Objective To examine the dose-response relation between reduction in dietary sodium and blood pressure change and to explore the impact of intervention duration. Design Systematic review and meta-analysis following PRISMA guidelines. Data sources Ovid MEDLINE(R), EMBASE, and Cochrane Central Register of Controlled Trials (Wiley) and reference lists of relevant articles up to 21 January 2019. Inclusion criteria Randomised trials comparing different levels of sodium intake undertaken among adult populations with estimates of intake made using 24 hour urinary sodium excretion. Data extraction and analysis Two of three reviewers screened the records independently for eligibility. One reviewer extracted all data and the other two reviewed the data for accuracy. Reviewers performed random effects meta-analyses, subgroup analyses, and meta-regression. Results 133 studies with 12 197 participants were included. The mean reductions (reduced sodium v usual sodium) of 24 hour urinary sodium, systolic blood pressure (SBP), and diastolic blood pressure (DBP) were 130 mmol (95% confidence interval 115 to 145, P Conclusions The magnitude of blood pressure lowering achieved with sodium reduction showed a dose-response relation and was greater for older populations, non-white populations, and those with higher blood pressure. Short term studies underestimate the effect of sodium reduction on blood pressure. Systematic review registration PROSPERO CRD42019140812.

https://www.bmj.com/content/bmj/368/bmj.m315.full.pdf

Effect of dose and duration of reduction in dietary sodium on blood pressure levels: systematic review and meta-analysis of randomised trials.

The Global Burden of Disease (GBD) 2010 study estimated national salt intake for 187 countries based on data available up to 2010. The purpose of this review was to identify studies that have measured salt intake in a nationally representative population using the 24-hour urine collection method since 2010, with a view to updating evidence on population salt intake globally. Studies published from January 2011 to September 2018 were searched for from MEDLINE, Scopus, and Embase databases using relevant terms. Studies that provided nationally representative estimates of salt intake among the healthy adult population based on the 24-hour urine collection were included. Measured salt intake was extracted and compared with the GBD estimates. Of the 115 identified studies assessed for eligibility, 13 studies were included: Four studies were from Europe, and one each from the United States, Canada, Benin, India, Samoa, Fiji, Barbados, Australia, and New Zealand. Mean daily salt intake ranged from 6.75 g/d in Barbados to 10.66 g/d in Portugal. Measured mean population salt intake in Italy, England, Canada, and Barbados was lower, and in Fiji, Samoa, and Benin was higher, in recent surveys compared to the GBD 2010 estimates. Despite global targets to reduce population salt intake, only 13 countries have published nationally representative salt intake data since the GBD 2010 study. In all countries, salt intake levels remain higher than the World Health Organization's recommendation, highlighting the need for additional global efforts to lower salt intake and monitor salt reduction strategies.

The Science of Salt: Updating the evidence on global estimates of salt intake.

Meat products are often perceived as unhealthy foods due to the significant amounts of additives, including NaCl and phosphates, thus being considered excellent reformulation targets. Green technologies such as ultrasound (US), high-pressure processing (HPP), and pulsed electric field (PEF) have gained importance in the food industry as they are environmental-friendly processes. In addition, US, HPP, and PEF can modify the protein structure and improve its functional properties allowing reducing the content of additives in meat products. The purpose of this short review is to highlight and summarize recent studies on green technologies (US, HPP, and PEF) to produce healthier meat products by reducing NaCl and phosphate levels.

Green technologies as a strategy to reduce NaCl and phosphate in meat products: an overview

Excess sodium from dietary salt (NaCl) is linked to elevations in blood pressure (BP). However, salt sensitivity of BP varies widely between individuals and there are data suggesting that salt adversely affects target organs, irrespective of BP. High dietary salt has been shown to adversely affect the vasculature, heart, kidneys, skin, brain, and bone. Common mediators of the target organ dysfunction include heightened inflammation and oxidative stress. These physiological alterations may contribute to disease development over time. Despite the adverse effects of salt on BP and several organ systems, there is controversy surrounding lower salt intakes and cardiovascular outcomes. Our goal here is to review the physiology contributing to BP-independent effects of salt and address the controversy around lower salt intakes and cardiovascular outcomes. We will also address the importance of background diet in modulating the effects of dietary salt.

The Influence of Dietary Salt Beyond Blood Pressure

Non-communicable diseases (NCDs) are the world's leading causes of death and disability, with cardiovascular disease (CVD) accounting for half of NCD deaths. An ambitious global target established by the United Nations Sustainable Development Goals - indicator 3.4.1 - aims to reduce the risk of premature death among people aged 30-69 years from CVD, cancer, diabetes, and chronic lung disease by one third by 2030. This article reviews the science and practice informing what is required to achieve this target, identifying seven interventions that can accelerate progress: 1) tobacco control; 2) treatment to reduce cardiovascular risk; 3) reduction of dietary sodium; 4) reduction of household air pollution; 5) elimination of artificial trans fat; 6) reduction of alcohol use; and 7) prevention, detection, and treatment of cancers. Achieving the target is possible - there has already been progress in some areas, particularly related to CVD reduction - but only if there is faster, more concerted action.

https://globalheartjournal.com/articles/10.5334/gh.531/galley/861/download/

Reducing Premature Mortality from Cardiovascular and Other Non-Communicable Diseases by One Third: Achieving Sustainable Development Goal Indicator 3.4.1

The publication in the last few years of a number of prospective observational studies suggesting a J-shaped association between levels of salt (sodium) consumption and cardiovascular outcomes has opened a debate on the pertinence of population-wide salt reduction policies to reduce cardiovascular disease burden, and some have even questioned the global World Health Organization guidelines, that recommend a 30% reduction in salt consumption by 2025, aiming at an ideal target of no more than 5 g of salt consumption per day. In September 2018 the European Salt Action Network (E.S.A.N.), after appraising the quality of publications questioning the appropriateness of population salt reduction, discussed the scientific evidence and identified the pitfalls of recent data. The new evidence was deemed inadequate and, in places, biased by flawed methodology. These were identified in the biased assessment of sodium intake from spot urine and the use of the Kawasaki formula, the biased assessment of the sodium–outcome relationships in prospective observational studies using spot urine samples, the impact of reverse causality in such studies, the inadequate analytical approaches to data analysis, the lack of biological plausibility and the lack of precision in assessing long-term salt consumption, as recently demonstrated in studies using more stringent quality features in their study designs. On the basis of such appraisal, the E.S.A.N. agreed a statement confirming the support to the implementation of national and regional programmes of moderate reduction in salt intake, as recommended by the World Health Organization.

M. Beer

Papers

Population dietary salt reduction and the risk of cardiovascular disease. A scientific statement from the European Salt Action Network.