Low-sodium dietary approaches to stop hypertension-type diet including lean red meat lowers blood pressure in postmenopausal women

Low-sodium Dietary Approaches to Stop Hypertension (DASH) diets are base producing but restrict red meat without clear justification. We hypothesized that a vitality diet (VD), a low-sodium DASH-type diet with a low dietary acid load containing 6 servings of 100 g cooked lean red meat per week, would be more effective in reducing blood pressure (BP) compared with a higher acid load reference healthy diet (RHD) based on general dietary guidelines to reduce fat intake and increase intake of breads and cereals. A randomized, parallel dietary intervention study was conducted to compare the BP-lowering effect of these 2 diets in postmenopausal women with high/normal BP. Women were randomly assigned to follow either VD or RHD for 14 weeks. Home BP was measured daily with an automated BP monitor under standard conditions. Of 111 women commencing the study, 95 completed (46 VD, 49 RHD). Systolic BP (SBP) throughout the intervention was lower in the VD group compared to the RHD group (repeated-measures analysis of variance time by diet, P = .04), such that at the end of the study, the VD had a fall of SBP by 5.6 ± 1.3 mm Hg (mean ± SEM) compared with a fall of 2.7 ± 1.0 mm Hg in the RHD (group difference, P = .08). When only those taking antihypertensive medications were assessed, the VD (n = 17) had a significant fall of 6.5 ± 2.5 mm Hg SBP (P = .02) and 4.6 ± 1.4 mm Hg diastolic BP (P = .005) after 14 weeks, and their BP was lower than that of the RHD group (n = 18) throughout the study (P < .05). We concluded that a low-sodium DASH diet with a low dietary acid load, which also included lean red meat on most days of the week, was effective in reducing BP in older women, particularly in those taking antihypertensive medications.

The effect of nitric oxide donor sodium nitroprusside on glucose uptake in human primary skeletal muscle cells

Nitric oxide (NO) has been implicated as an important signaling molecule in the insulin-independent, contraction-mediated glucose uptake pathway and may represent a novel strategy for blood glucose control in patients with type 2 diabetes (T2DM). The current study sought to determine whether the NO donor, sodium nitroprusside (SNP) increases glucose uptake in primary human skeletal muscle cells (HSkMC) derived from both healthy individuals and patients with T2DM. Vastus lateralis muscle cell cultures were derived from seven males with T2DM (aged 54 ± 2 years, BMI 31.7 ± 1.2 kg/m², fasting plasma glucose 9.52 ± 0.80 mmol/L) and eight healthy individuals (aged 46 ± 2 years, BMI 27.1 ± 1.5 kg/m², fasting plasma glucose 4.69 ± 0.12 mmol/L). Cultures were treated with both therapeutic (0.2 and 2 μM) and supratherapeutic (3, 10 and 30 mM) concentrations of SNP. An additional NO donor S-nitroso-N-acetyl-D,L-penicillamine (SNAP) was also examined at a concentration of 50 μM. Glucose uptake was significantly increased following both 30 and 60 min incubations with the supratherapeutic SNP treatments (P = 0.03) but not the therapeutic SNP doses (P = 0.60) or SNAP (P = 0.54). There was no difference in the response between the healthy and T2DM cell lines with any treatment or dose. The current study demonstrates that glucose uptake is elevated by supratherapeutic, but not therapeutic doses of SNP in human primary skeletal muscle cells derived from both healthy volunteers and patients with T2D. These data confirm that nitric oxide donors have potential therapeutic utility to increase glucose uptake in humans, but that SNP only achieves this in supratherapeutic doses. Further study to delineate mechanisms and the therapeutic window is warranted.

Relationship of heart failure patients' knowledge, perceived barriers, and attitudes regarding low-sodium diet recommendations to adherence.

The purposes of this study were to describe heart failure patient perceptions regarding instructions received for following a low-sodium diet and the benefits, barriers, and ease and frequency of following the diet. A total of 246 patients with heart failure referred from academic medical centers in the United States and Australia participated in the study. A subset of 145 patients provided 24-hour urine samples for sodium excretion assessment. While most (80%) patients reported receiving recommendations to follow a low-sodium diet, their recall of specific instructions was poor. Although the majority (75%) reported following a low-sodium diet most or all of the time, 24-hour urine sodium excretion indicated that only 25% of patients were adherent. Patients who reported being more adherent, however, had lower urine sodium excretion levels. Attitudes regarding difficulty in and perceived benefits of following the diet were not related to sodium excretion. Data on attitudes and barriers provided guidance for strategies to improve adherence.

Elevated dietary sodium intake exacerbates myocardial hypertrophy associated with cardiac-specific overproduction of angiotensin II

Introduction/hypothesis
Cardiac hypertrophy is an independent risk factor predictive of cardiovascular disease and is significantly associated with morbidity and mortality. The mechanism by which angiotensin II (Ang II) and dietary sodium exert additive effects on the development of cardiac hypertrophy is unclear. The goal of this study was to evaluate the hypothesis that, where there is a genetic predisposition to Ang II-dependent hypertrophy, there is also an increased susceptibility to sodium-induced hypertrophy mediated by AT₁-receptor expression.

Methods
Diets of low sodium (LS, 0.3% w:w) and high sodium (HS, 4.0% w:w) content were fed to adult (age 25 weeks) control wild-type mice (WT) and to weeks) control wild-type mice (WT) and to transgenic mice exhibiting cardiac specific overexpression of angiotensinogen (TG). At the conclusion of a 40-day dietary treatment period, cardiac tissue weights were compared and the relative expression levels of Ang II receptor subtypes (AT_1A and AT₂) were evaluated using RT-PCR.

Results
WT and TG mice fed HS and LS diets maintained comparable weight gains during the treatment period. The normalised heart weights of TG mice were elevated compared to WT, and the extent of the increase was greater for mice maintained on the HS diet treatments (WT 12% vs. TG 41% increase in cardiac weight index). While a similar pattern of growth was observed for ventricular tissues, the atrial weight parameters demonstrated an additional significant effect of dietary sodium intake on tissue weight, independent of animal genetic type. No differences in the relative (GAPDH normalised) expression levels of AT_1A- and AT₂-receptor mRNA were observed between diet or animal genetic groups.

Conclusion
This study demonstrates that, where there is a pre-existing genetic condition of Ang II-dependent cardiac hypertrophy, the pro-growth effect of elevated dietary sodium intake is selectively augmented. In TG and WT mice, this effect was evident with a relatively short dietary treatment intervention (40 days). Evaluation of the levels of Ang II receptor mRNA further demonstrated that this differential growth response was not associated with an altered relative expression of either AT_1A- or AT₂-receptor subtypes. The cellular mechanistic bases for this specific Ang II-dietary sodium interaction remain to be elucidated.

Determination of sodium oxalate in Bayer process liquors using flow analysis with tris(2,2'-bipyridyl)ruthenium(II) chemiluminescence detection

The research was a detailed investigation into a challenging analytical chemistry problem for the alumina industry. The successful outcomes were derived through innovative reagent chemistry and novel instrumental development. The resultant methodology and instrumentation deployed on this most demanding sample matrix is more robust, reliable and less expensive than anything currently used in this industry worldwide.

Sustained low-efficiency dialysis with filtration (SLEDD-f) in the management of acute sodium valproate intoxication

Hemodialysis is only infrequently used in drug overdosage situations. The efficacy of hemodialysis to remove the drug depends upon the pharmacokinetics and pharmacodynamics of the drug. At normal therapeutic concentrations, valproic acid is predominantly protein bound and therefore removal by hemodialysis is limited. In an overdose situation, protein binding is rapidly saturated and therefore the substantially larger quantities of the free drug can rapidly cause toxicity. Slow low-efficient daily diafiltration (SLEDD) has not previously been utilized in a drug overdose situation. We report the effective use of SLEDD to remove high toxic concentrations of valproic acid in an overdose situation. Slow low-efficient daily diafiltration also prevented the rebound phenomenon that can occur as the excess drug is released from its protein-bound stores. Hybrid dialysis therapies deserve further evaluation in the management of other poisonings where extra-corporeal therapy is indicated.

Strategies to reduce sodium consumption : a food industry perspective

The global high prevalence of hypertension and cardiovascular disease has raised concerns regarding the sodium content of the foods which we consume. Over 75% of sodium intake in industrialized diets is likely to come from processed and restaurant foods. Therefore international authorities, such as the World Health Organisation, are encouraging the food industry to reduce sodium levels in their products. Significant sodium reduction is not without complications as salt plays an important role in taste, and in some products is needed also for preservation and processing. The most promising sodium reduction strategy is to adapt the preference of consumers for saltiness by reducing sodium in products in small steps. However, this is a time-consuming approach that needs to be applied industry-wide in order to be effective. Therefore the food industry is also investigating solutions that will maintain the same perceived salt intensity at lower sodium levels. Each of these has specific advantages, disadvantages, and time lines for implementation. Currently applied approaches are resulting in sodium reduction between 20-30%. Further reduction will require new technologies. Research into the physiology of taste perception and salt receptors is an emerging area of science that is needed in order to achieve larger sodium reductions.

Sodium appetite in adult rats following ω-3 polyunsaturated fatty acid deficiency in early development

We examined the effect of ω-3 polyunsaturated fatty acid (PUFA) deficiency during development on sodium appetite. Being raised on an ω-3 PUFA deficient diet increased the intake of 0.5 M NaCl following furosemide-induced sodium depletion by 40%. This occurred regardless of the diet they were maintained on later in life, and the increased consumption persisted for 3 days. In a second study, animals were administered furosemide and low-dose captopril. Sodium consumption of deficient raised animals was again higher than that of the control raised. Fos immunoreactivity in brain areas associated with sodium appetite and excretion were not influenced by diet. Our findings indicate that inadequate dietary ω-3 PUFA during development results in an exaggerated sodium appetite later in life.

Ionic conductivity in poly(diethylene glycol-carbonate)/sodium triflate complexes

New polymer electrolytes were synthesized and characterized based on a new polymer host. The motivation was to produce a host polymer with a high dielectric constant which should reduce ion clustering with an attendant increased conductivity. The new polymer host, poly(diethylene glycol carbonate) and its sodium triflate complexes were characterized by thermal analysis and AC impedance measurements. The polycarbonate backbone appears less flexible than the polyether hosts as evidenced by the higher glass transition temperatures. The conductivity for the sodium triflate complexes was measured as ~ 10⁻⁵ S cm⁻¹ at 55 °C and the dielectric constant of the host polymer was found to be 3.6 at 3 GHz. The low conductivity is attributed to rigidity of the polycarbonate.

Ion clustering in molecular dynamics simulations of sodium iodide solutions

Model systems of sodium iodide dissolved in dimethyl ether or 1,2-dimethoxyethane (glyme) were studied in order to investigate the structural and dynamic properties of ionic solutions in small and polymeric ethers. Full molecular dynamics simulations were performed at a range of different salt concentrations. An algorithm was designed which assigns ions to clusters and then calculates all the terms which contribute to ionic conductivity. In dilute solutions, free ions are the most common ionic species, followed by ion pairs. As the concentration increases, pairs become the most common species, with significant concentrations of clusters with 3 through 6 ions. Changing the solvent from dimethyl ether to glyme significantly decreases the ion clustering due to the chelate effect in which the two oxygens on a solvent stabilize an associated cation. The conductivity in stable systems is shown to be primarily the result of the movement of free ions and the relative movement of ions within neutral pairs. The Nernst-Einstein relation, commonly used in the discussion of polymer electrolytes, is shown to be inadequate to quantitatively describe conductivity in the model systems.

Sources of Sodium in Australian children's diets and the effect of the application of sodium targets to food products to reduce sodium intake

The average reported dietary Na intake of children in Australia is high: 2694 mg/d (9–13 years). No data exist describing food sources of Na in Australian children's diets and potential impact of Na reduction targets for processed foods. The aim of the present study was to determine sources of dietary Na in a nationally representative sample of Australian children aged 2–16 years and to assess the impact of application of the UK Food Standards Agency (FSA) Na reduction targets on Na intake. Na intake and use of discretionary salt (note: conversion of salt to Na, 1 g of NaCl (salt) = 390 mg Na) were assessed from 24-h dietary recall in 4487 children participating in the Australian 2007 Children's Nutrition and Physical Activity Survey. Greatest contributors to Na intake across all ages were cereals and cereal-based products/dishes (43 %), including bread (13 %) and breakfast cereals (4 %). Other moderate sources were meat, poultry products (16 %), including processed meats (8 %) and sausages (3 %); milk products/dishes (11 %) and savoury sauces and condiments (7 %). Between 37 and 42 % reported that the person who prepares their meal adds salt when cooking and between 11 and 39 % added salt at the table. Those over the age of 9 years were more likely to report adding salt at the table (χ2 199·5, df 6, P < 0·001). Attainment of the UK FSA Na reduction targets, within the present food supply, would result in a 20 % reduction in daily Na intake in children aged 2–16 years. Incremental reductions of this magnitude over a period of years could significantly reduce the Na intake of this group and further reductions could be achieved by reducing discretionary salt use.

The influence of sodium on liking and consumption of salty food

Excessive sodium (Na) intake has been linked to development of hypertension and related pathologies. In this study, we assessed if the sodium chloride (NaCl) concentration in a prototypical food influences the liking and intake of that food. In study 1, detection and recognition thresholds for NaCl were assessed, and perceived salt intensity and liking for hash browns of varying sodium concentrations (40 mg, 120 mg, 170 mg, and 220 mg Na/100 g) were compared in a lab setting. In study 2, detection and recognition thresholds for NaCl were assessed in a lab setting, and lunches consisting of hash browns, basic salad, and beverages were consumed freely in a dining setting on 4 separate occasions. Intake and liking ratings for hash browns were recorded after the lunch. In both studies, detection and recognition thresholds for NaCl were not associated with perceived saltiness, liking, or intake of hash browns. Liking and perceived salt taste intensity of hash browns were correlated (r = 0.547 P < 0.01), and in study 1 the 220 mg sodium hash brown was most liked (P < 0.05). In study 2, there was no association between Na concentration and liking or consumption of hash browns. In summary, liking of hash browns were influenced by whether testing was in a lab or dining room environment. In a dining room environment, large decreases (>50%) of sodium content of food were achievable with only minor decrease in liking and no effect on consumption of the food.

Polycarbonate (PC) membrane fouling by protein and sodium alginate

This data was obtained from an experiment, where polycarbonate (PC) membranes were used to filter two types of organic foulants, including protein and sodium alginate, from suspension in a dead-end filtration cell. These model foulants were stained with fluorescent dyes before filtration. Consequently, a stack of images were captured from the fouling layers on the PC membrane surface using confocal laser scanning microscope (CLSM). This data collection contains 105 2D images of polycarbonate (PC) membranes fouling layer. This data collection would be useful to investigate membrane fouling mechanism by membrane materials researchers and water researchers.