assess taste and explore the relationship of dietary sodium intake with taste disturbance in CKD subjects. This was a cross-sectional study of 91 adult stage 3-5 CKD participants (78% male) aged 65.9 ± 13.5 years with mean estimated glomerular filtration rate of 33.1 ± 12.7 ml/min/1.73 m(2), and 30 controls (47% male) aged 55.2 ± 7.4 years without kidney dysfunction. Taste assessment was performed in both groups, presenting five basic tastes (sweet, sour, salty, umami and bitter) in blinded 2 ml solution which the participants tasted, identified (identification) and rated perceived strength (intensity) on a 10 cm visual analogue scale. Sodium intake was measured in the CKD group using validated food frequency questionnaire to determine high or low sodium intake (cut-off 100 mmol sodium/day). Differences between groups (CKD vs controls; high vs low sodium intake) were analysed using chi-square for identification and t-test for intensity. Multivariate analysis was used to adjust for age and gender differences between CKD and controls. The control group identified mean 3.9 ± 1.0 tastants correctly compared with 3.0 ± 1.2 for CKD group (p < 0.001), which remained significant after adjustment for age and gender. After adjustment for age and gender, sour identification and intensity and salty and umami intensity were impaired in CKD compared with controls. Participants with low sodium intake were more likely to correctly identify salty and umami, and rated intensity of umami and bitter significantly higher than those with high sodium intake. These findings add to the body of evidence suggesting that taste changes occur with CKD, independent of age and gender differences, with specific impairment in sour, umami and salty tastes. Our finding that sodium intake is related to umami and bitter disturbance as well as salty taste warrants further investigation.

Effect of 25% Sodium Reduction on Sales of a Top-Selling Bread in Remote Indigenous Australian Community Stores: A Controlled Intervention Trial.

Reducing sodium in the food supply is key to achieving population salt targets, but maintaining sales is important to ensuring commercial viability and maximising clinical impact. We investigated whether 25% sodium reduction in a top-selling bread affected sales in 26 remote Indigenous community stores. After a 23-week baseline period, 11 control stores received the regular-salt bread (400 mg Na/100 g) and 15 intervention stores received the reduced-salt version (300 mg Na/100 g) for 12-weeks. Sales data were collected to examine difference between groups in change from baseline to follow-up (effect size) in sales (primary outcome) or sodium density, analysed using a mixed model. There was no significant effect on market share (−0.31%; 95% CI −0.68, 0.07; p = 0.11) or weekly dollars (

Detection of 12.5% and 25% Salt Reduction in Bread in a Remote Indigenous Australian Community

58; −149, 266; p = 0.58). Sodium density of all purchases was not significantly reduced (−8 mg Na/MJ; −18, 2; p = 0.14), but 25% reduction across all bread could significantly reduce sodium (−12; −23, −1; p = 0.03). We found 25% salt reduction in a top-selling bread did not affect sales in remote Indigenous community stores. If achieved across all breads, estimated salt intake in remote Indigenous Australian communities would be reduced by approximately 15% of the magnitude needed to achieve population salt targets, which could lead to significant health gains at the population-level.

Altered dietary salt for people with CKD

Food reformulation is an important strategy to reduce the excess salt intake observed in remote Indigenous Australia. We aimed to examine whether 12.5% and 25% salt reduction in bread is detectable, and, if so, whether acceptability is changed, in a sample of adults living in a remote Indigenous community in the Northern Territory of Australia. Convenience samples were recruited for testing of reduced-salt (300 and 350 mg Na/100 g) versus Standard (~400 mg Na/100 g) white and wholemeal breads (n = 62 for white; n = 72 for wholemeal). Triangle testing was used to examine whether participants could detect a difference between the breads. Liking of each bread was also measured; standard consumer acceptability questionnaires were modified to maximise cultural appropriateness and understanding. Participants were unable to detect a difference between Standard and reduced-salt breads (all p values > 0.05 when analysed using binomial probability). Further, as expected, liking of the breads was not changed with salt reduction (all p values > 0.05 when analysed using ANOVA). Reducing salt in products commonly purchased in remote Indigenous communities has potential as an equitable, cost-effective and sustainable strategy to reduce population salt intake and reduce risk of chronic disease, without the barriers associated with strategies that require individual behaviour change.