Habitual Salt Intake Research Articles

Sodium and potassium intake in adults: the Italian Health Examination Survey 2023 – CUORE Project

Abstract Background The WHO recommends a 30% relative reduction in mean population intake of salt/sodium within 2025 (baseline 2010) and an adequate potassium intake. To these ends, the Italian Ministry of Health (MoH) has strengthened prevention/health promotion. To update the assessment of the habitual salt and potassium intake in the Italian general adult population, national health examination surveys (HESs), funded by the MoH-CCM, are conducted within the CUORE Project. Methods In 2023 a new HES started including salt and potassium intake assessment by the use of 24h urine collection. Up to now, data from random samples of residents in 7 Regions (of 20 regions) distributed in North, Centre and South of Italy and aged 35-74 years are available (686 men, 702 women). Urinary excretion is assayed by a central lab. Persons with urinary volume < 500 ml and/or a urinary creatinine content referred to body weight outside the range of population mean ± 2 standard deviations are excluded. Results Out of 657 men and 671 women, mean level of salt per day was 9,2 g (95% CI: 9,0-9.5 g) and 7,1 g (6,9-7,3 g) respectively, and mean level of potassium per day was 2,9 g (2,8-3,0 g) and 2,4 g (2,3-2,5 g) respectively. A salt intake level lower than the WHO recommended target of 5g/day was detected in 9,5 % (5,2 -13,9 %) of men and 23,7 % (17,5 -29,9 %) of women and a potassium intake level higher than the WHO recommended target of 3510 mg/day was detected in 22,4 % (16,3 -28,6 %) of men and 9,7 % (5,4 -14,0 %) of women. Conclusions These preliminary data showed that in Italian adults the average salt intake is still higher and the average potassium intake is still lower than recommended. Compared to 2008, the habitual salt intake decreased of about 12% in 2018 and remained stable in 2023; the habitual potassium intake remained stable in 2008, 2018 and 2023.These results justify and encourage the ongoing preventive initiatives of MoH, facilitating the meeting of WHO targets. Key messages • In Italian adults the average salt intake is still higher than recommended and the habitual salt intake decreased compared to 15 years ago. • In Italian adults the average potassium intake is still lower than recommended and remained stable compared to 15 years ago.

Abstract P136: Phosphorylation and regulation of URAT1 by insulin and NaCl: a possible mechanism linking insulin resistance and excessive salt intake to hyperuricemia

Objective: Insulin resistance (IR) is the key environmental factor associated with hyperuricemia; however, the underlying mechanisms are not fully understood. Although several studies suggested that excessive salt intake results in hyperuricemia, the association still remains controversial. Focusing on urate transporter 1 (URAT1), we here investigated the mechanisms by which insulin and salt intake contribute to hyperuricemia. Methods: In a large UK Biobank (UKB) dataset involving 377,358 participants, we evaluated the association of TyG index (a surrogate of IR) and habitual salt intake with serum uric acid levels using multivariable regression models. We addressed whether single nucleotide polymorphisms (SNPs) that influence URAT1 expression (eQTL) modify the association of TyG index with serum uric acid levels. We also analyzed underlying mechanisms by using HEK cells expressing hURAT1. Results: In UKB dataset, TyG index and habitual salt intake were significantly and independently associated with elevated serum uric acid levels (P < 0.05). From previous studies and imputation accuracy, we extracted an eQTL SNP for SLC22A12 gene and found that there is a positive interaction between TyG Index and the eQTL SNP. As post-translational modification is the key mechanism that enables adaptation to environmental changes, we evaluated the contribution of phosphorylation by AGC kinases, such as Akt, as possible downstream effectors of insulin signaling and salt-sensing pathway. Western blotting with phospho-Akt substrate motif antibody confirmed URAT1 phosphorylation and identified T350 and T408 as candidate sites. Among them, URAT1 carrying non-phosphorylatable A408 substitution (T408A-URAT1) suppressed glycosylation and plasma membrane translocation, while T350A had no effect. By using kinase screen assay involving 53 AGC and related Ser/Thr kinases, we found that SGK1, PKA, and PKG also phosphorylated URAT1-T408. Insulin and NaCl loading induced Akt and SGK1 expression respectively, which resulted in URAT1 phosphorylation and increased cell-surface membrane expression; this effect was abolished in T408A-URAT1. Finally, we found that URAT1-T408 phosphorylation was also detected in human kidney sections. Conclusion: IR and excessive salt intake contribute to hyperuricemia, and the effect is in part mediated by hURAT1. Mechanistically, insulin and NaCl promote membrane trafficking of URAT1 by inducing T408 phosphorylation through Akt and SGK1, respectively.

Feasibility of Assessment of Habitual Salt Intake Using a 24-h Urinary Salt Excretion Self-Measuring Device.

To assess habitual salt intake, tools are needed to measure 24-h urinary salt excretion repeatedly. We developed and validated a new portable salt monitor, which measures salt excreted per urination and sums the values to provide an accurate estimate of urinary salt excretion over 24 h. A previously developed salt monitor was improved with respect to the capacity, volume sensors, and equation for urinary sodium chloride concentration estimation. In 20 healthy Japanese female volunteers, 24-h urinary salt excretion was measured using the salt monitor and a conventional 24-h urine collection method on eight nonconsecutive days. In a total of 157 days, there were no fixed or proportional errors between the methods. The mean salt intake over 8 days was 8.5 ± 2.0 g/day for the 24-h urine collection and 8.3 ± 2.3 g/day for the salt monitor, showing a strong correlation (r = 0.912, p < 0.001). At a cut-off value of 6 g, the salt monitor was able to completely classify individuals by habitual salt intake. The validity of the new salt monitor was confirmed. The device can be considered an alternative to the traditional 24-h urine collection for repeated surveys and self-management of daily salt intake.

#2704 Effects of high dietary salt on immunome and microbiome composition – results from a randomized clinical trial

Abstract Background and Aims Increased dietary salt intake ranks among the most prominent nutritional risk factors worldwide and has been tied to arterial hypertension and all-cause mortality. The mechanisms responsible are incompletely understood and have recently been extended to include inflammatory and microbiome-associated mechanisms. Building on our preliminary data, the present study investigates whether a moderate increase in salt intake in healthy subjects primes host physiology to a more transiently unstable state, potentially leading to changes in the microbiome-immune axis. Method We conducted a prospective, randomized, double-blinded trial to evaluate the effect of high dietary salt in healthy participants (NCT03024567), where the intervention group (n = 19) was given 6 g of salt (NaCl capsules) in addition to the habitual salt intake, resulting in an average doubling of the salt intake recommended by expert societies. A placebo group (n = 19) received gelatin capsules for 14 days. Clinical parameters, fecal samples and PBMC were collected at baseline and day 14. Shotgun metagenomic sequencing, metabolomics (stool and serum), and single-cell sequencing (Cellular Indexing of Transcriptomes and Epitopes by Sequencing (CITEseq)) of whole PBMCs and CD4+ sorted T cells (∼150 k single cells) was performed. Results Microbiome analysis confirms previous findings showing an increased dissimilarity of microbiome composition (Jensen-Shannon Divergence) under a high-salt. Differential abundance of the microbiome's functional space, as quantified by functional gut-specific modules, picked up a salt-specific module (M00494, NatK-NatR (sodium extrusion) two-component regulatory system) in the salt intervention group. CITEseq revealed a significant reduction of circulating NK cells and an increase in classical monocytes as well as changes to several T cell subsets. Furthermore, within several immune cell subsets, we detected differently expressed genes (DEGs) solely in the salt group. We found 602 DEG in naïve conventional T cells (Tconv) and 202 DEGs in non-naïve Tconv, e.g. belonging to NF-kB and T cell receptor signaling pathways. Conclusion Our placebo-controlled study is the first to utilize different omics techniques to investigate and identify high-salt-induced changes in the microbiome and immunome in healthy individuals that may be relevant for health-to-disease transition.

Associations of a proinflammatory diet, habitual salt intake, and the onset of type 2 diabetes: A prospective cohort study from the UK Biobank.

To explore the relationship between proinflammatory diet, habitual salt intake and the onset of type 2 diabetes. This prospective study was conducted among 171 094 UK Biobank participants who completed at least one 24-h dietary questionnaire and were free of diabetes at baseline. Participants were followed up until 1 March 2023 for type 2 diabetes incidence, with diagnosis information obtained from linked medical records. An Energy-adjusted Diet Inflammatory Index (E-DII) was calculated based on 28 food parameters. Habitual salt intake was determined through the self-reported frequency of adding salt to foods. The associations between E-DII, habitual salt intake and type 2 diabetes incidence were tested by the Cox proportional hazard regression model. Over a median follow-up period of 13.5 years, 6216 cases of type 2 diabetes were documented. Compared with participants with a low E-DII (indicative of an anti-inflammatory diet), participants with a high E-DII (indicative of a proinflammatory diet) had an 18% heightened risk of developing type 2 diabetes. The association between E-DII and type 2 diabetes tends to be linear after adjustment for major confounders. Participants with a proinflammatory diet and always adding salt to foods had the highest risk of type 2 diabetes incidence (hazard ratio 1.60, 95% confidence interval 1.32-1.94). Our findings indicate that a proinflammatory diet and higher habitual salt intake were associated with an increased risk of type 2 diabetes. These results support the public health promotion of an anti-inflammatory diet and reducing salt intake to prevent the onset of type 2 diabetes.

중학생의 짠맛 미각판정과 짠맛⋅단맛식행동 및 당류식품 섭취와의 관련성

Objectives This study aimed to examine the habitual salt and sugar intake in middle school students and investigate whether salt taste preference using salt taste tests is associated with frequency of sugar food intake.
 Methods Survey questionnaires were conducted in 256 male and female students at middle schools in the Seoul province from December 11 to December 20, 2019. Habitual salt and sugar intake and frequency of sugar food consumption were assessed including the administration of salt taste tests.
 Results The salt taste tests showed that 39.9% of male students preferred a moderate (0.31% salinity) salty taste, whereas 38.7% of female students preferred a slightly bland (0.08% salinity) taste. In evaluating habitual salt intake, male students scored significantly higher than that of female students in one out of 10 items. In evaluating habitual sugar intake, female students scored significantly higher than that of male students in four out of 10 items. According to the salt taste test, preference for salty showed a positive correlation with habitual salt and sugar intake. Habitual salt and sugar intake were positively correlated to the consumption frequency of almost all sugar foods; whereby, the preference for salty was positively correlated to the consumption frequency of sweetened beverages, frozen desserts, and chocolates. The group that preferred salty had a higher score for habitual salt and sugar intake than that of the groups that preferred moderate and bland tastes. Additionally, the analysis showed that the group that preferred salty had a more frequent sugary foods consumption.
 Conclusions The perception of salty, habitual salty and sugary food intake, and frequency of sugar food consumption were all associated. Consequently, schools should provide middle school students with educational opportunities that help reduce sugar and sodium intake.

Renal denervation alters ambulatory blood pressure-derived salt sensitivity index in patients with uncontrolled hypertension.

Renal denervation (RDN) has been proven in multiple sham-controlled trials to lower blood pressure (BP) in various forms of hypertension. RDN-mediated interruption of sympathetic signaling through its effects on renal blood flow, salt retention, and renin release are likely contributors to the BP-lowering effects. However, the impact of RDN on salt sensitivity in humans has not yet been explored. We, therefore, investigated the effect of RDN on ambulatory BP monitoring-derived salt sensitivity in a cohort of patients with uncontrolled hypertension on habitual salt intake. RDN was performed in 153 hypertensive patients, who were categorized into low intermediate and high-salt sensitivity groups, based on the ambulatory BP monitoring-derived salt sensitivity index estimated prior to (baseline) and at 3, 6 and 12 months after the procedure as previously described. Crude and adjusted mixed effects ordinal regression models were fitted to test for changes in the proportions of salt sensitivity risk during follow-up. The proportions of individuals in the intermediate and high-salt sensitivity risk group increased after RDN and the odds for being in a higher estimated salt sensitivity risk group at 3, 6 and 12 months follow-up compared with baseline were highly significant during the 12 months follow-up period. Increased salt sensitivity after RDN may represent a compensatory mechanism to maintain renal capacity for adequate salt handling. This novel finding may have implications for patient management after RDN, such as prescription of salt moderation to further optimize RDN-induced BP-lowering efficacy.

Isolated systolic hypertension of the young and sodium intake.

Isolated systolic hypertension is associated with higher risk of cardiovascular disease and all-cause mortality. Despite being the most common form of hypertension in the elderly, it is also detectable among young and middle-aged subjects. Dietary salt (sodium chloride) intake is an important determinant of blood pressure, and high salt intake is associated with greater risk of hypertension and cardiovascular events. In most countries, habitual salt intake at all age categories largely exceeds the international recommendations. Excess salt intake, often interacting with overweight and insulin resistance, may contribute to the development and maintenance of isolated systolic hypertension in young individuals by causing endothelial dysfunction and promoting arterial stiffness through a number of mechanisms, namely increase in the renin-angiotensin-aldosterone system activity, sympathetic tone and salt-sensitivity. This short review focused on the epidemiological and clinical evidence, the mechanistic pathways and the cluster of pathophysiological factors whereby excess salt intake may favor the development and maintenance of isolated systolic hypertension in young people.

The influence of habitual salt intake on bone remodelling in young healthy people

Introduction: Sodium alters calcium metabolism by increasing calcium excretion, thus possibly influencing bone metabolism. The hypothesis of the present study is that amount of dietary sodium intake affects the bone remodelling. This study aimed to assess whether a habitual intake of sodium has an effect on peak bone mass and biochemical indicators of bone metabolism.
 Subjects and Methods: In a cross-sectional study that involved 41 young men and women, six biochemical markers were assessed from blood samples using ELISA: osteocalcin, C-terminal procollagen type I peptide, receptor activator kappa B ligand, pyridinoline, parathyroid hormone, and osteoprotegerin, while bone mineral density (BMD) and bone mineral content (BMC) were measured by dual x-ray absorptiometry. Subjects were divided into two groups according to habitual sodium intake (low-Na and high-Na group) assessed by questionnaire.
 Results: No difference was found between groups of low and high Na intake in BMD and BMC, or in biochemical markers of bone metabolism. Since the groups differed in Ca intake, energy and vitamin D, adjustments were made for those cofounders. Regression analysis showed that only the dietary intake of vitamin D was associated with dual femur BMD and BMC, and no correlation was found between bone remodelling indicators and Na intake after adjustment for vitamin D intake.
 Conclusion: The present results could not confirm that habitual sodium intake above recommended levels affects bone remodelling processes or decreases bone mineral density in young healthy people if combined with adequate calcium intake.

Trend of salt intake measured by 24-h urine collection in the Italian adult population between the 2008 and 2018 CUORE project surveys

Background and aimsThe WHO Global Action Plan for the Prevention of non-communicable diseases (NCDs) recommends a 30% relative reduction in mean population salt/sodium intake. The study assessed the trend in the habitual salt intake of the Italian adult population from 2008 to 2012 to 2018–2019 based on 24-h urinary sodium excretion, in the framework of the CUORE Project/MINISAL-GIRCSI/MENO SALE PIU’ SALUTE national surveys. Methods and resultsData were from cross-sectional surveys of randomly selected age and sex–stratified samples of resident persons aged 35–74 years in 10 (out of 20) Italian Regions distributed in North, Centre and South of the Country. Urinary sodium and creatinine measurements were carried out in a central laboratory. The analyses included 942 men and 916 women examined in 2008–2012, and 967 men and 1010 women examined in 2018–2019. The age-standardized mean daily population salt (sodium chloride) intake was 10.8 g (95% CI 10.5–11.1) in men and 8.3 g (8.1–8.5) in women in 2008–2012 and respectively 9.5 g (9.3–9.8) and 7.2 g (7.0–7.4) in 2018–2019. A statistically significant (p<0.0001) salt intake reduction was thus observed over 10 years for both genders, and all age, body mass index (BMI) and educational classes. ConclusionsThe average daily salt intake of the Italian general adult population remains higher than the WHO recommended level, but a significant reduction of 12% in men and 13% in women has occurred in the past ten years. These results encourage the initiatives undertaken by the Italian Ministry of Health aimed at the reduction of salt intake at the population level.

Sodium intake in Italy from 2008 to 2019: results of the CUORE Project-Health Examination Surveys

Abstract Background The WHO Global Action Plan for the Prevention of NCDs recommends a 30% relative reduction in mean population intake of salt/sodium. To this end, the Italian Ministry of Health (MoH) has strengthened prevention and health promotion through the “Gaining health: making healthy choices easy” Programme and the National Preventive Plan 2014-2019, in collaboration with the Interdisciplinary Working group for Salt Reduction in Italy. To estimate the habitual salt intake and its trend in the general adult population, national surveys, funded by the MoH-CCM, are conducted within the CUORE Project. Methods Baseline salt intake by the use of 24h urine collections was assessed in 2008-2012 from representative random samples of residents in all Italian Regions. A new survey was conducted in 2018-2019 involving random samples of residents in 10 Regions. Urinary sodium excretion is assayed by a central lab at Federico II University of Naples, subjected to strict quality controls. Comparisons are made considering, for both periods, the first seven regions examined in the 2018-2019 survey and the age range of 35-74 years. Results Within the 2008-2012 survey, mean level of sodium chloride per day in 642 men and 627 women were 10.6 g (10.3-11.0 g) and 8.0 g (7.7-8.3 g) respectively, whereas in the 2018-2019 survey the corresponding mean levels in 673 men and 709 women were 9.3 g (95% C.I.: 9.1-9.6 g) and 7.1 g (6.9-7.3 g), respectively. A sodium chloride intake level lower than the WHO recommended target of 5g/day (or 85 mmol/day) was detected in 5% (3-6%) of men and 16% (13-19%) of women examined in 2008-2012 vs 9% (6-11%) of men and 24% (20-27%) of women examined in 2018-2019. Conclusions These preliminary data show that the average habitual sodium intake in Italy is still higher than recommended but a significant reduction seems to occur. These results fully justify and encourage the ongoing preventive initiatives of MoH, facilitating the meeting of the WHO-NCD target. Key messages Habitual salt intake in the Italian general adult population is still higher than the recommended by the WHO. If confirmed, in the last ten years a reduction of habitual salt intake in Italian general adult population seems to be occurred.

Abstract P352: Trend of Salt Consumption in Italy From 2008 to 2018: Preliminary Results of the Cuore Project

Introduction: The WHO Global Action Plan for the Prevention of Non-Communicable Diseases (NCDs) recommends a 30% relative reduction in mean population intake of salt/sodium. To this end, the Italian Ministry of Health (MoH) has strengthened prevention and health promotion through the “Gaining health: making healthy choices easy” Programme and the National Preventive Plan (NPP) 2014-2019, with the collaboration of the Interdisciplinary Working group for Salt Reduction in Italy (GIRCSI). Hypothesis: Agreements between the MoH and the associations of artisan bakers and food industry companies were signed since 2009 to reduce the salt content in bread and in other food products. Within the NPP, initiatives as local inter-sectors agreements and information activities for the population and training for food sector operators are implemented. In order to estimate the habitual salt intake and its trend in the general adult population, national surveys, funded by the MoH-CCM, are conducted within the CUORE Project. Methods: Baseline salt intake by the use of 24h urine collections was assessed in 2008-2012 from random samples of persons aged 35-79 years, resident in all Italian 20 Regions. A new survey is ongoing (2018-2019) involving random samples of persons aged 35-74 years, resident in 10 Regions. Urinary sodium excretion is assayed by a central lab at Federico II University of Naples, subjected to strict quality controls. Comparisons are made considering, for both periods, the seven regions examined up to now in the ongoing survey and the age range of 35-74 years. Results: Within the 2018-2019 survey, mean level of sodium chloride per day in 673 men and 709 women was 161 mmol (95% confidence interval: 156-166 mmol) and 122 mmol (119-126 mmol) respectively, whereas in the 2008-2012 survey the corresponding mean levels in 642 men and 627 women was 183 mmol (95% confidence interval: 178-189 mmol) and 140 mmol (135-144 mmol), respectively. A sodium chloride intake level within the WHO recommended upper level of 85 mmol (or 5 grams of salt) per day was detected in 9% (6-11%) of men and 24% (20-27%) of women examined in 2018-2019 vs 5% (3-6%) of men and 16% (13-19%) of women examined in 2008-2012. Conclusions: These preliminary data show that the average habitual sodium intake in Italy is still largely higher than recommended but a significant reduction seems to occur. These results fully justify and encourage the ongoing preventive initiatives for reduction of sodium intake and its monitoring in the population.

Preventive actions for the gradual reduction of excessive salt intake and its monitoring in Italy

Abstract Issue The WHO Global Action Plan for the Prevention of NCDs recommends a 30% relative reduction in mean population intake of salt/sodium. To this end, the Italian Ministry of Health (MoH) has strengthened prevention and health promotion through the “Gaining health: making healthy choices easy” Programme and the National Preventive Plan (NPP) 2014-2019, with the collaboration of the Interdisciplinary Working group for Salt Reduction in Italy (GIRCSI). Description of the problem According to the “Gaining Health” Programme, agreements between the MoH and the associations of artisan bakers and food industry companies were signed since 2009 to reduce the salt content in bread and in other food products. The reduction of excessive salt intake is one of the main objective of the NPP 2014-2019 pursued by the Regions through initiatives as local inter-sectors agreements and information activities for the population and training for food sector operators. The Italian Institute of Health conducts national surveys to estimate habitual salt intake in the general adult population by collecting 24h urine. Baseline assessment was in 2008-2012 from random samples of persons aged 35-79 years, resident in all 20 Regions. A new survey is ongoing (2018-2019) involving persons aged 35-74 years, resident in 10 Regions. Surveys are funded by the MoH-CCM; urinary sodium excretion is effected by a central lab at Federico II University of Naples, subjected to strict quality controls. Results The baseline survey showed a mean sodium excretion of 10.6 g/24h (95% confidence interval 10.5-10.8) in 1963 men and 8.2g/24h (8.1-8.4) in 1894 women. Results of the ongoing survey are expected in the coming months. Lessons In Italy preventive actions of salt reduction supported by the MoH have been implemented. Estimation of salt intake in diet by 24h/urine is included. Results of baseline and on-going surveys will allow to estimate the possibility of meeting the WHO salt reduction target by 2025. Key messages In Italy inter-sectors preventive actions of salt reduction are implemented. Results of the baseline and on-going surveys will allow to estimate in Italy the possibility of meeting the WHO salt reduction target by 2025.

Efficacy of Monosodium Glutamate as a Flavour Potentiator in Salt Reduction: A Review

Sodium is an essential micro nutrient and an indispensable ingredient in most of the savoury foods. The salty taste is mainly contributed by sodium chloride through a proto-typical stimulus. The current sodium intake has been estimated to be exceeding normal recommendation at an alarming rate. This has given rise to health concerns since excessive sodium intake is associated with rise in blood pressure and eventually to cardiovascular diseases. The habitual salt intake among Asian population is around 10-12g/day against the WHO recommendation of 5-6g/day. Today food processing industries are facing challenges pertaining to sodium reduction, since it reduces the overall acceptability. In any food sodium can be reduced through a gradual lowering of salt level, however, this would require several months since it also decreases the overall palatability of foods. Another strategy that can be adopted to overcome this problem is to employ salt substitutes like monosodium glutamate (MSG). MSG has 30% less sodium in comparison to table salt and can help maintain palatability of foods. There are many studies supporting this observation. Our studies on the acceptability profile of salt reduced MSG incorporated fried preparations showed that approximately 25% of salt could be reduced in products without any significant effect on flavor profile. The results indicated that spice added product could be consumed with lower sodium levels and MSG had synergistic effect with spices. In salt reduced tomato soups, the control product with low salt was given lower scores as against MSG incorporated samples. It was also observed that increasing levels of MSG resulted in higher acceptance of products. Hence, it can be said that using MSG as a substitute would be a better option for maintaining adequate palatability in savoury foods with reduced sodium content.

Estimation of the salt intake distribution of Dutch kidney transplant recipients using 24-h urinary sodium excretion: the potential of external within-person variance

There is growing interest in assessing a population's prevalence of inadequate nutrient intake using biomarkers. However, within-person variation is generally ignored because repeated data collections are considered costly and burdensome. The study aimed to show the importance of estimating, from repeated 24-h urine collections, a population's habitual salt intake and to explore the potential of using the ratio of within-person variance to total variance from an external source (W:T variance) with single 24-h urine collection. Salt intake was predicted from data for 24-h urinary sodium excretion in adult kidney transplant recipients in 1992-1997 (n=432) and 2006-2011 (n=1159). The salt intake distribution of single-day measurements was compared with estimates from multiple 24-h urine collections, which were statistically corrected for within-person variance. Habitual salt intake was also estimated using single-day measurements and external variance estimates. From each distribution, the proportion below specified cut-off values was estimated. In 2006-2011 the average habitual salt intake was 10.6 g/d (men) and 8.5 g/d (women); in 1992-1997 these values were 8.6 g/d and 7.5 g/d, respectively. The proportion with salt intake <6 g/d was 5% and 13% in 2006-2011 and 22% and 28% in 1992-1997, respectively, for men and women. Correction for within-person variance significantly narrowed the salt intake distribution-the proportion with salt intake <6 g/d was overestimated by 3-13 percentage points using single-day data. Sensitivity analyses showed the importance of a sufficient sample size for estimating variance components. Variation of the W:T variance showed up to 40 percentage points deviation in the proportion with intakes below a specified cut-off value. To estimate a population's salt intake distribution, it is important to correct 24-h urinary sodium excretion for within-person variance. Predicting habitual salt intake distribution using single-day measurements with external variances is promising; a sensitivity analysis is recommended to show the effect of different external variances.

The Na+K+-ATPase Inhibitor Marinobufagenin and Early Cardiovascular Risk in Humans: a Review of Recent Evidence.

This review synthesizes recent findings in humans pertaining to the relationships between marinobufagenin (MBG), a steroidal Na+/K+-ATPase inhibitor and salt-sensitivity biomarker, and early cardiovascular risk markers. Twenty-four-hour urinary MBG strongly associates with habitual salt intake in young healthy adults (aged 20-30years). Furthermore, in young healthy adults free of detected cardiovascular disease, MBG associates with increased large artery stiffness and left ventricular mass independent of blood pressure. These findings in human studies corroborate mechanistic data from rat studies whereby stimulation of MBG by a high salt intake or MBG infusion increased vascular fibrosis and cardiac hypertrophy. Twenty-four-hour urinary MBG may be a potential biomarker of early cardiovascular risk. Adverse associations between MBG-which increases with salt consumption-and early cardiovascular risk markers support the global efforts to reduce population-wide salt intake in an effort to prevent and control the burden of non-communicable diseases.

Large artery stiffness is associated with salt intake in young healthy black but not white adults: the African-PREDICT study.

There is global consensus on the benefits of reducing excessive salt intake. Indeed, lower salt intake associates with reduced arterial stiffness, a well-established predictor of cardiovascular risk, in older populations. Whether high habitual salt intake in healthy normotensive youth may already contribute to increased arterial stiffness is unknown. We, therefore, determined whether estimated salt intake is associated with large artery stiffness in young healthy black and white adults. We included 693 black and white adults (51% black; 42% men), aged 20-30years. Participants were normotensive based on clinic blood pressure, and no previous diagnosed chronic illnesses. We measured carotid femoral pulse wave velocity (cfPWV) and determined estimated salt intake based on 24h urinary sodium excretion. We found estimated salt consumption of > 5g/day in 47% of our population, whereas 21% consumed > 10g/day. In multivariable-adjusted regression analyses a positive association existed between estimated salt intake and cfPWV in the total group (Adj. R2 = 0.32; std. β = 0.10; p = 0.007), and black adults (Adj. R2 = 0.37; std. β = 0.12; p = 0.029). This was independent of age, sex, mean arterial pressure, and other covariates. No association was evident in white individuals (p = 0.19). Excessive salt intake is positively associated with large artery stiffness-independent of blood pressure-in young adults, especially in black individuals. Our results suggest a potential contributory role of salt consumption towards early vascular aging.

A new index of sodium sensitivity risk from arterial blood pressure monitoring during habitual salt intake

A new index of sodium sensitivity risk from arterial blood pressure monitoring during habitual salt intake

Definition and Prevalence of Salt Sensitivity and Salt-sensitive Hypertension

High salt intake is associated with significantly increased risk of stroke and total cardiovascular disease. Reduction in habitual dietary salt intake of 6 g/day decreases systolic and diastolic BP, but not in all hypertensive subjects. Salt sensitivity is defined as the tendency for BP to fall during dietary salt restriction and rise during salt supplementation. Salt sensitivity is diagnosed by a low and high salt diet protocol or a rapid sodium, volume expansion and contraction protocol. Prevalence of salt sensitivity ranged from 30 to 60% in hypertensive subjects and from 15 to 46% in normotensive subjects. Salt sensitivity is more frequently found in hypertensive subjects, blacks, aged people, and women.

High salt intake and stroke: meta-analysis of the epidemiologic evidence.

Research on the potential impact of high salt intake on health has grown rapidly over the last decades. Recent studies have suggested that high salt intake could also be associated with adverse effects on cardiovascular system. The review evaluated the current level of epidemiologic evidence on the association between the level of habitual salt intake and stroke outcome. We also suggest further research direction. There were 21 independent samples from 12 studies, with 225,693 participants (follow-up, 3-19 years) and 8135 stroke events. High salt intake was associated with risk of stroke event (pooled odd ratio [OR], 1.34; 95% confidence interval [CI], 1.19-1.51), stroke death (1.40; 1.21-1.63) and stroke onset (1.11; 1.00-1.24), ischemic stroke death (2.15; 1.57-2.95), not associated with risk of ischemic stroke onset (1.07, 0.95-1.2), with no significant evidence of publication bias. High salt intake is associated with significantly increased risk of stroke event. Further research should be directed toward clarifying and quantifying these possible effects and generating testable hypotheses on plausible biologic mechanisms.