Understanding the science that supports population-wide salt reduction programs

Non-pharmacological factors for hypertension management: a systematic review of international guidelines

Lifestyle modifications are one of the cornerstones of hypertension prevention and treatment. We aimed to systematically review hypertension guidelines on their recommendations on non-pharmacological factors including lifestyle interventions, to highlight strength of evidence, similarities, and differences. This systematic review was registered with the international Prospective Register of Systematic Reviews (CRD42021288815). Publications in MEDLINE and EMBASE databases over 10 years since January 2010 to June 2020 were identified. We also included the search from websites of organizations responsible for guidelines development. Two reviewers screened the titles and abstracts to identify relevant guidelines. Two reviewers independently assessed rigour of guideline development using the AGREE II instrument, and one reviewer extracted recommendations. Of the identified guidelines, 10 showed good rigour of development (AGREE II ≥ 60%) and were included in the systematic review. The guidelines were consistent in most recommendations (reduced salt intake, weight, dietary patterns, increased physical activity and smoking cessation, and limiting alcohol intake). Some areas of disagreement were identified, regarding recommendations on novel psychological and environmental factors such as stress or air pollution, alcohol intake thresholds, meat, coffee and tea consumption and refined sugars. Current guidelines agree on the importance of lifestyle in the treatment and prevention of hypertension. Consensus on smoking cessation, limited salt intake, increased physical activity support their integration in management of hypertensive patients and in public health measurements in general population as preventative measurements. Further research into the role of environmental and psychological factors may help clarify future recommendations.

Sodium and Health: Old Myths and a Controversy Based on Denial

PURPOSE OF REVIEW

The scientific consensus on which global health organizations base public health policies is that high sodium intake increases blood pressure (BP) in a linear fashion contributing to cardiovascular disease (CVD). A moderate reduction in sodium intake to 2000 mg per day helps ensure that BP remains at a healthy level to reduce the burden of CVD.

RECENT FINDINGS

Yet, since as long ago as 1988, and more recently in eight articles published in the European Heart Journal in 2020 and 2021, some researchers have propagated a myth that reducing sodium does not consistently reduce CVD but rather that lower sodium might increase the risk of CVD. These claims are not well-founded and support some food and beverage industry's vested interests in the use of excessive amounts of salt to preserve food, enhance taste, and increase thirst. Nevertheless, some researchers, often with funding from the food industry, continue to publish such claims without addressing the numerous objections. This article analyzes the eight articles as a case study, summarizes misleading claims, their objections, and it offers possible reasons for such claims. Our study calls upon journal editors to ensure that unfounded claims about sodium intake be rigorously challenged by independent reviewers before publication; to avoid editorial writers who have been co-authors with the subject paper's authors; to require statements of conflict of interest; and to ensure that their pages are used only by those who seek to advance knowledge by engaging in the scientific method and its collegial pursuit. The public interest in the prevention and treatment of disease requires no less.

Dietary Sodium 'Controversy'-Issues and Potential Solutions

PURPOSE OF REVIEW

High dietary sodium is estimated to be the leading dietary risk for death attributed to 1.8 million deaths in 2019. There are uniform recommendations to reduce sodium consumption based on evidence that increased dietary sodium is responsible for approximately a third of the prevalence of hypertension, and meta-analyses of randomized controlled trials show that sodium reduction lowers blood pressure, cardiovascular disease, and total mortality. Nevertheless, there is a perception that the beneficial effect of reducing dietary sodium is controversial. We provide experiential evidence relating to some sources of the controversy and propose potential solutions.

RECENT FINDINGS

Inappropriate research methodology, lack of rigor in research, conflicts of interest and commercial bias, questions of professional conduct, and lack of policies to protect public interests are likely to contribute to the controversy about reducing dietary sodium. There is a failure to protect policies to reduce dietary sodium from nonscientific threats. Significant efforts need to be made to ensure the integrity of nutritional research and maintain public trust.

Dietary Salt Reduction, Prevalence of Hypertension and Avoidable Burden of Stroke in Vietnam: Modelling the Health and Economic Impacts

Dietary salt reduction has been recommended as a cost-effective population-wide strategy to prevent cardiovascular disease. The health and economic impact of salt consumption on the future burden of stroke in Vietnam is not known.

Objective: To estimate the avoidable incidence of and deaths from stroke, as well as the healthy life years and healthcare costs that could be gained from reducing salt consumption in Vietnam.

Methods: This was a macrosimulation health and economic impact assessment study. Data on blood pressure, salt consumption and stroke epidemiology were obtained from the Vietnam 2015 STEPS survey and the Global Burden of Disease study. A proportional multi-cohort multistate lifetable Markov model was used to estimate the impact of achieving the Vietnam national salt targets of 8 g/day by 2025 and 7 g/day by 2030, and to the 5 g/day WHO recommendation by 2030. Probabilistic sensitivity analysis was conducted to quantify the uncertainty in our projections.

Results: If the 8 g/day, 7 g/day, and 5 g/day targets were achieved, the prevalence of hypertension could reduce by 1.2% (95% uncertainty interval [UI]: 0.5 to 2.3), 2.0% (95% UI: 0.8 to 3.6), and 3.5% (95% UI: 1.5 to 6.3), respectively. This would translate, respectively, to over 80,000, 180,000, and 257,000 incident strokes and over 18,000, 55,000, and 73,000 stroke deaths averted. By 2025, over 56,554 stroke-related health-adjusted life years (HALYs) could be gained while saving over US$ 42.6 million in stroke healthcare costs. By 2030, about 206,030 HALYs (for 7 g/day target) and 262,170 HALYs (for 5 g/day target) could be gained while saving over US$ 88.1 million and US$ 122.3 million in stroke healthcare costs respectively.

Conclusion: Achieving the national salt reduction targets could result in substantial population health and economic benefits. Estimated gains were larger if the WHO salt targets were attained and if changes can be sustained over the longer term. Future work should consider the equity impacts of specific salt reduction programs.

Knowledge, Attitudes and Behaviours Related to Physician-Delivered Dietary Advice for Patients with Hypertension

Dietary modifications are key health behaviour recommendations for the prevention and management of hypertension, a leading contributor of global disease burden. Despite this, few primary care physicians discuss nutrition with their patients. This study describes the barriers and facilitators to the provision of dietary advice for hypertension prevention and management among Canadian physicians. A validated 62-item cross-sectional survey was distributed online to 103 Canadian primary care physicians between 2017 and 2019. Eighty participants were included in the analyses. The majority of participants were based in Ontario (68.7%) and saw 10-24 patients per week (53.5%). Fewer than half (47.5%) of participants were knowledgeable about the recommended sodium level by Hypertension Canada (< 2000 mg/day) and 38.8% felt it was difficult to know which foods are high or low in sodium. Approximately one quarter felt the findings about sodium and hypertension and cardiovascular disease are controversial. Other significant barriers were: not enough time to talk to patients about diet (76.3%), belief that patients are not truthful about their diet (76.3%), patients would not follow their advice (46.8%), and that it was difficult to keep up with so many guidelines (50.0%). Many identified that electronic medical record tools (80.8%), access to dietitians (84.9%), or more nutrition education in medical training (65.8%) would help facilitate advice. Given the importance of diet and the central role of physicians in motivating dietary change among patients, approaches are required to address identified barriers and facilitators to providing dietary advice to reduce the burden of hypertension.

Challenges in applying the GRADE approach in public health guidelines and systematic reviews: a concept article from the GRADE Public Health Group

BACKGROUND AND OBJECTIVE

This article explores the need for conceptual advances and practical guidance in the application of the GRADE approach within public health contexts.

METHODS

We convened an expert workshop and conducted a scoping review to identify challenges experienced by GRADE users in public health contexts. We developed this concept article through thematic analysis and an iterative process of consultation and discussion conducted with members electronically and at three GRADE Working Group meetings.

RESULTS

Five priority issues can pose challenges for public health guideline developers and systematic reviewers when applying GRADE: (1) incorporating the perspectives of diverse stakeholders; (2) selecting and prioritizing health and "nonhealth" outcomes; (3) interpreting outcomes and identifying a threshold for decision-making; (4) assessing certainty of evidence from diverse sources, including nonrandomized studies; and (5) addressing implications for decision makers, including concerns about conditional recommendations. We illustrate these challenges with examples from public health guidelines and systematic reviews, identifying gaps where conceptual advances may facilitate the consistent application or further development of the methodology and provide solutions.

CONCLUSION

The GRADE Public Health Group will respond to these challenges with solutions that are coherent with existing guidance and can be consistently implemented across public health decision-making contexts.

Hedonic thresholds and ideal sodium content reduction of bread loaves

Global public policies have advocated strategies for reducing sodium consumption due to the high incidence of non-communicable chronic diseases (NCDs) worldwide. The objectives of this study were to identify the bread loaves sodium content considered as ideal by the consumers and determine hedonic thresholds. In this descriptive cross-sectional study, 114 consumers evaluated the ideal sodium content in bread loaves by the Just About Right (JAR) test, (first sensorial stage) studying four decreased levels of sodium (10%, 20%, 30%, 40%) from the mean values observed from bread in 11 food composition tables from various regions of the world, and Brazil. This ideal sodium content was used as the control in pairwise acceptance tests with five other reduced-sodium samples of bread loaves (10%, 30%, 50%, 70%, 100% of reduction from the control), and hedonic threshold tests were performed with 156 consumers (a second stage sensorial test of five sessions). The data from the JAR were analyzed by a regression analysis graph and correlated with the consumption of salt and family income range by a Principal Component Analysis with a 5% significance level. In the Hedonic Threshold tests, each paired session was analyzed by Student's t-test (test t), and an adjusted regression graph was built. The Compromised Acceptance Threshold (CAT) was performed, where the calculated t corresponded to the tabulated t. In the Hedonic Rejection Threshold (HRT), the hedonic scale five ("indifferent" term) was considered. The average sodium content of bread marketed in different regions of the world was 457 mg Na/100 g of bread, and the ideal sodium content observed was 395 mg Na/100 g of bread. The gender, age and income family rates as well as attitudes and knowledge regarding the salt consumption of the trial consumers were not directly related to the evaluations of the bread loaves in the JAR test, according to the Principal Components Analysis at p ≤ 0.05. From this ideal content, a 42% reduction was possible according to the CAT test (267 mg Na/100 g of bread), and more reductions were acceptable until an 85% (to 58 mg Na/100 g of bread) reduction, as the samples began to be rejected according to HRT test. These findings demonstrated that this methodology can be applied to sodium reduction product formulations and bread as a food matrix. With this kind of methodology, it is possible to provide to the bakery industry a methodology to know a safe region to work on food reformulations and subsidize the formulation of new products without compromising consumer acceptability, in addition to meeting the demand for safer food.

Relationship between dietary sodium and sugar intake: A cross-sectional study of the National Health and Nutrition Examination Survey 2001-2016

Dietary sodium intake and cardiovascular outcomes have a reported J-shaped curve relationship. This study analyzes the relationship between dietary sodium and sugar intake as a potential mechanism to explain this association. The authors examined cross-sectional data from the National Health and Nutrition Examination Survey (NHANES) 2001-2016 where dietary sodium, carbohydrate, fat, cholesterol, and sugar intakes were assessed by 24-hour dietary recall and were standardized to a total daily intake of 2000 calories. Sodium intake was categorized into sodium quintiles (SQ) as follows: SQ1(0.06-2.6 g/d); SQ2(2.6-3.0 g/d); SQ3(3.0-3.4 g/d); SQ4(3.4-4.0 g/d); and SQ5(4.0-29.3 g/d). Simple and multivariate linear regression using SQ3 as reference were used to assess associations between daily sodium intake and the other nutrients. Our results showed that among 38 722 participants that met our study criteria, the mean age was 43.6 years (SD 16.8 years) and sex was equally distributed (48.8% male vs 51.2% female). Sugar intake went down across increasing SQs and was significantly higher in SQ1 (141.2 g/d) and SQ2 (118.6 g/d) and significantly lower in SQ4 (97.9 g/d) and SQ5 (85.6 g/d) compared to SQ3 (108.6 g/d; all P < .01). These same trends remained unchanged and significant in the fully adjusted multivariate model. In conclusion, NHANES study participants reporting low sodium intake on 24-hour dietary recall have a higher consumption of sugar. The negative impact of low sodium diet on cardiovascular health may be explained at least partially by the associated high sugar intake.

Three Public Health Interventions Could Save 94 Million Lives in 25 Years

BACKGROUND

Preventable noncommunicable diseases, mostly cardiovascular diseases, are responsible for 38 million deaths annually. A few well-documented interventions have the potential to prevent many of these deaths, but a large proportion of the population in need does not have access to these interventions. We quantified the global mortality impact of 3 high-impact and feasible interventions: scaling up treatment of high blood pressure to 70%, reducing sodium intake by 30%, and eliminating the intake of artificial trans fatty acids.

METHODS

We used global data on mean blood pressure levels and sodium and trans fat intake by country, age, and sex from a pooled analysis of population health surveys, and regional estimates of current coverage of antihypertensive medications, and cause-specific mortality rates in each country, as well, with projections from 2015 to 2040. We used the most recent meta-analyses of epidemiological studies to derive relative risk reductions for each intervention. We estimated the proportional effect of each intervention on reducing mortality from related causes by using a generalized version of the population-attributable fraction. The effect of antihypertensive medications and lowering sodium intake were modeled through their impact on blood pressure and as immediate increase/reduction to the proposed targets.

RESULTS

The combined effect of the 3 interventions delayed 94.3 million (95% uncertainty interval, 85.7-102.7) deaths during 25 years. Increasing coverage of antihypertensive medications to 70% alone would delay 39.4 million deaths (35.9-43.0), whereas reducing sodium intake by 30% would delay another 40.0 million deaths (35.1-44.6) and eliminating trans fat would delay an additional 14.8 million (14.7-15.0). The estimated impact of trans fat elimination was largest in South Asia. Sub-Saharan Africa had the largest proportion of premature delayed deaths out of all delayed deaths.

CONCLUSIONS

Three effective interventions can save almost 100 million lives globally within 25 years. National and international efforts to scale up these interventions should be a focus of cardiovascular disease prevention programs.

The Evaluation of IDEAL-REACH Program to Improve Nutrition among Asian American Community Members in the Philadelphia Metropolitan Area

Objective Asian Americans' food purchasing, cooking, and eating patterns are not well understood. Greater insight into these behaviors is urgently needed to guide public health interventions of dietary behaviors in this population. The present study aims to examine the effects of a community-level intervention on food purchasing and preparation, nutrition knowledge, and health awareness in Asian Americans. Methods From 2015 to 2017, we conducted the Improving Diets with an Ecological Approach for Lifestyle (IDEAL-REACH) intervention to increase access to healthy food or beverage options for the Asian-American population in the Philadelphia metropolitan area. Participants (1110 at pre- and 1098 at post-assessment) were recruited from 31 community-based organizations (CBOs). We assessed Asian Americans' dietary behaviors, nutrition knowledge, and awareness of heart health. Results The results of pre-post intervention comparisons showed that the IDEAL-REACH intervention was successful in promoting whole grains consumption, reducing sodium consumption, and raising knowledge and awareness related to nutrition and heart health. Conclusions To our knowledge, this is one of the first initiatives in the U.S. to engage CBOs to promote healthier dietary behaviors. The findings show that CBOs serve as a powerful platform for community-level interventions to improve healthy nutrition behaviors in Asian-American communities.

Science of Salt: A regularly updated systematic review of salt and health outcomes studies (April to October 2018)

The Science of Salt reviews identify, summarize, and critically appraise published studies on dietary salt and health outcomes according to pre-specified methods. This review covers the period April 3 to October 30, 2018. Here, nineteen studies that fit pre-specified criteria for review and summary are included. Three of these, one prospective cohort study, one randomized controlled trial, and a post hoc analysis of the Dietary Approaches to Stop Hypertension (DASH) sodium trial fulfilled the quality criteria for detailed critical appraisal, including risk of bias assessment, and commentary. Two trials demonstrated a positive association between salt intake and blood pressure. In a cohort of older Italians, increased risk of total mortality was observed with salt intake less than ~16 g/d (6300 mg sodium/d) at baseline; no association existed for incident cardiovascular disease (CVD) or CVD mortality. The paucity of published studies which met our criteria for methodological quality is of concern.

Twenty-Four-Hour Diet recall and Diet records compared with 24-hour urinary excretion to predict an individual's sodium consumption: A Systematic Review

This systematic literature review aimed to investigate whether 24 hour diet recall and diet records are reliable and valid ways to measure usual dietary sodium intake compared with 24 hour urinary assessment. We searched electronic databases Medline, Embase, Cinahl, Lilacs, Google Scholar and the Cochrane Library using pre-defined terms Studies were eligible for inclusion if they assessed adult humans in free-living settings, and if they included dietary assessment and 24 hours urinary collection for assessment of sodium intake in the same participants. Studies that included populations with an active disease state that might interfere with normal sodium metabolism were excluded. Results of 20 studies using 24 hour diet recall recall (including 14 validation studies) and 10 studies using food records (including six validation studies) are included in this review. Correlations between estimates from dietary assessment and urinary excretion ranged from 0.16 to 0.72 for 24 hour diet recall, and 0.11 to 0.49 for food diaries. Bland-Altman analysis in two studies of 24 hour diet recall showed poor agreement with 24 hours urinary sodium excretion. These results show that 24 hour diet recall and diet records inaccurately measure dietary sodium intake in individuals compared with the gold standard 24 hours urinary excretion. Validation studies of dietary assessment methods should include multiple days of assessment and 24 hours urine collection, use relevant food composition databases and Bland-Altman methods of analysis.

Effects of a nationwide strategy to reduce salt intake in Samoa

Objective:

Salt reduction is one of the most cost-effective interventions for the prevention of noncommunicable diseases, but there are no studies evaluating the effectiveness of national strategies in low or lower middle income countries. This study aimed to examine the effect of an 18-month nation-wide salt reduction strategy in Samoa.

Methods:

Two nationally representative cross-sectional surveys of adults aged 18–64 years, measuring 24-h urinary salt excretion and salt-related knowledge, attitudes and behaviours, were conducted before (2013) and after (2015) the intervention.

Results:

There were 234 participants at baseline (response rate 47%) and 479 at 18 months (response rate 61%). There was no change in mean population salt intake between 2013 (7.31 g/day) and 2015 (7.50 g/day) (0.19, 95% confidence interval −0.50 to 0.88; P = 0.588). There were significant changes in the proportion of the population who always or often add discretionary salt when eating (−16.2%, P = 0.002), the proportion who understood the adverse effects of salt (+9.0%, P = 0.049) and the proportion using one or more methods to control their salt intake (+20.9%, P < 0.001). A total of 73% reported that they had heard or seen the salt reduction messages.

Conclusion:

With widespread awareness of the salt reduction message and some improvements in salt-related knowledge and behaviours following the intervention, Samoa is now well positioned to implement much-needed structural initiatives or policies to reduce salt in the food supply.

Nutrition and Cardiovascular Disease-an Update

PURPOSE OF REVIEW

This review summarizes recent developments in nutrition and cardiovascular disease (CVD) prevention.

RECENT FINDINGS

Contemporary dietary guidance recommends healthy dietary patterns with emphasis on food-based recommendations because the totality of the diet (i.e., the combinations and quantities of foods and nutrients consumed) is an important determinant of health. In many guidelines, recommendations are still made for saturated fat, added sugar, sodium, and dietary cholesterol because these are over-consumed by many people and are related to chronic disease development. Epidemiological research illustrates the importance of considering the total diet and the interrelatedness of nutrients in a dietary pattern. Traditionally, epidemiological research focused on individual nutrients in isolation, which can result in erroneous conclusions. An example of this, which has led to substantial controversy, is the evidence from studies evaluating the association between saturated fat and CVD without considering the replacement nutrient. Another controversial topic is the relationship between dietary cholesterol and CVD, which is confounded by saturated fat intake. Finally, the totality of evidence shows that high sodium intake is associated with greater CVD risk; however, some epidemiological research has suggested that a low-sodium intake is detrimental, which has caused some controversy. Overall, this reductionist approach has led to a debate about recommendations for saturated fat, cholesterol, and sodium. However, if approaches that accounted for the interrelatedness of nutrients had been taken, it is likely that there would be less controversy about these nutrients. To encourage dietary pattern-based approaches and consideration of total intake, dietary guidelines should emphasize food-based recommendations that meet nutrient targets. Thus, nutrient targets should underpin food-based dietary guidelines, and recommended dietary patterns should comply with nutrient-based targets. The evidence reviewed shows that it is imperative to consider total dietary patterns for CVD prevention. Dietary guidance should be aligned with nutrient targets and recommendations should be food and dietary pattern based.

Applying a Consumer Behavior Lens to Salt Reduction Initiatives

Reformulation of food products to reduce salt content has been a central strategy for achieving population level salt reduction. In this paper, we reflect on current reformulation strategies and consider how consumer behavior determines the ultimate success of these strategies. We consider the merits of adopting a ‘health by stealth’, silent approach to reformulation compared to implementing a communications strategy which draws on labeling initiatives in tandem with reformulation efforts. We end this paper by calling for a multi-actor approach which utilizes co-design, participatory tools to facilitate the involvement of all stakeholders, including, and especially, consumers, in making decisions around how best to achieve population-level salt reduction.