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

Abstract

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.

Key points

  • Salt reduction causes a dose-dependent reduction in blood pressure: within the range of 3–12 g daily, the lower the salt intake, the lower the blood pressure.

  • Prospective cohort studies with salt intake measured by multiple 24-h urine collections demonstrate a direct linear relationship with cardiovascular events and all-cause mortality, down to a daily salt intake of 3 g.

  • The totality of the evidence strongly supports a population-wide reduction in salt intake; paradoxical J-shaped findings from studies with methodological problems should not derail action to reduce salt consumption.

  • Every country should implement a strategy to reduce daily salt intake to the WHO target of 5 g; this action will result in major public health improvements and cost savings.

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Fig. 1: Salt intake and blood pressure.
Fig. 2: Salt intake, blood pressure, and cardiovascular mortality.

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F.J.H. researched data for the article, and both authors discussed the content of the manuscript. F.J.H. wrote the article, and both authors reviewed and edited it before submission.

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Correspondence to Feng J. He.

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F.J.H. is a member of Consensus Action on Salt & Health (CASH) and World Action on Salt & Health (WASH). Both CASH and WASH are non-profit charitable organizations, and F.J.H. does not receive any financial support from CASH or WASH. G.A.M. is Chairman of Blood Pressure UK (BPUK), Chairman of CASH, and Chairman of WASH. BPUK, CASH, and WASH are non-profit charitable organizations, and G.A.M. does not receive any financial support from any of these organizations.

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He, F.J., MacGregor, G.A. Role of salt intake in prevention of cardiovascular disease: controversies and challenges. Nat Rev Cardiol 15, 371–377 (2018). https://doi.org/10.1038/s41569-018-0004-1

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