Low Salt Intake Research Articles

High and Low Salt Intake during Pregnancy: Impact on Cardiac and Renal Structure in Newborns.

IntroductionPrevious studies from our laboratory demonstrated that dietary salt overload and salt restriction during pregnancy were associated with cardiac and renal structural and/or functional alterations in adult offspring. The present study evaluated renal and cardiac structure and the local renin-angiotensin system in newborns from dams fed high-, normal- or low-salt diets during pregnancy.MethodsFemale Wistar rats were fed low- (LS, 0.15% NaCl), normal- (NS, 1.3% NaCl) or high- (HS, 8% NaCl) salt diets during pregnancy. Kidneys and hearts were collected from newborns (n = 6-8/group) during the first 24 hours after birth to evaluate possible changes in structure using stereology. Protein expression of renin-angiotensin system components was evaluated using an indirect enzyme-linked immunosorbent assay (ELISA).ResultsNo differences between groups were observed in total renal volume, volume of renal compartments or number of glomeruli. The transverse diameter of the nuclei of cardiomyocytes was greater in HS than NS males in the left and right ventricles. Protein expression of the AT1 receptor was lower in the kidneys of the LS than in those of the NS and HS males but not females. Protein expression of the AT2 receptor was lower in the kidneys of the LS males and females than in those of the NS males and females.ConclusionHigh salt intake during pregnancy induced left and right ventricular hypertrophy in male newborns. Salt restriction during pregnancy reduced the expression of renal angiotensin II receptors in newborns.

Adesão à dieta por idosos com síndrome metabólica assistidos na Estratégia Saúde da Família: frequência e associação com depressão

Aims: To describe diet adherence and to analyze its association with depression in elderly patients with metabolic syndrome treated by the Family Health Strategy.Methods: Cross-sectional study including elderly patients with metabolic syndrome diagnosed according to the National Cholesterol Education Program Adult Treatment Panel III criteria who participated in the Epidemiological and Clinical Study of Elderly Individuals Treated by the Family Health Strategy in Porto Alegre, Brazil. A questionnaire developed by the researchers based on the recommendations of the I Brazilian Guideline for Metabolic Syndrome was used to evaluate compliance with eight possible dietary guidelines provided by health professionals (intake of foods, sweets, sugar, fruits/vegetables/legumes, salt, fatty foods/fried foods, processed and fish). Diet adherence was considered when an individual followed all dietary guidelines (regardless of their number, which ranged from one to eight). The diagnosis of depression was based on the Mini International Neuropsychiatric Interview instrument, used by psychiatrists.Results: A total of 109 elderly patients were included in the study, most of whom were female (67.9%). The mean age was 68.4±6.6 years (61-90 years). Thirty-seven elderly patients (33.9%) were considered adherent to the diet. Lower salt intake was the dietary guidance with greater adherence (89.1%) while the consumption of whole foods exhibited less adherence (59.7%). There was no association of diet adherence with sociodemographic and clinical parameters and with metabolic syndrome components. The frequency of adherence to the recommendation against the consumption of sugar and sweets was significantly lower among individuals with depression (43.9% and 34.9%, respectively; p = 0.001).Conclusions: Diet adherence occurred in one third of elderly patients with metabolic syndrome treated at the primary health care level. There was lower adherence to the recommendation against the consumption of sweets and sugar in individuals diagnosed with depression.

Variation in blood pressure among adolescent schoolchildren in an urban slum of Kolkata, West Bengal

BackgroundHigh blood pressure in childhood is a potential risk factor for cardiovascular and cerebrovascular diseases. The roots of essential hypertension in adults may be initiated in childhood. This study was...

THE RELATION BETWEEN FIBRINOLYTIC SYSTEM AND THE RENIN ANGIOTENSIN SYSTEM

Several lines of evidence point to an interrelation of the renin-angiotensin system (RAS) with the endogenous fibrinolytic system. This study was planned to examine the effect of salt depletion as a method of activation of the endogenous RAS on plasma fibrinolytic balance in 10 healthy human subjects in the presence and absence of angiotensin converting enzyme inhibitor-ACEi (captopril). Activation of the RAS during low salt intake was documented by a significant increase in serum aldosterone concentration. The data suggest that activation of the RAS results in increased plasminogen activator inhibitors (PAI-I) antigen and that interruption of the RAS with the ACE inhibitor captopril significantly lowers PAI-I antigen without lowering tissue-type plasminogen activator (t-PA) antigen. In conclusion, this study provides an evidence of a direct functional link between the RAS and the fibrinolytic system in humans and these findings may help to elucidate possible mechanisms by which ACE inhibition exerts vasculo protective effects and reduces the risk of atherothrombotic events.

Preference of Food Saltiness and Willingness to Consume Low-Sodium Content Food in a Chinese Population.

To compare the preference of food saltiness and the willingness to consume low-sodium food among hypertensive older people, non-hypertensive older people and non-hypertensive young people in a Chinese population. A cross-sectional study based on a quota sample. Three saltiness options (low-sodium, medium-sodium and high-sodium) of soup and bread were offered to each participant who rated the taste of each food on a 5-point Likert scale. Then, the participants rated their willingness to consume the low-sodium content foods on a 5-point Likert scale, given they were informed of the benefit of the low-sodium option. Generalised linear mixed model and multiple linear regression were used to analyse the data. Elderly centres and community centres in Hong Kong. Sixty hypertensive older people, 49 non-hypertensive older people and 60 non-hypertensive young people were recruited from June to August 2014. The tastiness score and the willingness score were the primary outcome measures. The Chinese Health Literacy Scale for Low Salt Consumption - Hong Kong population (CHLSalt-HK) was also assessed. The tastiness rating of the high-sodium option of soup was significantly lower than the medium-sodium option (p<0.001), but there was no significant difference between the low-sodium and the medium-sodium options (p=0.204). For bread, tastiness rating of the low-sodium option and the high-sodium option were significantly lower than the medium-sodium option (p<0.001 for both options). The tastiness score of soup did not have significant difference across the groups (p=0.181), but that of bread from the hypertensive older adults (p=0.012) and the non-hypertensive older adults (p=0.006) was significantly higher than the non-hypertensive young adults. Higher willingness rating to consume the low-sodium option was significantly (p<0.001) associated with higher tastiness rating of the low-sodium option of soup and bread, and weakly associated with higher health literacy of low salt intake (soup: p=0.041; bread: p=0.024). Hypertensive older adults tended to be more willing to consume the low-sodium option than non-hypertensive older adults for soup (p=0.009), there was insignificant difference between non-hypertensive older adults and non-hypertensive young adults (p=0.156). For bread, there was insignificant difference in willingness rating to consume low-sodium option (p=0.375). Older people are at a higher risk of hypertension, reduction of salt intake is important for them to reduce their risk of cardiovascular diseases. There is room for reducing the sodium content of soup, while the sodium in bread should be reduced progressively. Improving the taste of low-sodium food may help to promote reduction in dietary sodium intake.

Association Between Protein Intake and Mortality in Hypertensive Patients Without Chronic Kidney Disease in the OLD-HTA Cohort.

Protein intake may have some benefits on reducing blood pressure and cardiovascular events, but their effects are still debated. The objective of this study was to test the prognostic value of protein intake assessed by 24-hour urinary urea in a cohort of hypertensive patients with preserved renal function. A total of 1128 hypertensive patients were followed according to tertile of protein intake adjusted for ideal body weight: <0.70, 0.70 to 0.93, and >0.93 g/kg. Baseline characteristics (mean±standard deviation) were age 45.1±13.2 years, systolic/diastolic blood pressure 185±32/107±20 mm Hg, and estimated glomerular filtration rate 82±32 mL/min. After 10 years of follow-up, 289 deaths occurred, 202 of which were of cardiovascular cause. After adjustment for major cardiovascular risk factors, patients in the second and third tertiles of protein intake had a decreased risk of all-cause death (hazard ratio [95% confidence interval], 0.71 [0.56-0.91]) and cardiovascular death (0.72 [0.54-0.96]), but not of stroke death (0.72 [0.41-1.28]) in comparison to patients in the low protein intake tertile. Normal-high protein intake was associated with a better outcome in a subset of the population: younger patients, low salt intake, without aortic atherosclerosis, or previous cardiovascular events (Pinteraction<0.10 for all). Hypertensive patients having a protein intake >0.7 g/kg ideal body weight, particularly those at low risk, had lower all-cause and cardiovascular mortality rates. Physicians may encourage hyper tensive patients to have normal or high protein diet in addition to low salt consumption, moderate alcohol consumption, and regular physical activity.

Abstract P322: Goals for Cardiometabolic Risk Factors are Still Not Being Attained in the Long Term After Stroke or Transient Ischaemic Attack

Introduction: Clinical guidelines for patients with stroke or TIA have focused on modification of lifestyle and treatment to achieve cardometabolic risk factor goals. However, there is limited evidence on effective attainment of these goals in this high-risk population. Hypothesis: We hypothesised that a one-year intervention program will improve the attainment of cardiometabolic risk factor goals in community-dwelling survivors of stroke or TIA. Methods: Shared Team Approach between Nurses and Doctors For Improved Risk Factor Management (STANDFIRM) trial is an on-going prospective, randomised controlled trial of risk factor management in people with stroke or TIA. Patients hospitalised for stroke/TIA, and aged ≥18 years, were provided an intervention comprising an individualised, evidence-based secondary prevention program, including nurse education visits, and management plan with specialist oversight. The study outcome was attainment of blood pressure, blood cholesterol, blood sugar, body composition, kidney function goals, and smoking cessation at 12 months, based on guideline recommendations. We assessed whether lifestyle or other factors were associated with achieving an increased number of goals. Data collection comprised surveys, anthropometric and biochemical measurements. Differences in the proportion of patients meeting the set goals at baseline and 12 months were determined using McNemar’s chi-square test. The association between baseline factors and goal attainment was determined using multivariable linear regression. Results: Between January 2010 and November 2013, 233 patients (66% male, median age 69 years, 77% ischaemic stroke) were recruited into the intervention arm of the trial. Between baseline and 12 months, there was no difference in the proportion of patients achieving each of the set goals. Overall, only 14 patients (3%) achieved all six measured goals. A total of 90 patients (34%) met ≥4 goals, 89 (34%) met 3 goals, and 84 (32%) met ≤2 goals. In multivariable analyses, factors independently associated with achieving more goals included being female (OR 1.70, 95% CI 1.27, 2.20), having vocational or higher education (OR 1.37, 95% CI 1.05, 1.80), and lower salt intake at baseline (OR 0.98, 95% CI 0.97, 1.00). Conclusion: The 12-month intervention did not have an impact on the attainment of cardiometabolic goals in patients with stroke or TIA. With few individual factors identified, further investigation of system-level factors is warranted to ascertain factors that could facilitate improved risk factor management in patients with stroke or TIA.

(Pro)renin receptor contributes to regulation of renal epithelial sodium channel.

Recent studies reported increased (Pro)renin receptor (PRR) expression during low-salt intake. We hypothesized that PRR plays a role in regulation of renal epithelial sodium channel (ENaC) through serum and glucocorticoid-inducible kinase isoform 1 (SGK-1)-neural precursor cell expressed, developmentally downregulated 4-2 (Nedd4-2) signaling pathway. Male Sprague-Dawley rats on normal-sodium diet and mouse renal inner medullary collecting duct cells treated with NaCl at 130 mmol/l (normal salt), or 63 mmol/l (low salt) were studied. PRR and α-ENaC expressions were evaluated 1 week after right uninephrectomy and left renal interstitial administration of 5% dextrose, scramble shRNA, or PRR shRNA (n = 6 each treatment). In-vivo PRR shRNA significantly reduced expressions of PRR throughout the kidney and α-ENaC subunits in the renal medulla. In inner medullary collecting duct cells, low salt or angiotensin II (Ang II) augmented the mRNA and protein expressions of PRR (P < 0.05), SGK-1 (P < 0.05), and α-ENaC (P < 0.05). Low salt or Ang II increased the phosphorylation of Nedd4-2. In cells treated with low salt or Ang II, PRR siRNA significantly downregulated the mRNA and protein expressions of PRR (P < 0.05), SGK-1 (P < 0.05), and α-ENaC expression (P < 0.05). We conclude that PRR contributes to the regulation of α-ENaC via SGK-1-Nedd4-2 signaling pathway.

Salt and miscarriage: Is there a link?

Salt is a major mineral element that plays fundamental roles in health and disease. Excessive salt intake is a major cause of hypertension, cardiovascular disease and stroke. Miscarriage and preeclampsia are the most common pregnancy complications with multiple etiological factors, including inflammatory and autoimmune conditions. More recently, different studies indicated that excessive salt intake is involved in the development of inflammatory processes through induction of T helper-17 pathway and their inflammatory cytokines. On the other hand, several studies indicated the pivotal role of inflammation in the etiology of miscarriage, preeclampsia and adverse pregnancy outcome. Here, it is hypothesized that excessive salt intake around the time of conception or during pregnancy can trigger inflammatory processes, which consequently associated with increased risk of miscarriage, preeclampsia or adverse pregnancy outcome. Thus, this hypothesis suggests that low salt intake around the time of conception or during pregnancy can decrease the risk of miscarriage or adverse pregnancy outcome. This hypothesis also offers new insights about the role of salt in the etiology of miscarriage and preeclampsia.

Daily salt intake estimated by overnight urine collections indicates a high cardiovascular disease risk in Thailand.

This cross-sectional study (February 2012 to March 2013) was conducted to estimate daily salt intake and basic characteristics among 793 community-dwelling participants at high risk of cardiovascular disease (Framingham risk score >15%), who had visited diabetes or hypertension clinics at health centres in the Muang district, Chiang Rai, Thailand. We performed descriptive analysis of baseline data and used an automated analyser to estimate the average of 24-hour salt intake estimated from 3 days overnight urine collection. Participants were divided into two groups based on median estimated daily salt intake. Mean age and proportion of males were 65.2 years and 37.6% in the higher salt intake group (>=10.0 g/day, n=362), and 67.5 years and 42.7% in the lower salt intake group (<10.0 g/day, n=431), respectively (p=0.01, p<0.01). The higher salt intake group comprised more patients with a family history of hypertension, antihypertensive drug use, less ideal body mass index (18.5-24.9), higher exercise frequency (>=2 times weekly) and lower awareness of high salt intake. Among higher salt intake participants, those with lower awareness of high salt intake were younger and more often had a family history of hypertension, relative to those with more awareness. Our data indicated that families often share lifestyles involving high salt intake, and discrepancies between actual salt intake and awareness of high salt intake may represent a need for salt reduction intervention aiming at family level. Awareness of actual salt intake should be improved for each family.

Recommendations and practice of healthy behaviors among patients with diagnosis and diabetes in Brazil: National Health Survey (PNS), 2013.

To analyze healthy life style recommendations given in health care and the adoption of healthy behaviors among hypertension and diabetes patients. We analyzed the recommendations according to the place of the last health care visit (primary health care, other public facilities, and private health care facilities). The effects of having a diagnosis of hypertension or diabetes on the adoption of healthy practices were analyzed by multivariate logistic regression models, using sex, age, and educational level as control variables, and the following outcomes: current use of tobacco products; regular physical activity during leisure time; recommended intake of fruits and vegetables; perception of low salt intake; frequent consumption of sweets; and excessive alcohol consumption. Approximately 88% of hypertension patients received recommendations to have a healthy diet, 91% to eat less salt, 83% to practice regular physical activity, and 76% to not to smoke. Among diabetic patients, all recommendations related to nutrition were very frequent, reaching 95% for the habit of having fruits and vegetables regularly. The effect of having a diagnosis of hypertension was significant for non-use of tobacco products and perception of low salt intake. The diagnosis of diabetes mainly influenced the habit of not consuming sweets often. Results evidenced that people with diagnosis of hypertension and diabetes give priority to not use (stop) harmful health behaviors than to adopt practices that will bring benefits to their health. It is necessary to promote not only the adverse effects of harmful habits, but also the benefits of healthy behaviors to aging well.

Glucose metabolism and hepatic Igf1 DNA methylation are altered in the offspring of dams fed a low-salt diet during pregnancy

A low-salt (LS) diet during pregnancy has been linked to insulin resistance in adult offspring, at least in the experimental setting. However, it remains unclear if this effect is due to salt restriction during early or late pregnancy. To better understand this phenomenon, 12-week-old female Wistar rats were fed a LS or normal-salt (NS) diet during gestation or a LS diet during either the first (LS10) or second (LS20) half of gestation. Glucose tolerance test, HOMA-IR, gene expression analysis and DNA methylation measurements were conducted for the Insr, Igf1, Igf1r, Ins1 and Ins2 genes in the livers of neonates and in the liver, white adipose tissue and muscle of 20-week-old male offspring. Birth weight was lower in the LS20 and LS animals compared with the NS and LS10 rats. In the liver, the Igf1 levels in the LS10, LS20 and LS neonates were lower than those in the NS neonates. Methylation of the Insr, Igf1r, Ins1 and Ins2 genes was influenced in a variable manner by low salt intake during pregnancy. Increased liver Igf1 methylation was observed in the LS and LS20 neonates compared with their NS and LS10 counterparts. Glucose intolerance was observed in adult offspring as an effect of low salt intake over the duration of pregnancy. Compared to the NS animals, the HOMA-IR was higher in the 12-week-old LS and 20-week-old LS-10 rats. Based on these results, it appears that the reason a LS diet during pregnancy induces a low birth weight is its negative correlation with Igf1 DNA methylation in neonates.

Renal Effects and Underlying Molecular Mechanisms of Long-Term Salt Content Diets in Spontaneously Hypertensive Rats.

Several evidences have shown that salt excess is an important determinant of cardiovascular and renal derangement in hypertension. The present study aimed to investigate the renal effects of chronic high or low salt intake in the context of hypertension and to elucidate the molecular mechanisms underlying such effects. To this end, newly weaned male SHR were fed with diets only differing in NaCl content: normal salt (NS: 0.3%), low salt (LS: 0.03%), and high salt diet (HS: 3%) until 7 months of age. Analysis of renal function, morphology, and evaluation of the expression of the main molecular components involved in the renal handling of albumin, including podocyte slit-diaphragm proteins and proximal tubule endocytic receptors were performed. The relationship between diets and the balance of the renal angiotensin-converting enzyme (ACE) and ACE2 enzymes was also examined. HS produced glomerular hypertrophy and decreased ACE2 and nephrin expressions, loss of morphological integrity of the podocyte processes, and increased proteinuria, characterized by loss of albumin and high molecular weight proteins. Conversely, severe hypertension was attenuated and renal dysfunction was prevented by LS since proteinuria was much lower than in the NS SHRs. This was associated with a decrease in kidney ACE/ACE2 protein and activity ratio and increased cubilin renal expression. Taken together, these results suggest that LS attenuates hypertension progression in SHRs and preserves renal function. The mechanisms partially explaining these findings include modulation of the intrarenal ACE/ACE2 balance and the increased cubilin expression. Importantly, HS worsens hypertensive kidney injury and decreases the expression nephrin, a key component of the slit diaphragm.

The role of IL-6 in the physiologic versus hypertensive blood pressure actions of angiotensin II.

Angiotensin II (AngII) is a critical physiologic regulator of volume homeostasis and mean arterial pressure (MAP), yet it also is known to induce immune mechanisms that contribute to hypertension. This study determined the role of interleukin-6 (IL-6) in the physiologic effect of AngII to maintain normal MAP during low-salt (LS) intake, and whether hypertension induced by plasma AngII concentrations measured during LS diet required IL-6. IL-6 knockout (KO) and wild-type (WT) mice were placed on LS diet for 7 days, and MAP was measured 19 h/day with telemetry. MAP was not affected by LS in either group, averaging 101 ± 4 and 100 ± 4 mmHg in WT and KO mice, respectively, over the last 3 days. Seven days of ACEI decreased MAP ∼25 mmHg in both groups. In other KO and WT mice, AngII was infused at 200 ng/kg per minute to approximate plasma AngII levels during LS. Surgical reduction of kidney mass and high-salt diet were used to amplify the blood pressure effect. The increase in MAP after 7 days was not different, averaging 20 ± 5 and 22 ± 6 mmHg in WT and KO mice, respectively. Janus Kinase 2 (JAK2)/signal transducer of activated transcription (STAT3) phosphorylation were not affected by LS, but were increased by AngII infusion at 200 and 800 ng/kg per minute. These data suggest that physiologic levels of AngII do not activate or require IL-6 to affect blood pressure significantly, whether AngII is maintaining blood pressure on LS diet or causing blood pressure to increase. JAK2/STAT3 activation, however, is tightly associated with AngII hypertension, even when caused by physiologic levels of AngII.

A REVIEW OF GRAPHICAL REPRESENTATIONS USED IN THE DIETARY GUIDELINES OF SELECTED COUNTRIES IN THE AMERICAS, EUROPE AND ASIA.

Food-Based Dietary Guidelines (FBDGs) are an initiative by the United Nations Food and Agriculture Organization (FAO) and the World Health Organization (WHO) designed to help countries establish their own nutrition education principles. Such principles should be expressed through clear and specific messages that provide guidance and promote good health among populations. Many of these guidelines contain graphical representations (GRs) as visual aids for dietary guidance. to analyze the characteristics of GRs used in various countries on four continents to identify international trends in these graphical messages and assess their usefulness as educational tools for their target populations. a review of GRs used in the FBDGs of countries in the Americas, Europe and Asia for which data were available in Spanish or English. the models most used are the food circle and pyramid. The GRs (n = 37) depict the following recommendations: food groups (37), physical activity (21), water intake (17), low salt intake (7), family meals (1) and relaxation (1). In addition, 10 quantitative recommendations were detected. The GRs of Greece and the United States do not show images of food. The aspects considered in the GRs vary by the regions, cultures and epidemiological characteristics of each country. A tendency to use the food circle and to include lifestyle recommendations in illustrations was observed in the United States, Spain and Mexico. Quantitative recommendations may help to clarify information provided during the educational process.

Endothelin-1 as a master regulator of whole-body Na+ homeostasis.

The current study was designed to determine whether vascular endothelial-derived endothelin-1 (ET-1) is important for skin Na(+) buffering. In control mice (C57BL/6J), plasma Na(+) and osmolarity were significantly elevated in animals on high- vs. low-salt (HS and LS, respectively) intake. The increased plasma Na(+) and osmolarity were associated with increased ET-1 mRNA in vascular tissue. There was no detectable difference in skin Na(+):H2O in HS fed mice (0.119 ± 0.005 mM vs. 0.127 ± 0.007 mM; LS vs. HS); however, skin Na(+):H2O was significantly increased by blockade of the endothelin type A receptor with ABT-627 (0.116 ± 0.006 mM vs. 0.137 ± 0.007 mM; LS vs. HS; half-maximal inhibitory concentration, 0.055 nM). ET-1 peptide content in skin tissue was increased in floxed control animals on HS (85.9 ± 0.9 pg/mg vs. 106.4 ± 6.8 pg/mg; P < 0.05), but not in vascular endothelial cell endothelin-1 knockout (VEET KO) mice (76.4 ± 5.7 pg/mg vs. 65.7 ± 7.9 pg/mg; LS vs. HS). VEET KO mice also had a significantly elevated skin Na(+):H2O (0.113 ± 0.007 mM vs. 0.137 ± 0.005 mM; LS vs. HS; P < 0.05). Finally, ET-1 production was elevated in response to increasing extracellular osmolarity in cultured human endothelial cells. These data support the hypothesis that increased extrarenal vascular ET-1 production in response to HS intake is mediated by increased extracellular osmolarity and plays a critical role in regulating skin storage of Na(+).

Salt Restriction in Diabetes.

There are no long-term interventions examining the effects of salt reduction in people with diabetes, and these are urgently required. Sodium reduction is controversial as it appears that an intake below 2.5g and above 6g/day of salt is associated with increased cardiovascular disease risk. However, pre-existing illness leading to a lower salt intake may confound the findings. Only a few studies have prospectively collected data on the sodium intake and excretion of people with diabetes and examined hard end points. In addition, future studies need to collect more data on food intake as well as coexistent illnesses to address potential confounding. The World Health Organization recommends a reduction to less than 5g/day salt in adults. Given that the available evidence suggests that the salt intake of people with type 2 diabetes is generally well above 6g/day it seems reasonable to ensure individuals with diabetes have an intake below 6g/day. However, such recommendations need to be individualized.

O14. Is preeclampsia a variant of Liddles syndrome with enhanced activity of the epithelial sodium channel in the kidneys?

Introduction Preeclampsia is characterized by hypertension accompanied by proteinuria. The plasma protease plasmin is aberrantly filtered to pre-urine in preeclampsia and may activate the epithelial sodium channel ENaC in the renal collecting ducts. This mechanism could contribute to impaired sodium excretion, suppression of renin–angiotensin–aldosterone and hypertension which are features of preeclampsia. Objectives It was hypothesized that established hypertension of pregnancy/preeclampsia share features with Liddles syndrome and display hyper-active ENaC and therefore blood pressure is more sensitive to NaCl intake compared to normal pregnancy whereas the renin–angiotensin–aldosterone system is suppressed and less sensitive. Experiments were designed to test the effect of controlled high and low dietary salt intake in patients with preeclampsia, healthy pregnant controls and non-pregnant controls. 24 h urine Na excretion, blood pressure, cardiac output – and extracellular volume (ECV) and plasma renin and aldosterone were measured. Secondary outcomes were pulsatile index (PI) in the umbilical artery and in the uterine artery. Methods The study (clintrialsgov NCT01828138) which is ongoing, is a randomized, cross-over, double-blinded, dietary intervention study (Ethic committee approval: 1-10-72-600-12). 7 patients with PE, 15 healthy pregnant women and 11 non pregnant women were included. The intervention was a fixed low-sodium diet (50–60 mmol/24 h) with addition of either placebo or salt tablets (200mmol) for 4 + 4 days. 24 h urine was collected for dietary compliance. After baseline measurements, outcome was measured after each of the two interventions. Results A significantly elevated systolic blood pressure (4 mmHg) was found in the healthy pregnant group ( P = 0.008) on a high salt diet. Plasma renin decreased significantly on a high salt diet in the healthy pregnant groups ( P = 0.02) and in non-pregnant group ( P P = 0.4). Comparing the delta values between groups, there was no difference. Plasma aldosterone decreased significantly on a high salt diet in all groups. Delta aldosterone was not different between groups. There was no statistically significant difference in cardiac output found in any of the groups. ECV increased significantly on a high salt diet in all groups. Umbilical artery PI was unaltered due to the intervention in both pregnant groups. PI in the uterine artery was significantly decreased in the group of preeclamptic women on a low salt diet ( P = 0.02) contrary to the healthy pregnant group ( P = 0.9). Conclusion There was a reduced reactivity of plasma renin concentration to altered salt intake in the pre-eclamptic group. Low salt intake was well-tolerated. PE/hypertension in pregnancy with proteinuria display features compatible with impaired sodium excretion that could involve ENaC activity.

Short-term dietary salt supplementation blunts telmisartan induced increases in plasma renin activity in hypertensive patients with type2 diabetes mellitus.

Current guidelines recommend low dietary salt intake (LDS) in patients with diabetes to reduce blood pressure (BP). However, low salt intake has been associated with higher mortality rates in people with diabetes. Our aim is to examine the effect of angiotensin II receptor blocker (ARB), telmisartan, with and without dietary sodium chloride (NaCl) supplementation, on BP [mean arterial pressure (MAP)], plasma renin activity (PRA), serum aldosterone level and estimated glomerular filtration rate (eGFR) in hypertensive patients with type2 diabetes. In a randomized, double-blind, placebo-controlled study (RCT), 28 patients with type2 diabetes, treated with telmisartan (40mg daily), received 2weeks of placebo or NaCl capsules (100mmol/24h). Following a 6-week washout, the protocol was repeated in reverse. Twenty-four-hour urinary sodium excretion (24hUNa), ambulatory BP (ABP) monitoring and blood tests were performed before and after each study phase. The telmisartan-associated increase in PRA was blunted by approximately 50% during salt supplementation compared with placebo; median PRA was 2.3μg/l/h with placebo compared with 1.7μg/l/h with salt (P<0.001). A trend towards blunting of ARB induced increases in serum aldosterone was also demonstrated. Salt supplementation significantly reduced the MAP lowering effects of telmisartan (P<0.05). The present study demonstrates that salt supplementation blunts the telmisartan induced increase in PRA in patients with type2 diabetes.

Dietary ratio of animal:plant protein is associated with 24-h urinary iodine excretion in healthy school children.

Adequate dietary iodine intake in children is essential for optimal physical and neurological development. Whether lower dietary animal food and salt intake may adversely affect iodine status is under discussion. We examined the association between dietary animal:plant protein ratio with 24-h urinary iodine excretion (24-h UI, μg/d), and whether this is modified by salt intake. A 24-h UI was measured in 1959 24-h urine samples from 516 6- to 12-year-old participants of the Dortmund Nutritional and Anthropometric Longitudinally Designed Study. Parallel 3 d weighed food records were used to estimate dietary intakes. Protein sources were classified as dairy, animal and plant. A repeated-measures regression model (PROC MIXED) was used to analyse the effect of animal:plant protein ratios on 24-h UI. plant protein ratios ranged from 0.5 (95 % CI 0.4, 0.6) to 1.6 (95 % CI 1.4, 1.9) (lowest and highest quartile). After adjustment for total energy intake, main dietary iodine sources (dairy and salt intake), and further covariates, the inter-individual variation in animal:plant protein ratio was significantly associated with variation in 24-h UI. One unit higher animal:plant protein ratio predicted 6 μg/d higher 24-h UI (P= 0.002) in boys and 5 μg/d (P= 0.03) in girls. This relationship was partially mediated by a higher salt intake at higher animal:plant protein ratios. These results suggest that lower consumption of animal protein is associated with a small decline in iodine excretion, partially mediated by decreased salt intake. Because limited salt and increased intake of plant-based foods are part of a preferable healthy food pattern, effective nutrition political strategies will be required in the future to ensure appropriate iodine nutrition in adherent populations.