Effect of modest salt reduction on blood pressure, urinary albumin, and pulse wave velocity in white, black, and Asian mild hypertensives

Dietary free L-glutamate contributes to maintaining a low sodium intake among Vietnamese

Background

The World Health Organization (WHO) and the Food and Agriculture Organization (FAO) recommend the consumption of less than 2,000 mg of sodium/day to reduce blood pressure and the risk of conditions such as cardiovascular disease and coronary heart disease. The sodium intake among Vietnamese was reported to be 7,200 mg/d or more. Free L-glutamate enhances flavor when it is added to food and improves the taste of sodium-reduced foods.

Objective

This study aims to investigate whether the intake of free L-glutamate-rich seasonings contributes to maintaining a low sodium intake in a cross-over study.

Methods

From a total of 145 subjects, 42 participants were screened for participation in the cross-over design study. Subjects were randomly allocated to the Low free L-glutamate group (Low free L-Gl) and the Normal free L-glutamate group (Normal free L-Gl). Both received a direct educational guideline to reduce sodium intake. The Low free L-Gl group started with a restriction in the variety of free L-glutamate-rich seasonings, and the Normal free L-Gl group had no restriction in the variety of seasonings. Blood pressure was measured at week 0 (baseline), week 2, week 4, and week 6, while body weight, height, urine sodium and potassium excretion, chromogranin-A (CgA pmol/mg protein) from saliva, and free L-glutamate from food were measured at week 0, week 3, and week 6.

Results

In Low free L-Gl, the amount of free L-glutamate in food decreased significantly from baseline to week 6 (p < 0.00), while it did not change in the Normal free L-Gl (p > 0.05). However, the reduction of sodium excretion at week 6 was 22% in Low free L-Gl (5,875 mg/d vs. 4,603 mg/d, p < 0.01) and 46% in Normal free L-Gl (6,107 mg/d vs. 3,277 mg/d, p < 0.00), both lower than the baseline. CgA (pmol/mg protein) did not show any difference between the two groups.

Conclusion

The group with Normal free L-Gl intake showed a 46% reduction in sodium excretion by week 6 compared to the baseline. This suggests that the consumption of L-glutamate-rich seasonings when complemented with direct educational guidelines, can contribute to maintaining a low sodium intake.

The Association between Urinary Sodium-Potassium Ratio, Kidney Function, and Blood Pressure in a Cohort from the General Population

INTRODUCTION

Subclinical kidney dysfunction may contribute to salt-sensitive hypertension. We assessed the association between the urinary sodium-potassium ratio (Na/K ratio) and blood pressure (BP) in a general population cohort without diabetes, chronic kidney disease, cardiovascular disease, or treated hypertension. We investigated whether any such association was mediated by the kidney function markers measured glomerular filtration rate (mGFR), urinary albumin-creatinine ratio (ACR), and urinary epidermal growth factor-creatinine ratio (EGF-Cr).

METHODS

The Tromsø Study is a population-based study of inhabitants of the municipality of Tromsø, Northern Norway. Participants aged 50-62 years, without diabetes, chronic kidney disease, or cardiovascular disease, were invited to the substudy Renal Iohexol Clearance Survey in Tromsø 6 (RENIS-T6; 2007-09). For the present study, we excluded participants reporting the use of 1 or more antihypertensive agents, leaving 1,311 RENIS-T6 participants for a cross-sectional analysis. We measured office BP, 24-h ambulatory blood pressure (ABP), and mGFR using iohexol clearance. Na/K ratio, ACR, and EGF-Cr were measured in morning urine samples.

RESULTS

Urinary Na/K ratio was significantly associated with systolic office BP and ABP independently of cardiovascular risk factors and kidney function markers. A one-standard deviation unit increase in the Na/K ratio was associated with increased systolic ABP by 1.0 (0.3-1.6) mm Hg. Urinary Na/K ratio showed a stronger association with office BP than ABP. EGF-Cr, ACR, and mGFR did not mediate the relationship between urinary Na/K ratio and systolic BP.

CONCLUSIONS

In a representative sample of the middle-aged North-European population without diabetes, chronic kidney disease, cardiovascular disease, or treated hypertension, there was a consistent association between urinary Na/K ratio and BP. The association with BP was not mediated through kidney function measures, suggesting a relationship between a diet with high sodium and low potassium and higher BP regardless of kidney function.

Salty Subjects: Unpacking Racial Differences in Salt-Sensitive Hypertension

PURPOSE OF REVIEW

To review underlying mechanisms and environmental factors that may influence racial disparities in the development of salt-sensitive blood pressure.

RECENT FINDINGS

Our group and others have observed racial differences in diet and hydration, which may influence salt sensitivity. Dietary salt elicits negative alterations to the gut microbiota and immune system, which may increase hypertension risk, but little is known regarding potential racial differences in these physiological responses. Antioxidant supplementation and exercise offset vascular dysfunction following dietary salt, including in Black adults. Furthermore, recent work proposes the role of racial differences in exposure to social determinants of health, and differences in health behaviors that may influence risk of salt sensitivity. Physiological and environmental factors contribute to the mechanisms that manifest in racial differences in salt-sensitive blood pressure. Using this information, additional work is needed to develop strategies that can attenuate racial disparities in salt-sensitive blood pressure.

Arterial Health After Preeclampsia: Role of Chronic Hypertension in the Early Vascular Aging (EVA) Study

BACKGROUND

Preeclampsia (PE) is associated with increased cardiovascular risk. Recent data have shown worse left ventricular remodeling and diastolic function in women with PE and persistent hypertension (HTN). We performed a comprehensive arterial hemodynamic assessment to evaluate the contribution of persistent HTN on arterial health after PE.

METHODS

We recruited 40 women with PE history and 40 age-matched controls (6 months to 6 years postpartum). We evaluated arterial hemodynamics with validated techniques combining applanation tonometry and transthoracic echocardiography, comparing three groups: previous PE with persistent HTN (PE-HTN), previous PE with normalized blood pressure (PE-noHTN) and controls, using multivariable linear regression adjusted for age, body surface area, heart rate, diabetes, smoking history, creatinine, and gravidity.

RESULTS

Eight (20%) of the post-PE women had persistent HTN. Mean age was 35.8 ± 3.9 years, median number of pregnancies was 2 (range 1-7), and time since last pregnancy 2.1 (range 0.5-5.7) years (not different between groups, P > 0.05). Compared to controls and to PE-noHTN, PE-HTN had higher aortic stiffness, wave reflections, pulsatile, and steady arterial load (P < 0.05 for each). Among PE-noHTN, aortic stiffness, wave reflections and steady arterial load were worse than controls (P < 0.05 for each), with smaller effect sizes.

CONCLUSIONS

This is the most comprehensive assessment of arterial hemodynamics and first to demonstrate the contribution of persistent HTN on worse arterial health following PE. Since measures of arterial health are associated with cardiovascular events in the population, the combination of previous PE and chronic HTN may represent a higher risk subgroup who could benefit from targeted prevention strategies.

Factors influencing normal blood pressure maintenance in young adults

Despite an alarming increase in the prevalence of hypertension among Chinese young adults, longitudinal studies investigating factors that affect the maintenance of normal blood pressure (BP) in this population are lacking. Our study aimed to address this knowledge gap. A total of 7100 participants from the Kailuan Study who had normal BP and were aged <30 years at their first physical examination between 2006 and 2016 were included in this study. Cox proportional hazards regression models were used to assess hazard ratios (HR), and 95% confidence intervals (CI) were calculated to assess the associations between influencing factors and the maintenance of normal BP in young adults. Analyses were stratified by sex. During the follow-up period (mean, 7.98 years), 1921 participants (27.06%) maintained normal BP. Higher education levels (HR, 1.11; 95% CI, 1.00-1.22), low salt intake (HR, 1.25; 95% CI, 1.04-1.51), being underweight (HR, 1.16; 95% CI, 1.02-1.31), and having normal weight (HR, 1.19; 95% CI, 1.01-1.39), normal blood glucose (HR, 1.22; 95% CI, 1.02-1.46), and no family history of hypertension (HR, 1.65; 95% CI, 1.41-1.92) at baseline were found to be associated with maintaining normal BP. Compared with female smokers, female non-smokers had 1.68 times higher odds of maintaining normal BP. This study identified factors that influence the maintenance of normal BP in the young population in China. This information can assist clinicians in establishing comprehensive and effective primary prevention measures for hypertension.

New Insights on the Role of Marinobufagenin from Bench to Bedside in Cardiovascular and Kidney Diseases

Marinobufagenin (MBG) is a member of the bufadienolide family of compounds, which are natural cardiac glycosides found in a variety of animal species, including man, which have different physiological and biochemical functions but have a common action on the inhibition of the adenosine triphosphatase sodium-potassium pump (Na+/K+-ATPase). MBG acts as an endogenous cardiotonic steroid, and in the last decade, its role as a pathogenic factor in various human diseases has emerged. In this paper, we have collated major evidence regarding the biological characteristics and functions of MBG and its implications in human pathology. This review focused on MBG involvement in chronic kidney disease, including end-stage renal disease, cardiovascular diseases, sex and gender medicine, and its actions on the nervous and immune systems. The role of MBG in pathogenesis and the development of a wide range of pathological conditions indicate that this endogenous peptide could be used in the future as a diagnostic biomarker and/or therapeutic target, opening important avenues of scientific research.

Moderate dietary salt restriction improves blood pressure and mental well-being in patients with primary aldosteronism: The salt CONNtrol trial

BACKGROUND

Primary aldosteronism (PA) is a frequent cause of hypertension. Aldosterone excess together with high dietary salt intake aggravates cardiovascular damage, despite guideline-recommended mineralocorticoid receptor antagonist (MRA) treatment.

OBJECTIVES

To investigate the antihypertensive impact of a moderate dietary salt restriction and associated physiological changes, including mental well-being.

METHODS

A total of 41 patients with PA on a stable antihypertensive regimen-including MRA-followed a dietary salt restriction for 12 weeks with structured nutritional training and consolidation by a mobile health app. Salt intake and adherence were monitored every 4 weeks using 24-h urinary sodium excretion and nutrition protocols. Body composition was assessed by bioimpedance analysis and mental well-being by validated questionnaires.

RESULTS

Dietary salt intake significantly decreased from 9.1 to 5.2 g/d at the end of the study. In parallel, systolic (130 vs. 121 mm Hg) and diastolic blood pressure (BP) (84 vs. 81 mm Hg) improved significantly. Patients' aptitude of estimating dietary salt content was refined significantly (underestimation by 2.4 vs. 1.4 g/d). Salt restriction entailed a significant weight loss of 1.4 kg, improvement in pulse pressure (46 vs. 40 mm Hg) and normalization of depressive symptoms (PHQD scale, p < 0.05). Salt restriction, cortisol after dexamethasone suppression test and dosage of renin-angiotensin-aldosterone-system (RAAS) blockers were independently associated with BP reduction.

CONCLUSION

A moderate restriction of dietary salt intake in patients with PA substantially reduces BP and depressive symptoms. Moreover, the findings underline that a sufficient RAAS blockade seems to augment the effects of salt restriction on BP and cardiovascular risk.

The Influence of Dietary Interventions on Arterial Stiffness in Overweight and Obese Subjects

Arterial stiffness is often increased in overweight/obese subjects before the development of hypertension. It is also one of the earliest indicators of increased cardiovascular disease risk and can be considered a good predictor of the development of subclinical cardiovascular dysfunction. Arterial stiffness is a significant prognostic factor influencing cardiovascular risk, which dietary habits can modify. Obese patients should use the caloric-restricted diet because it augments aortic distensibility, diminishes pulse wave velocity (PWV), and increases the activity of endothelial nitric oxide synthases. High intake of saturated fatty acids (SFA), trans fats, and cholesterol, typical for the Western diet, impairs endothelial function and raises brachial-ankle PMV. The replacement of SFA with monounsaturated (MUFA) or polyunsaturated fatty acids (PUFA) derived from seafood and plants diminishes the risk of arterial stiffness. The dairy product intake (excluding butter) decreases PWV in the general population. The high-sucrose diet causes toxic hyperglycemia and increases arterial stiffness. Complex carbohydrates with a low glycemic index (including isomaltose) should be recommended to keep vascular health. The high sodium intake (>10 g/day), particularly associated with low potassium consumption, has a deleterious effect on arterial stiffness (↑ baPWV). Since vegetables and fruits are good sources of vitamins and phytochemicals, they should be recommended in patients with high PMV. Thus, the dietary recommendation to prevent arterial stiffness should be similar to the Mediterranean diet, which is rich in dairy products, plant oils, and fish, with a minimal red meat intake and five servings of fruits and vegetables daily.

Longitudinal changes in blood pressure are preceded by changes in albuminuria and accelerated by increasing dietary sodium intake

BACKGROUND

Dietary sodium is a well-known risk factor for cardiovascular and renal disease; however, direct evidence of the longitudinal changes that occur with aging, and the influence of dietary sodium on the age-associated alterations are scarce.

METHODS

C57BL/6 mice were maintained for 13 months on a low (LS, 0.02 % Na+), normal (NS, 0.3 % Na+) or high (HS, 1.6 % Na+) salt diet. We assessed 1) the longitudinal trajectories for two markers of cardiovascular and renal dysfunction (blood pressure (BP) and albuminuria), as well as hormonal changes, and 2) end-of-study cardiac and renal parameters.

RESULTS

The effect of aging on BP and kidney damage did not reach significance levels in the LS group; however, relative to baseline, there were significant increases in these parameters for animals maintained on NS and HS diets, starting as early as month 7 and month 5, respectively. Furthermore, changes in albuminuria preceded the changes in BP relative to baseline, irrespective of the diet. Circulating aldosterone and plasma renin activity displayed the expected decreasing trends with age and dietary sodium loading. As compared to LS - higher dietary sodium consumption associated with increasing trends in left ventricular mass and volume indices, consistent with an eccentric dilated phenotype. Functional and molecular markers of kidney dysfunction displayed similar trends with increasing long-term sodium levels: higher renovascular resistance, increased glomerular volumes, as well as higher levels of renal angiotensin II type 1 and mineralocorticoid receptors, and lower renal Klotho levels.

CONCLUSION

Our study provides a timeline for the development of cardiorenal dysfunction with aging, and documents that increasing dietary salt accelerates the age-induced phenotypes. In addition, we propose albuminuria as a prognostic biomarker for the future development of hypertension. Last, we identified functional and molecular markers of renal dysfunction that associate with long-term dietary salt loading.

Etiological Diagnosis and Personalized Therapy for Hypertension: A Hypothesis of the REASOH Classification

With the epidemic of risk factors such as unhealthy lifestyle, obesity and mental stress, the prevalence of hypertension continues to rise across the world. Although standardized treatment protocols simplify the selection of antihypertensive drugs and ensure therapeutic efficacy, the pathophysiological state of some patients remains, which may also lead to the development of other cardiovascular diseases. Thus, there is an urgent need to consider the pathogenesis and selection of antihypertensive drug for different type of hypertensive patients in the era of precision medicine. We proposed the REASOH classification, based on the etiology of hypertension, including renin-dependent hypertension, elderly-arteriosclerosis-based hypertension, sympathetic-active hypertension, secondary hypertension, salt-sensitive hypertension and hyperhomocysteinemia hypertension. The aim of this paper is to propose a hypothesis and provide a brief reference for the personalized treatment of hypertensive patients.

Altered dietary salt intake for preventing diabetic kidney disease and its progression

BACKGROUND

There is strong evidence that our current consumption of salt is a major factor in the development of increased blood pressure (BP) and that a reduction in our salt intake lowers BP, whether BP levels are normal or raised initially. Effective control of BP in people with diabetes lowers the risk of strokes, heart attacks and heart failure and slows the progression of chronic kidney disease (CKD) in people with diabetes. This is an update of a review first published in 2010.

OBJECTIVES

To evaluate the effect of altered salt intake on BP and markers of cardiovascular disease and of CKD in people with diabetes.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Register of Studies up to 31 March 2022 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register were identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Register (ICTRP) Search Portal and ClinicalTrials.gov.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) of altered salt intake in individuals with type 1 and type 2 diabetes. Studies were included when there was a difference between low and high sodium intakes of at least 34 mmol/day.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed studies and resolved differences by discussion. We calculated mean effect sizes as mean difference (MD) and 95% confidence intervals (CI) using the random-effects model. Confidence in the evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

MAIN RESULTS

Thirteen RCTs (313 participants), including 21 comparisons (studies), met our inclusion criteria. One RCT (two studies) was added to this review update. Participants included 99 individuals with type 1 diabetes and 214 individuals with type 2 diabetes. Two RCTs (four studies) included some participants with reduced overall kidney function. The remaining studies either reported that participants with reduced glomerular filtration rate (GFR) were excluded from the study or only included participants with microalbuminuria and normal GFR. Five studies used a parallel study design, and 16 used a cross-over design. Studies were at high risk of bias for most criteria. Random sequence generation and allocation concealment were adequate in only three and two studies, respectively. One study was at low risk of bias for blinding of participants and outcome assessment, but no studies were at low risk for selective reporting. Twelve studies reported non-commercial funding sources, three reported conflicts of interest, and eight reported adequate washout between interventions in cross-over studies. The median net reduction in 24-hour urine sodium excretion (24-hour UNa) in seven long-term studies (treatment duration four to 12 weeks) was 76 mmol (range 51 to 124 mmol), and in 10 short-term studies (treatment duration five to seven days) was 187 mmol (range 86 to 337 mmol). Data were only available graphically in four studies. In long-term studies, reduced sodium intake may lower systolic BP (SBP) by 6.15 mm Hg (7 studies: 95% CI -9.27 to -3.03; I² = 12%), diastolic BP (DBP) by 3.41 mm Hg (7 studies: 95% CI -5.56 to -1.27; I² = 41%) and mean arterial pressure (MAP) by 4.60 mm Hg (4 studies: 95% CI -7.26 to -1.94; I² = 28%). In short-term studies, low sodium intake may reduce SBP by 8.43 mm Hg (5 studies: 95% CI -14.37 to -2.48; I² = 88%), DBP by 2.95 mm Hg (5 studies: 95% CI -4.96 to -0.94; I² = 70%) and MAP by 2.37 mm Hg (9 studies: 95% CI -4.75 to -0.01; I² = 65%). There was considerable heterogeneity in most analyses but particularly among short-term studies. All analyses were considered to be of low certainty evidence. SBP, DBP and MAP reductions may not differ between hypertensive and normotensive participants or between individuals with type 1 or type 2 diabetes. In hypertensive participants, SBP, DBP and MAP may be reduced by 6.45, 3.15 and 4.88 mm Hg, respectively, while in normotensive participants, they may be reduced by 8.43, 2.95 and 2.15 mm Hg, respectively (all low certainty evidence). SBP, DBP and MAP may be reduced by 7.35, 3.04 and 4.30 mm Hg, respectively, in participants with type 2 diabetes and by 7.35, 3.20, and 0.08 mm Hg, respectively, in participants with type 1 diabetes (all low certainty evidence). Eight studies provided measures of urinary protein excretion before and after salt restriction; four reported a reduction in urinary albumin excretion with salt restriction. Pooled analyses showed no changes in GFR (12 studies: MD -1.87 mL/min/1.73 m², 95% CI -5.05 to 1.31; I² = 32%) or HbA1c (6 studies: MD -0.62, 95% CI -1.49 to 0.26; I² = 95%) with salt restriction (low certainty evidence). Body weight was reduced in studies lasting one to two weeks but not in studies lasting for longer periods (low certainty evidence). Adverse effects were reported in only one study; 11% and 21% developed postural hypotension on the low-salt diet and the low-salt diet combined with hydrochlorothiazide, respectively.

AUTHORS' CONCLUSIONS

This systematic review shows an important reduction in SBP and DBP in people with diabetes with normal GFR during short periods of salt restriction, similar to that obtained with single drug therapy for hypertension. These data support the international recommendations that people with diabetes with or without hypertension or evidence of kidney disease should reduce salt intake to less than 5 g/day (2 g sodium).

Low Sodium Intake, Low Protein Intake, and Excess Mortality in an Older Dutch General Population Cohort: Findings in the Prospective Lifelines-MINUTHE Study

Background: Several studies have found a U-shaped association between sodium intake and mortality. The increased mortality risk of low sodium intake has raised debates and hampers widespread acceptance of public health campaigns and dietary guidelines on reducing sodium intake. Whether the excess risk can be attributed to low sodium intake alone or concomitant inadequate intake of other relevant nutrients is unknown. Objective: We investigated whether concomitant low protein intake could explain the lower part of the U-shaped association of sodium intake with all-cause mortality. Methods: We included 1603 individuals aged between 60 and 75 years old from the gender- and socioeconomic status-balanced prospective Lifelines-MINUTHE cohort study. Using multivariable Cox regression analyses, we investigated the association of sodium intake (24 h urinary sodium excretion) with all-cause mortality, including the interaction with protein intake calculated from the Maroni formula. Results: Mean intakes of sodium and protein were 3.9 ± 1.6 g/day and 1.1 ± 0.3 g/kg/day, respectively. After a median follow-up of 8.9 years, 125 individuals (7.8%) had died. The proportion of participants with insufficient protein intake (<0.8 g/kg/day) was inversely related to sodium intake (i.e., 23.3% in Q1 versus 2.8% in Q4, p < 0.001). We found an increased risk for mortality in both the highest quartile (Q4, >4.7 g/day; hazard ratio (HR) 1.74 (95% confidence interval (CI) 1.03−2.95)) and the lowest two quartiles of sodium intake (Q1, 0.7−2.8 g/day; 2.05 (1.16−3.62); p = 0.01 and Q2, 2.8−3.6 g/day; 1.85 (1.08−3.20); p = 0.03), compared with the third quartile of sodium intake (Q3, 3.6−4.7 g/day). This U-shaped association was significantly modified by protein intake (Pinteraction = 0.006), with the increased mortality risk of low sodium intake being reversed to the lowest mortality risk with concomitant high protein intake. In contrast, the increased mortality risk of low sodium intake was magnified by concomitant low protein intake. Conclusions: We found that a higher protein intake counteracts the increased mortality risk observed in subjects with a low sodium intake. In contrast, a joint low intake of sodium and protein is associated with an increased mortality risk, allegedly due to poor nutritional status. These findings support the guidelines that advocate a lower sodium intake, while highlighting the importance of recognizing overall nutritional status among older adults.

The perspective of hypertension and salt intake in Chinese population

Salt intake is too high nowadays. It has been widely recognized that there is a close relationship between hypertension (HTN) and dietary salt intake. Investigations reveal that long-term high salt intake, mainly sodium intake, induces a relevant increase in blood pressure in hypertensive and normotensive individuals. According to most scientific evidence, a diet with high salt intake in public increases cardiovascular risk, salted-related HTN, and other HTN-associated outcomes. Given the clinical importance, this review aims to present the prevalence of HTN and trends in salt intake in the Chinese population and will comprehensively discuss the risk factors, causes, and mechanisms of the association between salt intake and HTN. The review also highlights the education of Chinese people regarding salt intake and the cost-effectiveness of salt reduction from a global perspective. Finally, the review will emphasize the need to customize the unique Chinese practices to reduce salt intake and how awareness changes people's eating lifestyle and helps adopt diet salt reduction strategies.

Urinary Sodium Excretion and Salt Intake Are Not Associated With Blood Pressure Variability in a White General Population

Background Salt restriction may lower blood pressure variability (BPV), but previous studies have shown inconsistent results. Therefore, we investigated in an observational study and intervention trial whether urinary sodium excretion and salt intake are associated with 24-hour BPV. Methods and Results We used data from the cross-sectional population-based Maastricht Study (n=2652; 60±8 years; 52% men) and from a randomized crossover trial (n=40; 49±11 years; 33% men). In the observational study, we measured 24-hour urinary sodium excretion and 24-hour BPV and performed linear regression adjusted for age, sex, mean blood pressure, lifestyle, and cardiovascular risk factors. In the intervention study, participants adhered to a 7-day low- and high-salt diet (50 and 250 mmol NaCl/24 h) with a washout period of 14 days, 24-hour BPV was measured during each diet. We used linear mixed models adjusted for order of diet, mean blood pressure, and body mass index. In the observational study, 24-hour urinary sodium excretion was not associated with 24-hour systolic or diastolic BPV (β, per 1 g/24 h urinary sodium excretion: 0.05 mm Hg [95% CI, -0.02 to 0.11] and 0.04 mm Hg [95% CI, -0.01 to 0.09], respectively). In the intervention trial, mean difference in 24-hour systolic and diastolic BPV between the low- and high-salt diet was not statistically significantly different (0.62 mm Hg [95% CI, -0.10 to 1.35] and 0.04 mm Hg [95% CI, -0.54 to 0.63], respectively). Conclusions Urinary sodium excretion and salt intake are not independently associated with 24-hour BPV. These findings suggest that salt restriction is not an effective strategy to lower BPV in the White general population. Registration URL: https://clinicaltrials.gov/ct2/show/NCT02068781.

'Love with Less Salt': evaluation of a sodium reduction mass media campaign in China

OBJECTIVE

This study examines the impact of a salt reduction campaign on knowledge, attitudes, intentions, behaviours and barriers to behaviour change relating to salt consumption in two provinces of China.

METHODS

In 2019, the 'Love with Less Salt' campaign ran on China Central Television and on local television channels in Shandong and Anhui provinces. Data for this study come from two representative household surveys conducted among a sample of adults aged 25-65 years in Shandong and Anhui provinces: precampaign (n=2000) and postcampaign (n=2015). Logistic regression was performed to estimate the effects of the campaign on knowledge, attitudes, intentions, behaviours and barriers to behaviour change.

RESULTS

Overall, 13% of postcampaign respondents recalled seeing the campaign, and reactions towards the campaign were positive. Postcampaign respondents were more likely to plan to reduce their purchase of foods high in salt than precampaign respondents (OR=1.45, p=<0.05). Campaign-aware respondents were significantly more likely than campaign-unaware respondents to report higher levels of knowledge, attitudes and behaviours regarding salt reduction.

CONCLUSIONS

Findings reveal that salt reduction mass media campaigns can be an effective public health tool to support efforts to reduce salt consumption in China. Continued and sustained mass media investments are likely to be effective in addressing high salt consumption nationwide.

Association between Perceived Salt Intake and Arterial Stiffness

To explore the association of perceived salt intake (SI) level with arterial stiffness in the community population in northern China. We enrolled participants who completed the health questionnaire, physical examination, and brachial-ankle pulse wave velocity (baPWV) test during 2010-2019 and divided them into <6 g (low SI), 6-10 g (medium SI), and >10 g (high SI) groups based on their daily SI. The influence of SI on baPWV was analyzed using the multivariate logistic regression model. A total of 36324 subjects, aged (49.10 ± 12.57) years with a male to female ratio of 25934 : 10390, met the inclusion criteria and were enrolled. The average baPWV was (1527.73 ± 355.61) cm/s. Logistic regression analysis showed that after adjusting for other confounders, daily SI>10 g (high SI) was a risk factor for arterial stiffness (baPWV ≥1400 cm/s), with the odds ratio (95% confidence interval [CI]) of 1.17 (1.04-1.31). High SI is independently associated with arterial stiffness.

Clarifying Optimal Sodium InTake In Cardiovasular and Kidney (COSTICK) Diseases: a study protocol for two randomised controlled trials

Background: While low sodium intake (<2.3g/day) is recommended for all, there is uncertainty about feasibility and net cardiovascular effects. In COSTICK, we evaluated the effects of a dietary counselling intervention (reduced sodium intake) on intermediate cardiorenal outcomes in patients with (STICK) and without (COSIP) mild/moderate kidney disease. Methods: This is a protocol for two phase IIb randomised, two-group, parallel, open-label, controlled, single centre trials. Participants were aged >40 years with stable blood pressure, unchanged anti-hypertensive medications, willing to modify diet and provided written informed consent. Participants were excluded for abnormal sodium handling, heart failure, high dose diuretics, immunosuppression, pregnancy/lactation, postural hypotension, cognitive impairment, high or low body mass index (BMI) or inclusion in another trial. STICK participants had estimated glomerular filtration rate (eGFR) 30-60ml/min/1.73m2 and were excluded for acute kidney Injury, rapidly declining eGFR; known glomerular disease or current use of non-steroidal anti-inflammatory drugs. For COSIP, participants were excluded for known kidney or cardiovascular disease. Participants were randomized to usual care only (healthy eating) or an additional sodium lowering intervention (target <100mmol/day) through specific counseling (sodium use in foods, fresh over processed foods, sodium content of foods and eating outside of home). In STICK the primary outcome is change in 24-hour urinary creatinine clearance. In COSIP, the primary outcome is change in five biomarkers (renin, aldosterone, high sensitivity troponin T, pro-B-type natriuretic peptide and C-reactive protein). Our primary report (COSTICK), reports six biomarker outcome measures in the entire population at 2 years follow-up. Discussion: These Phase II trials will explore uncertainty about low sodium intake and cardiovascular and kidney biomarkers, and help determine the feasibility of low sodium intake. Trial results will also provide preliminary information to guide a future definitive clinical trial, if indicated. Trial registration: STICK: ClinicalTrials.gov NCT02738736 (04/04/2016); COSIP: ClinicalTrials.gov NCT02458248 (15/05/2016)

A Systematic Review of Literature on the Representation of Racial and Ethnic Minority Groups in Clinical Nutrition Interventions

The racial and ethnic disparities in diet-related chronic diseases are major concerns. This systematic review examines the extent to which diet-induced changes in health outcomes, such as cardiometabolic, inflammation, cancer, bone health, and kidney function outcomes, etc., have been reported and discussed by race or ethnicity in randomized trials with 2 or more diet arms that recruited both minority and non-Hispanic White groups. Databases (i.e., PubMed, Cochrane Library, and Web of Science) were searched up to August 2021. Thirty-four studies that discussed effects of defined dietary interventions on health outcomes by racial or ethnic minority group compared with non-Hispanic Whites were included in the systematic review (PROSPERO registration number: CRD42021229256). Acute trials and those with 1 diet arm that accounted for race or ethnicity in their analyses and studies that focused on a single racial or ethnic group were discussed separately. Most studies were conducted in Black compared with White adults testing effects of energy restriction, macronutrient modification, sodium reduction, or variations of the Dietary Approaches to Stop Hypertension (DASH) diet on cardiometabolic outcomes. There was limited focus on other minority groups. Evidence suggests greater blood pressure reduction for Black adults compared with Whites particularly with DASH (or similar) diets. Overall, there was limited consideration for group-specific eating patterns and diet acceptability. Overall risk of bias was low. With emerging precision nutrition initiatives that aim to optimize metabolic responses in population subgroups through tailored approaches, it is imperative to ensure adequate representation of racial and ethnic subgroups for addressing health disparities. Factors that help explain variability in responses such as socioecological context should be included and adequately powered. Given the racial and ethnic disparities in chronic diseases, studying the adoption, maintenance, and effectiveness of dietary interventions on health outcomes among different groups is critical for developing approaches that can mitigate diet-related health disparities.

Differential influences of dietary sodium on blood pressure regulation based on race and sex

There are clear differences between men and women, and differences among races, in the incidence and prevalence of hypertension. Furthermore, there is extensive inter-individual variability among humans in the extent to which sodium ingestion alters blood pressure. Orthostatic intolerance and orthostatic hypotension are more common in women; these are often treated with a high salt diet, which has variable efficacy in increasing blood volume and blood pressure. Conversely, people with certain forms of hypertension are often counseled to decrease their sodium intake. Non-Hispanic Black men and women have higher rates of hypertension compared to non-Hispanic White men and women and other racial/ethnic groups. In aggregate, Black women appear to have better orthostatic tolerance than White women. In the present paper, we summarize and evaluate the current evidence for mechanisms of blood pressure regulation in men and women, as well as differences between Black and White groups, with a focus on cardiovascular responses to salt and differences among these groups. We also provide a brief review of factors that are not traditionally considered to be "biological" - such as socio-economic disparities resulting from historic and contemporary inequity across racial groups. These non-biological factors have direct and substantial influences on cardiovascular mechanisms, as well as implications for the influences of salt and sodium intake on blood pressure and cardiovascular health. We conclude that both biological and socio-economic factors provide critical modulating influences when considering the impacts of sodium on cardiovascular health as functions of race and sex.

The impact of baseline potassium intake on the dose-response relation between sodium reduction and blood pressure change: systematic review and meta-analysis of randomized trials

Sodium and potassium appear to interact with each other in their effects on blood pressure with potassium supplementation having a greater blood pressure lowering-effect when sodium intake is high. Whether the effect of sodium reduction on blood pressure varies according to potassium intake levels is unclear. We carried out a systematic review and meta-analysis to examine the impact of baseline potassium intake on blood pressure response to sodium reduction in randomized trials in adult populations, with sodium and potassium intake estimated from 24-h urine samples. We included 68 studies involving 5708 participants and conducted univariable and multivariable meta-regression. The median intake of baseline potassium was 67.7 mmol (Interquartile range: 54.6-76.4 mmol), and the mean reduction in sodium intake was 128 mmol (95% CI: 107-148). Multivariable meta-regression that included baseline 24-h urinary potassium excretion, age, ethnicity, baseline blood pressure, change in 24-h urinary sodium excretion, as well as the interaction between baseline 24-h urinary potassium excretion and change in 24-h urinary sodium excretion did not identify a significant association of baseline potassium intake levels with the blood pressure reduction achieved with a 50 mmol lowering of sodium intake (p > 0.05 for both systolic and diastolic blood pressure). A higher starting level of blood pressure was consistently associated with a greater blood pressure reduction from reduced sodium consumption. However, the nonsignificant findings may subject to the limitations of the data available. Additional studies with more varied potassium intake levels would allow a more confident exclusion of an interaction.

Development of a Method for Estimating Dietary Salt Intake Using the Overnight Urinary Sodium/Potassium Ratio

Background

There are many patients who need to restrict and assess salt in their diet. However, it is difficult to estimate daily salt intake accurately and easily. Therefore, a method for estimating dietary salt intake using the overnight urinary sodium (Na)/potassium (K) ratio was developed.

Methods

The study involved 43 healthy adults (13 males, 30 females). From 2018 to 2020, subjects consumed a salt-adjusted diet for 11 - 30 days continuously, and overnight urine was collected daily. Using the previous day's salt intake as the objective variable, an equation for estimating the salt intake was developed using a general linear model. To verify the accuracy of the estimating equation, the estimated salt intake of the previous day was calculated using our equation and Tanaka's equation, which is an estimating equation from spot urine widely used in clinical practice and epidemiological studies to estimate dietary salt intake, and they were compared with the actual salt intake.

Results

The results of the analysis showed that model 1 (previous day's salt intake (g) = 3.62 + 0.64 × urinary Na/K ratio + 0.18 × conductivity (mS/cm) - 0.43 × sex (male 0, female 1)) was the optimal model. Then, salt intake was estimated using model 1 and Tanaka's equation, and compared with actual salt intake. The Pearson's product-moment correlation coefficient between the actual and estimated salt intake was r = 0.618 (P < 0.001) and r = 0.573 (P < 0.001) for model 1 estimates and Tanaka's equation estimates, respectively. The percentages of errors within ±30% from the actual salt intake were 64.2% and 58.4% for model 1 and Tanaka's equation, respectively.

Conclusion

An equation for estimating salt intake was developed using the Na/K ratio and conductivity of overnight urine. Although the applicability of this method to hypertensive patients and the elderly has not been studied and needs to be clarified in the future, the estimating equation developed is simple and may be a useful method for daily monitoring of dietary salt intake.

Feasibility of Low-Sodium, High-Potassium Processed Foods and Their Effect on Blood Pressure in Free-Living Japanese Men: A Randomized, Double-Blind Controlled Trial

We aimed to verify the effect of new low-sodium high-potassium seasonings and processed foods containing poly-γ-glutamic acid on blood pressure in free-living settings. To this end, we conducted a randomized, double-blind controlled trial on 187 Japanese men, aged 35–67 years, who did not use antihypertensives. Participants were randomly allocated to an intervention (n = 93) or a control group (n = 94). They were given a boxed lunch and miso soup (average Na and K content for the intervention group: 1175 and 1476 mg; for the control group: 2243 and 703 mg, respectively). Blood pressure was measured three times every morning for 1 week immediately before and during the final week of the trial. On the day before and the final day of the intervention period, 24 h urine samples were collected. After intervention, the intervention group showed a significantly stronger decrease in the urinary sodium-to-potassium ratio than the control group (p < 0.001). The mean difference in systolic blood pressure change after adjustment for baseline values between the two groups was −2.1 (95% CI: −3.6, −0.6) mmHg. Compliance between the groups was similar, suggesting successful blinding. In conclusion, the use of new seasonings and processed foods aimed at lowering blood pressure in free-living settings may be feasible and effective.

Association of Sodium, Potassium and Sodium-to-Potassium Ratio with Urine Albumin Excretion among the General Chinese Population

Mixed evidence was published regarding the association of sodium, potassium and sodium-to-potassium ratio (Na/K ratio) with renal function impairment. This study was conducted to further explore the relationship between sodium, potassium, NA/K ratio and kidney function in the general adult Chinese population. We performed a cross-sectional analysis using the baseline data from the Action on Salt China (ASC) study. 5185 eligible general adult participants from the baseline investigation of the ASC study were included in this analysis. Sodium, potassium and albumin excretion were examined from 24-h urine collection. Albuminuria was defined as albumin excretion rate (AER) greater than or equal to 30 mg/24-h. Mixed linear regression models, adjusted for confounders, were fitted to analyze the association between sodium, potassium and Na/K ratio, and natural log transformed AER. Mixed effects logistic regression models were performed to analyze the odds ratio of albuminuria at each quintile of sodium, potassium and Na/K ratio. The mean age of the participants was 49.5 ± 12.8 years, and 48.2% were male. The proportion of albuminuria was 7.5%.The adjusted mixed linear models indicated that sodium and Na/K ratio was positively associated with natural log transformed AER (Sodium: β = 0.069, 95%CI [0.050, 0.087], p < 0.001; Na/K ratio: β = 0.026, 95%CI [0.012, 0.040], p < 0.001). Mixed effects logistic regression models showed that the odds of albuminuria significantly increased with the quintiles of sodium (p < 0.001) and Na/K ratio (p = 0.001). No significant association was found between potassium and the outcome indicators. Higher sodium intake and higher Na/K ratio are associated with early renal function impairment, while potassium intake was not associated with kidney function measured by albumin excretion.

Preliminary Experiment on the Effect of 18% Substitute Salt on Home Blood Pressure Variability in Hypertensives

At present, the effect of substitute salt in reducing sodium intake and blood pressure is relatively clear. The present study is a phase I clinical trial involving 43 hypertensives in which the effect of 18% sodium substitute salt on the home blood pressure variability (BPV) was observed for 8 weeks with weekly follow-up. Finally, 4 patients were lost, and 39 patients completed the intervention and were included in the analysis. Daily home blood pressure and weekly adverse events were collected. The systolic blood pressure (SBP) in the morning (-10.0 mmHg, 95% CI: -16.5 to -3.5, P = 0.003), SBP at night (-10.2 mmHg, 95% CI: -16.1 to -4.3, P = 0.001), and diastolic blood pressure (DBP) at night (-4.0 mmHg, 95% CI: -7.1 to -0.8, P = 0.014) decreased significantly. Also, there was no statistically significant change in morning (F = 1.137, P = 0.352) and night diastolic (F = 0.344, P = 0.481) BPV and morning systolic BPV (F = 0.663, P = 0.930) over time during the intervention period, except for that night systolic BPV had a downward trend (F = 2.778, P = 0.016) and had decreased 2.04 mmHg (95% CI: 0.84 to 3.23, P = 0.001) after intervention. The use of 18% of the substitute salt did not increase BPV during the intervention and even may decrease it, which indicates its control effects on blood pressure. This study is the first one to observe the effect of 18% sodium substitute salt on the home blood pressure variability, providing a basis for further experiments.

Gram-scale synthesis of a neodymium chelate as a spectral CT and second near-infrared window imaging agent for visualizing the gastrointestinal tract in vivo

The diagnosis of gastrointestinal (GI) tract diseases is frequently performed in the clinic, so it is crucial to develop high-performance contrast agents for real-time and non-invasive imaging examination of the GI tract. Herein, we show a novel method to synthesize a neodymium (Nd) chelate, Nd-diethylenetriaminepentaacetic acid (Nd-DTPA), on a large scale without byproducts for spectral computed tomography (CT) and second near-infrared window imaging of the GI tract in vivo. The Nd-DTPA was simply generated by heating the mixture of Nd2O3 and DTPA in water at 85 °C for 2 h. This dual-modal imaging agent has the advantages of a simple and green synthesis route, no need of purification process, high yield (86.24%), large-scale production capability (>10 g in lab synthesis), good chemical stability and excellent water solubility (≈2 g mL-1). Moreover, the Nd-DTPA emitted strong near-infrared fluorescence at 1308 nm, and exhibited superior X-ray attenuation ability compared to clinical iohexol. The proposed Nd-DTPA can integrate the complementary merits of dual-modal imaging to realize spatial-temporal and highly sensitive imaging of the GI tract in vivo, and accurate diagnosis of the location of intestinal obstruction and monitor its recovery after surgery. The developed highly efficient method for the gram-scale synthesis of Nd-DTPA and the proposed spectral CT and second near-infrared window dual-modal imaging strategy provide a promising route for accurate visualization of the GI tract in vivo.

No evidence of racial disparities in blood pressure salt sensitivity when potassium intake exceeds levels recommended in the US dietary guidelines

On average, black individuals are widely believed to be more sensitive than white individuals to blood pressure (BP) effects of changes in salt intake. However, few studies have directly compared the BP effects of changing salt intake in black versus white individuals. In this narrative review, we analyze those studies and note that when potassium intake substantially exceeds the recently recommended US dietary goal of 87 mmol/day, black adults do not appear more sensitive than white adults to BP effects of short-term or long-term increases in salt intake (from an intake ≤50 mmol/day up to 150 mmol/day or more). However, with lower potassium intakes, racial differences in salt sensitivity are observed. Mechanistic studies suggest that racial differences in salt sensitivity are related to differences in vascular resistance responses to changes in salt intake mediated by vasodilator and vasoconstrictor pathways. With respect to cause and prevention of racial disparities in salt sensitivity, it is noteworthy that 1) on average, black individuals consume less potassium than white individuals and 2) consuming supplemental potassium bicarbonate, or potassium rich foods can prevent racial disparities in salt sensitivity. However, the new US dietary guidelines reduced the dietary potassium goal well below the amount associated with preventing racial disparities in salt sensitivity. These observations should motivate research on the impact of the new dietary potassium guidelines on racial disparities in salt sensitivity, the risks and benefits of potassium-containing salt substitutes or supplements, and methods for increasing consumption of foods rich in nutrients that protect against salt-induced hypertension.

Impact of Micronutrients on Hypertension: Evidence from Clinical Trials with a Special Focus on Meta-Analysis

Hypertension (HT) is one of the pivotal risk factors for various detrimental diseases like cardiovascular diseases (CVDs), cerebrovascular disease, and renal dysfunction. Currently, many researchers are paying immense attention to various diet formula (dietary approach) with a special focus on micro and macronutrients along with modified lifestyle and standard anti-hypertensive drugs. Micronutrients (minerals/vitamins) play a central role in the regulation of blood pressure (BP) as they aid the function of macronutrients and also improve the anti-hypertensive functions of some anti-hypertensive agents. Even though several studies have demonstrated the beneficial effects of micronutrients on controlling BP, still some ambiguity exists among the nutritionists/doctors, which combination or individual mineral (dietary approach) contributes to better BP regulation. Therefore, this critical review article was attempted to delineate the underlying role of micronutrients (minerals and vitamins) for the management and prevention or delaying of HT and their related complications with strong affirmation from clinical trials as well as its mechanism of controlling BP. Moreover, the major source and recommended daily allowance (RDA) of various micronutrients are included in this review for guiding common readers (especially HT subjects) and dieticians to choose/recommend a better micronutrient and their combinations (other nutrients and standard anti-hypertensive drugs) for lowering the risk of HT and its related co-morbid conditions like CVDs.

Clarifying Optimal Sodium InTake In Cardiovasular and Kidney (COSTICK) Diseases: a study protocol for two randomised controlled trials

Background: While low sodium intake (<2.3g/day) is recommended for all, there is uncertainty about feasibility and net cardiovascular effects. In COSTICK, we evaluated the effects of a dietary counselling intervention (reduced sodium intake) on intermediate cardiorenal outcomes in patients with (STICK) and without (COSIP) mild/moderate kidney disease. Methods: This is a protocol for two phase IIb randomised, two-group, parallel, open-label, controlled, single centre trials. Participants were aged >40 years with stable blood pressure, unchanged anti-hypertensive medications, willing to modify diet and provided written informed consent. Participants were excluded for abnormal sodium handling, heart failure, high dose diuretics, immunosuppression, pregnancy/lactation, postural hypotension, cognitive impairment, high or low body mass index (BMI) or inclusion in another trial. STICK participants had estimated glomerular filtration rate (eGFR) 30-60ml/min/1.73m2 and were excluded for acute kidney Injury, rapidly declining eGFR; known glomerular disease or current use of non-steroidal anti-inflammatory drugs. For COSIP, participants were excluded for known kidney or cardiovascular disease. Participants were randomized to usual care only (healthy eating) or an additional sodium lowering intervention (target <100mmol/day) through specific counseling (sodium use in foods, fresh over processed foods, sodium content of foods and eating outside of home). In STICK the primary outcome is change in 24-hour urinary creatinine clearance. In COSIP, the primary outcome is change in five biomarkers (renin, aldosterone, high sensitivity troponin T, pro-B-type natriuretic peptide and C-reactive protein). Our primary report (COSTICK), reports six biomarker outcome measures in the entire population at 2 years follow-up. Discussion: These Phase II trials will explore uncertainty about low sodium intake and cardiovascular and kidney biomarkers, and help determine the feasibility of low sodium intake. Trial results will also provide preliminary information to guide a future definitive clinical trial, if indicated. Trial registration: STICK: ClinicalTrials.gov NCT02738736 (04/04/2016); COSIP: ClinicalTrials.gov NCT02458248 (15/05/2016)

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 .

Effects of low sodium diet versus high sodium diet on blood pressure, renin, aldosterone, catecholamines, cholesterol, and triglyceride

BACKGROUND

Recent cohort studies show that salt intake below 6 g is associated with increased mortality. These findings have not changed public recommendations to lower salt intake below 6 g, which are based on assumed blood pressure (BP) effects and no side-effects.

OBJECTIVES

To assess the effects of sodium reduction on BP, and on potential side-effects (hormones and lipids) SEARCH METHODS: The Cochrane Hypertension Information Specialist searched the following databases for randomized controlled trials up to April 2018 and a top-up search in March 2020: the Cochrane Hypertension Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (from 1946), Embase (from 1974), the World Health Organization International Clinical Trials Registry Platform, and ClinicalTrials.gov. We also contacted authors of relevant papers regarding further published and unpublished work. The searches had no language restrictions. The top-up search articles are recorded under "awaiting assessment."

SELECTION CRITERIA

Studies randomizing persons to low-sodium and high-sodium diets were included if they evaluated at least one of the outcome parameters (BP, renin, aldosterone, noradrenalin, adrenalin, cholesterol, high-density lipoprotein, low-density lipoprotein and triglyceride,.

DATA COLLECTION AND ANALYSIS

Two review authors independently collected data, which were analysed with Review Manager 5.3. Certainty of evidence was assessed using GRADE.

MAIN RESULTS

Since the first review in 2003 the number of included references has increased from 96 to 195 (174 were in white participants). As a previous study found different BP outcomes in black and white study populations, we stratified the BP outcomes by race. The effect of sodium reduction (from 203 to 65 mmol/day) on BP in white participants was as follows: Normal blood pressure: SBP: mean difference (MD) -1.14 mmHg (95% confidence interval (CI): -1.65 to -0.63), 5982 participants, 95 trials; DBP: MD + 0.01 mmHg (95% CI: -0.37 to 0.39), 6276 participants, 96 trials. Hypertension: SBP: MD -5.71 mmHg (95% CI: -6.67 to -4.74), 3998 participants,88 trials; DBP: MD -2.87 mmHg (95% CI: -3.41 to -2.32), 4032 participants, 89 trials (all high-quality evidence). The largest bias contrast across studies was recorded for the detection bias element. A comparison of detection bias low-risk studies versus high/unclear risk studies showed no differences. The effect of sodium reduction (from 195 to 66 mmol/day) on BP in black participants was as follows: Normal blood pressure: SBP: mean difference (MD) -4.02 mmHg (95% CI:-7.37 to -0.68); DBP: MD -2.01 mmHg (95% CI:-4.37, 0.35), 253 participants, 7 trials. Hypertension: SBP: MD -6.64 mmHg (95% CI:-9.00, -4.27); DBP: MD -2.91 mmHg (95% CI:-4.52, -1.30), 398 participants, 8 trials (low-quality evidence). The effect of sodium reduction (from 217 to 103 mmol/day) on BP in Asian participants was as follows: Normal blood pressure: SBP: mean difference (MD) -1.50 mmHg (95% CI: -3.09, 0.10); DBP: MD -1.06 mmHg (95% CI:-2.53 to 0.41), 950 participants, 5 trials. Hypertension: SBP: MD -7.75 mmHg (95% CI:-11.44, -4.07); DBP: MD -2.68 mmHg (95% CI: -4.21 to -1.15), 254 participants, 8 trials (moderate-low-quality evidence).   During sodium reduction renin increased 1.56 ng/mL/hour (95%CI:1.39, 1.73) in 2904 participants (82 trials); aldosterone increased 104 pg/mL (95%CI:88.4,119.7) in 2506 participants (66 trials); noradrenalin increased 62.3 pg/mL: (95%CI: 41.9, 82.8) in 878 participants (35 trials); adrenalin increased 7.55 pg/mL (95%CI: 0.85, 14.26) in 331 participants (15 trials); cholesterol increased 5.19 mg/dL (95%CI:2.1, 8.3) in 917 participants (27 trials); triglyceride increased 7.10 mg/dL (95%CI: 3.1,11.1) in 712 participants (20 trials); LDL tended to increase 2.46 mg/dl (95%CI: -1, 5.9) in 696 participants (18 trials); HDL was unchanged -0.3 mg/dl (95%CI: -1.66,1.05) in 738 participants (20 trials) (All high-quality evidence except the evidence for adrenalin).

AUTHORS' CONCLUSIONS

In white participants, sodium reduction in accordance with the public recommendations resulted in mean arterial pressure (MAP) decrease of about 0.4 mmHg in participants with normal blood pressure and a MAP decrease of about 4 mmHg in participants with hypertension. Weak evidence indicated that these effects may be a little greater in black and Asian participants. The effects of sodium reduction on potential side effects (hormones and lipids) were more consistent than the effect on BP, especially in people with normal BP.

Trends in Sodium Intake in Children and Adolescents in the US and the Impact of US Department of Agriculture Guidelines: NHANES 2003-2016

OBJECTIVE

To examine trends in sodium intake and the impact of nutritional guidelines in the US pediatric population.

STUDY DESIGN

Sodium intake data collected between 2003 and 2016 in the US National Health and Nutrition Examination Surveys (NHANES) were analyzed. Trends in intake for individuals aged 4-17 years and subgroups based on age, sex, and race and ethnicity were examined. Adherence to US Department of Agriculture guidelines was assessed.

RESULTS

A total of 16 013 individuals (50.6% male) were included in the analysis. The median sodium intake was 2840 mg/day (95% CI, 2805-2875 mg/day), decreasing from 2912 mg/day (95% CI 2848-2961 mg/day) in 2003-2004 to 2787 mg/day (95% CI, 2677-2867 mg/day) in 2015-2016 (P = .005). Intake increased with age (2507 mg/day for individuals aged 4-8, 2934 mg/day for those aged 9-13 years, and 3124 mg/day for those aged 14-17 years; P < .001) and was greater in males than in females (3053 mg/day vs 2624 mg/day; P < .001). Caucasians, Hispanics, and African Americans consumed 2860, 2733, and 2880 mg/day, respectively (P < .001). Population adherence to US Department of Agriculture recommendations was 25.0% in 2003-2010 and 25.5% in 2011-2016 (P = .677). No age, sex, or racial/ethnicity subgroup had an adherence rate >30% after implementation of pediatric guidelines in 2010.

CONCLUSIONS

Sodium intake remains elevated in all pediatric population segments, and guideline adherence is poor. A greater effort to reduce sodium consumption is needed to mitigate future cardiovascular disease risk.

Nonpharmacologic Interventions for Reducing Blood Pressure in Adults With Prehypertension to Established Hypertension

Background

Nonpharmacologic interventions that modify lifestyle can lower blood pressure (BP) and have been assessed in numerous randomized controlled trials and pairwise meta‐analyses. It is still unclear which intervention would be most efficacious.

Methods and Results

Bayesian network meta‐analyses were performed to estimate the comparative effectiveness of different interventions for lowering BP. From 60 166 potentially relevant articles, 120 eligible articles (14 923 participants) with a median follow‐up of 12 weeks, assessing 22 nonpharmacologic interventions, were included. According to the surface under the cumulative ranking probabilities and Grading of Recommendations Assessment, Development and Evaluation (GRADE) quality of evidence, for adults with prehypertension to established hypertension, high‐quality evidence indicated that the Dietary Approach to Stop Hypertension (DASH) was superior to usual care and all other nonpharmacologic interventions in lowering systolic BP (weighted mean difference, 6.97 mm Hg; 95% credible interval, 4.50–9.47) and diastolic BP (weighted mean difference, 3.54 mm Hg; 95% credible interval, 1.80–5.28). Compared with usual care, moderate‐ to high‐quality evidence indicated that aerobic exercise, isometric training, low‐sodium and high‐potassium salt, comprehensive lifestyle modification, breathing‐control, and meditation could lower systolic BP and diastolic BP. For patients with hypertension, moderate‐ to high‐quality evidence suggested that the interventions listed (except comprehensive lifestyle modification) were associated with greater systolic BP and diastolic BP reduction than usual care; salt restriction was also effective in lowering both systolic BP and diastolic BP. Among overweight and obese participants, low‐calorie diet and low‐calorie diet plus exercise could lower more BP than exercise.

Conclusions

DASH might be the most effective intervention in lowering BP for adults with prehypertension to established hypertension. Aerobic exercise, isometric training, low‐sodium and high‐potassium salt, comprehensive lifestyle modification, salt restriction, breathing‐control, meditation and low‐calorie diet also have obvious effects on BP reduction.

Salt Reduction to Prevent Hypertension and Cardiovascular Disease: JACC State-of-the-Art Review

There is strong evidence for a causal relationship between salt intake and blood pressure. Randomized trials demonstrate that salt reduction lowers blood pressure in both individuals who are hypertensive and those who are normotensive, additively to antihypertensive treatments. Methodologically robust studies with accurate salt intake assessment have shown that a lower salt intake is associated with a reduced risk of cardiovascular disease, all-cause mortality, and other conditions, such as kidney disease, stomach cancer, and osteoporosis. Multiple complex and interconnected physiological mechanisms are implicated, including fluid homeostasis, hormonal and inflammatory mechanisms, as well as more novel pathways such as the immune response and the gut microbiome. High salt intake is a top dietary risk factor. Salt reduction programs are cost-effective and should be implemented or accelerated in all countries. This review provides an update on the evidence relating salt to health, with a particular focus on blood pressure and cardiovascular disease, as well as the potential mechanisms.

Associations Between Salt-Restriction Spoons and Long-Term Changes in Urinary Na+/K+ Ratios and Blood Pressure: Findings From a Population-Based Cohort

Background There have been few studies on the relationship between long-term changes in sodium intake and blood pressure. A method of reducing sodium intake in a population that is known for high-sodium intake based on homemade cooking is also needed. Methods and Results Our study was based on a baseline survey of 15 350 individuals aged 18 to 69 years with multistage random sampling and a 3-year salt-restriction campaign across Shandong Province, China. We included 339 individuals from six districts/counties in this cohort study, and the 24-hour urinary sodium-potassium ratio (Na⁺/K⁺) served as an indicator of sodium intake. The average change in ratio was 2.39 (95% CI, 2.17-2.61) from 6.81 (95% CI, 6.41-7.21) at baseline to 4.41 (95% CI, 4.18-4.64) during the resurvey. Following a reduction from low to high quartiles of urinary Na⁺/K⁺ ratio, the average increases were 10.9 (95% CI, 8.9-12.9), 9.2 (95% CI, 6.9-11.5), 6.3 (95% CI, 4.0-8.6), and 5.3 (95% CI, 2.9-7.7) mm Hg for systolic blood pressure (P for trend=0.019) and 3.8 (95% CI, 2.4-5.2), 2.9 (95% CI, 1.7-4.2), 1.6 (95% CI, 0.4-2.8), and -0.3 (95% CI, -1.4-0.8) mm Hg for diastolic blood pressure (P for trend=0.002), respectively. A reduction in salt intake was evident for people using a 2-g salt-restriction spoon for cooking (-3.49 versus -2.22; P=0.027) after adjustment of confounding factors, compared with nonusers. Similar findings were obtained for other salt-restriction spoon-based indicators. Conclusions Our study indicated that using a salt-restriction spoon for cooking was associated with reduced salt intake that led to a blunting of blood pressure deterioration. This finding further supports the salt-restriction spoon-based strategy for people whose primary salt intake is from homemade cooking.

Frequency of alcohol drinking modifies the association between salt intake and albuminuria: a 1-year observational study

Albuminuria is an important risk factor for end-stage kidney disease and cardiovascular mortality. This 1-year observational study aimed to assess the effect modification of alcohol drinking on the association between salt intake and albuminuria. Overall, 448 employees at a pharmaceutical company in Japan who underwent annual health checkups in both 2017 and 2018 were evaluated. The main exposure of interest was drinking frequency at their first checkups categorized as rarely, occasionally, and daily. To assess the association between the changes in salt intake and albuminuria, the differences in salt intake estimated from single-spot urine specimens and the urinary albumin-to-creatinine ratio (UACR) between 2017 and 2018 were calculated for each subject. A multivariable-adjusted linear regression model showed a significant association between ∆salt intake and ∆Log UACR (per 1 g/day of ∆salt intake, adjusted ß 0.16 [95% confidence interval 0.14, 0.19]) and an effect modification between drinking frequency and ∆salt intake (P for interaction = 0.088). The association between ∆salt intake and ∆Log UACR was enhanced by drinking frequency in a dose-dependent manner (per 1 g/day of ∆salt intake, adjusted ß 0.13 [0.06, 0.19], 0.16 [0.12, 0.20], and 0.20 [0.13, 0.27] in rare, occasional, and daily drinkers, respectively). In conclusion, the results of the present study indicated that salt-induced albuminuria was enhanced in subjects with higher drinking frequency, suggesting that salt restriction may have a stronger renoprotective effect in subjects with higher drinking frequency.

Role of Changes in State of Bound Water and Tissue Stiffness in Development of Age-Related Diseases

An essential effect of environmental stiffness on biological processes in cells at present is generally accepted. An increase in arterial stiffness with advanced age has been reported in many publications. The aim of the present review is to summarize current information about possible chemical reactions and physical processes that lead to tissue stiffening and result in age-related diseases in order to find methods that can prevent or retard time-dependent tissue stiffening. The analysis of published data shows that bound water acts as a plasticizer of biological tissues, a decrease in bound water content results in an increase in biological tissue stiffness, and increased tissue stiffness leads to NF-kB activation and triggered actin polymerization-NF-kB activation is associated with age-related diseases. It can be suggested that changes in bound water content through changing tissue stiffness can affect cellular processes and the development of pathologies related to aging. Both age-related diseases and COVID-19 may be associated with tight-junction disruption and increased tissue stiffness and permeability.

Modest Sodium Reduction Increases Circulating Short-Chain Fatty Acids in Untreated Hypertensives: A Randomized, Double-Blind, Placebo-Controlled Trial

High-sodium diet may modulate the gut microbiome. Given the circulating short-chain fatty acids (SCFAs) are microbial in origin, we tested the hypothesis that the modest sodium reduction would alter circulating SCFA concentrations among untreated hypertensives, and the changes would be associated with reduced blood pressure and improved cardiovascular phenotypes. A total of 145 participants (42% blacks, 19% Asian, and 34% females) were included from a randomized, double-blind, placebo-controlled cross-over trial of sodium reduction with slow sodium or placebo tablets, each for 6 weeks. Targeted circulating SCFA profiling was performed in paired serum samples, which were collected at the end of each period, so as all outcome measures. Sodium reduction increased all 8 SCFAs, among which the increases in 2-methylbutyrate, butyrate, hexanoate, isobutyrate, and valerate were statistically significant (Ps<0.05). Also, increased SCFAs were associated with decreased blood pressure and improved arterial compliance. There were significant sex differences of SCFAs in response to sodium reduction (Ps<0.05). When stratified by sex, the increases in butyrate, hexanoate, isobutyrate, isovalerate, and valerate were significant in females only (Ps<0.05), not in males (Ps>0.05). In females, changes in isobutyrate, isovalerate, and 2-methylbutyrate were inversely associated with reduced blood pressures (Ps<0.05). Increased valerate was associated with decreased carotid-femoral pulse wave velocity (P=0.040). Our results show that dietary sodium reduction increases circulating SCFAs, supporting that dietary sodium may influence the gut microbiome in humans. There is a sex difference in SCFA response to sodium reduction. Moreover, increased SCFAs are associated with decreased blood pressures and improved arterial compliance. Registration- URL: https://www.clinicaltrials.gov. Unique identifier: NCT00152074.

Association of a Province-Wide Intervention With Salt Intake and Hypertension in Shandong Province, China, 2011-2016

IMPORTANCE

High salt intake is associated with hypertension, which is a leading modifiable risk factor for cardiovascular disease.

OBJECTIVE

To assess the association of a government-led, multisectoral, and population-based intervention with reduced salt intake and blood pressure in Shandong Province, China.

DESIGN, SETTING, AND PARTICIPANTS

This cross-sectional study used data from the Shandong-Ministry of Health Action on Salt and Hypertension (SMASH) program, a 5-year intervention to reduce sodium consumption in Shandong Province, China. Two representative samples of adults (aged 18-69 years) were surveyed in 2011 (15 350 preintervention participants) and 2016 (16 490 postintervention participants) to examine changes in blood pressure, and knowledge, attitudes, and behaviors related to sodium intake. Urine samples were collected from random subsamples (2024 preintervention participants and 1675 postintervention participants) for measuring sodium and potassium excretion. Data were analyzed from January 20, 2017, to April 9, 2019.

INTERVENTIONS

Media campaigns, distribution of scaled salt spoons, promotion of low-sodium products in markets and restaurants, and activities to support household sodium reduction and school-based sodium reduction education.

MAIN OUTCOMES AND MEASURES

The primary outcome was change in urinary sodium excretion. Secondary outcomes were changes in potassium excretion, blood pressure, and knowledge, attitudes, and behaviors. Outcomes were adjusted for likely confounders. Means (95% CIs) and percentages were weighted.

RESULTS

Among 15 350 participants in 2011, 7683 (50.4%) were men and the mean age was 40.7 years (95% CI, 40.2-41.2 years); among 16 490 participants in 2016, 8077 (50.7%) were men and the mean age was 42.8 years (95% CI, 42.5-43.1 years). Among participants with 24-hour urine samples, 1060 (51.8%) were men and the mean age was 40.9 years (95% CI, 40.5-41.3 years) in 2011 and 836 (50.7%) were men and the mean age was 40.7 years (95% CI, 40.1-41.4 years) in 2016. The 24-hour urinary sodium excretion decreased 25% from 5338 mg per day (95% CI, 5065-5612 mg per day) in 2011 to 4013 mg per day (95% CI, 3837-4190 mg per day) in 2016 (P < .001), and potassium excretion increased 15% from 1607 mg per day (95% CI, 1511-1704 mg per day) to 1850 mg per day (95% CI, 1771-1929 mg per day) (P < .001). Adjusted mean systolic blood pressure among all participants decreased from 131.8 mm Hg (95% CI, 129.8-133.8 mm Hg) to 130.0 mm Hg (95% CI, 127.7-132.4 mm Hg) (P = .04), and diastolic blood pressure decreased from 83.9 mm Hg (95% CI, 82.6-85.1 mm Hg) to 80.8 mm Hg (95% CI, 79.4-82.1 mm Hg) (P < .001). Knowledge, attitudes, and behaviors associated with dietary sodium reduction and hypertension improved significantly.

CONCLUSIONS AND RELEVANCE

The findings suggest that a government-led and population-based intervention in Shandong, China, was associated with significant decreases in dietary sodium intake and a modest reduction in blood pressure. The results of SMASH may have implications for sodium reduction and blood pressure control in other regions of China and worldwide.

Antioxidant cocktail following a high-sodium meal does not affect vascular function in young, healthy adult humans: a randomized controlled crossover trial

Chronic high sodium intake is a risk factor for cardiovascular disease as it impairs vascular function through an increase in oxidative stress. The objective of this study was to investigate the acute effects of a high-sodium meal (HSM) and antioxidant (AO) cocktail on vascular function. We hypothesized that a HSM would impair endothelial function, and increase arterial stiffness and wave reflection, while ingestion of the AO cocktail would mitigate this response. Healthy adults ingested either an AO cocktail (vitamin C, E, alpha-lipoic acid) or placebo (PLA) followed by a HSM (1500 mg) in a randomized crossover blinded design. Blood pressure (BP), endothelial function (flow-mediated dilation; FMD) and measures of arterial stiffness (pulse wave velocity; PWV) and wave reflection (augmentation index; AIx) were made at baseline and 30, 60, 90, and 120 min after meal consumption. Forty-one participants (20M/21W; 24 ± 1 years; BMI 23.4 ± 0.4 kg/m²) completed the study. Mean BP increased at 120 min relative to 60 min (60 min: 79 ± 1; 120 min: 81 ± 1 mmHg; time effect P = .01) but was not different between treatments (treatment × time interaction P = .32). AIx decreased from baseline (time effect P < .001) but was not different between treatments (treatment × time interaction P = .31). PWV (treatment × time interaction, P = .91) and FMD (treatment × time interaction P = .65) were also not different between treatments. In conclusion, a HSM does not acutely impair vascular function suggesting young healthy adults can withstand the acute impact of sodium on the vasculature and therefore, the AO cocktail is not necessary to mitigate the response.

Increased Aortic Characteristic Impedance Explains Relations Between Urinary Na + /K + and Pulse or Systolic Blood Pressure

Alterations in sodium (Na + ) relative to potassium (K + ) intake increase systolic blood pressure, effects in-part attributed to enhanced pulsatile loads (pulse pressure) beyond steady-state pressures (mean arterial pressure). Whether this effect is through reversible changes (increases in blood volume and hence aortic flow [Q] or wave reflection [Pb]), or potentially irreversible structural changes in the proximal aorta, is unknown. In 581 black South Africans, we determined 24-hour urinary Na + and K + excretion and aortic function from central aortic pressure (radial pulse wave analysis [SphygmoCor software]), velocity, and diameter measurements. Proximal aortic function was assessed from characteristic impedance (Zc). Beyond mean arterial pressure and additional confounders, urinary Na + /K + was independently associated with Zc ( P <0.005) but not peak aortic Q ( P =0.30) or alternative aspects of Q or ejection volume. Although age was strongly associated with proximal aortic diameter, no independent relations between urinary Na + /K + and aortic diameter were noted ( P =0.17). Relations between urinary Na + /K + and Zc translated into independent relations with early systolic compression wave pressures (QxZc [P QxZc ]) and aortic forward wave pressures but not Pb. Moreover, neither reflected wave magnitude ( P =0.92) nor aortic pulse wave velocity were independently associated with urinary Na + /K + . In product of coefficient mediation analysis, the independent relations between urinary Na + /K + and peak aortic or brachial pulse pressure or systolic blood pressure were accounted for by Zc and P QxZc . In conclusion, abnormalities in Na + /K + intake determine pulse pressure or systolic blood pressure beyond mean arterial pressure mainly through potentially irreversible impacts on proximal aortic impedance rather than readily modifiable increases in aortic flow (blood volume) or wave reflection.

Critical review of nutrition, blood pressure and risk of hypertension through the lifecycle: do B vitamins play a role?

Hypertension is the leading cause of preventable mortality worldwide, contributing to over 9 million deaths per annum, predominantly owing to cardiovascular disease. The association of obesity, physical inactivity and alcohol with elevated blood pressure (BP) is firmly established. Weight loss or other dietary strategies, such as the Dietary Approaches to Stop Hypertension (DASH) diet, have been shown to be effective in lowering BP. Additionally, specific nutrients are recognised to contribute to BP, with higher sodium intake linked with an increased risk of hypertension, while potassium is associated with a reduced risk of hypertension. Of note, emerging evidence has identified a novel role for one-carbon metabolism and the related B vitamins, particularly riboflavin, in BP. Specifically in adults genetically at risk of developing hypertension, owing to the common C677T polymorphism in MTHFR, supplemental riboflavin (co-factor for MTHFR) was shown in randomised trials to lower systolic BP by up to 13 mmHg. A BP response to intervention of this magnitude could have important clinical impacts, given that a reduction in systolic BP of 10 mmHg is estimated to decrease stroke risk by 40%. This review aims to explore the factors contributing to hypertension across the lifecycle and to critically evaluate the evidence supporting a role for nutrition, particularly folate-related B vitamins, in BP and risk of hypertension. In addition, gaps in our current knowledge that warrant future research in this area, will be identified.

Association between 24-h urine sodium and proteinuria among hospitalized patients with type 2 diabetes

AIMS

This study used estimated sodium intake from 24-h urine sodium (24hU_Na) to explore the relationship of sodium intake with proteinuria among hospitalized patients with type 2 diabetes and with renal tubular injury markers [retinol-binding protein (RBP), beta 2-microglobulin (β₂-MG), N-acetyl-beta-D-glucosaminidase (NAG)].

METHODS

Hospitalized patients with type 2 diabetes (N = 269) were divided into two groups according to the median (0.08 g/day) 24-h urinary protein (24hU_pro) level. Logistic regression was used to analyze the association between 24hU_Na and 24hU_pro ≥ 0.08 g/L; scatter plots were used to analyze the association of RBP, β₂-MG, and NAG with 24hU_Na.

RESULTS

Overall, 269 patients with type 2 diabetes mellitus were enrolled (average age, 56 ± 12 years; men, 61.3%). Multivariate logistic regression analysis revealed a positive correlation between 24hU_Na and 24hU_pro ≥ 0.08 g/L; every 10 mmol of 24hU_Na had an increased risk of 24hU_pro elevation [odds ratio (OR) (95% confidence interval [CI]: 1.06 (1.01-1.11)]. Compared with the lowest quartile of 24hU_Na, the highest quartile had an increased risk of 24hU_pro elevation [OR (95% CI): 2.76 (1.25-6.05)]; 24hU_Na did not correlate with RBP, β₂-MG, or NAG.

CONCLUSIONS

In hospitalized patients with type 2 diabetes, 24hU_Na was independently related to 24hU_pro ≥ 0.08 g/day_. However, no correlation of 24hU_Na with RBP, β₂-MG, or NAG was found.

Effect of dose and duration of reduction in dietary sodium on blood pressure levels: systematic review and meta-analysis of randomised trials

OBJECTIVE

To examine the dose-response relation between reduction in dietary sodium and blood pressure change and to explore the impact of intervention duration.

DESIGN

Systematic review and meta-analysis following PRISMA guidelines.

DATA SOURCES

Ovid MEDLINE(R), EMBASE, and Cochrane Central Register of Controlled Trials (Wiley) and reference lists of relevant articles up to 21 January 2019.

INCLUSION CRITERIA

Randomised trials comparing different levels of sodium intake undertaken among adult populations with estimates of intake made using 24 hour urinary sodium excretion.

DATA EXTRACTION AND ANALYSIS

Two of three reviewers screened the records independently for eligibility. One reviewer extracted all data and the other two reviewed the data for accuracy. Reviewers performed random effects meta-analyses, subgroup analyses, and meta-regression.

RESULTS

133 studies with 12 197 participants were included. The mean reductions (reduced sodium v usual sodium) of 24 hour urinary sodium, systolic blood pressure (SBP), and diastolic blood pressure (DBP) were 130 mmol (95% confidence interval 115 to 145, P<0.001), 4.26 mm Hg (3.62 to 4.89, P<0.001), and 2.07 mm Hg (1.67 to 2.48, P<0.001), respectively. Each 50 mmol reduction in 24 hour sodium excretion was associated with a 1.10 mm Hg (0.66 to 1.54; P<0.001) reduction in SBP and a 0.33 mm Hg (0.04 to 0.63; P=0.03) reduction in DBP. Reductions in blood pressure were observed in diverse population subsets examined, including hypertensive and non-hypertensive individuals. For the same reduction in 24 hour urinary sodium there was greater SBP reduction in older people, non-white populations, and those with higher baseline SBP levels. In trials of less than 15 days' duration, each 50 mmol reduction in 24 hour urinary sodium excretion was associated with a 1.05 mm Hg (0.40 to 1.70; P=0.002) SBP fall, less than half the effect observed in studies of longer duration (2.13 mm Hg; 0.85 to 3.40; P=0.002). Otherwise, there was no association between trial duration and SBP reduction.

CONCLUSIONS

The magnitude of blood pressure lowering achieved with sodium reduction showed a dose-response relation and was greater for older populations, non-white populations, and those with higher blood pressure. Short term studies underestimate the effect of sodium reduction on blood pressure.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42019140812.

Cardiovascular Diseases Deaths Attributable to High Sodium Intake in Shandong Province, China

Background

High sodium intake elevates blood pressure and thereby raises cardiovascular diseases (CVDs). Sodium intake is high in northern China, including Shandong province where the SMASH (Shandong‐Ministry of Health Action on Sodium and Hypertension) is currently underway.

Methods and Results

Blood pressure values and sodium intake measurements using 24‐hour urinary excretion were collected from the 2011 SMASH baseline survey, which was conducted in 20 counties/districts using a multistage stratified cluster random sampling method. We derived cause‐specific mortality from the Shandong Death Registration System (SDRS) during the same year and used population‐attributable fraction to estimate annual CVDs deaths attributable to high sodium intake (mediated through elevated systolic blood pressure) and CVD deaths averted by achieving different sodium‐reduction targets. Overall, 16 100 (95% uncertainty intervals, 11 000–22 600) CVD deaths among adults aged 25 to 69 years, including 5600 (4000–6500) for ischemic heart disease and 9000 (6700–11 600) for stroke, were attributable to higher sodium intake (2000 mg/day or 5.0 g/day of salt as a reference) in Shandong in 2011, accounting for 19.9% (13.7–25.0%) of total CVD deaths. The benefit of CVD deaths from sodium reduction is considerable with 8800 (6400–13 600), 6700 (4900–11 600), and 8500 (6000–10 800) averted, respectively, if sodium intake was reduced from the 2011 baseline to 3500 mg/day, 4000 mg/day, or reduced by 30%.

Conclusions

Nearly 20% of CVD deaths among adults aged 25 to 69 years could be attributable to the systolic blood pressure–raising effect of high sodium intake in Shandong in 2011. Potential benefits from population reduction of sodium intake are considerable.

Current Data on Dietary Sodium, Arterial Structure and Function in Humans: A Systematic Review

Background: Subclinical arterial damage (SAD) (arteriosclerosis, arterial remodeling and atheromatosis) pre-exists decades before cardiovascular disease (CVD) onset. Worldwide, sodium (Na) intake is almost double international recommendations and has been linked with CVD and death, although in a J-shape manner. Studies regarding dietary Na and major types of SAD may provide pathophysiological insight into the association between Na and CVD. Objectives: Systematic review of data derived from observational and interventional studies in humans, investigating the association between dietary Na with (i) atheromatosis (arterial plaques); (ii) arteriosclerosis (various biomarkers of arterial stiffness); (iii) arterial remodeling (intima–media thickening and arterial lumen diameters). Data sources: Applying the PRISMA criteria, the PubMed and Scopus databases were used. Results: 36 studies were included: 27 examining arteriosclerosis, four arteriosclerosis and arterial remodeling, three arterial remodeling, and two arterial remodeling and atheromatosis. Conclusions: (i) Although several studies exist, the evidence does not clearly support a clinically meaningful and direct (independent from blood pressure) effect of Na on arterial wall stiffening; (ii) data regarding the association of dietary Na with arterial remodeling are limited, mostly suggesting a positive trend between dietary Na and arterial hypertrophy but still inconclusive; (iii) as regards to atheromatosis, data are scarce and the available studies present high heterogeneity. Further state-of-the-art interventional studies must address the remaining controversies.

Aging, Arterial Stiffness, and Blood Pressure Association in Chinese Adults

Arterial stiffness and blood pressure (BP) both increase with aging synchronously. Whether elevated BP results from thickening of arterial wall or vice versa is controversial in previous studies. This study included 17 862 participants without history of myocardial infarction, stroke, atrial fibrillation or flutter, or cancer and with brachial-ankle pulse wave velocity (baPWV) and BP measurements during 2010 to 2016. Age was calculated from the self-reported birthdate to the first date of baPWV examination. Mediation analyses were applied to assess the mediation effect by baPWV in the association between age and BP. Temporal relation between baPWV and BP was assessed by cross-lagged analyses among 1508 participants with repeated assessment of baPWV. We found that systolic BP increased 0.47 (95% CI, 0.45-0.49) mm Hg per 1 year older by the mediation effect of baPWV and that the direct effect of aging on systolic BP was -0.07 (95% CI, -0.09 to -0.05) mm Hg per 1 year older. The standard regression coefficient from baseline baPWV to follow-up systolic BP was 0.09 (95% CI, 0.04-0.15), which was greater than the standard regression coefficient from baseline systolic BP to follow-up baPWV (0.01; 95% CI, -0.04 to 0.06). Arterial stiffness mediated the positive association between aging and BP, and arterial stiffness might precede elevated BP. Clinical Trial Registration- URL: http://www.chictr.org.cn . Unique identifier: ChiCTR-TNRC-11001489.