Choose and prepare foods with less salt: dietary advice for all Americans

Spot urinary sodium-to-potassium ratio is associated with blood pressure levels in healthy adolescents: the Wakayama Study

The spot urinary sodium-to-potassium (Na/K) ratio is a simple measure of salt loading and has been shown to be associated with elevated blood pressure (BP) in middle-aged and older adults. This study aimed to evaluate the association between the spot urinary Na/K ratio and BP in 457 healthy adolescents aged 12-15 years in a school-based setting. The mean urinary Na/K ratio was 4.99 ± 2.76, and no significant difference was found between the boys and girls. When the participants were stratified based on urinary Na/K ratio quartile, age- and sex-adjusted systolic and diastolic BP gradually increased as Na/K ratio increased (systolic BP: 106.1, 106.9, 108.2, and 111.5 mmHg, Ptrend < 0.001; diastolic BP: 62.0, 62.4, 63.1, 64.3 mmHg, Ptrend = 0.022). The systolic and diastolic BP were more closely associated with urinary Na/K ratio than with Na and K levels, as well as estimated daily salt intake. In the multiple regression analysis, the urinary Na/K ratio was significantly associated with systolic BP (β = 0.144, P < 0.001) and diastolic BP (β = 0.114, P = 0.015) independent of potential confounding factors. An additional subgroup analysis revealed that the BP of the group with both high salt intake (≥8.5 g/day) and high Na/K ratio (≥6.60) was significantly higher than that of the group with high salt intake alone (systolic BP, 115.0 vs. 109.1 mmHg, P < 0.001; diastolic BP, 66.0 vs. 62.5 mmHg, P = 0.017). These results suggest that the urinary Na/K ratio is associated with BP levels in healthy adolescents and may be useful for assessing salt loading and its effects on BP elevation.

Evaluation of salt intake estimated from 24-h urinary sodium excretion in medical professionals in Darkhan-Uul Province, Mongolia: a cross-sectional study

This cross-sectional study aimed to estimate the daily salt intake of medical professionals working in public health facilities in Darkhan-Uul Province, Mongolia. We conducted a multiple logistic regression analysis to identify factors associated with their consumption of salt exceeding the recommended daily salt intake (≥ 5 g/day). A self-administered questionnaire and 24-h urine samples were used to obtain data on the participants' salt intake. Of 338 participants, 159 completed the 24-h urine collection. The mean sodium excretion into urine was 122.3 mmol/day, which was equivalent to a mean salt intake of 7.7 g/day when the urinary excretion rate was considered as 93%. Body mass index was positively correlated with excess salt intake (adjusted odds ratio [AOR]: 1.27; 95% confidence interval [CI] 1.10-1.46), while age was negatively correlated with excess salt intake (AOR: 0.95; 95% CI 0.91-1.00). Participants who consumed ≥ 2 cups of salted suutei tsai (Mongolian milk tea) daily had a higher risk of consuming ≥ 5 g/day of salt than those who consumed ≤ 1 cup/day. The average estimated salt intake of the participants was higher than the recommended value. Medical professionals should be aware of factors associated with excessive salt consumption and make appropriate adjustments to minimize it.

Arteriosclerosis with superimposed atherosclerosis is the cause not the consequence of essential hypertension

The arterial system is a closed loop and the pressure within this loop reflects cardiac output, resistance to outflow, volume of fluid within the circulation and stiffness of the arterial wall. Increased resistance to outflow or Bayliss's phenomena cannot be the cause of essential hypertension as it reverses with treatment of hypertension. There is no evidence for increased cardiac output in essential hypertension. Increased blood volume contributes to hypertension in obesity just as it does in hypertension secondary to renal failure. The principle cause of essential hypertension is increasing stiffness of the arterial wall. This is a consequence of arteriosclerosis that commences in utero and progressively increases in severity with increasing age. Arteriosclerotic arterial wall stiffening antedates the onset of essential hypertension by decades. It not only explains the increasing incidence of essential hypertension with increasing age, but it is the only thing that fulfils Koch's first postulate and that is it is present in 100% of individuals with essential hypertension.

Urinary Sodium and Potassium Levels and Blood Pressure in Population with High Sodium Intake

The purpose of this study was to examine the association of urinary sodium-to-creatinine ratio and potassium-to-creatinine ratio with blood pressure in a cross-sectional study comprising Korean adults who participated in the Healthy Twin Study. The participants consisted of 2653 men and women in the Healthy Twin Study aged ≥19 years. Participants’ urinary excretion of sodium, potassium, and creatinine was measured from overnight half-day urine samples. Food intake was assessed using a validated food frequency questionnaire. We examined systolic and diastolic blood pressures according to sodium- or potassium-to-creatinine ratios using the generalized linear model. We determined food groups explaining high urinary sodium- or potassium-to-creatinine ratio using the reduced rank regression and calculated sodium- or potassium-contributing food score. We observed that systolic blood pressure was higher among men and women in the highest quintile of urinary sodium-to-creatinine ratio or sodium-to-potassium ratio than it was in the lowest quintile. Geometric means (95% CIs) of the lowest and the highest quintiles of systolic blood pressure (mmHg) were 113.4 (111.8–115.0) and 115.6 (114.1–117.2; P for trend = 0.02), respectively, for sodium-to-creatinine ratio. The association between urinary sodium-to-creatinine and systolic blood pressure was more pronounced among individuals whose body mass index (BMI) was less than 25 kg/m² (P for interaction = 0.03). We found that vegetables, kimchi and seaweed intake contributed to high sodium intake and a sodium-contributing food score were associated with increased blood pressure. In our study, we identified the food groups contributing to high sodium intake and found that high urinary sodium levels were associated with increasing blood pressure among Korean adults.

Sources of dietary sodium and implications for a statewide salt reduction initiative in Victoria, Australia

In Victoria, Australia, a statewide salt reduction partnership was launched in 2015. The aim was to measure Na intake, food sources of Na (level of processing, purchase origin) and discretionary salt use in a cross-section of Victorian adults prior to a salt reduction initiative. In 2016/2017, participants completed a 24-h urine collection (n 338) and a subsample completed a 24-h dietary recall (n 142). Participants were aged 41·2 (sd 13·9) years, and 56 % were females. Mean 24-h urinary excretion was 138 (95 % CI 127, 149) mmol/d for Na. Salt equivalent was 8·1 (95 % CI 7·4, 8·7) g/d, equating to about 8·9 (95 % CI 8·1, 9·6) g/d after 10 % adjustment for non-urinary losses. Mean 24-h intake estimated by diet recall was 118 (95 % CI 103, 133) mmol/d for Na (salt 6·9 (95 % CI 6·0, 7·8 g/d)). Leading dietary sources of Na were cereal-based mixed dishes (12 %), English muffins, flat/savoury/sweet breads (9 %), regular breads/rolls (9 %), gravies and savoury sauces (7 %) and processed meats (7 %). Over one-third (38 %) of Na consumed was derived from discretionary foods. Half of all Na consumed came from ultra-processed foods. Dietary Na derived from foods was obtained from retail stores (51 %), restaurants and fast-food/takeaway outlets (28 %) and fresh food markets (9 %). One-third (32 %) of participants reported adding salt at the table and 61 % added salt whilst cooking. This study revealed that salt intake was above recommended levels with diverse sources of intake. Results from this study suggest a multi-faceted salt reduction strategy focusing on the retail sector, and food reformulation would most likely benefit Victorians and has been used to inform the ongoing statewide salt reduction initiative.

Dietary intake and sources of sodium and potassium among Australian schoolchildren: results from the cross-sectional Salt and Other Nutrients in Children (SONIC) study

OBJECTIVES

To examine sodium and potassium urinary excretion by socioeconomic status (SES), discretionary salt use habits and dietary sources of sodium and potassium in a sample of Australian schoolchildren.

DESIGN

Cross-sectional study.

SETTING

Primary schools located in Victoria, Australia.

PARTICIPANTS

666 of 780 children aged 4-12 years who participated in the Salt and Other Nutrients in Children study returned a complete 24-hour urine collection.

PRIMARY AND SECONDARY OUTCOME MEASURES

24-hour urine collection for the measurement of sodium and potassium excretion and 24-hour dietary recall for the assessment of food sources. Parent and child reported use of discretionary salt. SES defined by parental highest level of education.

RESULTS

Participants were 9.3 years (95% CI 9.0 to 9.6) of age and 55% were boys. Mean urinary sodium and potassium excretion was 103 (95% CI 99 to 108) mmol/day (salt equivalent 6.1 g/day) and 47 (95% CI 45 to 49) mmol/day, respectively. Mean molar Na:K ratio was 2.4 (95% CI 2.3 to 2.5). 72% of children exceeded the age-specific upper level for sodium intake. After adjustment for age, sex and day of urine collection, children from a low socioeconomic background excreted 10.0 (95% CI 17.8 to 2.1) mmol/day more sodium than those of high socioeconomic background (p=0.04). The major sources of sodium were bread (14.8%), mixed cereal-based dishes (9.9%) and processed meat (8.5%). The major sources of potassium were dairy milk (11.5%), potatoes (7.1%) and fruit/vegetable juice (5.4%). Core foods provided 55.3% of dietary sodium and 75.5% of potassium while discretionary foods provided 44.7% and 24.5%, respectively.

CONCLUSIONS

For most children, sodium intake exceeds dietary recommendations and there is some indication that children of lower socioeconomic background have the highest intakes. Children are consuming about two times more sodium than potassium. To improve sodium and potassium intakes in schoolchildren, product reformulation of lower salt core foods combined with strategies that seek to reduce the consumption of discretionary foods are required.

Sodium Reduction in US Households' Packaged Food and Beverage Purchases, 2000 to 2014

Importance

Initiatives to reduce sodium in packaged foods have been launched in the United States, yet corresponding changes in the amount of sodium that US households obtain from packaged foods have not been evaluated, to our knowledge.

Objective

To assess 15-year changes in the amount of sodium that US households acquire from packaged food purchases, the sodium content of purchases, and the proportion of households that have purchases with optimal sodium density.

Design, Setting, and Participants

Longitudinal study of US households in the 2000 to 2014 Nielsen Homescan Consumer Panel, a population-based sample of households that used barcode scanners to record all packaged foods purchased throughout the year. Time-varying brand- and product-specific nutrition information was used for 1 490 141 products.

Main Outcomes and Measures

Sociodemographic-adjusted changes in mean sodium per capita (mg/d) and sodium content (mg/100 g), overall and for top food group sources of sodium, and the proportion of households that have total purchases with sodium density of 1.1 mg/kcal or less.

Results

In a nationwide sample of 172 042 US households (754 608 year-level observations), the amount of sodium that households acquired from packaged food and beverage purchases decreased significantly between 2000 and 2014 by 396 mg/d (95% CI, -407 to -385 mg/d) per capita. The sodium content of households' packaged food purchases decreased significantly during this 15-year period by 49 mg/100 g (95% CI, -50 to -48 mg/100 g), a 12.0% decline; decreases began in 2005 and continued through 2014. Moreover, the sodium content of households' purchases decreased significantly for all top food sources of sodium between 2000 and 2014, including declines of more than 100 mg/100 g for condiments, sauces, and dips (-114 mg/100 g; 95% CI, -117 to -111 mg/100 g) and salty snacks (-142 mg/100 g; 95% CI, -144 to -141 mg/100 g). However, in all years, less than 2% of US households had packaged food and beverage purchases with sodium density of 1.1 mg/kcal or less.

Conclusions and Relevance

In this nationwide study, significant reductions in sodium from packaged food purchases were achieved in the past 15 years. Nonetheless, most US households had food and beverage purchases with excessive sodium density. Findings suggest that more concerted sodium reduction efforts are needed in the United States.

The association between cognitive function and objective adherence to dietary sodium guidelines in patients with heart failure

BACKGROUND

Although cognitive impairment is common in heart failure (HF) patients, its effects on sodium adherence recommendations are unknown.

PURPOSE

Our aim is to examine if cognitive function is associated with patient sodium adherence.

METHODS

Sodium collection/excretion and cognitive function were assessed for 339 HF patients over a 5-8-week period. Neuropsychological testing was performed at baseline (Visit 1), whereas two 24-hour urine samples were collected within 7 weeks postbaseline. The ability to collect two 24-hour urine samples and the estimation of sodium excretion levels from these samples were used to estimate sodium adherence recommendations.

RESULTS

Nearly half (47%) of the study participants (n=159) were unable to give two valid 24-hour urine samples. Participants who were unable to adhere to two valid 24-hour urine samples had significantly poorer attention and global cognition tests (P<0.044), with a trend for poorer executive function (P=0.064). Among those with valid samples, urine sodium level was not associated with global cognitive function, attention, executive function, or memory after adjusting for covariates. Female sex was associated with lower sodium excretion (all P<0.01); individuals with knowledge of sodium guidelines had less intake of sodium, resulting in excretion of less sodium (all P≤0.03). Conversely, higher socioeconomic status (SES) and body mass index (BMI) were associated with greater sodium (all P≤0.02 and P≤0.01).

CONCLUSION

Adherence to urine sodium collection was poor, especially among those with poorer cognitive function. Sodium consumption exceeded recommended amounts and was unrelated to cognitive function. Interventions for improving sodium adherence should focus on at-risk groups (high SES and BMI) and at improving knowledge of recommended salt intake.

Dietary sources and sodium intake in a sample of Australian preschool children

OBJECTIVES

To assess dietary sodium intake and the food sources of sodium in a sample of Australian preschool children.

DESIGN

Cross-sectional.

SETTING

Mothers were followed up when children were approximately 3.5 years of age after participating in a cluster randomised controlled trial: the Melbourne Infant Feeding Activity and Nutrition Trial Program.

PARTICIPANTS

251 Australian children aged 3.5 ± 0.19 (SD) years.

PRIMARY AND SECONDARY OUTCOME MEASURES

The average daily sodium intake was determined using three unscheduled 24 h dietary recalls. The contributions of food groups, core, discretionary and processed foods to daily sodium intake were assessed.

RESULTS

The average sodium intake was 1508 ± 495 (SD) mg/day, (salt equivalent 3.9 ± 1.3 (SD) g/day) and 87% of children exceeded the Australian Upper Level of Intake (UL) for sodium of 1000 mg/day (salt equivalent 2.6 g/day). Main food sources of sodium were cereal/cereal products (25%), milk products (19%), meat, poultry/game (17%) and cereal-based products (15%). Core foods contributed 65%, and discretionary foods 35% of total daily sodium intake, and within the total diet, minimally processed, processed, processed culinary ingredient and ultraprocessed foods contributed 16%, 35%, 1% and 48% of sodium, respectively.

CONCLUSIONS

Within this sample, most children exceeded the recommended UL for sodium. Core and ultraprocessed foods were key sources of sodium which suggests that reductions in the sodium content of these foods are required to reduce sodium intake in young children. These data also provide further support for public health campaigns that seek to reduce consumption of energy-dense, nutrient-poor foods.

Consumer attitudes, barriers, and meal satisfaction associated with sodium-reduced meal intake at worksite cafeterias

BACKGROUND/OBJECTIVES

Targeting consumers who consume lunches at their worksite cafeterias would be a valuable approach to reduce sodium intake in South Korea. To assess the relationships between socio-demographic factors, consumer satisfaction, attitudes, barriers and the frequency of sodium-reduced meal intake.

SUBJECTS/METHODS

We implemented a cross-sectional research, analyzing data from 738 consumers aged 18 years or older (327 males and 411 females) at 17 worksite cafeterias in South Korea. We used the ordinary least squares regression analysis to determine the factors related to overall satisfaction with sodium-reduced meal. General linear models with LSD tests were employed to examine the variables that differed by the frequency of sodium-reduced meal intake.

RESULTS

Most subjects always or usually consumed the sodium-reduced meal (49%), followed by sometimes (34%) and rarely or never (18%). Diverse menus, taste and belief in the helpfulness of the sodium-reduced meal significantly increased overall satisfaction with the sodium-reduced diet (P < 0.05). We found importance of needs in the following order: 1) 'menu diversity' (4.01 points), 2) 'active promotion' (3.97 points), 3) 'display of nutrition labels in a visible location' (3.96 points), 4) 'improvement of taste' (3.88 points), and 5) 'education of sodium-reduction self-care behaviors' (3.82 points).

CONCLUSION

Dietitians could lead consumers to choose sodium-reduced meals by improving their taste and providing diverse menus for the sodium-reduced meals at worksite cafeterias.

Use of Urine Biomarkers to Assess Sodium Intake: Challenges and Opportunities

This article summarizes current data and approaches to assess sodium intake in individuals and populations. A review of the literature on sodium excretion and intake estimation supports the continued use of 24-h urine collections for assessing population and individual sodium intake. Since 2000, 29 studies used urine biomarkers to estimate population sodium intake, primarily among adults. More than half used 24-h urine; the rest used a spot/casual, overnight, or 12-h specimen. Associations between individual sodium intake and health outcomes were investigated in 13 prospective cohort studies published since 2000. Only three included an indicator of long-term individual sodium intake, i.e., multiple 24-h urine specimens collected several days apart. Although not insurmountable, logistic challenges of 24-h urine collection remain a barrier for research on the relationship of sodium intake and chronic disease. Newer approaches, including modeling based on shorter collections, offer promise for estimating population sodium intake in some groups.

Difference between 24-h diet recall and urine excretion for assessing population sodium and potassium intake in adults aged 18-39 y

BACKGROUND

Limited data are available on the accuracy of 24-h dietary recalls used to monitor US sodium and potassium intakes.

OBJECTIVE

We examined the difference in usual sodium and potassium intakes estimated from 24-h dietary recalls and urine collections.

DESIGN

We used data from a cross-sectional study in 402 participants aged 18-39 y (∼50% African American) in the Washington, DC, metropolitan area in 2011. We estimated means and percentiles of usual intakes of daily dietary sodium (dNa) and potassium (dK) and 24-h urine excretion of sodium (uNa) and potassium (uK). We examined Spearman's correlations and differences between estimates from dietary and urine measures. Multiple linear regressions were used to evaluate the factors associated with the difference between dietary and urine measures.

RESULTS

Mean differences between diet and urine estimates were higher in men [dNa - uNa (95% CI) = 936.8 (787.1, 1086.5) mg/d and dK - uK = 571.3 (448.3, 694.3) mg/d] than in women [dNa - uNa (95% CI) = 108.3 (11.1, 205.4) mg/d and dK - uK = 163.4 (85.3, 241.5 mg/d)]. Percentile distributions of diet and urine estimates for sodium and potassium differed for men. Spearman's correlations between measures were 0.16 for men and 0.25 for women for sodium and 0.39 for men and 0.29 for women for potassium. Urinary creatinine, total caloric intake, and percentages of nutrient intake from mixed dishes were independently and consistently associated with the differences between diet and urine estimates of sodium and potassium intake. For men, body mass index was also associated. Race was associated with differences in estimates of potassium intake.

CONCLUSIONS

Low correlations and differences between dietary and urinary sodium or potassium may be due to measurement error in one or both estimates. Future analyses using these methods to assess sodium and potassium intake in relation to health outcomes may consider stratifying by factors associated with the differences in estimates from these methods. This trial was registered at clinicaltrials.gov as NCT01631240.

Cross-Sectional Study of 24-Hour Urinary Electrolyte Excretion and Associated Health Outcomes in a Convenience Sample of Australian Primary Schoolchildren: The Salt and Other Nutrients in Children (SONIC) Study Protocol

BACKGROUND

Dietary sodium and potassium are involved in the pathogenesis of cardiovascular disease. Data exploring the cardiovascular outcomes associated with these electrolytes within Australian children is sparse. Furthermore, an objective measure of sodium and potassium intake within this group is lacking.

OBJECTIVE

The primary aim of the Salt and Other Nutrient Intakes in Children ("SONIC") study was to measure sodium and potassium intakes in a sample of primary schoolchildren located in Victoria, Australia, using 24-hour urine collections. Secondary aims were to identify the dietary sources of sodium and potassium, examine the association between these electrolytes and cardiovascular risk factors, and assess children's taste preferences and saltiness perception of manufactured foods.

METHODS

A cross-sectional study was conducted in a convenience sample of schoolchildren attending primary schools in Victoria, Australia. Participants completed one 24-hour urine collection, which was analyzed for sodium, potassium, and creatinine. Completeness of collections was assessed using collection time, total volume, and urinary creatinine. One 24-hour dietary recall was completed to assess dietary intake. Other data collected included blood pressure, body weight, height, waist and hip circumference. Children were also presented with high and low sodium variants of food products and asked to discriminate salt level and choose their preferred variant. Parents provided demographic information and information on use of discretionary salt. Descriptive statistics will be used to describe sodium and potassium intakes. Linear and logistic regression models with clustered robust standard errors will be used to assess the association between electrolyte intake and health outcomes (blood pressure and body mass index/BMI z-score and waist circumference) and to assess differences in taste preference and discrimination between high and low sodium foods, and correlations between preference, sodium intake, and covariates.

RESULTS

A total of 780 children across 43 schools participated. The results from this study are expected at the end of 2015.

CONCLUSIONS

This study will provide the first objective measure of sodium and potassium intake in Australian schoolchildren and improve our understanding of the relationship of these electrolytes to cardiovascular risk factors. Furthermore, this study will provide insight into child taste preferences and explore related factors. Given the cardiovascular implications of consuming too much sodium and too little potassium, monitoring of these nutrients during childhood is an important public health initiative.

Urine sodium excretion increased slightly among U.S. adults between 1988 and 2010

Little information is available on temporal trends in sodium intake in the U.S. population using urine sodium excretion as a biomarker. Our aim was to assess 1988-2010 trends in estimated 24-h urine sodium (24hUNa) excretion among U.S. adults (age 20-59 y) participating in the cross-sectional NHANES. We used subsamples from a 1988-1994 convenience sample, a 2003-2006 one-third random sample, and a 2010 one-third random sample to comply with resource constraints. We estimated 24hUNa excretion from measured sodium concentrations in spot urine samples by use of calibration equations (for men and women) derived from the International Cooperative Study on Salt, Other Factors, and Blood Pressure study. Estimated 24hUNa excretion increased over the 20-y period [1988-1994, 2003-2006, and 2010; means ± SEMs (n): 3160 ± 38.4 mg/d (1249), 3290 ± 29.4 mg/d (1235), and 3290 ± 44.4 mg/d (525), respectively; P-trend = 0.022]. We observed significantly higher mean estimated 24hUNa excretion in each survey period (P < 0.001) for men compared with women (31-33%) and for persons with a higher body mass index (BMI; 32-35% for obese vs. normal weight) or blood pressure (17-26% for hypertensive vs. normal blood pressure). After adjusting for age, sex, and race-ethnicity, temporal trends in mean estimated 24hUNa excretion remained significant (P-trend = 0.004). We observed no temporal trends in mean estimated 24hUNa excretion among BMI subgroups, nor after adjusting for BMI. Although several limitations apply to this analysis (the use of a convenience sample in 1988-1994 and using estimated 24hUNa excretion as a biomarker of sodium intake), these first NHANES data suggest that mean estimated 24hUNa excretion increased slightly in U.S. adults over the past 2 decades, and this increase may be explained by a shift in the distribution of BMI.

Challenges in sodium intake reduction and meal consumption patterns among participants with metabolic syndrome in a dietary trial

Background

Dietary guidelines suggest limiting daily sodium intake to <2,300 mg for the general population, and <1,500 mg/d for those with certain cardiovascular risk factors. Despite these recommendations, few Americans are able to achieve this goal. Identifying challenges in meeting these guidelines is integral for successful compliance. This analysis examined patterns and amount of daily sodium intake among participants with metabolic syndrome enrolled in a one-year dietary intervention study.

Methods

Two hundred forty participants with metabolic syndrome enrolled in a dietary intervention trial to lose weight and improve dietary quality. Three 24-hour dietary recalls were collected at each visit which provided meal patterns and nutrient data, including sodium intake. A secondary data analysis was conducted to examine sodium consumption patterns at baseline and at one-year study visits. Sodium consumption patterns over time were examined using linear mixed models.

Results

The percentage of meals reported eaten in the home at both baseline and one-year follow-up was approximately 69%. Follow-up for the one-year dietary intervention revealed that the participants who consumed sodium greater than 2,300 mg/d declined from 75% (at baseline) to 59%, and those that consumed higher than 1,500 mg/d declined from 96% (at baseline) to 85%. Average sodium intake decreased from 2,994 mg at baseline to 2,558 mg at one-year (P < 0.001), and the sodium potassium ratio also decreased from 1.211 to 1.047 (P < 0.001). Sodium intake per meal varied significantly by meal type, location, and weekday, with higher intake at dinner, in restaurants, and on weekends. At-home lunch and dinner sodium intake decreased (P < 0.05), while dinner sodium intake at restaurant/fast food chains increased from baseline to one-year (P < 0.05).

Conclusion

Sodium intake for the majority of participants exceeded the recommended dietary guidelines. Findings support actions that encourage low-sodium food preparation at home and encourage public health policies that decrease sodium in restaurants and prepared foods.

Dietary sodium intake is associated with total fluid and sugar-sweetened beverage consumption in US children and adolescents aged 2-18 y: NHANES 2005-2008

BACKGROUND

Increasing dietary sodium drives the thirst response. Because sugar-sweetened beverages (SSBs) are frequently consumed by children, sodium intake may drive greater consumption of SSBs and contribute to obesity risk.

OBJECTIVE

We examined the association between dietary sodium, total fluid, and SSB consumption in a nationally representative sample of US children and adolescents aged 2-18 y.

DESIGN

We analyzed cross-sectional data from NHANES 2005-2008. Dietary sodium, fluid, and SSB intakes were assessed with a 24-h dietary recall. Multiple regression analysis was used to assess associations between sodium, fluid, and SSBs adjusted for age, sex, race-ethnic group, body mass index (BMI), socioeconomic status (SES), and energy intake.

RESULTS

Of 6400 participants, 51.3% (n = 3230) were males, and the average (±SEM) age was 10.1 ± 0.1 y. The average sodium intake was 3056 ± 48 mg/d (equivalent to 7.8 ± 0.1 g salt/d). Dietary sodium intake was positively associated with fluid consumption (r = 0.42, P < 0.001). After adjustment for age, sex, race-ethnic group, SES, and BMI, each additional 390 mg Na/d (1 g salt/d) was associated with a 74-g/d greater intake of fluid (P < 0.001). In consumers of SSBs (n = 4443; 64%), each additional 390 mg Na/d (1 g salt/d) was associated with a 32-g/d higher intake of SSBs (P < 0.001) adjusted for age, sex, race-ethnic group, SES, and energy intake.

CONCLUSIONS

Dietary sodium is positively associated with fluid consumption and predicted SSB consumption in consumers of SSBs. The high dietary sodium intake of US children and adolescents may contribute to a greater consumption of SSBs, identifying a possible link between dietary sodium intake and excess energy intake.

Dietary salt intake, sugar-sweetened beverage consumption, and obesity risk

OBJECTIVE

To determine the association among dietary salt, fluid, and sugar-sweetened beverage (SSB) consumption and weight status in a nationally representative sample of Australian children aged 2 to 16 years.

METHODS

Cross-sectional data from the 2007 Australian National Children's Nutrition and Physical Activity Survey. Consumption of dietary salt, fluid, and SSB was determined via two 24-hour dietary recalls. BMI was calculated from recorded height and weight. Regression analysis was used to assess the association between salt, fluid, SSB consumption, and weight status.

RESULTS

Of the 4283 participants, 62% reported consuming SSBs. Older children and those of lower socioeconomic status (SES) were more likely to consume SSBs (both Ps < .001). Dietary salt intake was positively associated with fluid consumption (r = 0.42, P < .001); each additional 1 g/d of salt was associated with a 46 g/d greater intake of fluid, adjusted for age, gender, BMI, and SES (P < .001). In those consuming SSBs (n = 2571), salt intake was positively associated with SSB consumption (r = 0.35, P < .001); each additional 1 g/d of salt was associated with a 17 g/d greater intake of SSB, adjusted for age, gender, SES, and energy (P < .001). Participants who consumed more than 1 serving (≥ 250 g) of SSB were 26% more likely to be overweight/obese (odds ratio: 1.26, 95% confidence interval: 1.03-1.53).

CONCLUSIONS

Dietary salt intake predicted total fluid consumption and SSB consumption within consumers of SSBs. Furthermore, SSB consumption was associated with obesity risk. In addition to the known benefits of lowering blood pressure, salt reduction strategies may be useful in childhood obesity prevention efforts.

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.

Reducing the sodium-potassium ratio in the US diet: a challenge for public health

BACKGROUND

The 2010 Dietary Guidelines emphasized that dietary sodium should be limited to 2300 mg/d, with a lower limit of 1500 mg/d for adults aged >50 y, non-Hispanic blacks, and those with diabetes, hypertension, or chronic kidney disease. The potassium goal remained at 4700 mg/d.

OBJECTIVE

The objective was to identify subpopulations for whom the 1500- or 2300-mg Na/d goals applied and to examine the joint sodium and potassium intakes for these persons.

DESIGN

The analyses were based on NHANES 2003-2008 data for 12,038 adult men and women aged ≥20 y. Persons aged >50 y, non-Hispanic blacks, and persons with hypertension, diabetes, and chronic kidney disease were identified. Mean sodium, potassium, and energy intakes were obtained from 2 nonconsecutive 24-h dietary recalls. Historical analyses of the sodium-potassium ratios in the American diet were based on NHANES 1971-2006.

RESULTS

Among persons recommended to consume <2300 mg Na/d, <0.12% jointly met the sodium and potassium guidelines. In the 1500-mg/d group, the guidelines were jointly met by <0.015%. Based on Dietary Guidelines, the corresponding dietary sodium-potassium ratio was either 0.49 (2300/4700) or 0.32 (1500/4700). Historical analyses of NHANES data by age-sex groups from 1971 to 2006 showed that sodium-potassium ratios were never <0.83.

CONCLUSIONS

Joint dietary guidelines for sodium and potassium, intended for most American adults, are currently being met by ≤0.015% of the population. Extraordinary efforts will be needed to meet the recommendations of the Dietary Guidelines.

Biochemical and sensory changes in dry-cured ham salted with partial replacements of NaCl by other chloride salts

The reduction of the content of sodium chloride in dry-cured ham was studied in to prevent the problems related to high sodium intake (i.e. the hypertension). One of the possibilities to reduce the sodium content is the partial replacement of sodium chloride by mixtures of potassium, magnesium and calcium chloride salts. The effect of two salting formulations (formulation II: 50% NaCl-50% KCl and formulation III: 55% NaCl, 25% KCl, 15 CaCl(2) and 5 MgCl(2)) on the protease activity through the dry-curing process and on the sensory characteristics of the final product was evaluated and compared to those of control hams (formulation I, 100% NaCl). Sensory attributes were all affected in the hams containing CaCl(2) and MgCl(2) while hams containing 50% KCl and NaCl (formulation II) were better valued, except for the attribute taste probably due to the potassium contribution to bitter taste.

Association of sodium and potassium intake with left ventricular mass: coronary artery risk development in young adults

High salt intake may affect left ventricular mass (LVM). We hypothesized that urinary sodium (UNa) and sodium/potassium ratio (UNa/K) are associated with LVM in a predominantly normotensive cohort of young adults. The Coronary Artery Risk Development in Young Adults (CARDIA) Study is a multicenter cohort of black and white men and women aged 30±3.6 years at the time of baseline echocardiographic examination (1990-1991). 2D guided M-mode LVM indexed to body size (grams per meter(2.7)) was calculated, and UNa and potassium excretion assessed (average of three 24-hour urinary samples, n=1042). Linear and logistic regression analysis was used. Participants were 57% women and 55% black. Only 4% were hypertensive. UNa, urinary potassium, and UNa/K ratios were (mean±SD) 175.6±131.0, 56.4±46.3, and 3.4±1.4 mmol/24 h, respectively. Participants in the highest versus the lowest UNa excretion quartile had the greatest LVM (37.5 versus 34.0 g/m(2.7); P<0.001). Adjusted for age, sex, education, and race, LVM averaged 0.945 g/m(2.7) higher per SD of UNa/K (P=0.001). The relationship between UNa/K and LVM persisted among 399 participants with repeat echocardiographic measures 5 years later. In logistic regression analysis adjusted for age, sex, education, and race, each SD higher baseline UNa/K was associated with 23% and 38% greater chances of being in the highest quartile of LVM at baseline (odds ratio: 1.23; P=0.005) and 5 years later (odds ratio: 1.38; P=0.02). A higher sodium/potassium excretion ratio is significantly related to cardiac structure, even among healthy young adults.

Trends in 24-h urinary sodium excretion in the United States, 1957-2003: a systematic review

BACKGROUND

Few studies have examined temporal trends in sodium intake in the US population. Collections of 24-h urine sodium excretions are reliable markers for dietary sodium intake.

OBJECTIVE

We examined temporal trends in 24-h urine sodium excretions to estimate temporal trends in sodium intake in the US population.

DESIGN

We performed a systematic search of English-language articles in MEDLINE for studies that reported collections of 24-h urine sodium excretions in the United States. We estimated mean urine sodium excretions over time for all studies and demographic subgroups.

RESULTS

We analyzed 38 studies, which dated from 1957 to 2003, and estimated a mean (± SE) 24-h urine sodium excretion per person of 3526 ± 75 mg Na. In a multivariate random-effects model with study year, sex, age, and race, the study year was not associated with any significant change in sodium excretions (coefficient = 154 mg Na · 24 h⁻¹ · 10 y⁻¹; 95% CI: -140, 448 mg Na · 24 h⁻¹ · 10 y⁻¹). In subgroup analyses, there was no significant temporal trend seen in male, female, black, or white study participants.

CONCLUSION

Sodium intake in the US adult population appears to be well above current guidelines and does not appear to have decreased with time.

Dietary predictors of the insulin-like growth factor system in adolescent females: results from the Dietary Intervention Study in Children (DISC)

BACKGROUND

The insulin-like growth factor (IGF) system is associated with the adult diet and chronic disease. Childhood diet may influence chronic disease through its effect on the IGF system; however, there is limited information describing the dietary predictors of the IGF system in adolescents.

OBJECTIVE

We examined associations between dietary food intake [fat, protein (animal and vegetable), carbohydrate, lactose, dietary fiber, calcium, zinc, and sodium] and serum IGF-I, IGF binding protein 1 (IGFBP-1), IGF binding protein 3 (IGFBP-3), and the IGF-I:IGFBP-3 molar ratio in adolescent females.

DESIGN

One hundred fifty-nine adolescent females in the Dietary Intervention Study in Children (age range: 14-18 y; 0.2-6.3 y postmenarche) were included. The dietary intake was assessed via three 24-h dietary recalls. IGF-related biomarkers were determined by using radioimmunoassays. Associations between dietary intakes and biomarkers were assessed with Pearson's correlations and multivariable linear regression. Dietary intakes and biomarkers were logarithmically transformed; thus, beta coefficients represented percentages.

RESULTS

In analyses adjusted for energy, age, and time since menarche, significant correlations (P < 0.05) were as follows: IGF-I with total protein, lactose, calcium, and sodium; IGFBP-3 with total fat (inverse), lactose, fiber, and calcium; IGF-I/IGFBP-3 with lactose and calcium; and IGFBP-1 with vegetable protein. In multivariable analyses, significant predictors of IGF-I were energy (beta = 0.14, P < 0.05) and calcium (beta = 0.14, P < 0.01), the significant predictor of IGFBP-3 was calcium (beta = 0.07, P < 0.05), and significant predictors of IGFBP-1 were vegetable protein (beta = 0.49, P < 0.05) and body mass index-for-age percentile (beta = -0.01, P < 0.001).

CONCLUSION

This study provides evidence that dietary intake affects IGF-related biomarkers-particularly elevated calcium with IGF-I and IGFBP-3 and elevated vegetable protein with IGFBP-1-and, to our knowledge, is novel in reporting these associations in adolescent females. The Dietary Intervention Study in Children was registered at clinicaltrials.gov as NCT00000459.

Vitamin D repletion does not alter urinary calcium excretion in healthy postmenopausal women

OBJECTIVE

To evaluate, in a posthoc analysis of a previous study, whether vitamin D repletion in postmenopausal women with insufficient vitamin D increases urinary calcium excretion, as vitamin D therapy might contribute to hypercalciuria and calcium stones in susceptible individuals, and the effect of vitamin D on the risk of urolithiasis warrants attention.

SUBJECTS AND METHODS

We recruited 18 women at > or =5 years after menopause who had vitamin D insufficiency (serum 25(OH)-vitamin D, 16-24 mg/dL). We excluded women with a history of urolithiasis and kidney disease. Women had one calcium absorption study when vitamin D-insufficient, received vitamin D therapy, and completed a second calcium absorption study when vitamin D-replete. We fed subjects meals that mirrored the nutrient composition from self-reported 7-day diet diaries. To measure calcium absorption, we collected urine for 24 h during both visits.

RESULTS

We achieved vitamin D repletion in all women (25(OH)-vitamin D before and after treatment, 22 and 63 mg/dL, respectively; P < 0.001). The mean calcium intake was 832 mg/day. Residual urine specimens were available for 16 women, allowing a measurement of 24-h urinary calcium. Calcium excretion did not change after vitamin D therapy (212 before vs 195 mg/day after; P = 0.60). Of four women with hypercalciuria (>247 mg/day), calcium excretion decreased in three (377-312 mg/day, not significant).

CONCLUSION

Vitamin D supplementation did not increase the urinary calcium excretion in healthy postmenopausal women. Many stone formers are at risk of premature bone loss, vitamin D insufficiency, or both. Based on the present results we suggest a study of patients with hypercalciuria and nephrolithiasis to determine the risks of vitamin D therapy.

Salt intakes around the world: implications for public health

BACKGROUND

High levels of dietary sodium (consumed as common salt, sodium chloride) are associated with raised blood pressure and adverse cardiovascular health. Despite this, public health efforts to reduce sodium consumption remain limited to a few countries. Comprehensive, contemporaneous sodium intake data from around the world are needed to inform national/international public health initiatives to reduce sodium consumption.

METHODS

Use of standardized 24-h sodium excretion estimates for adults from the international INTERSALT (1985-87) and INTERMAP (1996-99) studies, and recent dietary and urinary sodium data from observational or interventional studies--identified by a comprehensive search of peer-reviewed and 'grey' literature--presented separately for adults and children. Review of methods for the estimation of sodium intake/excretion. Main food sources of sodium are presented for several Asian, European and Northern American countries, including previously unpublished INTERMAP data.

RESULTS

Sodium intakes around the world are well in excess of physiological need (i.e. 10-20 mmol/day). Most adult populations have mean sodium intakes >100 mmol/day, and for many (particularly the Asian countries) mean intakes are >200 mmol/day. Possible exceptions include estimates from Cameroon, Ghana, Samoa, Spain, Taiwan, Tanzania, Uganda and Venezuela, though methodologies were sub-optimal and samples were not nationally representative. Sodium intakes were commonly >100 mmol/day in children over 5 years old, and increased with age. In European and Northern American countries, sodium intake is dominated by sodium added in manufactured foods ( approximately 75% of intake). Cereals and baked goods were the single largest contributor to dietary sodium intake in UK and US adults. In Japan and China, salt added at home (in cooking and at the table) and soy sauce were the largest sources.

CONCLUSIONS

Unfavourably high sodium intakes remain prevalent around the world. Sources of dietary sodium vary largely worldwide. If policies for salt reduction at the population level are to be effective, policy development and implementation needs to target the main source of dietary sodium in the various populations.

Dietary salt does not influence the disposition of verapamil enantiomers in relation to efflux transporter ABCB1 genetic polymorphism in healthy Korean subjects

To evaluate the effects of dietary salt on the stereoselective disposition of verapamil enantiomers in relation to the transporter ABCB1 2677GG/3435CC and 2677TT/3435TT haplotypes, ten healthy subjects were asked to take diets of three different salt levels for 7 days in a randomized, three-way crossover manner. The plasma concentrations of verapamil and norverapamil enantiomers were determined after a single oral dose of 240 mg verapamil on the last day of each phase. Pharmacokinetic parameters were calculated by non-compartmental analysis techniques and compared among the three different dietary salt phases. Compared with the medium salt diet, the high and low salt diets had no significant effect on the disposition of verapamil enantiomers. Moreover, the ABCB1 haplotypes did not alter the impact of dietary salt, although ABCB1 2677TT/3435TT subjects had slightly, but not significantly, higher C(max) and area under the curve (AUC) and lower T(max) for the verapamil enantiomers than did 2677GG/3435CC subjects in each salt phase.

Effects of pressurization on structure, water distribution, and sensory attributes of cured ham: can pressurization reduce the crucial sodium content?

This study investigated the replacement of tumbling (intermittent vacuum tumbling for 6 h) with pressure treatment (7 MPa for 4 s) in the production of a cured ham product with the aim of elucidating if the pressure treatment could reduce the amount of salt added to obtain a satisfactory product. Confocal laser scanning microscopy (CLSM) revealed a pressure-induced loosening of the meat structure, and proton nuclear magnetic resonance (NMR) relaxometry revealed that this structural modification of the meat had an impact on water properties and water distribution in both cooked and cooked/fried products. Three salt levels (0.6, 1.1, and 1.7% w/w) were investigated, and sensory profiling revealed that the pressured-cooked meat obtained a significantly higher juiciness score at low and medium salt levels. In addition, sensory profiling assessments revealed that at the lowest salt concentration the pressured product was perceived to be saltier compared with the tumbled product; however, the difference was not significant and was absent upon frying. In contrast, in sensory time intensity analysis the maximum intensity and the total salt taste were significantly higher in the pressured samples at the low and medium salt levels in the cooked samples. In conclusion, the present study showed strong evidence that the structure and biophysical characteristics of cured ham is altered by pressurization and suggested that pressurization may reduce the critical amount of salt required in a ham product.

PREMIER--a trial of lifestyle interventions for blood pressure control: intervention design and rationale

Interventions encouraging adoption of healthy diets and increased physical activity are needed to achieve national goals for preventing and treating hypertension, cardiovascular disease, diabetes, and other chronic diseases. PREMIER was a multicenter clinical trial testing the effects of two lifestyle interventions on blood pressure control, compared with advice only. Both interventions implemented established national guidelines for blood pressure control (weight loss, reduced sodium and alcohol intake, and increased physical activity), and one intervention also included the Dietary Approaches to Stop Hypertension (DASH) diet. Both interventions focused on behavioral self-management, motivational enhancement, and personalized feedback. This article describes the design and evaluation approaches for these interventions. Evaluation of multicomponent lifestyle change interventions can help us understand the benefits and difficulties of making multiple lifestyle changes concurrently and the effects such changes can have on blood pressure, particularly in minorities at higher risk for hypertension.

The 2005 USDA Food Guide Pyramid is associated with more adequate nutrient intakes within energy constraints than the 1992 Pyramid

The USDA issued the Food Guide Pyramid (FGP) to help Americans choose healthy diets. We examined whether adherence to the 1992 and 2005 FGP was associated with moderate energy and adequate nutrient intakes. We used data for 2138 men and 2213 women > 18 y old, from the 2001-2002 U.S. National Health and Nutrition Examination Survey (NHANES). Quadratic programming was used to generate diets with minimal departure from intakes reported for the NHANES 2001-02. We examined the effect of the number of servings/d of Food Pyramid groups set at 1992 and at 2005 FGP recommendations for 1600, 2200, and 2800 kcal (1 kcal = 4.184 kJ) levels. We calculated energy and nutrients provided by different FGP dietary patterns. Within current U.S. dietary practices, following the 1992 FGP without sodium restriction may provide 200 more kcal than recommended for each energy level. Although it can meet most of old nutrient recommendations (1989), it fails to meet the latest dietary reference intakes, especially for the 1600 kcal level. The 2005 FGP appears to provide less energy and more adequate nutrient intakes, with the exception of vitamin E and potassium for some groups. However, without discretionary energy restriction, Americans are at risk of having excessive energy intake even if they follow the 2005 FGP food serving recommendations. Our analysis suggests that following the 2005 FGP may be associated with lower energy and optimal nutrient intake. Careful restriction of discretionary calories appears necessary for appropriate energy intakes to be maintained.