Modest Reduction In Salt Intake Research Articles

Salt reduction to prevent hypertension: the reasons of the controversy.

There is a causal relationship between dietary salt intake and blood pressure. A reduction in salt intake from the current world average of ∼10 g/day to the WHO recommended level of <5 g/day, lowers blood pressure and reduces the risk of cardiovascular disease and all-cause mortality. However, a few cohort studies have claimed that there is a J-shaped relationship between salt intake and cardiovascular risk, i.e. both high and low salt intakes are associated with an increased risk. These cohort studies have several methodological problems, including reverse causality, and inaccurate and biased estimation of salt intake, e.g. from a single spot urine sample with formulas. Recent studies have shown that the formulas used to estimate salt intake from spot urine cause a spurious J-curve. Research with inappropriate methodology should not be used to refute the robust evidence on the enormous benefits of population-wide reduction in salt intake. Several countries, e.g. Finland, the UK, have successfully reduced salt intake, which has resulted in falls in population blood pressure and deaths from stroke and ischaemic heart disease. Every country should develop and implement a coherent, workable strategy to reduce salt intake. Even a modest reduction in salt intake across the whole population will lead to a major improvement in public health, along with huge cost-savings to the healthcare service.

Barriers of dietary salt reduction among hypertensive patients: a cross sectional study

Background: Healthy dietary practice is an important lifestyle modification and one of the key adjuncts to pharmacotherapy in management of hypertension. A modest reduction in salt intake of 5 gm/day lowered blood pressure by 7/4 mmHg diastolic in hypertensive patients. Despite knowledge about the ill consequences, many people continue to consume high levels of salt in their diet. To motivate people to reduce salt in their diet, a solid understanding of barriers encountered by those under salt reduction recommendation is necessary. Hence, this study was conducted with the aim of identifying the barriers to dietary salt reduction among hypertensive patients.Methods: A community based cross sectional study was conducted on a sample of 356 hypertensive patients in field practice areas (urban and rural) in Department of Community Medicine, JNMC, AMU, Aligarh. A pretested semi-structured questionnaire was used for the study. Compliance to dietary salt intake was assessed by calculating average salt intake per person per day. The tenets of health belief model were used to examine the key determinants of human behavior. Analysis was done by using correlation, proportions, chi-square and multiple linear regression.Results: 31.4% of the participants took salt &lt;5 gm per day. A significant association was noticed with area, religion, social class, family size, perceived benefits and perceived susceptibility. A significant positive correlation was seen with total adherence score and family size.Conclusions: A lot of barriers hinder the compliance to dietary salt reduction. Health Education stressing the role of salt reduction in control of blood pressure is recommended.

Sodium Intake and Hypertension.

The close relationship between hypertension and dietary sodium intake is widely recognized and supported by several studies. A reduction in dietary sodium not only decreases the blood pressure and the incidence of hypertension, but is also associated with a reduction in morbidity and mortality from cardiovascular diseases. Prolonged modest reduction in salt intake induces a relevant fall in blood pressure in both hypertensive and normotensive individuals, irrespective of sex and ethnic group, with larger falls in systolic blood pressure for larger reductions in dietary salt. The high sodium intake and the increase in blood pressure levels are related to water retention, increase in systemic peripheral resistance, alterations in the endothelial function, changes in the structure and function of large elastic arteries, modification in sympathetic activity, and in the autonomic neuronal modulation of the cardiovascular system. In this review, we have focused on the effects of sodium intake on vascular hemodynamics and their implication in the pathogenesis of hypertension.

Potential impact of a modest reduction in salt intake on blood pressure, cardiovascular disease burden and premature mortality: a modelling study

ObjectiveTo assess the potential impact of reduction in salt intake on the burden of cardiovascular disease (CVD) and premature mortality in Cameroon.MethodsUsing a multicohort proportional multistate life table model with...

Role of salt intake in prevention of cardiovascular disease: controversies and challenges.

Strong evidence indicates that reduction of salt intake lowers blood pressure and reduces the risk of cardiovascular disease (CVD). The WHO has set a global target of reducing the population salt intake from the current level of approximately 10 g daily to <5 g daily. This recommendation has been challenged by several studies, including cohort studies, which have suggested a J-shaped relationship between salt intake and CVD risk. However, these studies had severe methodological problems, such as reverse causality and measurement error due to assessment of salt intake by spot urine. Consequently, findings from such studies should not be used to derail vital public health policy. Gradual, stepwise salt reduction as recommended by the WHO remains an achievable, affordable, effective, and important strategy to prevent CVD worldwide. The question now is how to reduce population salt intake. In most developed countries, salt reduction can be achieved by a gradual and sustained reduction in the amount of salt added to food by the food industry. The UK has pioneered a successful salt-reduction programme by setting incremental targets for >85 categories of food; many other developed countries are following the UK's lead. In developing countries where most of the salt is added by consumers, public health campaigns have a major role. Every country should adopt a coherent, workable strategy. Even a modest reduction in salt intake across the whole population can lead to a major improvement in public health and cost savings.

Gastrorenal Axis.

Gastrorenal Axis.

Sustained modest reduction in salt intake: reduced BP, no adverse effect on lipids or hormones

Sustained modest reduction in salt intake: reduced BP, no adverse effect on lipids or hormones

Consuming moderately less salt in the long-term can lower blood pressure significantly.

A modest reduction in salt intake for four or more weeks causes significant falls in blood pressure.

Effect of longer-term modest salt reduction on blood pressure.

A reduction in salt intake lowers blood pressure (BP) and, thereby, reduces cardiovascular risk. A recent meta-analysis by Graudal implied that salt reduction had adverse effects on hormones and lipids which might mitigate any benefit that occurs with BP reduction. However, Graudal's meta-analysis included a large number of very short-term trials with a large change in salt intake, and such studies are irrelevant to the public health recommendations for a longer-term modest reduction in salt intake. We have updated our Cochrane meta-analysis. To assess (1) the effect of a longer-term modest reduction in salt intake (i.e. of public health relevance) on BP and whether there was a dose-response relationship; (2) the effect on BP by sex and ethnic group; (3) the effect on plasma renin activity, aldosterone, noradrenaline, adrenaline, cholesterol, low-density lipoprotein (LDL), high-density lipoprotein (HDL) and triglycerides. We searched MEDLINE, EMBASE, Cochrane Hypertension Group Specialised Register, Cochrane Central Register of Controlled Trials, and reference list of relevant articles. We included randomised trials with a modest reduction in salt intake and duration of at least 4 weeks. Data were extracted independently by two reviewers. Random effects meta-analyses, subgroup analyses and meta-regression were performed. Thirty-four trials (3230 participants) were included. Meta-analysis showed that the mean change in urinary sodium (reduced salt vs usual salt) was -75 mmol/24-h (equivalent to a reduction of 4.4 g/d salt), the mean change in BP was -4.18 mmHg (95% CI: -5.18 to -3.18, I (2)=75%) for systolic and -2.06 mmHg (95% CI: -2.67 to -1.45, I (2)=68%) for diastolic BP. Meta-regression showed that age, ethnic group, BP status (hypertensive or normotensive) and the change in 24-h urinary sodium were all significantly associated with the fall in systolic BP, explaining 68% of the variance between studies. A 100 mmol reduction in 24 hour urinary sodium (6 g/day salt) was associated with a fall in systolic BP of 5.8 mmHg (95%CI: 2.5 to 9.2, P=0.001) after adjusting for age, ethnic group and BP status. For diastolic BP, age, ethnic group, BP status and the change in 24-h urinary sodium explained 41% of the variance between studies. Meta-analysis by subgroup showed that, in hypertensives, the mean effect was -5.39 mmHg (95% CI: -6.62 to -4.15, I (2)=61%) for systolic and -2.82 mmHg (95% CI: -3.54 to -2.11, I (2)=52%) for diastolic BP. In normotensives, the mean effect was -2.42 mmHg (95% CI: -3.56 to -1.29, I (2)=66%) for systolic and -1.00 mmHg (95% CI: -1.85 to -0.15, I (2)=66%) for diastolic BP. Further subgroup analysis showed that the decrease in systolic BP was significant in both whites and blacks, men and women. Meta-analysis of hormone and lipid data showed that the mean effect was 0.26 ng/ml/hr (95% CI: 0.17 to 0.36, I (2)=70%) for plasma renin activity, 73.20 pmol/l (95% CI: 44.92 to 101.48, I (2)=62%) for aldosterone, 31.67 pg/ml (95% CI: 6.57 to 56.77, I (2)=5%) for noradrenaline, 6.70 pg/ml (95% CI: -0.25 to 13.64, I (2)=12%) for adrenaline, 0.05 mmol/l (95% CI: -0.02 to 0.11, I (2)=0%) for cholesterol, 0.05 mmol/l (95% CI: -0.01 to 0.12, I (2)=0%) for LDL, -0.02 mmol/l (95% CI: -0.06 to 0.01, I (2)=16%) for HDL, and 0.04 mmol/l (95% CI: -0.02 to 0.09, I (2)=0%) for triglycerides. A modest reduction in salt intake for 4 or more weeks causes significant and, from a population viewpoint, important falls in BP in both hypertensive and normotensive individuals, irrespective of sex and ethnic group. With salt reduction, there is a small physiological increase in plasma renin activity, aldosterone and noradrenaline. There is no significant change in lipid levels. These results provide further strong support for a reduction in population salt intake. This will likely lower population BP and, thereby, reduce cardiovascular disease. Additionally, our analysis demonstrates a significant association between the reduction in 24-h urinary sodium and the fall in systolic BP, indicating the greater the reduction in salt intake, the greater the fall in systolic BP. The current recommendations to reduce salt intake from 9-12 to 5-6 g/d will have a major effect on BP, but are not ideal. A further reduction to 3 g/d will have a greater effect and should become the long term target for population salt intake.

Effect of longer term modest salt reduction on blood pressure: Cochrane systematic review and meta-analysis of randomised trials

Objective To determine the effects of longer term modest salt reduction on blood pressure, hormones, and lipids.Design Systematic review and meta-analysis.Data sources Medline, Embase, Cochrane Hypertension Group Specialised Register, Cochrane...

Salt and cardiovascular risk

A report has suggested a J-shaped association between estimated sodium excretion and cardiovascular risk. However, because spot urinary sodium does not reflect daily salt intake, the results from this study do not change the strong evidence showing that a modest reduction in salt intake has major beneficial effects on health.

World Salt Awareness Week

Cardiovascular disease (CVD), including stroke, heart attack and heart failure, is the leading cause of death and disability worldwide. Raised blood pressure (BP) is a major cause of CVD, responsible for 62% of stroke and 49% of coronary heart disease cases. There is much evidence for a causal relationship between salt intake and BP. The current salt intake in many countries around the world is between 9 g ⁄d and 12 g ⁄d (ie, 3.6–4.8 g of sodium). Randomized trials have demonstrated that a modest reduction in salt intake lowers BP in individuals with raised BP and also in those with ‘‘normal’’ BP. Furthermore, there is a dose-response relationship. Within the range of 12 g ⁄d to 3 g ⁄d, the lower the salt intake, the lower the BP. Because raised BP throughout its range is a major cause of CVD, salt reduction would reduce cardiovascular risk. It was estimated that a reduction of 6 g ⁄d in salt intake would reduce stroke by 24% and coronary heart disease by 18%. This would prevent approximately 35,000 stroke and coronary heart disease deaths a year in the United Kingdom and approximately 2.5 million deaths worldwide. Both prospective studies and outcome trials have demonstrated that a lower salt intake is related to a reduced risk of CVD. Salt reduction is one of the most cost-effective interventions to reduce CVD in both developed and developing countries. For example, the UK salt reduction campaign, which resulted in a fall in salt intake by approximately 10% (ie, from 9.5 g ⁄d in 2003 to 8.6 g ⁄d by May 2008), cost just £15 million and led to approximately 6000 fewer CVD deaths per year, saving the UK economy approximately £1.5 billion per annum according to the recent report by the UK government’s health advisory agency, the National Institute for Health and Clinical Excellence. In most developed countries, approximately 80% of salt consumed is added to foods at the stage of manufacturing, and the consumers have no say over how much salt is added. Therefore, to achieve a reduction in population salt intake, it is imperative that the food industry make a gradual and sustained reduction in the amount of salt that is added to all foods. This approach has been successful in the United Kingdom and is now being expanded worldwide. World Salt Awareness Week was introduced by the salt reduction action group World Action on Salt and Health (WASH) in 2008. The event serves as a platform for international experts in the fields of hypertension and nephrology to raise the profile of the importance of salt reduction to both the public and health professionals worldwide.

Altered dietary salt intake for preventing and treating diabetic kidney disease.

There is strong evidence that our current consumption of salt is a major factor for increased blood pressure (BP) and a modest reduction in salt intake lowers BP whether BP levels are normal or raised. Tight control of BP in diabetics lowers the risk of strokes, heart attacks and heart failure and slows the progression of diabetic kidney disease (DKD). Currently there is no consensus in restricting salt intake in diabetic patients. To evaluate the effect of altered salt intake on BP and markers of cardiovascular disease and DKD. In January 2010, we searched the Cochrane Renal Group's Specialised Register, CENTRAL (in The Cochrane Library), MEDLINE (from 1966) and EMBASE (from 1980) to identify appropriate articles. We included all randomised controlled trials of salt reduction in individuals with type 1 and type 2 diabetes. Two authors independently assessed studies and resolved differences by discussion with a third independent author. We calculated mean effect sizes using both the fixed-effect and random-effects models. Thirteen studies (254 individuals) met our inclusion criteria. These included 75 individuals with type 1 diabetes and 158 individuals with type 2 diabetes. The median reduction in urinary sodium was 203 mmol/24 h (11.9 g/day) in type 1 diabetes and 125 mmol/24 h (7.3 g/day) in type 2 diabetes. The median duration of salt restriction was one week in both type 1 and type 2 diabetes. BP was reduced in both type 1 and type 2 diabetes. In type 1 diabetes (56 individuals), salt restriction reduced BP by -7.11/-3.13 mm Hg (systolic/diastolic); 95% CI: systolic BP (SBP) -9.13 to -5.10; diastolic BP (DBP) -4.28 to -1.98). In type 2 diabetes (56 individuals), salt restriction reduced BP by -6.90/-2.87 mm Hg (95% CI: SBP -9.84 to -3.95; DBP -4.39 to -1.35). There was a greater reduction in BP in normotensive patients, possibly due to a larger decrease in salt intake in this group. Although the studies are not extensive, this meta-analysis shows a large fall in BP with salt restriction, similar to that of single drug therapy.All diabetics should consider reducing salt intake at least to less than 5-6 g/day in keeping with current recommendations for the general population and may consider lowering salt intake to lower levels, although further studies are needed.

Genetics of Salt-Sensitive Hypertension

The assessment of salt sensitivity of blood pressure is difficult because of the lack of universal consensus on definition. Regardless of the variability in the definition of salt sensitivity, increased salt intake, independent of the actual level of blood pressure, is also a risk factor for cardiovascular morbidity and mortality and kidney disease. A modest reduction in salt intake results in an immediate decrease in blood pressure, with long-term beneficial consequences. However, some have suggested that dietary sodium restriction may not be beneficial to everyone. Thus, there is a need to distinguish salt-sensitive from salt-resistant individuals, but it has been difficult to do so with phenotypic studies. Therefore, there is a need to determine the genes that are involved in salt sensitivity. This review focuses on genes associated with salt sensitivity, with emphasis on the variants associated with salt sensitivity in humans that are not due to monogenic causes. Special emphasis is given to gene variants associated with salt sensitivity whose protein products interfere with cell function and increase blood pressure in transgenic mice.

WASH—World Action on Salt and Health

There is overwhelming evidence that our current high-salt intake is the major factor increasing blood pressure (BP) and, thereby, a major cause of cardiovascular disease and kidney disease worldwide. A reduction in salt intake to the recommended level of <5-6 g/day is very beneficial, and could prevent millions of deaths each year and make major savings for healthcare services. Several countries, e.g., Finland and the UK, have already reduced the amount of salt being consumed by a combined policy of getting the food industry to decrease the amount of salt added to foods, clear labelling on food products, and increasing public awareness of the harmful effects of salt on health. Many other developed countries, e.g., Australia, Canada, and the US, are also stepping up their activities. The major challenge now is to spread this out worldwide, particularly to developing countries where ≈80% of global BP-related disease burden occurs. In many developing countries, most of the salt consumed comes from salt added during cooking or from sauces; therefore, public health campaigns are needed to encourage consumers to use less salt. A modest reduction in salt intake across the whole population will result in major improvements in public health and have huge economic benefits in all countries around the world. World Action on Salt and Health (WASH) is a coalition of health professionals from different countries who know very well the harm of high BP and has a major role in implementing changes in their own countries. We welcome nephrologists to join (http://www.worldactiononsalt.com).

Effect of Modest Salt Reduction on Skin Capillary Rarefaction in White, Black, and Asian Individuals With Mild Hypertension

Microvascular rarefaction occurs in hypertension. We carried out a 12-week randomized double-blind crossover trial to determine the effect of a modest reduction in salt intake on capillary rarefaction in 71 whites, 69 blacks, and 29 Asians with untreated mildly raised blood pressure. Both basal and maximal (during venous congestion) skin capillary density were measured by capillaroscopy at the dorsum and the side of the fingers. In addition, we used orthogonal polarization spectral imaging to measure skin capillary density at the dorsum of the fingers and the hand web. With a reduction in salt intake from 9.7 to 6.5 g/day, there was an increase in capillary density (capillaries per millimeter squared) from 101+/-21 to 106+/-23 (basal) and 108+/-22 to 115+/-22 (maximal) at the dorsum, and 101+/-25 to 107+/-26 (basal) and 110+/-26 to 116+/-26 (maximal) at the side of the fingers (P<0.001 for all). Orthogonal polarization spectral imaging also showed a significant increase in capillary density both at the dorsum of the fingers and the web. Subgroup analysis showed that most of the changes were significant in all of the ethnic groups. Furthermore, there was a significant relationship between the change in 24-hour urinary sodium and the change in capillary density at the side of the fingers. These results demonstrate that a modest reduction in salt intake, as currently recommended, improves both functional and structural capillary rarefactions that occur in hypertension, and a larger reduction in salt intake would have a greater effect. The increase in capillary density may possibly carry additional beneficial effects on target organs.

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.

Salt Intake Is Related to Soft Drink Consumption in Children and Adolescents: A Link to Obesity?

To the Editor: The hypothesis that salt intake is a driver of soft drink consumption1 is an interesting one, but unfortunately this study takes us no further than speculation. Having experience in epidemiological analysis of the National Diet and Nutrition Survey, I beg to differ with the calculations in this article and also the authors’ interpretations. Specifically, I suggest the following: (1) the energy from soft drinks in the National Diet and Nutrition Survey is half what these authors estimate; (2) their study does not “demonstrate that salt is a major determinant of fluid and sugar-sweetened soft drink consumption during childhood” (only ≈2% of the …

Salt, blood pressure and cardiovascular disease

To review the evidence that relates salt intake to blood pressure and cardiovascular disease. Raised blood pressure throughout the range seen in developed countries is the major cause of cardiovascular disease, responsible for 62% of strokes and 49% of coronary heart disease. There is overwhelming evidence that dietary salt is a major cause of raised blood pressure, and a modest reduction in salt intake lowers blood pressure, which is predicted to reduce cardiovascular disease. Several lines of evidence including ecological, population and prospective cohort studies, as well as follow-up studies of individuals who participated in short-term salt reduction trials, have consistently shown a direct relation between salt intake and cardiovascular risk, and a reduction in population salt intake is associated with a reduction in cardiovascular mortality in the population. The evidence for universal salt reduction is strong, and reducing salt from the current intake of 10-12 g/day to the recommended level of 5-6 g/day will have a major effect on blood pressure and cardiovascular mortality. Additionally, this will result in considerable savings on health expenditure as, not only is raised blood pressure the biggest cause of death, but the second biggest cause of disability worldwide.

Salt Reduction for Preventing Hypertension and Cardiovascular Disease

Many lines of investigation have led to overwhelming evidence for a causal relationship between dietary salt intake and blood pressure levels in adults. Importantly, these include numerous randomized clinical trials of salt reduction that have been the subject of several meta-analyses.1 In children age ≥2 years, a previous review of 37 observational and intervention studies concluded, “the results suggest that higher sodium intake is related to higher BP in children and adolescents.”2 He and MacGregor3 have now conducted the first meta-analysis of salt reduction trials in children and adolescents and have clearly demonstrated that “modest reduction in salt intake causes immediate falls in blood pressure.” They conclude that such effects “if continued, may well lessen the subsequent rise in blood pressure with age.” One may ask, why does any of this matter? The reductions in blood pressure were modest, and no hard disease end point results were documented. The importance is based on 3 relationships: (1) the moderately strong correlation of blood pressure in childhood with blood pressure in adulthood4; (2) the association of blood pressure with early atherosclerosis during the second decade of life5; and (3) intriguing evidence for a specific early programming effect between salt intake in infancy and blood pressure later in life.6 The latter relationship is supported by experimental evidence in animal models, but more research is needed. Furthermore, in virtually every population throughout the world except those totally unacculturated to an industrialized lifestyle, blood pressure rises with increasing age. This results in rising hypertension prevalence, especially from middle …