Salt intakes around the world: implications for public health

Processed foods as an integral part of universal salt iodization programs: a review of global experience and analyses of Bangladesh and Pakistan

BACKGROUND

Despite the reference to salt for food processing in the original definition of universal salt iodization (USI), national USI programs often do not explicitly address food industry salt. This may affect program impact and sustainability, given the increasing consumption of processed foods in developing countries.

OBJECTIVE

To review experience of the use of iodized salt in the food industry globally, and analyze the market context in Bangladesh and Pakistan to test whether this experience may be applicable to inform improved national USI programming in developing countries.

METHODS

A review of relevant international experience was undertaken. In Bangladesh and Pakistan, local rural market surveys were carried out. In Bangladesh, structured face-to-face interviews with bakers and indepth interviews with processed food wholesalers and retailers were conducted. In Pakistan, face-to-face structured interviews were conducted with food retailers and food labels were checked.

RESULTS

Experience from industrialized countries reveals impact resulting from the use of iodized salt in the food industry. In Bangladesh and Pakistan, bread, biscuits, and snacks containing salt are increasingly available in rural areas. In Bangladesh, the majority of bakers surveyed claimed to use iodized salt. In Pakistan, 6 of 362 unique product labels listed iodized salt.

CONCLUSIONS

Successful experience from developed countries needs to be adapted to the developing country context. The increasing availability of processed foods in rural Bangladesh and Pakistan provides an opportunity to increase iodine intake. However, the impact of this intervention remains to be quantified. To develop better national USI programs, further data are required on processed food consumption across population groups, iodine contents of food products, and the contribution of processed foods to iodine nutrition.

Effect of increased potassium intake on cardiovascular risk factors and disease: systematic review and meta-analyses

OBJECTIVE

To conduct a systematic review of the literature and meta-analyses to fill the gaps in knowledge on potassium intake and health.

DATA SOURCES

Cochrane Central Register of Controlled Trials, Medline, Embase, WHO International Clinical Trials Registry Platform, Latin American and Caribbean Health Science Literature Database, and the reference lists of previous reviews.

STUDY SELECTION

Randomised controlled trials and cohort studies reporting the effects of potassium intake on blood pressure, renal function, blood lipids, catecholamine concentrations, all cause mortality, cardiovascular disease, stroke, and coronary heart disease were included.

DATA EXTRACTION AND SYNTHESIS

Potential studies were independently screened in duplicate, and their characteristics and outcomes were extracted. When possible, meta-analysis was done to estimate the effects (mean difference or risk ratio with 95% confidence interval) of higher potassium intake by using the inverse variance method and a random effect model.

RESULTS

22 randomised controlled trials (including 1606 participants) reporting blood pressure, blood lipids, catecholamine concentrations, and renal function and 11 cohort studies (127,038 participants) reporting all cause mortality, cardiovascular disease, stroke, or coronary heart disease in adults were included in the meta-analyses. Increased potassium intake reduced systolic blood pressure by 3.49 (95% confidence interval 1.82 to 5.15) mm Hg and diastolic blood pressure by 1.96 (0.86 to 3.06) mm Hg in adults, an effect seen in people with hypertension but not in those without hypertension. Systolic blood pressure was reduced by 7.16 (1.91 to 12.41) mm Hg when the higher potassium intake was 90-120 mmol/day, without any dose response. Increased potassium intake had no significant adverse effect on renal function, blood lipids, or catecholamine concentrations in adults. An inverse statistically significant association was seen between potassium intake and risk of incident stroke (risk ratio 0.76, 0.66 to 0.89). Associations between potassium intake and incident cardiovascular disease (risk ratio 0.88, 0.70 to 1.11) or coronary heart disease (0.96, 0.78 to 1.19) were not statistically significant. In children, three controlled trials and one cohort study suggested that increased potassium intake reduced systolic blood pressure by a non-significant 0.28 (-0.49 to 1.05) mm Hg.

CONCLUSIONS

High quality evidence shows that increased potassium intake reduces blood pressure in people with hypertension and has no adverse effect on blood lipid concentrations, catecholamine concentrations, or renal function in adults. Higher potassium intake was associated with a 24% lower risk of stroke (moderate quality evidence). These results suggest that increased potassium intake is potentially beneficial to most people without impaired renal handling of potassium for the prevention and control of elevated blood pressure and stroke.

Effect of lower sodium intake on health: systematic review and meta-analyses

OBJECTIVE

To assess the effect of decreased sodium intake on blood pressure, related cardiovascular diseases, and potential adverse effects such as changes in blood lipids, catecholamine levels, and renal function.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

Cochrane Central Register of Controlled Trials, Medline, Embase, WHO International Clinical Trials Registry Platform, the Latin American and Caribbean health science literature database, and the reference lists of previous reviews.

STUDY SELECTION

Randomised controlled trials and prospective cohort studies in non-acutely ill adults and children assessing the relations between sodium intake and blood pressure, renal function, blood lipids, and catecholamine levels, and in non-acutely ill adults all cause mortality, cardiovascular disease, stroke, and coronary heart disease.

STUDY APPRAISAL AND SYNTHESIS

Potential studies were screened independently and in duplicate and study characteristics and outcomes extracted. When possible we conducted a meta-analysis to estimate the effect of lower sodium intake using the inverse variance method and a random effects model. We present results as mean differences or risk ratios, with 95% confidence intervals.

RESULTS

We included 14 cohort studies and five randomised controlled trials reporting all cause mortality, cardiovascular disease, stroke, or coronary heart disease; and 37 randomised controlled trials measuring blood pressure, renal function, blood lipids, and catecholamine levels in adults. Nine controlled trials and one cohort study in children reporting on blood pressure were also included. In adults a reduction in sodium intake significantly reduced resting systolic blood pressure by 3.39 mm Hg (95% confidence interval 2.46 to 4.31) and resting diastolic blood pressure by 1.54 mm Hg (0.98 to 2.11). When sodium intake was <2 g/day versus ≥ 2 g/day, systolic blood pressure was reduced by 3.47 mm Hg (0.76 to 6.18) and diastolic blood pressure by 1.81 mm Hg (0.54 to 3.08). Decreased sodium intake had no significant adverse effect on blood lipids, catecholamine levels, or renal function in adults (P>0.05). There were insufficient randomised controlled trials to assess the effects of reduced sodium intake on mortality and morbidity. The associations in cohort studies between sodium intake and all cause mortality, incident fatal and non-fatal cardiovascular disease, and coronary heart disease were non-significant (P>0.05). Increased sodium intake was associated with an increased risk of stroke (risk ratio 1.24, 95% confidence interval 1.08 to 1.43), stroke mortality (1.63, 1.27 to 2.10), and coronary heart disease mortality (1.32, 1.13 to 1.53). In children, a reduction in sodium intake significantly reduced systolic blood pressure by 0.84 mm Hg (0.25 to 1.43) and diastolic blood pressure by 0.87 mm Hg (0.14 to 1.60).

CONCLUSIONS

High quality evidence in non-acutely ill adults shows that reduced sodium intake reduces blood pressure and has no adverse effect on blood lipids, catecholamine levels, or renal function, and moderate quality evidence in children shows that a reduction in sodium intake reduces blood pressure. Lower sodium intake is also associated with a reduced risk of stroke and fatal coronary heart disease in adults. The totality of evidence suggests that most people will likely benefit from reducing sodium intake.

Sodium chloride drives autoimmune disease by the induction of pathogenic TH17 cells

There has been a marked increase in the incidence of autoimmune diseases in the past half-century. Although the underlying genetic basis of this class of diseases has recently been elucidated, implicating predominantly immune-response genes, changes in environmental factors must ultimately be driving this increase. The newly identified population of interleukin (IL)-17-producing CD4(+) helper T cells (TH17 cells) has a pivotal role in autoimmune diseases. Pathogenic IL-23-dependent TH17 cells have been shown to be critical for the development of experimental autoimmune encephalomyelitis (EAE), an animal model for multiple sclerosis, and genetic risk factors associated with multiple sclerosis are related to the IL-23-TH17 pathway. However, little is known about the environmental factors that directly influence TH17 cells. Here we show that increased salt (sodium chloride, NaCl) concentrations found locally under physiological conditions in vivo markedly boost the induction of murine and human TH17 cells. High-salt conditions activate the p38/MAPK pathway involving nuclear factor of activated T cells 5 (NFAT5; also called TONEBP) and serum/glucocorticoid-regulated kinase 1 (SGK1) during cytokine-induced TH17 polarization. Gene silencing or chemical inhibition of p38/MAPK, NFAT5 or SGK1 abrogates the high-salt-induced TH17 cell development. The TH17 cells generated under high-salt conditions display a highly pathogenic and stable phenotype characterized by the upregulation of the pro-inflammatory cytokines GM-CSF, TNF-α and IL-2. Moreover, mice fed with a high-salt diet develop a more severe form of EAE, in line with augmented central nervous system infiltrating and peripherally induced antigen-specific TH17 cells. Thus, increased dietary salt intake might represent an environmental risk factor for the development of autoimmune diseases through the induction of pathogenic TH17 cells.

Assessment of salt intake: how accurate is it?

The aims of this review paper are to provide an overview of the association of sodium intake with cardiovascular health, to identify sodium in our global food supply and to describe problems associated with assessment of dietary sodium intake. Excess sodium intake may contribute to the development of hypertension in some individuals, consequently increasing CVD risk. The average intake of sodium in populations around the world far exceeds the actual body's needs. Processed and restaurant foods contribute the most dietary sodium for Americans and other populations worldwide. There is a worldwide focus on reducing sodium content of food products in an effort to reduce health related issues associated with excessive salt and sodium intake in individuals. In several countries, regulations have been introduced to lower the sodium content of foods. Manufacturers are complying with these regulations by formulating new products to meet these standards. However, the variability in food sodium content poses challenges to researchers to accurately assess dietary sodium intakes of individuals. There are differences in sodium content of foods in databases compared with nutritional information provided by manufacturers for the same food products. Variations also exist in restaurant foods, where values differ from those available on restaurant websites. Sodium may be either underestimated or overestimated; it is not always on target. Awareness of the variability among food products is crucial but capturing sodium content of every food in the market is not feasible. Whenever possible, updating databases is critical. In conclusion, it is not feasible to capture the sodium content of every food in the marketplace but being aware of these differences is essential to assessing actual sodium consumption. Since biological determinations are burdensome and impractical, it is imperative for researchers and other health professionals to participate in the development and implementation of tools to accurately assess sodium intake in individuals.

The impact of adding front-of-package sodium content labels to grocery products: an experimental study

OBJECTIVE

Canadians consume approximately twice the daily Adequate Intake of sodium. The present study examined the efficacy of four types of front-of-package (FOP) sodium labels at influencing consumers' selection of products low v. high in sodium.

DESIGN

Participants were randomly assigned to one of five experimental conditions: (i) control condition with no FOP label; (ii) basic numeric FOP label; (iii) numeric FOP label with 'high' and 'low' sodium content descriptors; (iv) detailed Traffic Light (TL) label with colour coding, content descriptors and numeric information; and (v) simple TL label with no numeric information. Participants were shown pairs of grocery products that varied in sodium content and told they could choose a free sample. Selection of the low-sodium v. the high-sodium product was the primary behavioural outcome, in addition to ratings of effectiveness, understanding, liking and believability.

SETTING

Waterloo, Ontario, Canada.

SUBJECTS

Adults (n 430) aged ≥18 years, recruited from community settings.

RESULTS

Participants in the three FOP conditions with 'high/low' sodium content descriptors were significantly more likely to choose the lower-sodium product compared with the control group. The detailed TL label was ranked most effective at helping participants select low-sodium products, and was rated significantly higher than other formats in liking, understanding and believability. Product selection did not differ significantly across sociodemographic groups.

CONCLUSIONS

FOP labels that include content descriptors may be more effective in helping consumers to select lower-sodium products. TL labels, which incorporate content descriptors and colour coding, should be considered for future FOP labelling initiatives.

Development and validation of the dietary sodium reduction self-care agency scale

A scale did not exist for measuring the capability or self-care agency of lowering salt consumption in older adults with hypertension. Therefore, our objectives were to develop and validate the Dietary Sodium Reduction Self-Care Agency Scale (DSR-SCA Scale). A 24-item scale was developed and tested in 242 older adults with hypertension. Exploratory factor analysis using principal components extraction, Rasch analysis, and internal consistency reliability were used to evaluate the DSR-SCA Scale. Principal components extraction with Promax rotation was used. An 11-item DSR-SCA Scale with three factor loadings, which measure proficiency, persuasiveness, and resourcefulness, was finalized after it was found to meet the criteria of a minimal factor loading of 0.40, with eigenvalues of 2.20, 1.73, and 1.64, respectively. The Kaiser-Meyer-Olkin was 0.80, and Bartlett's test was significant, χ(2) (df = 55) 403.71, p < 0.0001. The measures accounted for 51% of the total variance. Item infit and outfit mean square ranged from 0.88 to 1.18 and the infit and outfit standardized mean square was -1.8 to 1.7. The 11-item scale demonstrated internal consistency with a Cronbach's alpha coefficient of 0.73 for the total scale. The results showed that the DSR-SCA Scale consisted of three factors that have adequate construct validity and reliability to measure power components and enabling capability related to Orem's self-care theory. This scale is brief, easy-to-complete, and useful for measuring salt reduction self-care agency in older adults with hypertension

Scaling up chronic disease prevention interventions in lower- and middle-income countries

Chronic diseases are increasingly becoming a health burden in lower- and middle-income countries, putting pressure on public health efforts to scale up interventions. This article reviews current efforts in interventions on a population and individual level. Population-level interventions include ongoing efforts to reduce smoking rates, reduce intake of salt and trans-fatty acids, and increase physical activity in increasingly sedentary populations. Individual-level interventions include control and treatment of risk factors for chronic diseases and secondary prevention. This review also discusses the barriers in interventions, particularly those specific to low- and middle-income countries. Continued discussion of proven cost-effective interventions for chronic diseases in the developing world will be useful for improving public health policy.

A salty-congruent odor enhances saltiness: functional magnetic resonance imaging study

Excessive intake of dietary salt (sodium chloride) may increase the risk of chronic diseases. Accordingly, various strategies to reduce salt intake have been conducted. This study aimed to investigate whether a salty-congruent odor can enhance saltiness on the basis of psychophysical (Experiment 1) and neuroanatomical levels (Experiment 2). In Experiment 1, after receiving one of six stimulus conditions: three odor conditions (odorless air, congruent, or incongruent odor) by two concentrations (low or high) of either salty or sweet taste solution, participants were asked to rate taste intensity and pleasantness. In Experiment 2, participants received the same stimuli during the functional magnetic resonance imaging scan. In Experiment 1, compared with an incongruent odor and/or odorless air, a congruent odor enhanced not only taste intensity but also either pleasantness of sweetness or unpleasantness of saltiness. In Experiment 2, a salty-congruent combination of odor and taste produced significantly higher neuronal activations in brain regions associated with odor-taste integration (e.g., insula, frontal operculum, anterior cingulate cortex, and orbitofrontal cortex) than an incongruent combination and/or odorless air with taste solution. In addition, the congruent odor-induced saltiness enhancement was more pronounced in the low-concentrated tastant than in the high-concentrated one. In conclusion, this study demonstrates the congruent odor-induced saltiness enhancement on the basis of psychophysical and neuroanatomical results. These findings support an alternative strategy to reduce excessive salt intake by adding salty-congruent aroma to sodium reduced food. However, there are open questions regarding the salty-congruent odor-induced taste unpleasantness.

Is socioeconomic status associated with dietary sodium intake in Australian children? A cross-sectional study

OBJECTIVE

To assess the association between socioeconomic status (SES) and dietary sodium intake, and to identify if the major dietary sources of sodium differ by socioeconomic group in a nationally representative sample of Australian children.

DESIGN

Cross-sectional survey.

SETTING

2007 Australian National Children's Nutrition and Physical Activity Survey.

PARTICIPANTS

A total of 4487 children aged 2-16 years completed all components of the survey.

PRIMARY AND SECONDARY OUTCOME MEASURES

Sodium intake was determined via one 24 h dietary recall. The population proportion formula was used to identify the major sources of dietary salt. SES was defined by the level of education attained by the primary carer. In addition, parental income was used as a secondary indicator of SES.

RESULTS

Dietary sodium intake of children of low SES background was 2576 (SEM 42) mg/day (salt equivalent 6.6 (0.1) g/day), which was greater than that of children of high SES background 2370 (35) mg/day (salt 6.1 (0.1) g/day; p<0.001). After adjustment for age, gender, energy intake and body mass index, low SES children consumed 195 mg/day (salt 0.5 g/day) more sodium than high SES children (p<0.001). Low SES children had a greater intake of sodium from processed meat, gravies/sauces, pastries, breakfast cereals, potatoes and potato snacks (all p<0.05).

CONCLUSIONS

Australian children from a low SES background have on average a 9% greater intake of sodium from food sources compared with those from a high SES background. Understanding the socioeconomic patterning of salt intake during childhood should be considered in interventions to reduce cardiovascular disease.

A school-based education programme to reduce salt intake in children and their families (School-EduSalt): protocol of a cluster randomised controlled trial

INTRODUCTION

The current salt intake is very high for children as well as adults in China. A reduction in salt intake is one of the most cost-effective measures to curb the rapidly growing disease burden attributed to blood pressure and cardiovascular disease in the Chinese population. A lower salt diet starting from childhood has the potential to prevent the development of such conditions. The School-EduSalt (School-based Education Programme to Reduce Salt) study aims to determine whether an education programme targeted at school children can lower salt intake in children and their families.

METHODS AND ANALYSIS

The study is designed as a cluster randomised controlled trial. The location is Changzhi, Shanxi province in northern China. The study population will consist of 28 primary schools with 280 children aged ≈11 years and 560 adult family members. Children in the intervention group will be educated on how to reduce salt intake. They will then be empowered to deliver the salt reduction message home to their families. In particular, children need to persuade the person who does the cooking to reduce the amount of salt used during food preparations. The duration of the intervention is one school term (≈4.5 months). The primary outcome is the difference between the intervention and the control group in the change in 24 h urinary sodium and the secondary outcome is the difference between the intervention and control group in the change of blood pressure. An economic evaluation will be undertaken to assess cost-effectiveness.

ETHICS AND DISSEMINATION

The study has been approved by The Queen Mary Research Ethics Committee (QMREC2012/81) and Peking University Health Science Centre IRB (IRB00001052-12072). Study findings will be disseminated widely through conference presentations and peer-reviewed publications.

PROTOCOL REGISTRATION

Protocol Registered on ClinicalTrials.gov NCT01821144.

A lowered salt intake does not compromise iodine status in Cape Town, South Africa, where salt iodization is mandatory

OBJECTIVE

Universal salt iodization is an effective strategy to optimize population-level iodine. At the same time as salt-lowering initiatives are encouraged globally, there is concern about compromised iodine intakes. This study investigated whether salt intakes at recommended levels resulted in a suboptimal iodine status in a country where salt is the vehicle for iodine fortification.

METHODS

Three 24-h urine samples were collected for the assessment of urinary sodium and one sample was taken for urinary iodine concentrations (UICs) in a convenience sample of 262 adult men and women in Cape Town, South Africa. Median UIC was compared across categories of sodium excretion equivalent to salt intakes lower than 5, 5 to 9, and greater than or equal to 9 g/d.

RESULTS

The median UIC was 120 μg/L (interquartile range 75.3-196.3), indicating iodine sufficiency. Less one-fourth (23.2%) of subjects had urinary sodium excretion values within the desirable range (salt <5 g/d), 50.7% had high values (5-9 g/d), and 22.8% had very high values (≥9 g/d). No association between urinary iodine and mean 3 × 24-h urinary sodium concentration was found (r = 0.087, P = 0.198) and UIC status did not differ according to urinary sodium categories (P = 0.804).

CONCLUSION

In a country with mandatory universal salt iodization, consumers with salt intakes within the recommended range (<5 g/d) are iodine replete, and median UIC does not differ across categories of salt intake. This indicates that much of the dietary salt is provided from non-iodinated sources, presumably added to processed foods.

Assessment of iodine nutrition in populations: past, present, and future

Iodine status has been historically assessed by palpation of the thyroid and reported as goiter rates. Goiter is a functional biomarker that can be applied to both individuals and populations, but it is subjective. Iodine status is now assessed using an objective biomarker of exposure, i.e., urinary iodine concentrations (UICs) in spot samples and comparison of the median UIC to UIC cut-offs to categorize population status. This has improved standardization, but inappropriate use of the crude proportion of UICs below the cut-off level of 100 µg/L to estimate the number of iodine-deficient children has led to an overestimation of the prevalence of iodine deficiency. In this review, a new approach is proposed in which UIC data are extrapolated to iodine intakes, adjusted for intraindividual variation, and then interpreted using the estimated average requirement cut-point model. This may allow national programs to define the prevalence of iodine deficiency in the population and to quantify the necessary increase in iodine intakes to ensure sufficiency. In addition, thyroglobulin can be measured on dried blood spots to provide an additional sensitive functional biomarker of iodine status.

Alkaline salts to counteract bone resorption and protein wasting induced by high salt intake: results of a randomized controlled trial

High sodium chloride (NaCl) intake can induce low-grade metabolic acidosis (LGMA) and may thus influence bone and protein metabolism. We hypothesized that oral potassium bicarbonate (KHCO(3)) supplementation may compensate for NaCl-induced, LGMA-associated bone resorption and protein losses. Eight healthy male subjects participated in a randomized trial with a crossover design. Each of two study campaigns consisted of 5 d of dietary and environmental adaptation followed by 10 d of intervention and 1.5 d of recovery. In one study campaign, 90 mmol KHCO(3)/d were supplemented to counteract NaCl-induced LGMA, whereas the other campaign served as a control with only high NaCl intake. When KHCO(3) was ingested during high NaCl intake, postprandial buffer capacity ([HCO(3)(-)]) increased (P = 0.002). Concomitantly, urinary excretion of free potentially bioactive glucocorticoids [urinary free cortisol (UFF) and urinary free cortisone (UFE)] was reduced by 14% [∑(UFF,UFE); P = 0.024]. Urinary excretion of calcium and bone resorption marker N-terminal telopeptide of type I collagen was reduced by 12 and 8%, respectively (calcium, P = 0.047; N-terminal bone collagen telopeptide, P = 0.044). There was a trend of declining net protein catabolism when high NaCl was combined with KHCO(3) (P = 0.052). We conclude that during high salt intake, the KHCO(3)-induced postprandial shift to a more alkaline state reduces metabolic stress. This leads to decreased bone resorption and protein degradation, which in turn might initiate an anticatabolic state for the musculoskeletal system in the long run.

Greenhouse evaluation and environmental impact assessment of different urine-derived struvite fertilizers as phosphorus sources for plants

A selection of six urine-derived struvite fertilizers generated by innovative precipitation technologies was assessed for their quality and their effectiveness as phosphorus sources for crops. Struvite purity was influenced by drying techniques and magnesium dosage. In a greenhouse experiment, the urine fertilizers led to biomass yields and phosphorus uptakes comparable to or higher than those induced by a commercial mineral fertilizer. Heavy metal concentrations of the different struvite fertilizers were below the threshold limits specified by the German Fertilizer and Sewage Sludge Regulations. The computed loading rates of heavy metals to agricultural land were also below the threshold limits decreed by the Federal Soil Protection Act. Urine-derived struvite contributed less to heavy metal inputs to farmland than other recycling products or commercial mineral and organic fertilizers. When combined with other soil conditioners, urine-derived struvite is an efficient fertilizer which covers the magnesium and more than half of the phosphorus demand of crops.

Urinary and dietary sodium and potassium associated with blood pressure control in treated hypertensive kidney transplant recipients: an observational study

Background

In kidney transplant (Kt) recipients , hypertension is a major risk for cardiovascular complications but also for graft failure. Blood pressure (BP) control is therefore mandatory. Office BP (OBP) remains frequently used for clinical decisions, however home BP (HBP) have brought a significant improvement in the BP control. Sodium is a modifiable risk factor, many studies accounted for a decrease of BP with a sodium restricted diet. Increased potassium intake has been also recommended in hypertension management. Using an agreement between office and home BP, the present study investigated the relations between the BP control in Kt recipients and their urinary excretion and dietary consumption of sodium and potassium.

Methods

The BP control defined by OBP <140/90 mmHg and HBP <135/85 mmHg was tested in 70 Kt recipients (mean age 56 ± 11.5 years; mean graft survival 7 ± 6.6 years) treated with antihypertensive medications. OBP and HBP were measured with a validated oscillometric device (Omron M6®). The 24-hour urinary sodium (Na+) and potassium (K+) excretions as well as dietary intakes were compared between controlled and uncontrolled (in office and at home) recipients. Non parametric Wilcoxon Mann–Whitney Test was used for between groups comparisons and Fisher's exact test for frequencies comparisons. Pearson correlation coefficients and paired t-test were used when sample size was >30.

Results

Using an agreement between OBP and HBP, we identified controlled (21%) and uncontrolled recipients (49%). Major confounding effects susceptible to interfere with the BP regulation did not differ between groups, the amounts of sodium excretion were similar (154 ± 93 vs 162 ± 88 mmol/24 h) but uncontrolled patients excreted less potassium (68 ± 14 vs 54 ± 20 mmol/24 h; P = 0.029) and had significantly lower potassium intakes (3279 ± 753 vs 2208 ± 720 mg/24 h; P = 0.009), associated with a higher urinary Na+/K + ratio. Systolic HBP was inversely and significantly correlated to urinary potassium (r = −0.48; P = 0.002), a positive but non significant relation was observed with urinary sodium (r = 0,30;P = 0.074).

Conclusions

Half of the treated hypertensive Kt recipients remained uncontrolled in office and at home. Restoring a well-balanced sodium/potassium ratio intakes could be a non pharmacological opportunity to improve blood pressure control.

Qualidade da dieta de adolescentes: estudo de base populacional em Campinas, SP

O objetivo deste estudo foi avaliar a qualidade global da dieta e a adequação do consumo de cada componente da dieta de adolescentes segundo fatores demográficos, socioeconômicos e índice de massa corporal (IMC). Trata-se de estudo transversal, de base populacional, que analisou amostra representativa de 409 adolescentes, de 12 a 19 anos, utilizando o Índice de Qualidade da Dieta (IQD). Foram estimadas as prevalências de dietas classificadas no 1º quartil do IQD e as médias de escores de cada componente do IQD. Regressões múltiplas linear e de Poisson foram utilizadas nas análises. O escore médio do IQD foi de 59,7. Observou-se menor prevalência de dietas inadequadas no segmento de melhor escolaridade do chefe da família. Os estratos de menor nível socioeconômico, avaliados por renda e escolaridade, mostram um consumo inferior de verduras e legumes, frutas, leite e derivados e menor variedade da dieta e uma ingestão superior de cereais e derivados e leguminosas. Adolescentes com sobrepeso/obesidade consomem mais carnes e ovos e menos frutas comparados aos que apresentam baixo peso/eutrofia. As meninas tiveram maior ingestão de gordura total e menor ingestão de sódio. Os resultados identificam os componentes que merecem atenção nas estratégias de promoção de alimentação saudável e os segmentos mais vulneráveis à má alimentação.

Foods contributing to sodium intake and urinary sodium excretion in a group of Australian women

OBJECTIVES

To identify food sources of Na in a group of community-dwelling women in Adelaide, South Australia. A secondary aim was to measure Na excretion in this group.

DESIGN

Survey.

SETTING

Community setting, Adelaide, South Australia.

SUBJECTS

Seventy healthy women (mean age 48.6 (SD 8.1) years, mean BMI 28.6 (SD 6.3) kg/m2) living in metropolitan Adelaide, South Australia and participating in a validation study of an FFQ. Dietary intake was derived from two 4 d weighed food records. Foods from the 4 d weighed food records were grouped according to foods or food groups to establish contributors to Na intake. Na excretion was measured in two 24 h urine samples. Completeness of urine collections was verified using creatinine excretion.

RESULTS

Bread alone contributed 19.0% of Na intake, with an overall contribution from the breads and cereals group of 32.5%. Meat products contributed 14.4% of intake, the dairy and eggs group (excluding cheese) 9.6% and combination dishes (e.g. pizza, quiche, sandwiches and stir fry dishes) 8.4%. Na excretion was 126 (SD 42) mmol/d, i.e. approximately 7.6 (SD 2.5) g salt/d. Seventy per cent of participants (n 48) had Na excretion ≥100 mmol/d (146 (SD 34) mmol/d).

CONCLUSIONS

Effective Na reduction could be achieved by reducing the amount in staple foods such as bread and meat products.

Dietary salt intake assessed by 24 h urinary sodium excretion in Australian schoolchildren aged 5–13 years

Objective

To measure total daily salt intake using 24 h urinary Na excretion within a sample of Victorian schoolchildren aged 5–13 years and to assess discretionary salt use habits of children and parents.

Design

Cross-sectional study.

Setting

Completed within a convenience sample of independent primary schools (n9) located in Victoria, Australia.

Subjects

Two hundred and sixty children completed a 24 h urine collection over a school (34 %) or non-school day (66 %). Samples deemed incomplete (n18), an over-collection (n1) or that were incorrectly processed at the laboratory (n3) were excluded.

Results

The sample comprised 120 boys and 118 girls with a mean age of 9·8 (sd1·7) years. The average 24 h urinary Na excretion (n238) was 103 (sd43) mmol/24 h (salt equivalent 6·0 (sd2·5) g/d). Daily Na excretion did not differ by sex; boys 105 (sd46) mmol/24 h (salt equivalent 6·1 (sd2·7) g/d) and girls 100 (sd41) mmol/24 h (salt equivalent 5·9 (sd2·4) g/d;P= 0·38). Sixty-nine per cent of children (n164) exceeded the recommended daily Upper Limit for Na. Reported discretionary salt use was common: two-thirds of parents reported adding salt during cooking and almost half of children reported adding salt at the table.

Conclusions

The majority of children had salt intakes exceeding the recommended daily Upper Limit. Strategies to lower salt intake in children are urgently required, and should include product reformulation of lower-sodium food products combined with interventions targeting discretionary salt use within the home.

Hypertension in developing countries

Data from different national and regional surveys show that hypertension is common in developing countries, particularly in urban areas, and that rates of awareness, treatment, and control are low. Several hypertension risk factors seem to be more common in developing countries than in developed regions. Findings from serial surveys show an increasing prevalence of hypertension in developing countries, possibly caused by urbanisation, ageing of population, changes to dietary habits, and social stress. High illiteracy rates, poor access to health facilities, bad dietary habits, poverty, and high costs of drugs contribute to poor blood pressure control. The health system in many developing countries is inadequate because of low funds, poor infrastructure, and inexperience. Priority is given to acute disorders, child and maternal health care, and control of communicable diseases. Governments, together with medical societies and non-governmental organisations, should support and promote preventive programmes aiming to increase public awareness, educate physicians, and reduce salt intake. Regulations for the food industry and the production and availability of generic drugs should be reinforced.

The role of number of meals, coffee intake, salt and type of cookware on colorectal cancer development in the context of the Mediterranean diet

OBJECTIVE

To investigate the association between dietary behaviours and colorectal cancer (CRC) in the context of the Mediterranean diet.

DESIGN

Case-control study.

SETTING

All patients (cases) were recruited from Saint Savvas Cancer Hospital and Alexandra General Hospital in Athens, Greece. Controls were voluntarily selected from the general population and matched to cases by age group (±10 years) and sex.

SUBJECTS

Two hundred and fifty cases with newly diagnosed CRC (mean age 63 (sd 12) years, 59·6 % males) and 250 controls matched on age and sex were studied. A standardized questionnaire assessing sociodemographic, clinical, lifestyle, dietary characteristics and nutritional behaviours was applied. Multiple logistic regression analysis was used to evaluate the aforementioned factors in addition to the MedDietScore (an index that evaluates adherence to the Mediterranean diet) on CRC development.

RESULTS

The higher the daily number of meals, the lower the likelihood of having CRC (OR = 0·74, 95 % CI 0·61, 0·89); coffee drinking was associated with higher likelihood of having CRC (OR = 3·27, 95 % CI 1·09, 9·8); the use of non-stick cookware was positively associated with CRC (OR = 1·57, 95 % CI 1·02, 2·4). However, these associations slightly lost their significance when adherence to the Mediterranean diet was taken into account. Moreover, a 1/75 increase in the modified-MedDietScore plus the aforementioned nutritional behaviours was associated with 13 % lower odds (95 % CI 0·83, 0·91, P < 0·001) of having CRC.

CONCLUSIONS

Nutritional behaviours in addition to dietary habits should be taken into account in detecting individuals prone to the development of CRC.

The Dutch Healthy Diet index (DHD-index): an instrument to measure adherence to the Dutch Guidelines for a Healthy Diet

BACKGROUND

The objective was to develop an index based on the Dutch Guidelines for a healthy Diet of 2006 that reflects dietary quality and to apply it to the Dutch National Food Consumption Survey (DNFCS) to examine the associations with micronutrient intakes.

METHODS

A total of 749 men and women, aged 19-30 years, contributed two 24-hour recalls and additional questionnaires in the DNFCS of 2003. The Dutch Healthy Diet index (DHD-index) includes ten components representing the ten Dutch Guidelines for a Healthy Diet. Per component the score ranges between zero and ten, resulting in a total score between zero (no adherence) and 100 (complete adherence).

RESULTS

The mean ± SD of the DHD-index was 60.4 ± 11.5 for women and 57.8 ± 10.8 for men (P for difference = 0.002). Each component score increased across the sex-specific quintiles of the DHD-index. An inverse association was observed between the sex-specific quintiles of the DHD-index and total energy intake. Calcium, riboflavin, and vitamin E intake decreased with increasing DHD-index, an inverse association which disappeared after energy adjustment. Vitamin C showed a positive association across quintiles, also when adjusted for energy. For folate, iron, magnesium, potassium, thiamin, and vitamin B6 a positive association emerged after adjustment for energy.

CONCLUSIONS

The DHD-index is capable of ranking participants according to their adherence to the Dutch Guidelines for a Healthy Diet by reflecting variation in nine out of ten components that constitute the index when based on two 24-hour recalls. Furthermore, the index showed to be a good measure of nutrient density of diets.

Enhancing saltiness in emulsion based foods

Background

The concept of enhancing saltiness perception in emulsions and a liquid food formulated with the emulsions (ambient vegetable soup) through increasing salt concentration in the continuous phase while retaining the fat content of the (aqueous continuous) product was evaluated. This was accomplished by increasing the droplet phase volume using duplex emulsion technology. Viscosity and droplet size distribution was measured. Saltiness evaluation was based on simple paired comparison testing (2-Alternate Forced Choice tests, BS ISO 5495:2007).

Results

Single and duplex emulsions and emulsion-based products had comparable mean oil droplet diameters (25 to 30 μm); however, viscosity of the duplex emulsion systems was considerably higher. Sensory assessment of saltiness of emulsion pairs (2AFC) indicated duplex technology enhanced saltiness perception compared to a single emulsion product at the same salt content (6.3 g/100 g) in both simple emulsions and the formulated food product (P = 0.0596 and 0.0004 respectively) although assessors noted the increased viscosity of the duplex systems. The formulated food product also contained pea starch particles which may have aided product mixing with saliva and thus accelerated tastant transport to the taste buds. Lowering salt content in the duplex systems (to levels of aqueous phase salt concentration similar to the level in the single systems) resulted in duplex systems being perceived as less salty than the single system. It appears that the higher viscosity of the duplex systems could not be “overruled” by enhanced mixing through increased droplet phase volume at lowered salt content.

Conclusions

The results showed that salt reduction may be possible despite the added technology of duplex systems increasing the overall measured viscosity of the product. The changes in viscosity behavior impact mouthfeel, which may be exploitable in addition to the contribution towards salt reduction. With a view to applying this technology to real processed foods, it needs to be tested for the product in question but it should be considered as part of a salt reduction tool box.

Determination of salt content in hot takeaway meals in the United Kingdom

High sodium intake is associated with negative health outcomes, including an independent correlation with high blood pressure which increases the risk of cardiovascular disease. A high proportion of sodium intake in the UK is from processed and out of the home food; this includes takeaway food which is increasing in popularity. The aim of the present study was to evaluate salt levels in popular hot takeaway meals. A total of 411 samples of 23 different types of takeaway meals were analysed. Obtained results show the salt content in these kinds of foods is alarmingly high. Comparing medians (interquartile range) for different meal categories, Pizzas contained the highest salt content per portion (9.45 g (6.97-12.83)), followed by Chinese meals (8.07 g (5.47-10.99 g)), Kebabs (6.21 g (4.01-8.35)) and Indian meals (4.73 g (3.61-6.10)). In addition, significant differences in the salt content between meals within the same category were reported. To enable the consumer to meet the UK's target salt intake, a significant reduction in the salt content of hot takeaway meals should be considered.

Key opportunities for sodium reduction in New Zealand processed foods

OBJECTIVE

To identify key opportunities for reformulation of processed foods that could best decrease population sodium intakes in New Zealand (NZ).

METHOD

Relevant national literature and reports were used to identify major food groups contributing to population sodium intakes in NZ. Sodium content data for these food groups were collected from the Nutrition Information Panels of processed foods in one large supermarket. Key opportunities for reformulation were identified by comparing mean sodium content with 2012 targets from the United Kingdom (UK) Food Standards Agency (FSA) and mean sodium values from Australia and the UK.

RESULTS

Major contributors to NZ sodium intakes are: bread (26%), processed meats (10%), and sauces (6%). Mean (SD) sodium contents of these processed foods were: 447 (125) mg/100 g, 1,169 (444) mg/100 g, and 1,046 (1,235) mg/100 g, respectively. Food categories with the lowest percentage of products meeting corresponding FSA targets were: sausages/hot dogs and sliced meat (0%); salami/cured meat (2%); liquid meal-based sauces (4%); and multigrain bread (14%). Mean sodium contents of NZ products were higher than for similar products in the UK. Key opportunities identified for sodium reduction were: white bread, sausages and hot dogs, and salami/cured meats.

CONCLUSION

There is substantial scope to reduce the sodium content of NZ processed foods.

IMPLICATIONS

This paper identifies three key opportunities for reformulation of processed foods that could produce substantial decreases in sodium intakes in NZ, and benefits to population health.

Fluid Balance and Dehydration in the Young Athlete

Many young athletes train and compete under conditions that put their body fluid balance at risk, and hypohydration is usually the major concern. Another less frequent condition is hyperhydration that—if accompanied by other risk factors—may cause hyponatremia. Water and electrolyte losses during physical activities occur primarily from sweat. Such losses have been identified mostly in active (but nonathletic) young populations under laboratory settings. Studies have been trying to estimate fluid losses in the athletic population under field conditions, taking into account the sport modality and environmental conditions. Besides these external conditions, young athletes adopt different drinking attitudes, which may depend on knowledge, education, and the opportunities to drink during the break periods as well as fluid availability. Focusing on the young athlete, this review will discuss water and sodium losses from sweat, the effects of hypohydration on performance, and fluid intake attitudes within and during practices and competitions. Some considerations related to the methods of identifying hydration status and guidelines are also given, with the understanding that they should be individually adapted for the athlete and activity. The young athlete, parents, coaches, and athletic/health professionals should be aware of such information to prevent fluid imbalances and the consequent hazardous effects on performance and health.

Salt intake, plasma sodium, and worldwide salt reduction

There is overwhelming evidence that a reduction in salt intake from the current level of approximately 9-12 g/d in most countries of the world to the recommended level of 5-6 g/d lowers blood pressure (BP) in both hypertensive and normotensive individuals. A further reduction to 3-4 g/d has a greater effect. Prospective studies and outcome trials have demonstrated that a lower salt intake is related to a reduced risk of cardiovascular disease. Cost-effectiveness analyses have documented that salt reduction is more or at the very least just as cost-effective as tobacco control in reducing cardiovascular disease, the leading cause of death and disability worldwide. The mechanisms whereby salt raises blood pressure and increases cardiovascular risk are not fully understood. The existing concepts focus on the tendency for an increase in extracellular fluid volume. Increasing evidence suggests that small increases in plasma sodium may have a direct effect on BP and the cardiovascular system, independent of extracellular volume. All countries should adopt a coherent and workable strategy to reduce salt intake in the whole population. Even a modest reduction in population salt intake will have major beneficial effects on health, along with major cost savings.

Preference and intake frequency of high sodium foods and dishes and their correlations with anthropometric measurements among Malaysian subjects

This study investigated the preference and intake frequency of a list of 15 commonly available high sodium Malaysian foods/dishes, discretionary salt use, and their possible association with demographics, blood pressures and anthropometric measurements among 300 Malaysian university students (114 males, 186 females; 259 ethnic Chinese, 41 Indians; 220 lean, 80 overweight). French fries and instant soup noodle were found to be the most preferred and most frequently consumed salty food, respectively, while salted fish was least preferred and least frequently consumed. Males had a significantly higher intake frequency of at least 6 of the salty foods, but the preference of most salty foods was not significantly different between genders. Ethnic Chinese significantly preferred more and took more frequently traditional and conventional Malaysian foods like asam laksa (a Malaysian salty-sour-spicy noodle in fish stock), salted biscuits and salted vegetable, while Indians have more affinity and frequency towards eating salty Western foods. Body Mass Index was significantly negatively correlated with the intake frequency of canned/packet soup and salted fish while waist circumference was significantly positively correlated with the preference of instant noodle. Also, an increased preference of potato chips and intake frequency of salted biscuits seemed to lead to a decreased WHR. Other than these, all the other overweight/obesity indicators did not seem to fully correlate with the salty food preference and intake frequency. Nevertheless, the preference and intake frequency of asam laksa seemed to be significant negative predictors for blood pressures. Finally, increased preference and intake frequency of high sodium shrimp paste (belacan)-based foods like asam laksa and belacan fried rice seemed to discourage discretionary salt use. In conclusion, the preference and intake frequency of the high sodium belacan-based dish asam laksa seems to be a good predictor for ethnic difference, discretionary salt use and blood pressures.

Patterns of sodium and potassium excretion and blood pressure in the African Diaspora

Habitual levels of dietary sodium and potassium are correlated with age-related increases in blood pressure (BP) and likely have a role in this phenomenon. Although extensive published evidence exists from randomized trials, relatively few large-scale community surveys with multiple 24-h urine collections have been reported. We obtained three 24-h samples from 2704 individuals from Nigeria, Jamaica and the United States to evaluate patterns of intake and within-person relationships with BP. The average (±s.d.) age and weight of the participants across all the three sites were 39.9±8.6 years and 76.1±21.2 kg, respectively, and 55% of the total participants were females. Sodium excretion increased across the East-West gradient (for example, 123.9±54.6, 134.1±48.8, 176.6±71.0 (±s.d.) mmol, Nigeria, Jamaica and US, respectively), whereas potassium was essentially unchanged (for example, 46.3±22.9, 40.7±16.1, 44.7±16.4 (±s.d.) mmol, respectively). In multivariate analyses both sodium (positively) and potassium (negatively) were strongly correlated with BP (P<0.001); quantitatively the association was stronger, and more consistent in each site individually, for potassium. The within-population day-to-day variation was also greater for sodium than for potassium. Among each population group, a significant correlation was observed between sodium and urine volume, supporting the prior finding of sodium as a determinant of fluid intake in free-living individuals. These data confirm the consistency with the possible role of dietary electrolytes as hypertension risk factors, reinforcing the relevance of potassium in these populations.

Three-year safety and effectiveness of fixed-dose losartan/hydrochlorothiazide combination therapy in Japanese patients with hypertension under clinical setting (PALM-1 Extension Study)

Concerns about metabolic complications often disturb prolonged use of diuretics in Japan. We investigated 3-year safety and efficacy in Japanese patients with hypertension who were uncontrolled with angiotensin receptor blocker or angiotensin-converting enzyme inhibitor regimens and then switched to losartan (50 mg)/hydrochlorothiazide (12.5 mg; HCTZ) combinations. Blood pressure decreased favorably and maintained a steady state for 3 years (157 ± 16/88 ± 11 mm Hg to 132 ± 13/75 ± 9 mm Hg, P < .0001). Metabolic parameters maintained a limited range of changes after 3 years, and adverse events were markedly decreased after 1-year treatment. The losartan/HCTZ combination minimized diuretic-related adverse effects and thus may be useful for the treatment of Japanese patients with hypertension.

Antihypertensive effect of a fixed-dose combination of losartan/hydrochlorothiazide in patients with uncontrolled hypertension: a multicenter study

BACKGROUND

Achieving adequate blood pressure (BP) control often requires more than one antihypertensive agent. The purpose of this study was to determine whether a fixed-dose formulation of losartan (LOS) plus hydrochlorothiazide (HCTZ) (LOS/HCTZ) is effective in achieving a greater BP lowering in patients with uncontrolled hypertension.

METHODS

The study was a prospective, multicenter, observational trial exploring the antihypertensive effect of a single tablet of LOS 50 mg/HCTZ 12.5 mg. A total of 228 patients whose BP had previously been treated with more than one antihypertensive agents without having achieved BP goal below 130/80 mmHg enrolled in the study.

RESULTS

A significant decrease in systolic and diastolic BP was observed in both clinic and home measurement after switching from the previous treatment to LOS/HCTZ. There was a significant decrease in both B-type natriuretic peptide (BNP) and urinary albumin creatinine (Cr) excretion ratio (ACR), especially in patients with elevated values. In contrast, there was a significant increase in serum Cr concentration in conjunction with a decrease in estimated glomerular filtration rate (eGFR). Overall serum uric acid (UA) concentration increased, whereas in patients with hyperuricemia there was a significant reduction in this value.

CONCLUSION

Switching to LOS/HCTZ provides a greater reduction in clinic and home BP in patients with uncontrolled hypertension. This combination therapy may lead to cardio-, reno protection and improve UA metabolism.

Salt-inducible kinase 1 influences Na(+),K(+)-ATPase activity in vascular smooth muscle cells and associates with variations in blood pressure

OBJECTIVES

Essential hypertension is a complex condition whose cause involves the interaction of multiple genetic and environmental factors such as salt intake. Salt-inducible kinase 1 (SIK1) is a sucrose-nonfermenting-like kinase isoform that belongs to the AMPK (5' adenosine monophosphate-activated protein kinase) family. SIK1 activity is increased by high salt intake and plays an essential role in regulating the plasma membrane Na(+),K(+)-ATPase. The objective of this study was to examine whether SIK1 is present in vascular smooth muscle cells (VSMCs) and endothelial cells, whether it affects VSMC Na(+),K(+)-ATPase activity and whether human SIK1 (hSIK1) represents a potential candidate for blood pressure regulation.

METHODS

Localization of SIK1 was performed using immunohistochemistry, mRNA and western blot. Functional assays (Na(+),K(+)-ATPase activity) were performed in VSMCs derived from rat aorta. Genotype-phenotype association studies were performed in three Swedish and one Japanese population-based cohorts.

RESULTS

SIK1 was localized in human VSMCs and endothelial cells, as well as a cell line derived from rat aorta. A nonsynonymous single nucleotide polymorphism in the hSIK1 gene exon 3 (C→T, rs3746951) results in the amino acid change (15)Gly→Ser in the SIK1 protein. SIK1-(15)Ser was found to increase plasma membrane Na(+),K(+)-ATPase activity in cultured VSMC line from rat aorta. Genotype-phenotype association studies in three Swedish and one Japanese population-based cohorts suggested that T allele (coding for (15)Ser) was associated with lower blood pressure (P = 0.005 for SBP and P = 0.002 for DBP) and with a decrease in left ventricular mass (P = 0.048).

CONCLUSION

The hSIK1 appears to be of potential relevance within VSMC function and blood pressure regulation.

Sodium Consumption: An Individual's Choice?

Excess intake of dietary salt is estimated to be one of the leading risks to health worldwide. Major national and international health organizations, along with many governments around the world, have called for reductions in the consumption of dietary salt. This paper discusses behavioural and population interventions as mechanisms to reduce dietary salt. In developed countries, salt added during food processing is the dominant source of salt and largely outside of the direct control of individuals. Population-based interventions have the potential to improve health and to be cost saving for these countries. In developing economies, where salt added in cooking and at the table is the dominant source, interventions based on education and behaviour change have been estimated to be highly cost effective. Regardless, countries with either developed or developing economies can benefit from the integration of both population and behavioural change interventions.