A High-Sodium Diet Modulates the Immune Response of Food Allergy in a Murine Model

Mounting evidence demonstrates that a high-salt diet (HSD) not only affects hemodynamic changes but also disrupts immune homeostasis. The T helper 17 (Th17) and regulatory T cells (Tregs) are susceptible to hypersalinity. However, research on the influence of sodium on Th2-mediated food allergies remains scarce. We aimed to investigate the effect of dietary sodium on the immune response to food allergies. Mice maintained on an HSD (4% NaCl), low-salt diet (LSD; 0.4% NaCl), or control diet (CTRL; 1.0% NaCl) were orally sensitized with ovalbumin (OVA) and a cholera toxin (CT) adjuvant, and then subjected to an intragastric OVA challenge. OVA-specific immunoglobulin G (IgG), IgG1, IgG2a, and IgE antibodies were significantly higher in the HSD group than in the CTRL group (p < 0.001, p < 0.05, p < 0.01, and p < 0.05, respectively). Mice on HSD had significantly higher interleukin (IL)-4 levels than the CTRL group (p < 0.01). The IL-10 levels were significantly lower in the HSD group than in the CTRL group (p < 0.05). The serum levels of interferon-γ (IFN-γ), sodium, and chloride did not differ among the three groups. This study indicates that excessive salt intake promotes Th2 responses in a mouse model of food allergy.

Comparison of Salt-Related Knowledge and Behaviors Status of WeChat Users between 2019 and 2020

In order to identify the status of salt-related knowledge and behavior of the residents who were active in WeChat software between 2019 and 2020, 10-day salt-related surveys were conducted in 2019 and 2020 based on the WeChat public platform of China Healthy Lifestyle for All Campaign. Distribution and scores of salt-related knowledge, salt reduction behavior and high-salt intake behavior between 2019 and 2020 were compared. Data of 2109 participants in 2019 and 12,732 participants in 2020 were left for analysis. Overall, 88.2% of participants in 2019 had a willingness to reduce the amount of cooking salt in their households, significantly lower than 90.2% in 2020 (p-value < 0.05). In 2019 and 2020, over 80% of the participants knew fine dried noodles contain salt, but less than 30% knew ice cream contains salt. Over 78% of participants chose 5 g or 6 g for the maximum daily salt intake of healthy adults, and about 98% of participants knew that excessive salt intake would increase the risk of hypertension in both years. The percentage of participants who used salt measuring spoons asked restaurants to use less salt, read the sodium content on the nutrition facts table, chose foods with low sodium content and regularly used low-sodium salt, were 36.1%, 45.0%, 44.1%, 40.3% and 35.8% in 2019, and the percentage increased significantly to 46.4%, 49.2%, 50.8%, 47.1% and 43.4% in 2020 (all p-value < 0.05). The percentage of people regularly eating pickled mustard tubers, salted vegetables and sauce foods or using high-salt condiments also increased from 2019 to 2020. The median of salt-related knowledge scores, salt reduction behavior scores and high-salt intake behavior scores were 11, 2, 5 points in 2019, and 10, 3, 5 points in 2020, respectively. Compared to 2019, the salt-related knowledge score was relatively lower, while the salt reduction behavior score and high-salt intake behavior score were relatively higher in 2020. Besides, the score of salt-related knowledge and behaviors differed in different gender, age and hypertension groups. The COVID-19 epidemic may have influenced the salt-related knowledge and behaviors status of WeChat users in China. Promotion and education of salt-related knowledge and online behavior intervention are still needed, particularly for male and hypertension patients in the future.

Effects of Sodium-Specific Medical Nutrition Therapy from a Registered Dietitian Nutritionist in Individuals with Chronic Kidney Disease: An Evidence Analysis Center Systematic Review and Meta-Analysis

Dietary sodium intake can increase risk of hypertension, a leading cause of kidney failure in individuals with chronic kidney disease. The objective of this systematic review was to examine the effect of sodium-specific medical nutrition therapy provided by a registered dietitian nutritionist or international equivalent on blood pressure and urinary sodium excretion in individuals with chronic kidney disease, stages 2 through 5, receiving maintenance dialysis and posttransplant. Medline, the Cumulative Index to Nursing and Allied Health Literature, Cochrane Cochrane Central Register of Controlled Trials, and other databases were searched to identify eligible controlled trials published in the English language from January 2000 until June 2020 that addressed the research question. Risk of bias was assessed using the RoB 2.0 tool and quality of evidence was examined by outcome using the Grading of Recommendations Assessment, Development, and Evaluation method. Of the 5,642 articles identified, eight studies were included in the final analyses. Six studies targeted clients who were not dialyzed, including one with clients who were posttransplantation, and two studies with clients receiving maintenance hemodialysis. Sodium-specific medical nutrition therapy from a registered dietitian nutritionist significantly reduced clinic systolic blood pressure (mean difference -6.7, 95% CI -11.0 to -2.4 mm Hg; I² = 51%) and diastolic blood pressure (mean difference -4.8, 95% CI, -7.1 to -2.4 mm Hg; I² = 23%) as well as urinary sodium excretion (mean difference -67.6, 95% CI -91.6 to -43.6 mmol/day; I² = 84.1%). Efficacy was limited to individuals who were not dialyzed, including posttransplantation, but the intervention did not significantly improve blood pressure in individuals receiving maintenance hemodialysis. Adults with chronic kidney disease should begin to work with registered dietitian nutritionist early in the course of disease to receive individualized, effective counseling to improve risk factors and, ultimately, health outcomes.

The Feasibility of Using Computrition Software for Nutrition Research-A Pilot Study

We evaluated the feasibility of using Computrition to design and implement a low vs. typical sodium meal plan intervention for older adults. Dietitians used Computrition to design a 7-day meal plan with three caloric levels (≤1750, 2000, ≥2250 kcals/day) and two sodium densities (low = 0.9 mg/kcal; n = 11 or typical = 2 mg/kcal; n = 9). Feasibility was determined by post-hoc definitions of effectiveness, sodium compliance, palatability of diet, sustainability, and safety. Given the low number of participants in one of the three calorie groups, the higher calorie groups were combined. Thus, comparisons are between low vs. typical meal plans at two calorie levels (≤1750 or ≥2000 kcals/day). Overall, regardless of the calorie group, the meal plans created with Computrition were effective in reaching the targeted sodium density and were safe for participants. Furthermore, individuals appeared to be equally compliant and reported similar palatability across meal plans. However, one of the three criteria for the sustainability definition was not met. In conclusion, we successfully used Computrition to design low and typical sodium meal plans that were effective, compliable, and safe. Future studies of older adults in similar settings should focus on improving the palatability of the meal plans and scaling this protocol to larger studies in older adults.

Comparative analysis of visit and home blood pressure in a pilot trial on the effect of 18% sodium substitute salt on blood pressure

Aim to compare the home blood pressure monitoring (HBPM) and visit blood pressure monitoring in a clinical phase I single-arm pilot trial. The 18% sodium substitute salt was used in 43 hypertensives for 8 weeks, and visited once a week, while weekly visit blood (VBP) pressure, daily home blood pressure (HBP) and urine test results before and after intervention were collected. 43 hypertensive patients were recruited, 4 were lost. And enrolled 39 patients for analysis. The VBP were lower than morning HBP and night HBP (P < 0.05). And VBP was good correlated with morning BP (SBP: r = 0.692, P < 0.001, DBP: r = 0.789, P < 0.001) and night BP (SBP: r = 0.571, P < 0.001, DBP: r = 0.738, P < 0.001). The results of mixed linear model analysis showed that patients' visit SBP (- 11.4 mmHg, 95% CI: - 17.0 to - 5.7, P < 0.001), morning home SBP (- 10.0 mmHg, 95% CI: - 16.4 to - 3.6, P = 0.003) and night home SBP (- 10.2 mmHg, 95% CI: - 15.8 to - 4.6, P = 0.001) decreased significantly, after intervention. Both HBP and VBP showed that 18% substitute salt intervention could decrease the blood pressure of hypertensives. Medication led to VBP lower than HBP, but the two still had a good correlation.Trial registration: NCT03226327. Registered 21 July 2017-Retrospectively registered, http://www.clinicaltrials.gov .

Short-Term Effects of Salt Restriction via Home Dishes Do Not Persist in the Long Term: A Randomized Control Study

Salt intake reduction is crucial to prevent non-communicable diseases (NCDs) globally. This study aimed to investigate the short- and long-term effects of monitoring salt concentration in homemade dishes on reducing salt intake in a Japanese population. A double-blind randomized controlled trial using a 2 × 2 factorial design with two interventions was conducted in 195 participants; they were assigned to both interventions for a group monitoring salt concentration in soups (control: no monitoring) and a group using low-sodium seasoning (control: regular seasoning). We evaluated 24-hour urinary sodium excretions at baseline and after a three-month intervention for the changes as major outcomes, at six- and twelve-months after baseline as long-term follow-up surveys. Urinary sodium excretion decreased in both intervention and control groups after the intervention. However, differences in the change for both monitoring and low-sodium seasoning interventions were statistically non-significant (p = 0.29 and 0.52, respectively). Urinary sodium excretion returned to the baseline level after twelve-months for all groups. Monitoring of salt concentration is ineffective in reducing salt intake for short- and long-term among the people studied in this cohort.

Priority Actions to Advance Population Sodium Reduction

High sodium intake is estimated to cause approximately 3 million deaths per year worldwide. The estimated average sodium intake of 3.95 g/day far exceeds the recommended intake. Population sodium reduction should be a global priority, while simultaneously ensuring universal salt iodization. This article identifies high priority strategies that address major sources of sodium: added to packaged food, added to food consumed outside the home, and added in the home. To be included, strategies needed to be scalable and sustainable, have large benefit, and applicable to one of four measures of effectiveness: (1) Rigorously evaluated with demonstrated success in reducing sodium; (2) suggestive evidence from lower quality evaluations or modeling; (3) rigorous evaluations of similar interventions not specifically for sodium reduction; or (4) an innovative approach for sources of sodium that are not sufficiently addressed by an existing strategy. We identified seven priority interventions. Four target packaged food: front-of-pack labeling, packaged food reformulation targets, regulating food marketing to children, and taxes on high sodium foods. One targets food consumed outside the home: food procurement policies for public institutions. Two target sodium added at home: mass media campaigns and population uptake of low-sodium salt. In conclusion, governments have many tools to save lives by reducing population sodium intake.

Salt Reduction Strategies in Portuguese School Meals, from Pre-School to Secondary Education-The Eat Mediterranean Program

High sodium (salt) consumption is associated with an increased risk of developing non-communicable diseases. However, in most European countries, Portugal included, sodium intake is still high. This study aimed to assess the sodium content of school meals before and after the Eat Mediterranean (EM) intervention—a community-based program to identify and correct nutritional deviations through the implementation of new school menus and through schools’ food handlers training. EM (2015–2017) was developed in 25 schools (pre to secondary education) of two Portuguese Municipalities, reaching students aged 3–21 years old. Samples of the complete meals (soup + main course + bread) from all schools were collected, and nutritional quality and laboratory analysis were performed to determine their nutritional composition, including sodium content. Overall, there was a significant decrease (−23%) in the mean sodium content of the complete school meals, which was mainly achieved by the significant reduction of 34% of sodium content per serving portion of soup. In conclusion, EM had a positive effect on the improvement of the school meals’ sodium content, among the participant schools. Furthermore, school setting might be ideal for nutrition literacy interventions among children, for flavors shaping, and for educating towards less salty food acceptance.

Disentangling the Relationships Between the Renin-Angiotensin-Aldosterone System, Calcium Physiology, and Risk for Kidney Stones

CONTEXT

Complex relationships between aldosterone and calcium homeostasis have been proposed.

OBJECTIVE

To disentangle the influence of aldosterone and intravascular volume on calcium physiology.

DESIGN

Patient-oriented and epidemiology studies.

SETTING

Clinical research center and nationwide cohorts.

PARTICIPANTS/INTERVENTIONS

Patient-oriented study (n = 18): Participants were evaluated after completing a sodium-restricted (RES) diet to contract intravascular volume and after a liberalized-sodium (LIB) diet to expand intravascular volume. Cross-sectional studies (n = 3755): the association between 24h urinary sodium and calcium excretion and risk for kidney stones was assessed.

RESULTS

Patient-oriented study: compared to a RES-diet, a LIB-diet suppressed renin activity (LIB: 0.3 [0.1, 0.4] vs. RES: 3.1 [1.7, 5.3] ng/mL/h; P < 0.001) and plasma aldosterone (LIB: 2.0 [2.0, 2.7] vs. RES: 20.0 [16.1, 31.0] vs. ng/dL; P < 0.001), but increased calciuria (LIB: 238.4 ± 112.3 vs. RES: 112.9 ± 60.8 mg/24hr; P < 0.0001) and decreased serum calcium (LIB: 8.9 ± 0.3 vs. RES: 9.8 ± 0.4 mg/dL; P < 0.0001). Epidemiology study: mean urinary calcium excretion was higher with greater urinary sodium excretion. Compared to a urinary sodium excretion of < 120 mEq/day, a urinary sodium excretion of ≥220 mEq/day was associated with a higher risk for having kidney stones in women (risk ratio = 1.79 [95% confidence interval 1.05, 3.04]) and men (risk ratio = 2.06 [95% confidence interval 1.27, 3.32]).

CONCLUSIONS

High dietary sodium intake suppresses aldosterone, decreases serum calcium, and increases calciuria and the risk for developing kidney stones. Our findings help disentangle the influences of volume from aldosterone on calcium homeostasis and provide support for the recommendation to restrict dietary sodium for kidney stone prevention.

The Effects of Two Intervention Strategies to Reduce the Intake of Salt and the Sodium-To-Potassium Ratio on Cardiovascular Risk Factors. A 4-Month Randomised Controlled Study among Healthy Families

The aim was to examine the effects of two different salt reduction strategies on selected cardiovascular risk factors. The study was a four-month cluster randomised controlled study. Eighty-nine healthy Danish families (309 individuals) were randomly assigned to either (A) gradually salt-reduced bread, (B) gradually salt-reduced bread and dietary counselling to further reduce salt intake and increase potassium intake or (C) standard bread (control). The effect was assessed using linear mixed models. Intention to treat analyses comparing changes in the three groups showed a significant reduction in body fat percent (−1.31% (−2.40; −0.23)) and a borderline significant reduction in total plasma cholesterol (−0.25 mmol/L (−0.51; 0.01) and plasma renin (−0.19 pmol/L (−0.39; 0.00) in group A compared to the control group. Adjusted complete case analyses showed a significant reduction in total plasma cholesterol (−0.29 mmol/L (−0.50; −0.08), plasma LDL cholesterol (−0.08 mmol/L (−0.15; −0.00)), plasma renin (−0.23 pmol/L (−0.41; −0.05)), plasma adrenaline (−0.03 nmol/L (−0.06; −0.01)) and body fat percent (−1.53% (−2.51; −0.54)) in group A compared to the control group. No significant changes were found in group B compared to the control group. In conclusion, receiving sodium reduce bread was associated with beneficial changes in cardiovascular risk factors. No adverse effects were observed.

Effectiveness of a multifactorial intervention, consisting of self-management of antihypertensive medication, self-measurement of blood pressure, hypocaloric and low sodium diet, and physical exercise, in patients with uncontrolled hypertension taking 2 or more antihypertensive drugs: The MEDICHY study

INTRODUCTION

High blood pressure is the leading modifiable risk factor for cardiovascular disease, and is associated with high morbidity and mortality and with significant health care costs for individuals and society. However, fewer than half of the patients with hypertension receiving pharmacological treatment have adequate blood pressure control. The main reasons for this are therapeutic inertia, lack of adherence to treatment, and unhealthy lifestyle (i.e., excess dietary fat and salt, sedentary lifestyle, and overweight). Cardiovascular risk and mortality are greater in hypertensive patients who are receiving treatment but have suboptimal control of blood pressure.

METHODS/DESIGN

This is a multicentre, parallel, 2-arm, single-blind (outcome assessor), controled, cluster-randomized clinical trial. General practitioners and nurses will be randomly allocated to the intervention group (self-management of antihypertensive medication, self-measurement of blood pressure, hypocaloric and low sodium diet, and physical exercise) or the control group (regular clinical practice). A total of 424 patients in primary care centers who use 2 or more antihypertensive drugs and blood pressure of at least 130/80 during 24-hambulatory blood pressure monitoring will be recruited. The primary outcome is systolic blood pressure at 12 months. The secondary outcomes are blood pressure control (<140/90 mm Hg); quality of life (EuroQol 5D); direct health care costs; adherence to use of antihypertensive medication; and cardiovascular risk (REGICOR and SCORE scales).

DISCUSSION

This trial will be conducted in the primary care setting and will evaluate the impact of a multifactorial intervention consisting of self-management of blood pressure, antihypertensive medications, and lifestyle modifications (hypocaloric and low sodium diet and physical exercise).

Effect of salt reduction interventions in lowering blood pressure in Chinese populations: a systematic review and meta-analysis of randomised controlled trials

RATIONALE AND OBJECTIVE

Salt reduction remains a global challenge and different salt reduction strategies have been studied in China. This study is to systematically evaluate evidence from randomised controlled trials (RCT) in China and inform the effective salt reduction strategies.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

MEDLINE, Embase, Cochrane Central Register of Controlled Trials, Wanfang Data and the China National Knowledge Infrastructure databases through October 2019.

ELIGIBILITY CRITERIA

RCTs conducted in China with at least 4 weeks' duration of study and blood pressure (BP) reported.

DATA EXTRACTION AND SYNTHESIS

Data were screened, extracted and appraised by two independent reviewers. The quality of study was assessed using a modified Cochrane Collaboration's risk of bias tool. The primary outcome was the difference in BP change from baseline to the end of study between interventions and control. The effects were pooled using a random effects model and associated factors were explored by a meta-regression.

RESULTS

We identified 24 studies involving 10 448 participants, including 8 studies on health education (4583 participants), 2 studies on salt restriction diet (162 participants), 1 study on salt restriction spoon (50 participants) and 13 studies on salt substitute (5653 participants). Six studies on salt substitute and three studies on health education were identified with high quality. Pooled results from the six studies showed that salt substitutes significantly reduced systolic BP (-5.7 mm Hg; 95% CI -8.5 to -2.8) and diastolic BP (-2.0 mm Hg; 95% CI -3.5 to -0.4). The School-EduSalt study showed that the school-based health education significantly reduced systolic BP among parents (-2.3 mm Hg; 95% CI -4.5 to -0.04).

CONCLUSIONS

Among four salt reduction strategies studied in China with RCT design, only salt substitute was proved effective in lowering BP by the pooled effect from multiple studies with high quality. More well-designed studies are warranted for other strategies.

Evaluation of the efficacy of simplified nutritional instructions from physicians on dietary salt restriction for patients with type 2 diabetes mellitus consuming excessive salt: protocol for a randomized controlled trial

BACKGROUND

Hypertension is present in more than 50% of patients with type 2 diabetes mellitus. Dietary salt restriction is recommended for the management of high blood pressure. Instructions on dietary salt restriction, provided by a dietitian, have been shown to help patients reduce their salt intake. However, appointments for the dietitians in hospitals are often already fully booked, making it difficult for patients to receive instructions on the same day as the outpatient clinic visit.

AIM

The aim of this trial is to test a new intervention to assess whether guidance on dietary salt restriction provided by physicians during outpatient visits is effective in reducing salt intake in patients with type 2 diabetes mellitus who have an excessive salt intake.

METHODS

In this unblinded randomized controlled trial (RCT), a total of 200 patients, male or female, aged between 20 and 90 years, who have type 2 diabetes mellitus and consume excessive salt will be randomly assigned to two groups: an intervention group and a control group. In addition to being given routine treatment, participants in the intervention group will be given individual guidance on restricting their dietary salt intake by a physician upon enrollment. The control group will only be given routine treatment. Participants will be followed up for 24 weeks. The primary outcome will be dietary salt intake, which will be assessed at baseline and at 8, 16, and 24 weeks. The secondary outcomes, including body weight, body mass index, hemoglobin A1c level, blood pressure, blood glucose level, serum lipid profile, and urinary albumin excretion level, will be assessed at baseline and at 8, 16, and 24 weeks.

DISCUSSION

The results of this RCT have the potential to provide a simple and novel clinical approach to reduce salt intake among patients with type 2 diabetes, making regular visits to their physician, in outpatient facilities. This protocol will contribute to the literature because it describes a practical intervention that has not been tested previously, and it may serve as guidance to other researchers interested in testing similar interventions.

TRIAL REGISTRATION

University Hospital Medical Information Network (UMIN), UMIN000028809. Registered retrospectively on 24 August 2017. http://www.umin.ac.jp.

Salt restriction lowers blood pressure at rest and during exercise without altering peripheral hemodynamics in hypertensive individuals

Dietary salt restriction is a well-established approach to lower blood pressure and reduce cardiovascular disease risk in hypertensive individuals. However, little is currently known regarding the effects of salt restriction on central and peripheral hemodynamic responses to exercise in those with hypertension. Therefore, this study sought to determine the impact of salt restriction on the central and peripheral hemodynamic responses to static-intermittent handgrip (HG) and dynamic single-leg knee extension (KE) exercise in individuals with hypertension. Twenty-two subjects (14 men and 8 women, 51 ± 10 yr, 173 ± 11 cm, 99 ± 23 kg) forewent their antihypertensive medication use for at least 2 wk before embarking on a 5-day liberal salt (LS: 200 mmol/day) diet followed by a 5-day restricted salt (RS: 10 mmol/day) diet. Subjects were studied at rest and during static intermittent HG exercise at 15, 30, and 45% of maximal voluntary contraction and KE exercise at 40, 60, and 80% of maximum KE work rate. Salt restriction lowered resting systolic blood pressure (supine: -12 ± 12 mmHg, seated: -17 ± 12 mmHg) and diastolic blood pressure (supine: -3 ± 9 mmHg, seated: -5 ± 7 mmHg, P < 0.05). Despite an ~8 mmHg lower mean arterial blood pressure during both HG and KE exercise following salt restriction, neither central nor peripheral hemodynamics were altered. Therefore, salt restriction can lower blood pressure during exercise in subjects with hypertension, reducing the risk of cardiovascular events, without impacting central and peripheral hemodynamics during either arm or leg exercise.NEW & NOTEWORTHY This is the first study to examine the potential blood pressure-lowering benefit of a salt-restrictive diet in individuals with hypertension without any deleterious effects of exercising blood flow. While mean arterial pressure decreased by ~8 mmHg following salt restriction, these findings provide evidence for salt restriction to provide protective effects of reducing blood pressure without inhibiting central or peripheral hemodynamics required to sustain arm or leg exercise in subjects with hypertension.

Reducing Dietary Sodium to 1000 mg per Day Reduces Neurovascular Transduction Without Stimulating Sympathetic Outflow

The American Heart Association recommends no more than 1500 mg of sodium/day as ideal. Some cohort studies suggest low-sodium intake is associated with increased cardiovascular mortality. Extremely low-sodium diets (≤500 mg/d) elicit activation of the renin-angiotensin-aldosterone system and stimulate sympathetic outflow. The effects of an American Heart Association-recommended diet on sympathetic regulation of the vasculature are unclear. Therefore, we assessed whether a 1000 mg/d diet alters sympathetic outflow and sympathetic vascular transduction compared with the more commonly recommended 2300 mg/d. We hypothesized that sodium reduction from 2300 to 1000 mg/d would not affect resting sympathetic outflow but would reduce sympathetic transduction in healthy young adults. Seventeen participants (age: 26±2 years, 9F/8M) completed 10-day 2300 and 1000 mg/d sodium diets in this randomized controlled feeding study (crossover). We measured resting renin activity, angiotensin II, aldosterone, blood pressure, muscle sympathetic nerve activity, and norepinephrine. We quantified beat-by-beat changes in mean arterial pressure and leg vascular conductance (femoral artery ultrasound) following spontaneous sympathetic bursts to assess sympathetic vascular transduction. Reducing sodium to 1000 mg/d increased renin activity, angiotensin II, and aldosterone ( P<0.01 for all) but did not alter mean arterial pressure (78±2 versus 77±2 mm Hg, P=0.56), muscle sympathetic nerve activity (13.9±1.3 versus 13.9±0.8 bursts/min, P=0.98), or plasma/urine norepinephrine. Sympathetic vascular transduction decreased ( P<0.01). These data suggest that reducing sodium from 2300 to 1000 mg/d stimulates the renin-angiotensin-aldosterone system, does not increase resting basal sympathetic outflow, and reduces sympathetic vascular transduction in normotensive adults.

Effects of sodium intake on postural lightheadedness: Results from the DASH-sodium trial

Lightheadedness after standing contributes to adverse clinical events, including falls. Recommendations for higher sodium intake to treat postural lightheadedness have not been evaluated in a trial setting. The Dietary Approaches to Stop Hypertension (DASH)-Sodium trial (1998-1999) tested the effects of the DASH diet and sodium reduction on blood pressure (BP). Participants were randomly assigned to DASH or a typical Western diet (control). During either diet, participants ate three sodium levels (50, 100, 150 meq/d at 2100 kcal) in random order for 30-days, separated by 5-day breaks. Participants reported the presence and severity of postural lightheadedness at baseline and after each feeding period. There were 412 participants (mean age 48 years; 57% women; 57% black). Mean baseline SBP/DBP was 135/86 mm Hg; 9.5% reported baseline lightheadedness. Among those consuming the DASH diet, high vs low sodium increased lightheadedness (OR 1.71; 95% CI: 1.01, 2.90; P = 0.047) and severity of lightheadedness (P = 0.02), but did not affect lightheadedness in those consuming the control diet (OR 0.77; 95% CI: 0.46, 1.29; P = 0.32). Among those consuming high vs low sodium in the context of the DASH diet, adults <60 vs ≥60 years old experienced more lightheadedness (P-interaction = 0.04), along with obese vs non-obese adults (P-interaction = 0.01). In the context of the DASH diet, higher sodium intake was associated with more frequent and severe lightheadedness. These findings challenge traditional recommendations to increase sodium intake to prevent lightheadedness.

Paucity of high-quality studies reporting on salt and health outcomes from the science of salt: A regularly updated systematic review of salt and health outcomes (April 2017 to March 2018)

The purpose of this review is to identify, summarize, and critically appraise studies on dietary salt and health outcomes that were published from April 2017 to March 2018. The search strategy was adapted from a previous systematic review on dietary salt and health. Identified studies were screened based on a priori defined criteria to identify publications eligible for detailed critical appraisals. Overall, 6747 citations were identified by the search strategy, and 42 health outcome studies were identified. Three of the 42 studies met the criteria for methodological quality and health outcomes and underwent detailed critical appraisals and commentary. In addition, a systematic review and meta-analysis was critically appraised, although it did not strictly meet our methodological criteria. All four of the studies critically appraised found that sodium reduction improved blood pressure, especially in individuals with hypertension. In addition, sodium reduction reduced albuminuria in patients with stage 1-3 chronic kidney disease. Examination of the time course of blood pressure responses to sodium reduction revealed lowering sodium in the context of an average American diet may not produce maximal blood pressure reductions within a 4-week intervention period. This review provides further evidence of the benefit of sodium reduction for blood pressure lowering and gives insights into the subgroups of the population that may derive the greatest benefit from sodium reduction and the time course required to see benefit. Only three high-quality studies were identified during this 12-month review period, highlighting the critical need for more well-conducted rigorous studies in this area.

Rationale and design of the Study of Dietary Intervention Under 100 MMOL in Heart Failure (SODIUM-HF)

BACKGROUND

Patients with heart failure (HF) remain at high risk for future events despite medical and device therapy. Dietary sodium reduction is often recommended based on limited evidence. However, it is not known whether dietary sodium reduction reduces the morbidity or mortality associated with HF.

METHODS

The SODIUM study is a pragmatic, randomized, open-label trial assessing the efficacy of dietary sodium reduction to <1500 mg daily counseling compared to usual care for patients with chronic HF. The intervention is provided by trained personnel at the site and uses 3-day food records for directing counseling. The primary outcome is an intention-to-treat analysis on the time to first cardiovascular event or death measured at 12 months. Secondary end points include the change in quality of life (using the Kansas City Cardiomyopathy Questionnaire), change in New York Heart Association class, and change in 6-minute walk test. The first patient was enrolled in March 2014, and subsequently, 27 sites in 6 countries enrolled patients.

CONCLUSIONS

The SODIUM-HF trial will provide a robust evaluation of the effects of dietary sodium reduction in patients with HF. Results are expected in 2020.

Protocol for the Process Evaluation of a Complex, Statewide Intervention to Reduce Salt Intake in Victoria, Australia

Systematic reviews of trials consistently demonstrate that reducing salt intake lowers blood pressure. However, there is limited evidence on how interventions function in the real world to achieve sustained population-wide salt reduction. Process evaluations are crucial for understanding how and why an intervention resulted in its observed effect in that setting, particularly for complex interventions. This project presents the detailed protocol for a process evaluation of a statewide strategy to lower salt intake in Victoria, Australia. We describe the pragmatic methods used to collect and analyse data on six process evaluation dimensions: reach, dose or adoption, fidelity, effectiveness, context and cost, informed by Linnan and Steckler's framework and RE-AIM. Data collection methods include routinely collected administrative data; surveys of processed foods, the population, food industry and organizations; targeted campaign evaluation and semi-structured interviews. Quantitative and qualitative data will be triangulated to provide validation or context for one another. This process evaluation will contribute new knowledge about what components of the intervention are important to salt reduction strategies and how the interventions cause reduced salt intake, to inform the transferability of the program to other Australian states and territories. This protocol can be adapted for other population-based, complex, disease prevention interventions.

Effects of a low salt diet on isolated systolic hypertension: A community-based population study

Evidence has shown that long-term sodium reduction can not only reduce blood pressure, but also provide cardiovascular benefits. To date, there is little evidence related to the effects of salt reduction on isolated systolic hypertension (ISH).A total of 126 hypertensive patients were divided into an ISH group (n = 51) and a non-ISH (NISH) group (n = 75). The members of each group were then randomly assigned to low sodium salt (LSSalt) or normal salt (NSalt) diets for 6 months. Their blood pressure was measured every 2 months. Serum plasma renin-angiotensin activity, blood biochemical assays and urinary measurements were determined at the baseline and at the end of the 6 months.At the end of the study, the mean systolic blood pressure (SBP) of the ISH LSSalt group had significantly decreased by 10.18 mm Hg (95% confidence interval (CI): 3.13 to 17.2, P = .006) compared with that of the ISH NSalt group, while the mean SBP only decreased by 5.10 mm Hg (95% CI: -2.02 to 12.2, P = .158) in the NISH LSSalt group compared with that of the NISH NSalt group. The mean diastolic blood pressure (DBP) had no significant differences in the ISH and NISH groups. No obvious renin angiotensin system activation was found after LSSalt intervention. Regarding the urinary excretion of electrolytes and blood biochemical assays, the LSSalt treatment had the same effects on the ISH group as on the NISH group.The present study showed that the SBP of ISH patients was significantly decreased with the LSSalt intervention, while neither the SBP of the NISH patients nor the DBP of either group were similarly decreased, which indicated that ISH patients were more sensitive to salt restriction.

Association between blood cholesterol and sodium intake in hypertensive women with excess weight

Restricted sodium intake has been recommended for more than 1 century for the treatment of hypertension. However, restriction seems to increase blood cholesterol. In women with excess weight, blood cholesterol may increase even more because of insulin resistance and the high lipolytic activity of adipose tissue.The aim of this study was to assess the association between blood cholesterol and sodium intake in hypertensive women with and without excess weight.This was a cross-sectional study with hypertensive and nondiabetic women aged 20 to 59 years, recruited at the primary healthcare units of Maceio, Alagoas, Brazilian Northeast. Excess weight was defined as body mass index (BMI) ≥25.0 kg/m. Sodium intake was estimated by the 24-hour urinary excretion of sodium. Blood cholesterol was the primary outcome investigated by this study, and its relationship with sodium intake and other variables was assessed by Pearson correlation and multivariate linear regression using a significance level of 5%.This study included 165 hypertensive women. Of these, 135 (81.8%) were with excess weight. The mean sodium intake was 3.7 g (±1.9) and 3.4 g (±2.4) in hypertensive women with and without excess weight, respectively. The multiple normal linear regression models fitted to the "blood cholesterol" in the 2 groups reveal that for the group of hypertensive women without excess weight only 1 independent variable "age" is statistically significant to explain the variability of the blood cholesterol levels. However, for the group of hypertensive women with excess weight, 2 independent variables, age and sodium intake, can statistically explain variations of the blood cholesterol levels.Blood cholesterol is statistically inversely related to sodium intake for hypertensive women with excess weight, but it is not statistically related to sodium intake for hypertensive women without excess weight.

The Science of Salt: A regularly updated systematic review of the implementation of salt reduction interventions (September 2016-February 2017)

This periodic review aims to identify, summarize, and appraise studies relating to the implementation of salt reduction strategies that were published between September 2016 and February 2017. A total of 41 studies were included as relevant to the design, assessment, and implementation of salt reduction strategies, and a detailed appraisal was conducted on the seven studies that evaluated the impact of salt reduction strategies. Of these, three were national studies or included large populations and four were conducted in communities with small participant sample sizes. Each study used a different strategy for reducing salt intake varying from category-specific sodium targets for packaged food to use of a low-sodium salt substitute to behavior change interventions. Four studies found statistically significant decreases in dietary salt intake and one study showed statistically significant decreases in mean sodium density of packaged food products. Four of the seven studies used either spot or 24-hour urine samples to measure dietary salt intake and five were conducted in East or Southeast Asia-two of which were in low- and middle-income countries. Study quality varied among the seven studies and all except one had one or more risks related to bias.

Rationale, design, and baseline characteristics of the Salt Substitute and Stroke Study (SSaSS)-A large-scale cluster randomized controlled trial

Lowering sodium intake with a reduced-sodium, added potassium salt substitute has been proved to lower blood pressure levels. Whether the same strategy will also reduce the risks of vascular outcomes is uncertain and controversial. The SSaSS has been designed to test whether sodium reduction achieved with a salt substitute can reduce the risk of vascular disease. The study is a large-scale, open, cluster-randomized controlled trial done in 600 villages across 5 provinces in China. Participants have either a history of stroke or an elevated risk of stroke based on age and blood pressure level at entry. Villages were randomized in a 1:1 ratio to intervention or continued usual care. Salt substitute is provided free of charge to participants in villages assigned to the intervention group. Follow-up is scheduled every 6months for 5years, and all potential endpoints are reviewed by a masked adjudication committee. The primary end point is fatal and nonfatal stroke, and the 2 secondary endpoints are total major cardiovascular events and total mortality. The study has been designed to provide 90% statistical power (with 2-sided α = .05) to detect a 13% or greater relative risk reduction for stroke. The power estimate assumes a primary outcome event rate of 3.5% per year and a systolic blood pressure difference of 3.0mm Hg between randomized groups. Recruitment is complete and there are 20,996 participants (about 35 per village) that have been enrolled. Mean age is 65years and 49% are female. There were 73% enrolled on the basis of a history of stroke. The trial is well placed to describe the effects of salt substitution on the risks of vascular disease and death and will provide important policy-relevant data.

Associations Between Genetic Variants of NADPH Oxidase-Related Genes and Blood Pressure Responses to Dietary Sodium Intervention: The GenSalt Study

BACKGROUND

The aim of this study was to comprehensively test the associations of genetic variants of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase-related genes with blood pressure (BP) responses to dietary sodium intervention in a Chinese population.

METHODS

We conducted a 7-day low-sodium intervention followed by a 7-day high-sodium intervention among 1,906 participants in rural China. BP measurements were obtained at baseline and each dietary intervention using a random-zero sphygmomanometer. Linear mixed-effect models were used to assess the additive associations of 63 tag single-nucleotide polymorphisms in 11 NADPH oxidase-related genes with BP responses to dietary sodium intervention. Gene-based analyses were conducted using the truncated product method. The Bonferroni method was used to adjust for multiple testing in all analyses.

RESULTS

Systolic BP (SBP) response to high-sodium intervention significantly decreased with the number of minor T allele of marker rs6967221 in RAC1 (P = 4.51 × 10-4). SBP responses (95% confidence interval) for genotypes CC, CT, and TT were 5.03 (4.71, 5.36), 4.20 (3.54, 4.85), and 0.56 (-1.08, 2.20) mm Hg, respectively, during the high-sodium intervention. Gene-based analyses revealed that RAC1 was significantly associated with SBP response to high-sodium intervention (P = 1.00 × 10-6) and diastolic BP response to low-sodium intervention (P = 9.80 × 10-4).

CONCLUSIONS

These findings suggested that genetic variants of NADPH oxidase-related genes may contribute to the variation of BP responses to sodium intervention in Chinese population. Further replication of these findings is warranted.

The Science of Salt: A regularly updated systematic review of the implementation of salt reduction interventions (March-August 2016)

This review aims to identify, summarize, and appraise studies reporting on the implementation of salt reduction interventions that were published between March and August 2016. Overall, 40 studies were included: four studies evaluated the impact of salt reduction interventions, while 36 studies were identified as relevant to the design, assessment, and implementation of salt reduction strategies. Detailed appraisal and commentary were undertaken on the four studies that measured the impact of the interventions. Among them, different evaluation approaches were adopted; however, all demonstrated positive health outcomes relating to dietary salt reduction. Three of the four studies measured sodium in breads and provided consistent evidence that sodium reduction in breads is feasible and different intervention options are available. None of the studies were conducted in low- or lower middle-income countries, which stresses the need for more resources and research support for the implementation of salt reduction interventions in these countries.

The Effects of a Community-Based Sodium Reduction Program in Rural China - A Cluster-Randomized Trial

BACKGROUND

Average sodium intake and stroke mortality in northern China are both among the highest in the world. An effective, low-cost strategy to reduce sodium intake in this population is urgently needed.

OBJECTIVE

We sought to determine the effects of a community-based sodium reduction program on salt consumption in rural northern China.

DESIGN

This study was a cluster-randomized trial done over 18 months in 120 townships (one village from each township) from five provinces. Sixty control villages were compared to 60 intervention villages that were given access to a reduced-sodium, added-potassium salt substitute in conjunction with a community-based health education program focusing on sodium reduction. The primary outcome was the difference in 24-hour urinary sodium excretion between randomized groups.

RESULTS

Among 1,903 people with valid 24-hour urine collections, mean urinary sodium excretion in intervention compared with control villages was reduced by 5.5% (-14mmol/day, 95% confidence interval -26 to -1; p = 0.03), potassium excretion was increased by 16% (+7mmol/day, +4 to +10; p<0.001), and sodium to potassium ratio declined by 15% (-0.9, -1.2 to -0.5; p<0.001). Mean blood pressure differences were -1.1 mm Hg systolic (-3.3 to +1.1; p = 0.33) and -0.7 mm Hg diastolic (-2.2 to +0.8, p = 0.35) and the difference in the proportion with hypertension was -1.3% (-5.1 to 2.5, p = 0.56).

CONCLUSION

There were clear differences in population sodium and potassium intake between villages that were most likely a consequence of increased use of salt substitute. The absence of effects on blood pressure reflects the moderate changes in sodium and potassium intake achieved.

TRIAL REGISTRATION

Clinicaltrials.gov identifier: NCT01259700.

Influence of Kidney Function on Blood Pressure Response to Lifestyle Modifications: Secondary Analysis From the Exercise and Nutritional Interventions for Cardiovascular Health (ENCORE) Trial

The kidney is an important regulator of blood pressure (BP). To determine whether BP response to lifestyle modification varies across normal ranges of kidney function, the authors examined the moderating role of estimated glomerular filtration rate (eGFR) on clinic and ambulatory systolic BP (SBP) response in overweight and obese adults with unmedicated high BP. Among 144 participants of the Exercise and Nutritional Interventions for Cardiovascular Health (ENCORE) trial, mean age was 52.0±9.6 years and median eGFR was 89.1 (53-146) mL/min/1.73m2 . After multivariable regression, the interaction between eGFR and weight loss was significant for clinic (P=.023) and ambulatory SBP (P=.041). Similarly, the interaction between eGFR and improved fitness was significant for clinic (P=.041) and ambulatory SBP (P=.044). The relationship between reduced dietary sodium and SBP was not moderated by eGFR. SBP findings were inconsistent for adherence to the Dietary Approaches to Stop Hypertension (DASH) diet. These findings suggest that the effects of lifestyle modifications on SBP may be influenced by eGFR, even when kidney function is preserved.

Does education level affect the efficacy of a community based salt reduction program? - A post-hoc analysis of the China Rural Health Initiative Sodium Reduction Study (CRHI-SRS)

BACKGROUND

Whether educational level influences the effects of health education is not clearly defined. This study examined whether the impact of a community-based dietary salt reduction program was affected by the level of education of participants.

METHODS

The China Rural Health Initiative Sodium Reduction Study (CRHI-SRS) was a cluster-randomized controlled trial conducted in 120 villages from five Northern Chinese provinces. The intervention comprised a village-wide health education program and availability of salt substitute at village shops. 24-h urine samples were collected among 1903 participants for primary evaluation of the intervention effect. A post-hoc analysis was done to explore for heterogeneity of intervention effects by education level using generalized estimating equations. All models were adjusted for age, sex, body mass index and province.

RESULTS

Daily salt intake was lower in intervention than in control at all educational levels with no evidence of a difference in the effect of the intervention across different levels of education. P value for the interaction term between education level and the intervention was 0.35. There was likewise no evidence of an interaction for effects of the intervention on potassium intake (p = 0.71), the sodium to potassium ratio (p = 0.07), or knowledge and behaviors related to salt (all p > 0.05).

CONCLUSIONS

The study suggests that the effects of the intervention were achieved regardless of the level of education and that the intervention should therefore be broadly effective in rural Chinese populations.

TRIAL REGISTRATION

The trial was registered with clinicaltrial.gov ( NCT01259700 ).

Role of sodium-restricted dietary approaches to control blood pressure in Pakistani hypertensive population

OBJECTIVE

To assess the change in systolic and diastolic blood pressure in post-interventional phase through dietary approaches to stop hypertension/salt-restricted diet.

METHODS

This randomised controlled clinical study was conducted from February 2014 to March 2015 at the Armed Forces Institute of Cardiology, Rawalpindi, and Ali Medical Centre, Islamabad, Pakistan, and involved hypertensive patients and matching controls. The control group followed routine diet while the intervention group was given a diet plan containing 1,500mg of sodium providing 2,000 calories. Both groups were advised not to consume sodium-rich foods. Paired sample t-test was applied to determine the change in blood pressure among the groups at two different occasions.

RESULTS

Of the 1,492 participants, 710(47.6%) were controls and 782(52.4%) were in the interventional group. Overall, 417(27.9%) participants got their blood pressure checked less than twice in six months, while 409(27.4%) had it done on a regular basis. Moreover, 941(63.1%)) subjects had a family history of high blood pressure and 149(10.0%) participants did not exercise at all. The overall mean age was 53.42±9.302 years. Mean systolic blood pressure and diastolic blood pressure after five weeks was 126.33±3.35 and 84.40±3.04mmHg in the intervention group, and128.41±3.52 and 84.04±2.953mmHg in the control group. Changes in blood pressure between the two groups were minimal but statistically significant (p<0.05).

CONCLUSIONS

A diet which is restricted in salt, rich in fruits, vegetables, and low-fat dairy foods and reduced saturated and total fat can substantially lower blood pressure. Such a diet offers an additional nutritional approach to the prevention and treatment of hypertension.

Dietary Salt Restriction in Heart Failure: Where Is the Evidence?

Several dietary guidelines, health organizations and government policies recommend population-wide sodium restriction to prevent hypertension and related comorbidities like heart failure (HF). The current European Society of Cardiology and American College of Cardiology/American Heart Association Heart Failure guidelines recommend restricting sodium in HF patients. However, these recommendations are based on expert opinion (level C), leading to wide variability in application and lack of consensus among providers pertaining to dietary salt restriction. To evaluate the strength of current evidences to recommend dietary salt restriction among HF patients, we performed a comprehensive literature review and explored the safety and efficacy of such recommendations.

The effect of a dietary portfolio compared to a DASH-type diet on blood pressure

BACKGROUND AND AIM

Compared to a DASH-type diet, an intensively applied dietary portfolio reduced diastolic blood pressure at 24 weeks as a secondary outcome in a previous study. Due to the importance of strategies to reduce blood pressure, we performed an exploratory analysis pooling data from intensively and routinely applied portfolio treatments from the same study to assess the effect over time on systolic, diastolic and mean arterial pressure (MAP), and the relation to sodium (Na(+)), potassium (K(+)), and portfolio components.

METHODS AND RESULTS

241 participants with hyperlipidemia, from four academic centers across Canada were randomized and completed either a DASH-type diet (control n = 82) or a dietary portfolio that included, soy protein, viscous fibers and nuts (n = 159) for 24 weeks. Fasting measures and 7-day food records were obtained at weeks 0, 12 and 24, with 24-h urines at weeks 0 and 24. The dietary portfolio reduced systolic, diastolic and mean arterial blood pressure compared to the control by 2.1 mm Hg (95% CI, 4.2 to -0.1 mm Hg) (p = 0.056), 1.8 mm Hg (CI, 3.2 to 0.4 mm Hg) (p = 0.013) and 1.9 mm Hg (CI, 3.4 to 0.4 mm Hg) (p = 0.015), respectively. Blood pressure reductions were small at 12 weeks and only reached significance at 24 weeks. Nuts, soy and viscous fiber all related negatively to change in mean arterial pressure (ρ = -0.15 to -0.17, p ≤ 0.016) as did urinary potassium (ρ = -0.25, p = 0.001), while the Na(+)/K(+) ratio was positively associated (ρ = 0.20, p = 0.010).

CONCLUSIONS

Consumption of a cholesterol-lowering dietary portfolio also decreased blood pressure by comparison with a healthy DASH-type diet. CLINICAL TRIAL REG. NO.: NCT00438425, clinicaltrials.gov.

A large-scale cluster randomized trial to determine the effects of community-based dietary sodium reduction--the China Rural Health Initiative Sodium Reduction Study

BACKGROUND

Cardiovascular diseases are the leading cause of death and disability in China. High blood pressure caused by excess intake of dietary sodium is widespread and an effective sodium reduction program has potential to improve cardiovascular health.

DESIGN

This study is a large-scale, cluster-randomized, trial done in five Northern Chinese provinces. Two counties have been selected from each province and 12 townships in each county making a total of 120 clusters. Within each township one village has been selected for participation with 1:1 randomization stratified by county. The sodium reduction intervention comprises community health education and a food supply strategy based upon providing access to salt substitute. Subsidization of the price of salt substitute was done in 30 intervention villages selected at random. Control villages continued usual practices. The primary outcome for the study is dietary sodium intake level estimated from assays of 24-hour urine.

TRIAL STATUS

The trial recruited and randomized 120 townships in April 2011. The sodium reduction program was commenced in the 60 intervention villages between May and June of that year with outcome surveys scheduled for October to December 2012. Baseline data collection shows that randomisation achieved good balance across groups.

DISCUSSION

The establishment of the China Rural Health Initiative has enabled the launch of this large-scale trial designed to identify a novel, scalable strategy for reduction of dietary sodium and control of blood pressure. If proved effective, the intervention could plausibly be implemented at low cost in large parts of China and other countries worldwide.

Blood pressure management in patients with chronic kidney disease: an appraisal and summary of existing guidelines

BACKGROUND

Hypertension is a prevalent problem with huge impact on health and health care budgets. Several guidelines on how to manage blood pressure have been published, and it is unclear which one should be preferred.

METHODS

Eight guidelines dealing with blood pressure management of chronic kidney disease patients were evaluated for methodological quality by the AGREE II instrument by 4 appraisers. They were also analysed for consistency in their recommendations.

RESULTS

Most problematic domains were "applicability", "stakeholder involvement" and "editorial independence". Three guidelines scored below 50% for 5, and one for 4 of the 6 AGREE II domains. The guideline produced by Canadian Hypertension Education Program was preferred most, followed by KDIGO. There were discrepancies between the different guidelines with regard to blood pressure targets and thresholds, with the best and most recent advocating 140/90 mmHg. There was a consensus on the use of ACE-I/ARB's in patients with but not for those without proteinuria. However, only two guidelines specify a second line treatment (thiazides), whereas others do not, although it is well known that most patients need more than one drug to control their blood pressure. Three out of eight guidelines did not provide guidance on life-style modification. Those who did, advocated different levels of sodium restriction,, weight control, and physical activity. Remarkably, 5 out of 8 guidelines did not specify how exactly blood pressure should be measured.

CONCLUSION

Blood pressure guidelines seem to be of low methodological quality, with clear improvements for the ones produced the latest. Especially the "applicability" domain, evaluating how the guideline can be put into practice, seems problematic, with as biggest hurdles that it is unclear what should be second or third line treatments, and how blood pressure should be measured or defined. The most recent guidelines advocate an office blood pressure of 140/90 mmHg for patients with chronic kidney disease.

Compliance with the Dietary Approaches to Stop Hypertension (DASH) diet: a systematic review

BACKGROUND

The Dietary Approaches to Stop Hypertension (DASH) diet has been recognized as effective to lower blood pressure in feeding trials, but compliance with the diet must be persistent to maximize health benefits in clinical practice. This paper reports a systematic review of the latest evidence on the method to assess DASH compliance and the corresponding patients' compliance in interventional settings.

METHODS

The databases including MEDLINE, EBM Reviews, EMBASE, and CINAHL Plus were searched for original research studies published in the period of January 1992-December 2012 that evaluated compliance with DASH diet. Studies written in English language, with DASH intervention, with complete documentation of the degree of DASH compliance and the assessment method used were included in this review. The search terms included: dietary approaches to stop hypertension, DASH, compliance, adherence, consistency, and concordance.

RESULTS

Nine studies were included. Different types of interventions were identified, ranging from feeding trial to dietary counseling. These studies differed in the assessment methods used to evaluate DASH compliance, which included objective approaches like measurement of urinary excretion, and subjective approaches like dietary intake assessment for DASH target comparison and construction of DASH scoring systems. Compliance levels were lower in educational interventions than that of the original DASH feeding trial.

CONCLUSIONS

To conclude, although no consensus existed regarding the best approach to assess DASH compliance, its suboptimal compliance warrants attention. This study implied a need to investigate effective approaches to sustain the DASH dietary pattern beyond counselling alone.

Hypertension management and lifestyle changes following screening for hypertension in an Asian low socioeconomic status community: a prospective study

INTRODUCTION

This study investigated the effect of an access-enhanced intervention on hypertension screening and management, as well as on health behaviours among newly diagnosed hypertensives, in a multi-ethnic low socioeconomic status (SES) community. Factors associated with hypertension screening, treatment, and control in the community were also determined.

MATERIALS AND METHODS

The study involved all residents aged ≥40 years in 2 public rental housing precincts (low SES), between 2009 and 2011, who were followed-up prospectively for 1 year after a 6-month community-based intervention comprising a 3-month access-enhanced screening component and a 3-month follow-up (outreach) component. Blood pressure was measured at baseline and follow-up. Multivariate Cox regression determined predictors of hypertension management at follow-up.

RESULTS

The follow-up rate was 80.9% (467/577). At baseline, 60.4% (282/467) were hypertensive; 53.5% (151/282) were untreated; 54.2% (71/131) uncontrolled. One year later, postintervention, 51.6% (78/151) of untreated hypertensives were treated; combined with treated hypertensives previously uncontrolled, 53.0% (79/149) achieved control. Older age independently predicted treatment (adjusted relative risk, aRR = 1.98, CI, 1.08 to 3.65); majority ethnicity (aRR = 1.76, CI, 1.05 to 2.96), employment (aRR = 1.85, CI, 1.26 to 2.80) and newly treated hypertension (aRR=1.52, CI, 1.01 to 2.32) predicted control. A total of 52.4% (97/185) were irregularly screened at baseline; at follow-up 61.9% (60/97) were regularly screened. Cost and misperceptions were common barriers to screening and treatment. Newly diagnosed hypertensives were also less likely to go for additional cardiovascular screening (aRR = 0.54, CI, 0.29 to 0.99).

CONCLUSION

An access-enhanced intervention had some success in improving hypertension management within low SES communities; however, it was less successful in improving cardiovascular risk management, especially in encouraging lifestyle changes and additional cardiovascular screening amongst newly diagnosed hypertensives.

[Influence of non-sodium restricted diet with diuretics on plasma rennin, renal blood flow and in patients with cirrhotic ascites]

OBJECTIVE

To explore influence of sodium restricted diet and non-sodium restricted diet on plasma rennin (PRA), angiotensin II (All), ALD, renal blood flow (RBF) and subside of ascites in patients with cirrhotic ascites.

METHODS

Eighty cases of hepatitis B with cirrhotic ascites were randomly divided into sodium restricted diet group and non-sodium restricted diet group. 39 cases were in non-sodium restricted diet group, taking sodium chloride 6500-8000 mg daily; 41 cases were in sodium restricted diet group, taking sodium chloride 5000 mg daily. Both groups received diuretics furosemide and spironolactone. Blood sodium, urine sodium, PRA, AII, ALD, RBF ascites subsiding were compared after treatment.

RESULTS

In non-sodium restricted diet group, blood sodium and urine sodium increased 10 days after treatment compared with those before treatment, and compared with those of sodium restricted diet group 10 days after treatment, P <0. 01. RBF increased compared with that before treatment, and compared with that of sodium restricted diet group 10 days after treatment, P < 0. 01. Renal damage induced by low blood sodium after treatment was less in non-sodium restricted diet group than that in sodium restricted diet group, P <0. 05. Ascites disappearance upon discharge was more in sodium restricted diet group than that in non-sodium restricted diet group, P <0. 01. Time of ascites disappearance was shorter in non-sodium restricted diet group than that in sodium restricted diet group, P < 0. 01.

CONCLUSION

Compared with sodium restricted diet, while using diuretics of both groups, non-sodium restricted diet can increase level of blood sodium, thus increasing excretion of urine sodium and diuretic effect. It can also decrease levels of PRA, AII and ALD, increase renal blood flow and prevent renal damage induced by low blood sodium and facilitate subsiding of ascites.

[Salt consumption and arterial hypertension: are there reasons to change point of view?]

The review presents modern data on interrelationships between sodium consumption, blood pressure level, and risk of cardiovascular complications. Phenomenon of salt sensitivity and methods of its detection are described. Results of epidemiological and interventional studies are used as a basis for formulation of populational strategy of limitation of sodium consumption. Possibilities of antihypertensive therapy with natriuretic effect are also presented.

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

BACKGROUND

Despite 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/DESIGN

The 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.

DISCUSSION

The 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 REGISTRATION

Universal Trial Number: U1111-1125-2149. Australian New Zealand Clinical Trials Registry Number: ACTRN12611001097932.

DIETARY STRATEGIES TO HALT THE PROGRESSION OF CHRONIC KIDNEY DISEASE

Chronic kidney disease is fast becoming a worldwide epidemic. There is an estimated annual increase of 8% with an associated economical and clinical burden. Recent research into lifestyle factors has confirmed different dietary attributes play a part in slowing the progression of chronic nephropathies. This has important implications and a potentially cost-saving way, to help reduce the progression of the disease. The roles of obesity, lipids, protein, diabetes and blood pressure are discussed to show how the current literature reflects how to modify the dietary aspects of these. The mechanisms behind these are not fully understood, but the message remains the same that there is an increased need for dietary advice in the pre-dialysis population.

Characteristics of sodium sensitivity in Korean populations

Sodium sensitivity (SS) is a variable response of blood pressure (BP) to changes in sodium intake. The present study evaluated the existence and the characteristics of subjects with SS in Koreans. One hundred one subjects with (n = 31, 57.7 ± 9.8 yr) or without hypertension (n = 70, 40.8 ± 16.5 yr) were given a low-sodium dietary approache to stop hypertension (DASH) diet (LSD) for 7 days and a high-sodium DASH diet (HSD) for the following 7 days. The prevalence of SS in the present study population was 27.7% (17.6% in the non-hypertensive subjects and 51.6% in the hypertensive subjects). Analysis of the non-hypertensive subjects showed that systolic BP, diastolic BP, and mean arterial pressure at baseline and after HSD were higher in the subjects with SS than the subjects without SS, and there were no differences after LSD. In the hypertensive subjects, there was no difference in the BP at baseline and after HSD whether or not the subjects had SS. However, the systolic BP of hypertensive subjects with SS was lower than hypertensive subjects without SS after LSD. In the present study population, subjects with SS have distinctive BP features unlike to subjects without SS.

Moderate dietary sodium restriction added to angiotensin converting enzyme inhibition compared with dual blockade in lowering proteinuria and blood pressure: randomised controlled trial

OBJECTIVE

To compare the effects on proteinuria and blood pressure of addition of dietary sodium restriction or angiotensin receptor blockade at maximum dose, or their combination, in patients with non-diabetic nephropathy receiving background treatment with angiotensin converting enzyme (ACE) inhibition at maximum dose.

DESIGN

Multicentre crossover randomised controlled trial.

SETTING

Outpatient clinics in the Netherlands.

PARTICIPANTS

52 patients with non-diabetic nephropathy.

INTERVENTIONS

All patients were treated during four 6 week periods, in random order, with angiotensin receptor blockade (valsartan 320 mg/day) or placebo, each combined with, consecutively, a low sodium diet (target 50 mmol Na(+)/day) and a regular sodium diet (target 200 mmol Na(+)/day), with a background of ACE inhibition (lisinopril 40 mg/day) during the entire study. The drug interventions were double blind; the dietary interventions were open label.

MAIN OUTCOME MEASURES

The primary outcome measure was proteinuria; the secondary outcome measure was blood pressure.

RESULTS

Mean urinary sodium excretion, a measure of dietary sodium intake, was 106 (SE 5) mmol Na(+)/day during a low sodium diet and 184 (6) mmol Na(+)/day during a regular sodium diet (P<0.001). Geometric mean residual proteinuria was 1.68 (95% confidence interval 1.31 to 2.14) g/day during ACE inhibition plus a regular sodium diet. Addition of angiotensin receptor blockade to ACE inhibition reduced proteinuria to 1.44 (1.07 to 1.93) g/day (P=0.003), addition of a low sodium diet reduced it to 0.85 (0.66 to 1.10) g/day (P<0.001), and addition of angiotensin receptor blockade plus a low sodium diet reduced it to 0.67 (0.50 to 0.91) g/day (P<0.001). The reduction of proteinuria by the addition of a low sodium diet to ACE inhibition (51%, 95% confidence interval 43% to 58%) was significantly larger (P<0.001) than the reduction of proteinuria by the addition of angiotensin receptor blockade to ACE inhibition (21%, (8% to 32%) and was comparable (P=0.009, not significant after Bonferroni correction) to the reduction of proteinuria by the addition of both angiotensin receptor blockade and a low sodium diet to ACE inhibition (62%, 53% to 70%). Mean systolic blood pressure was 134 (3) mm Hg during ACE inhibition plus a regular sodium diet. Mean systolic blood pressure was not significantly altered by the addition of angiotensin receptor blockade (131 (3) mm Hg; P=0.12) but was reduced by the addition of a low sodium diet (123 (2) mm Hg; P<0.001) and angiotensin receptor blockade plus a low sodium diet (121 (3) mm Hg; P<0.001) to ACE inhibition. The reduction of systolic blood pressure by the addition of a low sodium diet (7% (SE 1%)) was significantly larger (P=0.003) than the reduction of systolic blood pressure by the addition of angiotensin receptor blockade (2% (1)) and was similar (P=0.14) to the reduction of systolic blood pressure by the addition of both angiotensin receptor blockade and low sodium diet (9% (1)), to ACE inhibition.

CONCLUSIONS

Dietary sodium restriction to a level recommended in guidelines was more effective than dual blockade for reduction of proteinuria and blood pressure in non-diabetic nephropathy. The findings support the combined endeavours of patients and health professionals to reduce sodium intake. Trial registration Netherlands Trial Register NTR675.

Apparent mineralocorticoid excess: time of manifestation and complications despite treatment

Here we describe the case of a patient followed from birth because of a positive family history for apparent mineralocorticoid excess (AME) in an older brother. The patient, a girl, had normal serum electrolyte and blood pressure measurements in the first months after birth. Not until the age of 11 months did she develop anorexia and failure to thrive in combination with hypertension, hypokalemia, and metabolic alkalosis, which are consistent with the diagnosis of AME. This diagnosis was confirmed by mutation analysis of the HSD11B2 gene (C1228T). Treatment with amiloride and furosemide electrolyte disturbances normalized her blood pressure. At the age of 19 years she unexpectedly suffered a stroke. Additional investigations revealed no accepted risk factor for stroke. We discuss the possible underlying mechanisms for the delayed manifestation of hypertension and electrolyte disturbances in AME, propose an additional explanation for the stroke in this patient, and advise treatment with a mineralocorticoid receptor antagonist to reduce stroke risk in patients with AME.