24-Hour Urinary Sodium and Potassium Excretion and Cardiovascular Risk

Adding Salt to Foods and Risk of Cardiovascular Disease

BACKGROUND

We recently found that the frequency of adding salt to foods could reflect a person's long-term salt taste preference and sodium intake, and was significantly related to life expectancy.

OBJECTIVE

We analyzed whether the frequency of adding salt to foods was associated with incident cardiovascular disease (CVD) risk.

METHODS

This study included 176,570 adults in UK Biobank who were initially free of CVD. Cox proportional hazards models were used to estimate the association between the frequency of adding salt to foods and incident CVD events.

RESULTS

During a median of 11.8 years of follow-up, 9,963 total CVD events, 6,993 ischemic heart disease (IHD) cases, 2,007 stroke cases, and 2,269 heart failure cases were documented. Lower frequency of adding salt to foods was significantly associated with lower risk of total CVD events after adjustment for covariates and the DASH (Dietary Approaches to Stop Hypertension) diet (a modified DASH score was used without considering sodium intake). Compared with the group of always adding salt to foods, the adjusted HRs were 0.81 (95% CI: 0.73-0.90), 0.79 (95% CI: 0.71-0.87), and 0.77 (95% CI: 0.70-0.84) across the groups of usually, sometimes, and never/rarely, respectively (P trend < 0.001). Among the subtypes of CVD, adding salt showed the strongest association with heart failure (P trend <0.001), followed by IHD (P trend < 0.001), but was not associated with stroke. We found that participants who combined a DASH-style diet with the lowest frequency of adding salt had the lowest CVD risk.

CONCLUSIONS

Our findings indicate that lower frequency of adding salt to foods is associated with lower risk of CVD, particularly heart failure and IHD.

Mortality prediction of the nutrient profile of the Chilean front-of-pack warning labels: Results from the Seguimiento Universidad de Navarra prospective cohort study

Background and aims

Front-of-Pack (FoP) nutrition labelling has been established as a policy, empowering consumers to choose healthy food options for preventing diet-related non-communicable diseases. This study aimed to evaluate the association between the nutrient profile underlying the Chilean warning label score and all-cause mortality and to conduct a calibration with the Nutri-Score in a large cohort of Spanish university graduates.

Materials and methods

This prospective cohort study analysed 20,666 participants (8,068 men and 12,598 women) with a mean (standard deviation) age of 38 years (±12.4) from the SUN cohort. Dietary food intake was assessed by a validated semi-quantitative food-frequency questionnaire at baseline and after 10 years of follow-up. The warning label score was calculated by considering the threshold of nutrients (sugar, saturated fat, and sodium) and energy density per 100 g/ml of product, as established by Chilean Legislation. Participants were classified according to quartiles of consumption of daily label score: Q1 (≤5.0), Q2 (>5.0–7.1), Q3 (>7.1–9.8), and Q4 (>9.8). Time-dependent, multivariable-adjusted Cox models were applied. To compare the performance of the warning label score and Nutri-Score to predict mortality, we used the Akaike information criterion (AIC) and Bayesian information criterion (BIC) methods.

Results

During a median of 12.2 years of follow-up, 467 deaths were identified. A higher score in the warning label values (lower nutritional quality) was associated with an increased risk of all-cause mortality [HR (95% CI) Q4 vs. Q1: 1.51 (1.07–2.13); p-trend = 0.010] and cancer mortality [HR (95% CI) Q4 vs. Q1: 1.91 (1.18–3.10); p-trend = 0.006]. However, no statistically significant association was found for cardiovascular mortality. Furthermore, the warning label score and Nutri-Score exhibited comparable AIC and BIC values, showing similar power of prediction for mortality.

Conclusion

A diet with a higher warning label score (>9.8 per day) was a good predictor of all cases and cancer mortality in a large Spanish cohort of university graduates. Also, the warning label score was capable to predict mortality as well as the Nutri-Score. Our findings support the validity of the warning label score as a FoP nutrition labelling policy since it can highlight less healthy food products.

Sodium-glucose co-transporter 2 inhibitor therapy: use in chronic kidney disease and adjunctive sodium restriction

The global burden of chronic kidney disease (CKD) has increased significantly over the past few decades. This reflects the rising prevalence of type 2 diabetes mellitus (T2DM) and hypertension, two leading causes of CKD. Hypertension, which can also be a complication of CKD, accelerates renal disease progression and augments cardiovascular risk, especially in individuals with diabetic kidney disease. Hence, blood pressure (BP) reduction is a vital component of CKD management. Sodium-glucose co-transporter 2 (SGLT2) inhibitors are a relatively novel class of medications developed to treat T2DM by inducing glycosuria and hence, lowering glycaemia. Additionally, SGLT2 inhibitors are antihypertensive, renoprotective and cardioprotective, even in individuals without T2DM, making them effective therapeutic agents for CKD. Another therapy that has proven to be antihypertensive, renoprotective and cardioprotective is dietary sodium restriction. This review evaluates the potential combined benefits of SGLT2 inhibition and dietary sodium restriction on the BP and renal parameters of individuals with CKD.

Estimated Benefits and Risks of Using a Reduced-Sodium, Potassium-Enriched Salt Substitute in India: A Modeling Study

BACKGROUND

Salt substitution (ie, replacement of table and cooking salt with potassium-enriched salt substitutes) is a promising strategy to reduce blood pressure and prevent cardiovascular disease, particularly in countries like India where there is high sodium intake, mainly from discretionary salt, and low potassium intake. Life-threatening hyperkalemia from increased potassium intake is a postulated concern for individuals with chronic kidney disease.

METHODS

We used comparative risk assessment models to estimate the number of (1) cardiovascular deaths averted due to blood pressure reductions; (2) potential hyperkalemia-related deaths from increased potassium intake in individuals with advanced chronic kidney disease; and (3) net averted deaths from nationwide salt substitution in India. We evaluated a conservative scenario, based on a large, long-term pragmatic trial in rural China; and an optimistic scenario informed by our recent trial in India. Sensitivity analyses were conducted to assess the robustness of the findings.

RESULTS

In the conservative scenario, a nationwide salt substitution intervention was estimated to result in ≈214 000 (95% uncertainty interval, 92 764-353 054) averted deaths from blood pressure reduction in the total population and ≈52 000 (22 961-80 211) in 28 million individuals with advanced chronic kidney disease, while ≈22 000 (15 221-31 840) hyperkalemia-deaths might be caused by the intervention. The corresponding estimates for the optimistic scenario were ≈351 000 (130 470-546 255), ≈66 000 (24 925-105 851), and ≈9000 (4251-14 599). Net benefits were consistent across sensitivity analyses.

CONCLUSIONS

Modeling nationwide salt substitution in India consistently estimated substantial net benefits, preventing around 8% to 14% of annual cardiovascular deaths. Even allowing for potential hyperkalemia risks there were net benefits estimated for individuals with chronic kidney disease.

Dietary Effects of Introducing Salt-Reduced Bread with and without Dietary Counselling-A Cluster Randomized Controlled Trial

Successful strategies for policy makers and the food industry are required to reduce population salt intake. A 4-month cluster randomized controlled trial was conducted to evaluate whether the provision of salt-reduced bread with or without dietary counselling affected the dietary intake of selected food groups, energy, macronutrients, sodium, and potassium. Eighty-nine families (n = 309) consisting of minimum one parent and one child were assigned to receive bread gradually reduced in salt content alone (Intervention A), combined with dietary counselling (Intervention B), or bread with regular salt content (control). Food intake was recorded for seven consecutive days at baseline and follow-up. Salt intake was reduced in both Intervention A (-1.0 g salt/10 MJ, p = 0.027) and Intervention B (-1.0 g salt/10 MJ, p = 0.026) compared to the control. Consumption of bread and both total and salt-rich bread fillings remained similar between groups, while 'cheese and cheese products' were reduced in Intervention A (-38%, p = 0.011). Energy intake and macronutrient distribution were not affected in Intervention A, but Intervention B resulted in a higher energy intake (512 kJ, p = 0.019) and a lower energy % (E%) from saturated fat (-1.0 E%, p = 0.031) compared to the control. In conclusion, provision of salt-reduced bread both with and without dietary counselling successfully reduced dietary salt intake without adversely affecting the dietary nutritional quality.

Sodium, Potassium and Iodine Intake in an Adult Population of Lithuania

Hypertension is a leading risk factor for cardiovascular events and death. A reduction in salt intake is among the most cost-effective strategies to reduce blood pressure and the risk of cardiovascular diseases. Increasing potassium lowers blood pressure and is associated with lower cardiovascular risk. Adequate iodine intake is important to prevent iodine deficiency disorders. Salt iodization is a key strategy to prevent such deficiency. In Lithuania, no surveys have been performed to directly assess sodium, potassium and iodine consumption. The aim of the present study was to measure sodium, potassium and iodine intake in a randomly selected adult Lithuanian adult population using 24 h urine collections, and to assess knowledge, attitudes and behavior towards salt consumption. Salt and potassium intakes were estimated in 888 randomly selected participants by 24 h urine sodium and potassium excretion and 679 individuals provided suitable 24 h urine samples for the analysis of iodine excretion. Average salt intake was 10.0 (SD 5.3) g/24 h and average potassium intake was 3.3 (SD 1.3) g/24 h. Only 12.5% of participants consumed less than 5 g/24 h of salt. The median value of urinary iodine concentration (UIC) was 95.5 μg/L. Our study showed that average salt intake is twice as high as the maximum level recommended by the World Health Organization while potassium and iodine intakes in Lithuania are below the recommended levels.

Middle age serum sodium levels in the upper part of normal range and risk of heart failure

AIMS

With increasing prevalence of heart failure (HF) owing to the ageing population, identification of modifiable risk factors is important. In a mouse model, chronic hypohydration induced by lifelong water restriction promotes cardiac fibrosis. Hypohydration elevates serum sodium. Here, we evaluate the association of serum sodium at middle age as a measure of hydration habits with risk to develop HF.

METHODS AND RESULTS

We analysed data from Atherosclerosis Risk in Communities study with middle age enrolment (45-66 years) and 25 years of follow-up. Participants without water balance dysregulation were selected: serum sodium within normal range (135-146 mmol/L), not diabetic, not obese and free of HF at baseline (N = 11 814). In time-to-event analysis, HF risk was increased by 39% if middle age serum sodium exceeded 143 mmol/L corresponding to 1% body weight water deficit [hazard ratio 1.39, 95% confidence interval (CI) 1.14-1.70]. In a retrospective case-control analysis performed on 70- to 90-year-old attendees of Visit 5 (N = 4961), serum sodium of 142.5-143 mmol/L was associated with 62% increase in odds of left ventricular hypertrophy (LVH) diagnosis [odds ratio (OR) 1.62, 95% CI 1.03-2.55]. Serum sodium above 143 mmol/L was associated with 107% increase in odds of LVH (OR 2.07, 95% CI 1.30-3.28) and 54% increase in odds of HF (OR 1.54, 95% CI 1.06-2.23). As a result, prevalence of HF and LVH was increased among 70- to 90-year-old participants with higher middle age serum sodium.

CONCLUSION

Middle age serum sodium above 142 mmol is a risk factor for LVH and HF. Maintaining good hydration throughout life may slow down decline in cardiac function and decrease prevalence of HF.

Leaf elemental composition analysis in spider plant [Gynandropsis gynandra L. (Briq.)] differentiates three nutritional groups

Understanding the genetic variability within a plant species is paramount in implementing a successful breeding program. Spider plant (Gynandropsis gynandra) is an orphan leafy vegetable and an extraordinary source of vitamins, secondary metabolites and minerals, representing an important resource for combatting malnutrition. However, an evaluation of the leaf elemental composition, using a worldwide germplasm collection to inform breeding programs and the species valorization in human nutrition is still lacking. The present study aimed to profile the leaf elemental composition of G. gynandra and depict any potential geographical signature using a collection of 70 advanced lines derived from accessions originating from Asia and Eastern, Southern and West Africa. The collection was grown in a greenhouse using a 9 × 8 alpha lattice design with two replications in 2020 and 2021. Inductively coupled plasma-optical emission spectrometry was used to profile nine minerals contents. A significant difference (p < 0.05) was observed among the lines for all nine minerals. Microelements such as iron, zinc, copper and manganese contents ranged from 12.59-430.72, 16.98-166.58, 19.04-955.71, 5.39-25.10 mg kg-1 dry weight, respectively, while the concentrations of macroelements such as potassium, calcium, phosphorus and magnesium varied in the ranges of 9992.27-49854.23, 8252.80-33681.21, 3633.55-14216.16, 2068.03-12475.60 mg kg-1 dry weight, respectively. Significant and positive correlations were observed between iron and zinc and calcium and magnesium. Zinc, calcium, phosphorus, copper, magnesium, and manganese represented landmark elements in the genotypes. Eastern and Southern African genotypes were clustered together in group 1 with higher phosphorus, copper and zinc contents than Asian and West African lines, which clustered in group 2 and were characterized by higher calcium, magnesium and manganese contents. An additional outstanding group 3 of six genotypes was identified with high iron, zinc, magnesium, manganese and calcium contents and potential candidates for cultivar release. The genotype × year interaction variance was greater than the genotypic variance, which might translate to phenotypic plasticity in the species. Broad-sense heritability ranged from low to high and was element-specific. The present results reveal the leaf minerals diversity in spider plant and represent a baseline for implementing a minerals-based breeding program for human nutrition.

Effects of Short-Term Potassium Chloride Supplementation in Patients with CKD

BACKGROUND

Observational studies suggest that adequate dietary potassium intake (90-120 mmol/day) may be renoprotective, but the effects of increasing dietary potassium and the risk of hyperkalemia are unknown.

METHODS

This is a prespecified analysis of the run-in phase of a clinical trial in which 191 patients (age 68±11 years, 74% males, 86% European ancestry, eGFR 31±9 ml/min per 1.73 m2, 83% renin-angiotensin system inhibitors, 38% diabetes) were treated with 40 mmol potassium chloride (KCl) per day for 2 weeks.

RESULTS

KCl supplementation significantly increased urinary potassium excretion (72±24 to 107±29 mmol/day), plasma potassium (4.3±0.5 to 4.7±0.6 mmol/L), and plasma aldosterone (281 [198-431] to 351 [241-494] ng/L), but had no significant effect on urinary sodium excretion, plasma renin, BP, eGFR, or albuminuria. Furthermore, KCl supplementation increased plasma chloride (104±3 to 105±4 mmol/L) and reduced plasma bicarbonate (24.5±3.4 to 23.7±3.5 mmol/L) and urine pH (all P<0.001), but did not change urinary ammonium excretion. In total, 21 participants (11%) developed hyperkalemia (plasma potassium 5.9±0.4 mmol/L). They were older and had higher baseline plasma potassium.

CONCLUSIONS

In patients with CKD stage G3b-4, increasing dietary potassium intake to recommended levels with potassium chloride supplementation raises plasma potassium by 0.4 mmol/L. This may result in hyperkalemia in older patients or those with higher baseline plasma potassium. Longer-term studies should address whether cardiorenal protection outweighs the risk of hyperkalemia.Clinical trial number: NCT03253172.

Lower urinary potassium excretion was associated with higher risk of cerebro-cardiovascular- and renal events in patients with hypertension under treatment with anti-hypertensive drugs

BACKGROUND

Hypertension is one of the risk factors for cerebro-cardiovascular and renal (CCR) diseases. High blood pressure is affected by the amount of salt (NaCl) and potassium (K) intake. There are many studies reporting the relationship between urinary sodium or potassium excretion and CCR events or all-cause mortality in general populations. Thus, it is necessary to investigate the relationship between urinary NaCl or K excretion and CCR events or all-cause mortality in hypertensive patients under control with anti-hypertensive drugs.

METHODS

A prospective, multi-center cohort study was performed in 3210 hypertensives under treatment with anti-hypertensive drugs for 5 years. The primary outcome was the CCR events, and the secondary outcome was all-cause mortality. A time-dependent Cox proportional hazards regression analysis was performed to assess the association between outcomes and urinary NaCl and K excretion, blood pressure, or heart rate.

RESULTS

During the follow-up period, 61 CCR events and 110 all-cause deaths occurred. There was no association between urinary NaCl excretion and CCR events or all-cause mortality. Lower urinary K excretion and higher Na/K ratio were associated with higher risk of CCR events or all-cause mortality. The CCR events were not associated with systolic, diastolic blood pressure, or heart rate.

CONCLUSION

Lower urinary K excretion was associated with higher risk of CCR events or all-cause mortality in hypertensive patients under treatment with anti-hypertensive drugs.

Adding salt to foods and hazard of premature mortality

AIMS

We analyzed whether the frequency of adding salt to foods was associated with the hazard of premature mortality and life expectancy.

METHODS AND RESULTS

A total of 501 379 participants from UK biobank who completed the questionnaire on the frequency of adding salt to foods at baseline. The information on the frequency of adding salt to foods (do not include salt used in cooking) was collected through a touch-screen questionnaire at baseline. We found graded relationships between higher frequency of adding salt to foods and higher concentrations of spot urinary sodium or estimated 24-h sodium excretion. During a median of 9.0 years of follow-up, 18 474 premature deaths were documented. The multivariable hazard ratios [95% confidence interval (CI)] of all-cause premature mortality across the increasing frequency of adding salt to foods were 1.00 (reference), 1.02 (0.99, 1.06), 1.07 (1.02, 1.11), and 1.28 (1.20, 1.35) (P-trend < 0.001). We found that intakes of fruits and vegetables significantly modified the associations between the frequency of adding salt to foods and all-cause premature mortality, which were more pronounced in participants with low intakes than those with high intakes of these foods (P-interaction = 0.02). In addition, compared with the never/rarely group, always adding salt to foods was related to 1.50 (95% CI, 0.72-2.30) and 2.28 (95% CI, 1.66-2.90) years lower life expectancy at the age of 50 years in women and men, respectively.

CONCLUSIONS

Our findings indicate that higher frequency of adding salt to foods is associated with a higher hazard of all-cause premature mortality and lower life expectancy.

Sex-specific associations between potassium intake, blood pressure, and cardiovascular outcomes: the EPIC-Norfolk study

AIMS

A potassium replete diet is associated with lower blood pressure (BP) and lower risk of cardiovascular disease (CVD). Whether these associations differ between men and women and whether they depend on daily sodium intake is unknown.

METHODS AND RESULTS

An analysis was performed in 11 267 men and 13 696 women from the EPIC-Norfolk cohort. Twenty-four hour excretion of sodium and potassium, reflecting intake, was estimated from sodium and potassium concentration in spot urine samples using the Kawasaki formula. Linear and Cox regression were used to explore the association between potassium intake, systolic BP (SBP), and CVD events (defined as hospitalization or death due to CVD). After adjustment for confounders, interaction by sex was found for the association between potassium intake and SBP (P < 0.001). In women, but not in men, the inverse slope between potassium intake and SBP was steeper in those within the highest tertile of sodium intake compared with those within the lowest tertile of sodium intake (P < 0.001 for interaction by sodium intake). Both in men and women, higher potassium intake was associated with a lower risk of CVD events, but the hazard ratio (HR) associated with higher potassium intake was lower in women than in men [highest vs. lowest potassium intake tertile: men: HR 0.93, 95% confidence interval (CI) 0.87-1.00; women: HR 0.89, 95% CI 0.83-0.95, P = 0.033 for interaction by sex].

CONCLUSION

The association between potassium intake, SBP, and CVD events is sex specific. The data suggest that women with a high sodium intake in particular benefit most from a higher potassium intake with regard to SBP.

Healthy Eating Index-2015 and Predicted 10-Year Cardiovascular Disease Risk, as Well as Heart Age

Background and Aims

Dietary factor plays an important role in the prevention of cardiovascular disease (CVD). The healthy eating index-2015 (HEI-2015), an indicator of the overall dietary quality, has been introduced to reflect adherence to the 2015–2020 Dietary Guidelines for Americans (DGA). This study aims to explore the associations of the HEI-2015 with predicted 10-year CVD risk and heart age among United States adults aged 30–74 years old using data from the National Health and Nutrition Examination Survey (NHANES) 2011–2014.

Methods and Results

We conducted a cross-sectional analysis among 6,614 participants aged 30–74 years old. The HEI-2015 scores were calculated from 2-days 24-h dietary recall interviews. The 10-year CVD risk and heart age were derived from the sex-specific Framingham general cardiovascular disease risk score. We defined high cardiovascular disease risk as a predicted 10-year cardiovascular disease risk of > 20%. Multiple linear regression and binary logistic regression models were used to investigate the associations of the HEI-2015 with predicted 10-year CVD risk and heart age. Compared with participants in the lowest HEI-2015 quartile, those in the highest quartile had lower predicted 10-year CVD risk (β = −2.37, 95% CI: −3.09 to –1.65, P < 0.0001), lower heart age (β = −2.63, 95% CI: −3.29 to –1.96, P < 0.0001) and lower odds for high risk of CVD (OR = 0.62, 95% CI: 0.49 to 0.80, P-trend < 0.0001) after adjusting for multiple covariates.

Conclusion

Higher adherence to the 2015–2020 Dietary Guidelines for Americans is associated with lower predicted 10-year cardiovascular disease risk and lower heart age among United States adults.

Spot urinary sodium to monitor relative changes in population salt intake during the UK salt reduction programme

OBJECTIVES

The most accurate method to measure population salt intake is to collect the complete 24-h urinary sodium excretion (24-h UNa) but it is resource intensive and is rarely carried out frequently. We, therefore, assessed the use of spot urinary sodium concentration to monitor relative changes in population salt intake in between 24-h urine surveys.

METHODS

We used 24-h (n = 2020) and spot urine (n = 21 711) samples drawn from adult participants in separate, cross-sectional, nationally representative surveys in England, repeated between 2006 and 2014.

RESULTS

As population average 24-h UNa fell from 2006 to 2014 (from 8.7 to 7.6 g/day, i.e. by 12%) with the ongoing salt reduction programme, spot sodium concentration fell by a similar extent (from 106.1 to 93.1 mmol/l, i.e. by 13%). The regression slopes of 24-h UNa and spot sodium concentration ran parallel (P value = 0.1009) in a linear regression modelling the difference in their year-on-year changes [by regressing the 24-h UNa or sodium concentration values on time, estimation method (24-h versus spot), and their interaction term]. In contrast, when 24-h UNa was estimated by applying the Kawasaki, Tanaka, or INTERSALT formulas to spot sodium concentrations, almost no change was detected from 2006 to 2014 (±1%) and their regression slopes were significantly different from that of the measured 24-h UNa (all P values <0.0001).

CONCLUSION

Spot urinary sodium concentration drawn from random and representative samples of the population accurately reflected relative changes in population average 24-h UNa, and can therefore, be used in between 24-h urine surveys to monitor population salt reduction programmes. Formulas commonly used to estimate 24-h UNa were unsuitable to do so.

New wrinkles in hypertension management 2022

PURPOSE OF REVIEW

High blood pressure (BP) is the world's leading risk factor for cardiovascular disease (CVD) and death. This review highlights findings during the past 18 months that apply to the management of high BP in adults in the context of the 2017 American College of Cardiology/American Heart Association (AHA) BP guideline.

RECENT FINDINGS

A comprehensive meta-analysis of clinical trials that employed a novel statistical method identified a substantially linear relationship between dietary sodium intake and BP, strongly supporting the AHA daily dietary sodium intake recommendation of less than 1500 mg/day but suggesting that any reduction in sodium intake is likely to be beneficial. Among adults with hypertension, use of a salt substitute (containing reduced sodium and enhanced potassium) led to striking reductions in CVD outcomes. Young adults with stage 1 hypertension and a low 10-year atherosclerotic CVD risk score should be started on a 6-month course of vigorous lifestyle modification; if their BP treatment goal is not achieved, a first-line antihypertensive agent should be added to the lifestyle modification intervention. In patients with stage 4 renal disease, the thiazide-like diuretic chlorthalidone (as add-on therapy) lowered BP markedly compared with placebo. Nonsteroidal mineralocorticoid receptor antagonists (MRAs) represent a new class of MRA that has been shown to lower BP and provide significant CVD protection. In Chinese adults aged 60-80 years at baseline, intensive BP control with a SBP target of 110-129 compared with 130-149 mmHg reduced CVD events with minimal side effects.

SUMMARY

Recent findings have advanced our knowledge of hypertension management, clarifying, amplifying and supporting the 2017 ACC/AHA BP guideline recommendations.

The association between salt intake and blood pressure is mediated by body mass index but modified by hypertension: The ELSA-Brasil study

High salt intake has been linked to both obesity and high blood pressure (BP). Part of the variability of BP attributed to salt intake might be BMI-mediated. To investigate whether hypertension would be an effect modifier in the complex network including salt intake, obesity, and BP, we tested the hypothesis that salt intake has direct and BMI-mediated effects on systolic (SBP) and diastolic blood pressure (DBP). Data from 9,028 participants (aged 34-75 years, 53.6% women) were analyzed. A validated formula was used to estimate daily salt intake from the sodium excretion (12 h urine collection). A path model adjusted for covariates was designed in which salt intake has both a direct and a BMI-mediated effect on BP. In normotensives, standardized beta coefficients showed significant direct (Men: 0.058 and 0.052, Women: 0.072 and 0,061, P < 0.05) and BMI-mediated (Men: 0.040 and 0.065, Women: 0.038 and 0.067, P < 0.05) effect of salt intake on the SBP and DBP, respectively. However, in hypertensive individuals, neither the direct (Men: 0.006 and 0.056, Women: 0.048 and 0.017) nor the indirect effect (Men: -0.044 and 0.014, Women: 0.011 and 0.050) of salt intake on the SBP and DBP were significant. These data suggest that cardiovascular risk stratification should consider the complex interaction between salt intake and weight gain, and their effects on BP of normotensive and hypertensive individuals.

Validity of the Food Frequency Questionnaire-Estimated Intakes of Sodium, Potassium, and Sodium-to-Potassium Ratio for Screening at a Point of Absolute Intake among Middle-Aged and Older Japanese Adults

Using Food Frequency Questionnaires (FFQs) to compare dietary references for screening has been in high demand. However, FFQs have been widely used for ranking individuals in a population based on their dietary intake. We determined the validity of sodium (salt equivalent) intake, potassium intake, and sodium-to-potassium (Na/K) ratio obtained using the FFQ for identifying individuals who deviated from the dietary reference intakes (DRIs) measured using multiple 24-h urinary excretion measurements or 12-day weighed food records (WFR). This study included 235 middle-aged subjects. The correlation coefficients (CCs) between the FFQ and WFR estimates were mostly moderate (0.24−0.54); the CCs between the FFQ and 24-h urinary excretion measurements were low or moderate (0.26−0.38). Values of area under the receiver-operating curve (AUC) at the point of DRIs for salt equivalent or potassium were >0.7 with the WFR as the reference standard and 0.60−0.76 with the 24-h urinary excretion as the reference standard. Using both standard measures, the AUC for the Na/K ratio was <0.7. The accuracy of salt equivalent and potassium intake estimation using the FFQ to determine absolute intake point was comparable to that using WFR, allowing for quantified error, but not as good as that of 24-h urinary excretion.

The modulatory effect of high salt on immune cells and related diseases

BACKGROUND

The adverse effect of excessive salt intake has been recognized in decades. Researchers have mainly focused on the association between salt intake and hypertension. However, studies in recent years have proposed the existence of extra-renal sodium storage and provided insight into the immunomodulatory function of sodium.

OBJECTIVES

In this review, we discuss the modulatory effects of high salt on various innate and adaptive immune cells and immune-regulated diseases.

METHODS

We identified papers through electronic searches of PubMed database from inception to March 2022.

RESULTS

An increasing body of evidence has demonstrated that high salt can modulate the differentiation, activation and function of multiple immune cells. Furthermore, a high-salt diet can increase tissue sodium concentrations and influence the immune responses in microenvironments, thereby affecting the development of immune-regulated diseases, including hypertension, multiple sclerosis, cancer and infections. These findings provide a novel mechanism for the pathology of certain diseases and indicate that salt might serve as a target or potential therapeutic agent in different disease contexts.

CONCLUSION

High salt has a profound impact on the differentiation, activation and function of multiple immune cells. Additionally, an HSD can modulate the development of various immune-regulated diseases.

Chronic Hyperkaliemia in Chronic Kidney Disease: An Old Concern with New Answers

Increasing potassium intake ameliorates blood pressure (BP) and cardiovascular (CV) prognoses in the general population; therefore the World Health Organization recommends a high-potassium diet (90–120 mEq/day). Hyperkalaemia is a rare condition in healthy individuals due to the ability of the kidneys to effectively excrete dietary potassium load in urine, while an increase in serum K⁺ is prevalent in patients with chronic kidney disease (CKD). Hyperkalaemia prevalence increases in more advanced CKD stages, and is associated with a poor prognosis. This scenario generates controversy on the correct nutritional approach to hyperkalaemia in CKD patients, considering the unproven link between potassium intake and serum K⁺ levels. Another concern is that drug-induced hyperkalaemia leads to the down-titration or withdrawal of renin-angiotensin system inhibitors (RASI) and mineralocorticoids receptors antagonists (MRA) in patients with CKD, depriving these patients of central therapeutic interventions aimed at delaying CKD progression and decreasing CV mortality. The new K⁺-binder drugs (Patiromer and Sodium-Zirconium Cyclosilicate) have proven to be adequate and safe therapeutic options to control serum K⁺ in CKD patients, enabling RASI and MRA therapy, and possibly, a more liberal intake of fruit and vegetables.

Prevalence, time-trends and clinical characteristics of hypertension in young adults: nationwide cross-sectional study of 1.7 million Swedish 18-year-olds, 1969-2010

OBJECTIVE

The prevalence of hypertension in young adulthood, as well as the clinical characteristics associated with different hypertension subtypes, have been inconsistently described. Our aim was to assess the prevalence, time-trends and characteristics associated with isolated systolic hypertension (ISH), isolated diastolic hypertension and combined systodiastolic hypertension.

METHODS

Serial cross-sectional analysis, using data from the Swedish conscription registry, including 1701 314 (99.2% male) individuals from 1969 to 2010. Risk factor associations were assessed through multivariable logistic regression.

RESULTS

The prevalence of hypertension increased progressively during the study period, from 20.4% in 1969 to 29.3% in 2010, with ISH being the most common subtype (94.3%). ISH was associated with elevated resting heart rate (odds ratio 1.85, 95% confidence interval 1.84-1.86, per SD), increased exercise capacity (1.37, 1.36-1.39) and increased BMI (1.30, 1.29-1.31). Isolated diastolic hypertension and combined hypertension were also associated with elevated resting heart rate (1.37, 1.32-1.41 and 2.05, 1.99-2.11, respectively) and more strongly associated with increased BMI (1.36, 1.33-1.40 and 1.54, 1.51 - 1.58), but inversely associated with exercise capacity (0.79, 0.75-0.83 and 0.90, 0.86-0.95).

CONCLUSION

The prevalence of hypertension in young adulthood has increased substantially over time, predominantly due to an increase in ISH. Risk factor patterns differed between ISH and other forms of hypertension, suggesting potentially different underlying mechanisms.

Sodium and Health: Old Myths and a Controversy Based on Denial

PURPOSE OF REVIEW

The scientific consensus on which global health organizations base public health policies is that high sodium intake increases blood pressure (BP) in a linear fashion contributing to cardiovascular disease (CVD). A moderate reduction in sodium intake to 2000 mg per day helps ensure that BP remains at a healthy level to reduce the burden of CVD.

RECENT FINDINGS

Yet, since as long ago as 1988, and more recently in eight articles published in the European Heart Journal in 2020 and 2021, some researchers have propagated a myth that reducing sodium does not consistently reduce CVD but rather that lower sodium might increase the risk of CVD. These claims are not well-founded and support some food and beverage industry's vested interests in the use of excessive amounts of salt to preserve food, enhance taste, and increase thirst. Nevertheless, some researchers, often with funding from the food industry, continue to publish such claims without addressing the numerous objections. This article analyzes the eight articles as a case study, summarizes misleading claims, their objections, and it offers possible reasons for such claims. Our study calls upon journal editors to ensure that unfounded claims about sodium intake be rigorously challenged by independent reviewers before publication; to avoid editorial writers who have been co-authors with the subject paper's authors; to require statements of conflict of interest; and to ensure that their pages are used only by those who seek to advance knowledge by engaging in the scientific method and its collegial pursuit. The public interest in the prevention and treatment of disease requires no less.

Mosaic theory revised: inflammation and salt play central roles in arterial hypertension

The mosaic theory of hypertension was advocated by Irvine Page ~80 years ago and suggested that hypertension resulted from the close interactions of different causes. Increasing evidence indicates that hypertension and hypertensive end-organ damage are not only mediated by the proposed mechanisms that result in hemodynamic injury. Inflammation plays an important role in the pathophysiology and contributes to the deleterious consequences of arterial hypertension. Sodium intake is indispensable for normal body function but can be detrimental when it exceeds dietary requirements. Recent data show that sodium levels also modulate the function of monocytes/macrophages, dendritic cells, and different T-cell subsets. Some of these effects are mediated by changes in the microbiome and metabolome due to high-salt intake. The purpose of this review is to propose a revised and extended version of the mosaic theory by summarizing and integrating recent advances in salt, immunity, and hypertension research. Salt and inflammation are placed in the middle of the mosaic because both factors influence each of the remaining pieces.

Mechanism-based strategies to prevent salt sensitivity and salt-induced hypertension

High-salt diets are a major cause of hypertension and cardiovascular (CV) disease. Many governments are interested in using food salt reduction programs to reduce the risk for salt-induced increases in blood pressure and CV events. It is assumed that reducing the salt concentration of processed foods will substantially reduce mean salt intake in the general population. However, contrary to expectations, reducing the sodium density of nearly all foods consumed in England by 21% had little or no effect on salt intake in the general population. This may be due to the fact that in England, as in other countries including the U.S.A., mean salt intake is already close to the lower normal physiologic limit for mean salt intake of free-living populations. Thus, mechanism-based strategies for preventing salt-induced increases in blood pressure that do not solely depend on reducing salt intake merit attention. It is now recognized that the initiation of salt-induced increases in blood pressure often involves a combination of normal increases in sodium balance, blood volume and cardiac output together with abnormal vascular resistance responses to increased salt intake. Therefore, preventing either the normal increases in sodium balance and cardiac output, or the abnormal vascular resistance responses to salt, can prevent salt-induced increases in blood pressure. Suboptimal nutrient intake is a common cause of the hemodynamic disturbances mediating salt-induced hypertension. Accordingly, efforts to identify and correct the nutrient deficiencies that promote salt sensitivity hold promise for decreasing population risk of salt-induced hypertension without requiring reductions in salt intake.

Dietary salt intake in Japan - past, present, and future

Salt reduction is the most important lifestyle modification, especially in Japanese individuals who still consume a significant amount of salt. The Dietary Reference Intakes for Japanese 2020, issued by the Ministry of Health, Labour and Welfare, propose a salt intake goal of <7.5 g/day for men and <6.5 g/day for women. Regarding the goal of salt reduction in hypertensive patients, the hypertension guideline by the Japanese Society of Hypertension 2019 (JSH2019) proposes a goal of <6 g/day. Although the average salt intake in Japan gradually decreased in the early 2000s, the declining trend has not been seen in recent years, and thus, it seems difficult to achieve these target salt intake levels. To overcome this challenge, the JSH announced the 'JSH Tokyo Declaration' and pledged to create a specific action plan to achieve the target salt intake level of <6 g/day. The six strategies to achieve the target salt intake level are as follows: (1) educating citizens on the harms of excessive salt intake and the importance of reducing salt intake; (2) recommending the assessment of the salt intake of individuals or populations and proposing adequate methods to reduce salt intake; (3) promoting salt reduction for children as a part of dietary education at school; (4) promoting salt reduction in takeout food, prepared dishes, canteens, and school lunches; (5) encouraging companies to develop and promote low-salt foods; and (6) encouraging the government to take measures to promote salt reduction. Through these activities, a society with a low salt intake will be expected in the near future.

Dietary Sodium and Potassium Intake and Risk of Non-Fatal Cardiovascular Diseases: The Million Veteran Program

Objective: To examine the association between intakes of sodium and potassium and the ratio of sodium to potassium and incident myocardial infarction and stroke. Design, Setting and Participants: Prospective cohort study of 180,156 Veterans aged 19 to 107 years with plausible dietary intake measured by food frequency questionnaire (FFQ) who were free of cardiovascular disease (CVD) and cancer at baseline in the VA Million Veteran Program (MVP). Main outcome measures: CVD defined as non-fatal myocardial infarction (MI) or acute ischemic stroke (AIS) ascertained using high-throughput phenotyping algorithms applied to electronic health records. Results: During up to 8 years of follow-up, we documented 4090 CVD cases (2499 MI and 1712 AIS). After adjustment for confounding factors, a higher sodium intake was associated with a higher risk of CVD, whereas potassium intake was inversely associated with the risk of CVD [hazard ratio (HR) comparing extreme quintiles, 95% confidence interval (CI): 1.09 (95% CI: 0.99−1.21, p trend = 0.01) for sodium and 0.87 (95% CI: 0.79−0.96, p trend = 0.005) for potassium]. In addition, the ratio of sodium to potassium (Na/K ratio) was positively associated with the risk of CVD (HR comparing extreme quintiles = 1.26, 95% CI: 1.14−1.39, p trend < 0.0001). The associations of Na/K ratio were consistent for two subtypes of CVD; one standard deviation increment in the ratio was associated with HRs (95% CI) of 1.12 (1.06−1.19) for MI and 1.11 (1.03−1.19) for AIS. In secondary analyses, the observed associations were consistent across race and status for diabetes, hypertension, and high cholesterol at baseline. Associations appeared to be more pronounced among participants with poor dietary quality. Conclusions: A high sodium intake and a low potassium intake were associated with a higher risk of CVD in this large population of US veterans.

High blood pressure in children and adolescents: current perspectives and strategies to improve future kidney and cardiovascular health

Hypertension is one of the most common causes of preventable death worldwide. The prevalence of pediatric hypertension has increased significantly in recent decades. The cause of this is likely multifactorial, related to increasing childhood obesity, high dietary sodium intake, sedentary lifestyles, perinatal factors, familial aggregation, socioeconomic factors, and ethnic blood pressure (BP) differences. Pediatric hypertension represents a major public health threat. Uncontrolled pediatric hypertension is associated with subclinical cardiovascular disease and adult-onset hypertension. In children with chronic kidney disease (CKD), hypertension is also a strong risk factor for progression to kidney failure. Despite these risks, current rates of pediatric BP screening, hypertension detection, treatment, and control remain suboptimal. Contributing to these shortcomings are the challenges of accurately measuring pediatric BP, limited access to validated pediatric equipment and hypertension specialists, complex interpretation of pediatric BP measurements, problematic normative BP data, and conflicting society guidelines for pediatric hypertension. To date, limited pediatric hypertension research has been conducted to help address these challenges. However, there are several promising signs in the field of pediatric hypertension. There is greater attention being drawn on the cardiovascular risks of pediatric hypertension, more emphasis on the need for childhood BP screening and management, new public health initiatives being implemented, and increasing research interest and funding. This article summarizes what is currently known about pediatric hypertension, the existing knowledge-practice gaps, and ongoing research aimed at improving future kidney and cardiovascular health.

Potassium and the kidney: a reciprocal relationship with clinical relevance

By controlling urinary potassium excretion, the kidneys play a key role in maintaining whole-body potassium homeostasis. Conversely, low urinary potassium excretion (as a proxy for insufficient dietary intake) is increasingly recognized as a risk factor for the progression of kidney disease. Thus, there is a reciprocal relationship between potassium and the kidney: the kidney regulates potassium balance but potassium also affects kidney function. This review explores this relationship by discussing new insights into kidney potassium handling derived from recently characterized tubulopathies and studies on sexual dimorphism. These insights reveal a central but non-exclusive role for the distal convoluted tubule in sensing potassium and subsequently modifying the activity of the sodium-chloride cotransporter. This is another example of reciprocity: activation of the sodium-chloride cotransporter not only reduces distal sodium delivery and therefore potassium secretion but also increases salt sensitivity. This mechanism helps explain the well-known relationship between dietary potassium and blood pressure. Remarkably, in children, blood pressure is related to dietary potassium but not sodium intake. To explore how potassium deficiency can cause kidney injury, we review the mechanisms of hypokalemic nephropathy and discuss if these mechanisms may explain the association between low dietary potassium intake and adverse kidney outcomes. We discuss if potassium should be repleted in patients with kidney disease and what role dietary potassium plays in the risk of hyperkalemia. Supported by data and physiology, we reach the conclusion that we should view potassium not only as a potentially dangerous cation but also as a companion in the battle against kidney disease.

Molecular mechanisms for the modulation of blood pressure and potassium homeostasis by the distal convoluted tubule

Epidemiological and clinical observations have shown that potassium ingestion is inversely correlated with arterial hypertension prevalence and cardiovascular mortality. The higher the dietary potassium, the lower the blood pressure and mortality. This phenomenon is explained, at least in part, by the interaction between salt reabsorption in the distal convoluted tubule (DCT) and potassium secretion in the connecting tubule/collecting duct of the mammalian nephron: In order to achieve adequate K⁺ secretion levels under certain conditions, salt reabsorption in the DCT must be reduced. Because salt handling by the kidney constitutes the basis for the long‐term regulation of blood pressure, losing salt prevents hypertension. Here, we discuss how the study of inherited diseases in which salt reabsorption in the DCT is affected has revealed the molecular players, including membrane transporters and channels, kinases, and ubiquitin ligases that form the potassium sensing mechanism of the DCT and the processes through which the consequent adjustments in salt reabsorption are achieved.