A comprehensive review on salt and health and current experience of worldwide salt reduction programmes

Potentially modifiable factors affecting the progression of autosomal dominant polycystic kidney disease

BACKGROUND AND OBJECTIVES

The Consortium for Radiologic Imaging Studies of Polycystic Kidney Disease (CRISP) was created to identify markers of disease progression in patients with autosomal dominant polycystic kidney disease (ADPKD).

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Linear mixed models were utilized to model effects of baseline parameters on changes in natural-log (ln)-transformed total kidney volume (TKV) and iothalamate clearance (GFR) across time in CRISP participants (creatinine clearance at entry >70 ml/min). Stepwise selection was used to obtain a final main effect model.

RESULTS

TKV increased from year to year, whereas GFR uncorrected for body surface area (BSA) decreased only at year 6. Higher lnTKV and urine sodium excretion (U(Na)V), lower serum HDL-cholesterol, and younger age at baseline associated with greater lnTKV growth from baseline to year 3 and to year 6. Higher lnTKV at baseline associated with greater GFR decline from year 1 to year 3 and to year 6. Higher BSA and 24-hour urine osmolality at baseline associated with greater GFR decline from year 1 to year 6. Higher U(Na)V and lower serum HDL-cholesterol at baseline associated with greater GFR decline from year 1 to year 6 by univariate analysis only. Associations seen during year 1 to year 6 (not seen during year 1 to year 3) reflect the time lag between structural and functional disease progression.

CONCLUSIONS

Serum HDL-cholesterol, U(Na)V, and 24-hour urine osmolality likely affect ADPKD progression. To what extent their modification may influence the clinical course of ADPKD remains to be determined.

Estimation of salt intake by 24 h urinary sodium excretion in a representative sample of Spanish adults

The present study reports the Na intake of a representative sample of Spanish young and middle-aged adults aged 18–60 years (n418, 53·1 % women, selected from the capitals of fifteen provinces and the surrounding semi-urban/rural area), measured with a 24 h urinary Na excretion method. To validate the paper collection of 24 h urine, the correlation between fat-free mass determined by electrical bioimpedance (50·8 (sd11·3) kg) and that determined via urinary creatinine excretion (51·5 (sd18·8) kg) was calculated (r0·633,P < 0·001). Urinary Na excretion correlated with systolic and dyastolic blood pressure data (r0·243 and 0·153, respectively). Assuming that all urinary Na (168·0 (sd78·6) mmol/d) comes from the diet, Na excretion would correspond with a dietary salt intake of 9·8 (sd4·6) g/d, and it would mean that 88·2 % of the subjects had salt intakes above the recommended 5 g/d. Logistic regression analysis, adjusted for sex, age and BMI, showed male sex (OR 3·678, 95 % CI 2·336, 5·791) and increasing BMI (OR 1·069, 95 % CI 1·009, 1·132) (P < 0·001) to be associated with excreting >200 mmol/d urinary Na – a consequence of the higher salt intake in men and in participants with higher BMI. The present results help us to know the baseline salt intake in the Spanish young and middle-aged adult population, and can be used as the baseline to design policies to reduce salt consumption.

Salt and hypertension

Current salt intake is too high. Current evidence documents that salt is crucial to the genesis of hypertension.

Cardiovascular disease risk factors are highly prevalent in the office-working population of Nanjing in China

OBJECTIVE

To establish a profile of the modifiable cardiovascular disease (CVD) risk factors in the office-working population of Nanjing, China.

BACKGROUND

With increasing modernization in China, CVD is now common among Chinese. Relevant information on the prevalence of CVD risk factors in China is, however, limited.

METHODS

We recruited 2648 office working people aged 23-79 years without history of CVD or diabetes from 7 work units of Nanjing during the years 2003 to 2005. Information from a self-reported questionnaire on lifestyle, physical examination, fasting blood for lipid profiles, and a 75-gram oral glucose tolerance test (OGTT) were obtained from each participant. We analyzed the following 7 CVD risk factors: smoking, inadequate physical activity, unhealthy dietary habit, obesity, hypertension, dyslipidemia, and hyperglycemia.

RESULTS

The whole study population had an average of 2.8 risk factors, while 95.6%, 79.4% and 55.6% of them had respectively ≥ 1, ≥ 2 and ≥ 3 of the 7 CVD risk factors. Men had a higher proportion of smoking, hypertension, dyslipidemia, hyperglycemia, but lower in light physical activity compared with women. Number of CVD risk factors increased with age. Although risk factors in men were more common than women, they increased alarmingly in postmenopausal women.

CONCLUSIONS

CVD risk factors are common in office-working people in Nanjing, China. Effective interventions and treatment against risk factors should be adopted in the high risk population, which may greatly reduce the future burden of CVD in the Chinese population.

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

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

Influence of dietary modifications on the blood pressure response to antihypertensive medication

Identifying dietary modifications that potentiate the blood pressure (BP)-lowering effects of antihypertensive medications and that are practical for free-living people may assist in achieving BP reduction goals. We assessed whether two dietary patterns were effective in lowering BP in persons on antihypertensive therapy and in those not on therapy. Ninety-four participants (38/56 females/males), aged 55·6 (sd 9·9) years, consumed two 4-week dietary regimens in random order (Dietary Approaches to Stop Hypertension (DASH)-type diet and low-Na high-K (LNAHK) diet) with a control diet before each phase. Seated home BP was measured daily for the last 2 weeks in each phase. Participants were grouped based on antihypertensive drug therapy. The LNAHK diet produced a greater fall in systolic BP (SBP) in those on antihypertensive therapy ( − 6·2 (sd 6·0) mmHg) than in those not on antihypertensive therapy ( − 2·8 (sd 4·0) mmHg) (P = 0·036), and this was greatest for those on renin–angiotensin system (RAS) blocker therapy ( − 9·5 (sd 6·4) mmHg) (interaction P = 0·007). The fall in SBP on the DASH-type diet, in those on therapy (overall − 1·1 (sd 6·2) mmHg; renin–angiotensin blocker therapy − 4·2 (sd 4·7) mmHg), was not as marked as that observed on the LNAHK diet. Dietary modifications are an important part of all hypertension management regimens, and a low-Na and high-K diet enhances the BP-lowering effect of antihypertensive medications, particularly those targeting the RAS.

ASH position paper: dietary approaches to lower blood pressure

A substantial body of evidence has implicated several aspects of diet in the pathogenesis of elevated blood pressure (BP). Well-established risk factors for elevated BP include excess salt intake, low potassium intake, excess weight, high alcohol consumption, and suboptimal dietary pattern. African Americans are especially sensitive to the BP-raising effects of excess salt intake, insufficient potassium intake, and suboptimal diet. In this setting, dietary changes have the potential to substantially reduce racial disparities in BP and its consequences. In view of the age-related rise in BP in both children and adults, the direct, progressive relationship of BP with cardiovascular-renal diseases throughout the usual range of BP, and the worldwide epidemic of BP-related disease, efforts to reduce BP in nonhypertensive as well as hypertensive individuals are warranted. In nonhypertensives, dietary changes can lower BP and delay, if not prevent, hypertension. In uncomplicated stage I hypertension, dietary changes serve as initial treatment before drug therapy. In hypertensive individuals already on drug therapy, lifestyle modifications can further lower BP. The current challenge is designing and implementing effective clinical and public health interventions that lead to sustained dietary changes among individuals and more broadly in the general population.

Nutritional profiles in a public health perspective: a critical review

Nutritional profiling is defined as 'the science of categorizing foods according to their nutritional composition' and it is useful for food labelling and regulation of health claims. The evidence for the link between nutrients and health outcomes was reviewed. A reduced salt intake reduces blood pressure, but only a few randomized controlled trials have verified the effect of salt on overall and cardiovascular mortality. Evidence linking a reduced fat intake with cardiovascular mortality and obesity is generally non-significant. Studies that have examined the relationship between obesity and diet have produced contrasting results. A simulation exercise that demonstrated that the impact of a reduced salt and fat intake on overall mortality would be negligible in the European population was carried out. Consideration of the literature and the results of this simulation exercise suggest that the introduction of nutritional profiles in Europe would be expected to have a very limited impact on health outcomes.

Salt restriction for the prevention of cardiovascular disease

BACKGROUND

Restricting the dietary intake of sodium chloride is associated with a reduction of the arterial blood pressure by approximately 4/2 mm Hg in hypertensive patients and by approximately 1/0.6 mm Hg in normotensive persons. As the cardiovascular risk is known to rise steadily with systolic blood pressure values starting from 115 mm Hg, lowering the mean blood pressure of the general population by dietary salt restriction would seem to be a practicable form of primary prevention of cardiovascular disease.

METHOD

Selective literature search and review.

RESULTS

Multiple studies have shown dietary salt restriction to be associated with lower cardiovascular morbidity and mortality. The reduction of adjusted relative risk in controlled observational studies ranges from 25% over 15 years to 41% over three years.

CONCLUSION

On the basis of the available studies, it seems likely that a moderate lowering of the daily intake of sodium chloride by the general population from 8 to 12 grams per day (the current value) to 5 to 6 grams per day would be a useful public health measure, with economic benefits as well. The potential risks for certain groups of individuals are foreseeable and controllable. A general reduction of dietary salt intake can only be achieved by reducing the sodium chloride content of industrially processed foods, as these account for 75% to 80% of the sodium chloride consumed daily. Aside from a general reduction of dietary salt intake, further important primary prevention measures for the general population include changes in lifestyle and in dietary habits.

Implications of salt and sodium reduction on microbial food safety

Excess sodium consumption has been cited as a primary cause of hypertension and cardiovascular diseases. Salt (sodium chloride) is considered the main source of sodium in the human diet, and it is estimated that processed foods and restaurant foods contribute 80% of the daily intake of sodium in most of the Western world. However, ample research demonstrates the efficacy of sodium chloride against pathogenic and spoilage microorganisms in a variety of food systems. Notable examples of the utility and necessity of sodium chloride include the inhibition of growth and toxin production by Clostridium botulinum in processed meats and cheeses. Other sodium salts contributing to the overall sodium consumption are also very important in the prevention of spoilage and/or growth of microorganisms in foods. For example, sodium lactate and sodium diacetate are widely used in conjunction with sodium chloride to prevent the growth of Listeria monocytogenes and lactic acid bacteria in ready-to-eat meats. These and other examples underscore the necessity of sodium salts, particularly sodium chloride, for the production of safe, wholesome foods. Key literature on the antimicrobial properties of sodium chloride in foods is reviewed here to address the impact of salt and sodium reduction or replacement on microbiological food safety and quality.

Dietary sources of sodium in China, Japan, the United Kingdom, and the United States, women and men aged 40 to 59 years: the INTERMAP study

Public health campaigns in several countries encourage population-wide reduced sodium (salt) intake, but excessive intake remains a major problem. Excessive sodium intake is independently related to adverse blood pressure and is a key factor in the epidemic of prehypertension/hypertension. Identification of food sources of sodium in modern diets is critical to effective reduction of sodium intake worldwide. We used data from the INTERMAP Study to define major food sources of sodium in diverse East Asian and Western population samples. INTERMAP is an international, cross-sectional, epidemiologic study of 4, 680 individuals ages 40 to 59 years from Japan (four samples), People's Republic of China (three rural samples), the United Kingdom (two samples), and the United States (eight samples); four in-depth, multipass 24-hour dietary recalls/person were used to identify foods accounting for most dietary sodium intake. In the People's Republic of China sample, most (76%) dietary sodium was from salt added in home cooking, about 50% less in southern than northern samples. In Japan, most (63%) dietary sodium came from soy sauce (20%), commercially processed fish/seafood (15%), salted soups (15%), and preserved vegetables (13%). Processed foods, including breads/cereals/grains, contributed heavily to sodium intake in the United Kingdom (95%) and the United States (for methodological reasons, underestimated at 71%). To prevent and control prehypertension/hypertension and improve health, efforts to remove excess sodium from diets in rural China should focus on reducing salt in home cooking. To avoid excess sodium intake in Japan, the United Kingdom, and the United States, salt must be reduced in commercially processed foods.

Longitudinal trends in major cardiovascular risk factors in the Czech population between 1985 and 2007/8. Czech MONICA and Czech post-MONICA

OBJECTIVE

The aim of our study was to assess longitudinal trends in major CV risk factors in a representative population sample of the Czech Republic.

METHODS

Three cross-sectional surveys of CV risk factors were conducted within the WHO MONICA project in six Czech districts in 1985 (n=2570), 1988 (n=2768), and 1992 (n=2343). In 1997/98, 2000/01, and 2007/08, another three screenings for CV risk factors (a 1% random sample, aged 25-64, mean age 45 years) were conducted in the six original districts (n=1990; 2055; and 2246, respectively).

RESULTS

Over a period of 22/23 years, there was a significant decrease in the prevalence of smoking in males (from 45.0 to 30.5%; p<0.001) and no change in smoking habits in females. BMI increased in males and did not change in females. Both systolic and diastolic blood pressure decreased significantly in both genders, while the prevalence of hypertension declined only in females. Awareness of hypertension also rose as did the proportion of individuals treated by antihypertensive drugs in both genders. Hypertension control improved in either gender. A remarkable drop in total cholesterol was seen in both sexes (males: from 6.21 + or - 1.29 to 5.29 + or - 1.10 mmol/L; p<0.001; females: from 6.18 + or - 1.26 to 5.30 + or - 1.06 mmol/L; p<0.001).

CONCLUSIONS

The striking improvement in CV risk factors documented between 1985 and 2007/8 most likely contributed to the decrease in CV mortality in the Czech Republic.

Salt sensitivity and circadian rhythm of blood pressure: the keys to connect CKD with cardiovascular events

In healthy subjects, blood pressure (BP) drops by 10-20% during the night. Conversely, in patients with the salt-sensitive type of hypertension or chronic kidney disease, nighttime BP does not fall, resulting in an atypical pattern of circadian BP rhythm that does not dip. This pattern is referred to as the 'non-dipper' pattern. Loss of renal functional reserve, due to either reduced ultrafiltration capacity or enhanced tubular sodium reabsorption, induces the salt-sensitive type of hypertension. When salt intake is excessive in patients with salt-sensitive hypertension, the defect in sodium excretory capability becomes evident, resulting in elevated BP during the night. This nocturnal hypertension compensates for diminished natriuresis during the daytime and enhances pressure natriuresis during the night. Nocturnal hypertension and the non-dipper pattern of circadian BP rhythm cause cardiovascular events. When excess salt intake is loaded in patients who are in a salt-sensitive state, glomerular capillary pressure is also elevated, resulting in glomerular sclerosis and eventual renal failure. In this way, salt sensitivity and excess salt intake contribute to both cardiovascular and renal damage at the same time. We propose that salt sensitivity of BP and excess salt intake have important roles in the genesis of the cardiorenal connection. Salt sensitivity and circadian rhythm of BP are the keys to understanding the connections between cardiovascular and renal complications.

Reducing population salt intake worldwide: from evidence to implementation

Raised blood pressure is a major cause of cardiovascular disease, responsible for 62% of stroke and 49% of coronary heart disease. There is overwhelming evidence that dietary salt is the major cause of raised blood pressure and that a reduction in salt intake lowers blood pressure, thereby, reducing blood pressure-related diseases. Several lines of evidence including ecological, population, and prospective cohort studies, as well as outcome trials, demonstrate that a reduction in salt intake is related to a lower risk of cardiovascular disease. Increasing evidence also suggests that a high salt intake may directly increase the risk of stroke, left ventricular hypertrophy, and renal disease; is associated with obesity through soft drink consumption; is related to renal stones and osteoporosis; is linked to the severity of asthma; and is probably a major cause of stomach cancer. In most developed countries, a reduction in salt intake can be achieved by a gradual and sustained reduction in the amount of salt added to foods by the food industry. In other countries where most of the salt consumed comes from salt added during cooking or from sauces, a public health campaign is needed to encourage consumers to use less salt. Several countries have already reduced salt intake. The challenge now is to spread this out to all other countries. A modest reduction in population salt intake worldwide will result in a major improvement in public health.

Stopping the cardiovascular disease continuum: Focus on prevention

The cardiovascular disease continuum (CVDC) is a sequence of events, which begins from a host of cardiovascular risk factors that consists of diabetes mellitus, dyslipidemia, hypertension, smoking and visceral obesity. If it is not intervened with early, it inexorably progresses to atherosclerosis, coronary artery disease, myocardial infarction, left ventricular hypertrophy, and left ventricular dilatation, which lead to left ventricular diastolic or systolic dysfunction and eventually end-stage heart failure and death. Treatment intervention at any stage during its course will either arrest or delay its progress. In this editorial, the cardiovascular risk factors that initiate and perpetuate the CVDC are briefly discussed, with an emphasis on their early prevention or aggressive treatment.

Salt content in canteen and fast food meals in Denmark

Background

A high salt (=NaCl) intake is associated with high blood pressure, and knowledge of salt content in food and meals is important, if the salt intake has to be decreased in the general population.

Objective

To determine the salt content in worksite canteen meals and fast food.

Design

For the first part of this study, 180 canteen meals were collected from a total of 15 worksites with in-house catering facilities. Duplicate portions of a lunch meal were collected from 12 randomly selected employees at each canteen on two non-consecutive days. For the second part of the study, a total of 250 fast food samples were collected from 52 retail places representing both city (Aarhus) and provincial towns. The canteen meals and fast food samples were analyzed for chloride by potentiometric titration with silver nitrate solution, and the salt content was estimated.

Results

The salt content in lunch meals in worksite canteens were 3.8±1.8 g per meal and 14.7±5.1 g per 10 MJ for men (n=109), and 2.8±1.2 g per meal and 14.4±6.2 g per 10 MJ for women (n=71). Salt content in fast food ranged from 11.8±2.5 g per 10 MJ (burgers) to 16.3±4.4 g per 10 MJ (sausages) with a mean content of 13.8±3.8 g per 10 MJ.

Conclusion

Salt content in both fast food and in worksite canteen meals is high and should be decreased.

Projected effect of dietary salt reductions on future cardiovascular disease

BACKGROUND

The U.S. diet is high in salt, with the majority coming from processed foods. Reducing dietary salt is a potentially important target for the improvement of public health.

METHODS

We used the Coronary Heart Disease (CHD) Policy Model to quantify the benefits of potentially achievable, population-wide reductions in dietary salt of up to 3 g per day (1200 mg of sodium per day). We estimated the rates and costs of cardiovascular disease in subgroups defined by age, sex, and race; compared the effects of salt reduction with those of other interventions intended to reduce the risk of cardiovascular disease; and determined the cost-effectiveness of salt reduction as compared with the treatment of hypertension with medications.

RESULTS

Reducing dietary salt by 3 g per day is projected to reduce the annual number of new cases of CHD by 60,000 to 120,000, stroke by 32,000 to 66,000, and myocardial infarction by 54,000 to 99,000 and to reduce the annual number of deaths from any cause by 44,000 to 92,000. All segments of the population would benefit, with blacks benefiting proportionately more, women benefiting particularly from stroke reduction, older adults from reductions in CHD events, and younger adults from lower mortality rates. The cardiovascular benefits of reduced salt intake are on par with the benefits of population-wide reductions in tobacco use, obesity, and cholesterol levels. A regulatory intervention designed to achieve a reduction in salt intake of 3 g per day would save 194,000 to 392,000 quality-adjusted life-years and $10 billion to $24 billion in health care costs annually. Such an intervention would be cost-saving even if only a modest reduction of 1 g per day were achieved gradually between 2010 and 2019 and would be more cost-effective than using medications to lower blood pressure in all persons with hypertension.

CONCLUSIONS

Modest reductions in dietary salt could substantially reduce cardiovascular events and medical costs and should be a public health target.

A framework for public health action: the health impact pyramid

A 5-tier pyramid best describes the impact of different types of public health interventions and provides a framework to improve health. At the base of this pyramid, indicating interventions with the greatest potential impact, are efforts to address socioeconomic determinants of health. In ascending order are interventions that change the context to make individuals' default decisions healthy, clinical interventions that require limited contact but confer long-term protection, ongoing direct clinical care, and health education and counseling. Interventions focusing on lower levels of the pyramid tend to be more effective because they reach broader segments of society and require less individual effort. Implementing interventions at each of the levels can achieve the maximum possible sustained public health benefit.

Aldosterone and arterial hypertension

In the setting of primary aldosteronism, elevated aldosterone levels are associated with increased blood pressure. Aldosterone concentrations within the normal range, however, can also alter blood pressure. Furthermore, the aldosterone-to-renin ratio, an indicator of aldosterone excess, is associated with hypertension, even in patients without excessive absolute aldosterone levels. In this Review we assess the data on the role of aldosterone in the development and maintenance of hypertension. We provide an overview of the complex crosstalk between genetic and environmental factors, and about aldosterone-mediated arterial hypertension and target organ damage. The discussion is organized according to major targets of aldosterone action: the collecting duct in the kidney, the vasculature and the central nervous system. The antihypertensive efficacy of mineralocorticoid-receptor blockers, even in patients with aldosterone values in the normal range, supports the evidence that aldosterone plays a part in blood pressure elevation in the absence of primary aldosteronism.

Reducing dietary sodium intake: the Canadian context

Sodium is a required nutrient; Adequate Intakes for adults range from 1200 to 1500 mg·day–1, depending on age. The Tolerable Upper Intake Level (UL) for sodium is 2300 mg·day–1 for adults, based on the relationship between sodium intake and increased blood pressure. Elevated blood pressure, which is prevalent among Canadians, is, in turn, a major risk factor for stroke, cardiovascular disease, and renal disease. Sodium intake is not the only determinant of blood pressure; other modifiable risk factors include relative mass, physical activity, overall dietary quality, and alcohol consumption. However, because >90% of adult Canadian men and two thirds of Canadian women have sodium intakes above the UL, Health Canada’s Working Group on Dietary Sodium Reduction has been charged with developing, implementing, and overseeing a strategy to reduce Canadians’ sodium intakes. It is estimated that ∼75% of dietary sodium is added during food processing; in addition to taste and palatability, sodium also has functional roles in food manufacturing and preservation, although the amounts used often exceed those required. Because of the central role of processed foods in sodium intake, the strategy proposed by Health Canada’s Working Group includes voluntary reduction of sodium in processed foods and foods sold in food service establishments. It will also include an education and awareness campaign, and research and surveillance. Initiatives to reduce sodium in other parts of the world have demonstrated that it will be challenging to reduce sodium intake to the recommended range and will likely require many years to accomplish.

Analysis of salt content in meals in kindergarten facilities in Novi Sad

Introduction. Investigations have brought evidence that salt intake is positively related to systolic blood pressure and that children with higher blood pressure are more susceptible to hypertension in adulthood. In developed countries the main source of salt is processed food. Objective The aim of this paper was to determine total sodium chloride (NaCl) in average daily meal (breakfast, snack and dinner) and in each of three meals children receive in kindergarten. Methods. From kindergarten, in the meal time, 88 samples of daily meals ( breakfast, snacks and dinner) offered to children aged 4-6 years were taken. Standardized laboratory methods were applied to determine proteins, fats, ash and water in order to calculate energy value of meal. The titrimetric method with AgNO3, and K2CrO4 as indicator, was applied in order to determine chloride ion. Content of NaCl was calculated as %NaCl = mlAgNO3 ? 0.05844 ? 5 ? 100/g tested portion. NaCl content in total daily meal and each meal and in 100 kcal of each meal was calculated using descriptive statistical method. Student?s t-test was applied to determine statistical differences of NaCl amount among meals. Results. NaCl content in average daily meal was 5.2?1.7 g (CV 31.7%), in breakfast 1.5?0.6 g (CV 37.5%), in dinner 3.5?1.6 g (CV 46.1%) and in snack 0.3?0.4 g (CV 163.3%). NaCl content per 100 kcal of breakfast was 0.4?0.1 g (CV 29.5%), dinner 0.7?0.2 g (CV 27.8%) and snack 0.13?0.19 g (CV 145.8%). The difference of NaCl content among meals was statistically significant (p<0.01). Conclusion. Children in kindergarten, through three meals, received NaCl in a quantity that exceeded internationally established population nutrient goal for daily salt intake. The main source of NaCl was dinner, a meal that is cooked at place.

Salt intake, stroke, and cardiovascular disease: meta-analysis of prospective studies

OBJECTIVE

To assess the relation between the level of habitual salt intake and stroke or total cardiovascular disease outcome.

DESIGN

Systematic review and meta-analysis of prospective studies published 1966-2008.

DATA SOURCES

Medline (1966-2008), Embase (from 1988), AMED (from 1985), CINAHL (from 1982), Psychinfo (from 1985), and the Cochrane Library. Review methods For each study, relative risks and 95% confidence intervals were extracted and pooled with a random effect model, weighting for the inverse of the variance. Heterogeneity, publication bias, subgroup, and meta-regression analyses were performed. Criteria for inclusion were prospective adult population study, assessment of salt intake as baseline exposure, assessment of either stroke or total cardiovascular disease as outcome, follow-up of at least three years, indication of number of participants exposed and number of events across different salt intake categories.

RESULTS

There were 19 independent cohort samples from 13 studies, with 177 025 participants (follow-up 3.5-19 years) and over 11 000 vascular events. Higher salt intake was associated with greater risk of stroke (pooled relative risk 1.23, 95% confidence interval 1.06 to 1.43; P=0.007) and cardiovascular disease (1.14, 0.99 to 1.32; P=0.07), with no significant evidence of publication bias. For cardiovascular disease, sensitivity analysis showed that the exclusion of a single study led to a pooled estimate of 1.17 (1.02 to 1.34; P=0.02). The associations observed were greater the larger the difference in sodium intake and the longer the follow-up.

CONCLUSIONS

High salt intake is associated with significantly increased risk of stroke and total cardiovascular disease. Because of imprecision in measurement of salt intake, these effect sizes are likely to be underestimated. These results support the role of a substantial population reduction in salt intake for the prevention of cardiovascular disease.

ASH Position Paper: Dietary approaches to lower blood pressure

A substantial body of evidence has implicated several aspects of diet in the pathogenesis of elevated blood pressure (BP). Well-established risk factors for elevated BP include excess salt intake, low potassium intake, excess weight, high alcohol consumption, and suboptimal dietary pattern. African Americans are especially sensitive to the BP-raising effects of excess salt intake, insufficient potassium intake, and suboptimal diet. In this setting, dietary changes have the potential to substantially reduce racial disparities in BP and its consequences. In view of the age-related rise in BP in both children and adults, the direct, progressive relationship of BP with cardiovascular-renal diseases throughout the usual range of BP, and the worldwide epidemic of BP-related disease, efforts to reduce BP in nonhypertensive as well as hypertensive individuals are warranted. In nonhypertensives, dietary changes can lower BP and delay, if not prevent, hypertension. In uncomplicated stage I hypertension, dietary changes serve as initial treatment before drug therapy. In hypertensive individuals already on drug therapy, lifestyle modifications can further lower BP. The current challenge is designing and implementing effective clinical and public health interventions that lead to sustained dietary changes among individuals and more broadly in the general population.

Effect of modest salt reduction on blood pressure, urinary albumin, and pulse wave velocity in white, black, and Asian mild hypertensives

A reduction in salt intake lowers blood pressure. However, most previous trials were in whites with few in blacks and Asians. Salt reduction may also reduce other cardiovascular risk factors (eg, urinary albumin excretion, arterial stiffness). However, few well-controlled trials have studied these effects. We carried out a randomized double-blind crossover trial of salt restriction with slow sodium or placebo, each for 6 weeks, in 71 whites, 69 blacks, and 29 Asians with untreated mildly raised blood pressure. From slow sodium to placebo, urinary sodium was reduced from 165+/-58 (+/-SD) to 110+/-49 mmol/24 hours (9.7 to 6.5 g/d salt). With this reduction in salt intake, there was a significant decrease in blood pressure from 146+/-13/91+/-8 to 141+/-12/88+/-9 mm Hg (P<0.001), urinary albumin from 10.2 (IQR: 6.8 to 18.9) to 9.1 (6.6 to 14.0) mg/24 hours (P<0.001), albumin/creatinine ratio from 0.81 (0.47 to 1.43) to 0.66 (0.44 to 1.22) mg/mmol (P<0.001), and carotid-femoral pulse wave velocity from 11.5+/-2.3 to 11.1+/-1.9 m/s (P<0.01). Subgroup analysis showed that the reductions in blood pressure and urinary albumin/creatinine ratio were significant in all groups, and the decrease in pulse wave velocity was significant in blacks only. These results demonstrate that a modest reduction in salt intake, approximately the amount of the current public health recommendations, causes significant falls in blood pressure in all 3 ethnic groups. Furthermore, it reduces urinary albumin and improves large artery compliance. Although both could be attributable to the falls in blood pressure, they may carry additional benefits on reducing cardiovascular disease above that obtained from the blood pressure falls alone.