Salt and Cardiovascular Disease: Insufficient Evidence to Recommend Low Sodium intake

Martin O'Donnell; Andrew Mente; Michael H. Alderman; Adrian J.B. Brady; Rafael Diaz; Rajeev Gupta; Patricio López-Jaramillo; Friedrich C. Luft; Thomas F. Lüscher; Giuseppe Mancia; Johannes F.E. Mann; David McCarron; Martin McKee; Franz H. Messerli; Lynn L. Moore; Jagat Narula; Suzanne Oparil; Milton Packer; Dorairaj Prabhakaran; Alta Schutte; Karen Sliwa; Jan A. Staessen; Clyde Yancy; Salim Yusuf

Disclosures

Eur Heart J. 2020;41(35):3363-3373. 

In This Article

Why Is There Such Disagreement on the Same Evidence?

There is agreement that lowering sodium will be associated with a small reduction in blood pressure, but there is no agreement that all reductions will translate into a reduction in cardiovascular events and mortality, as there are no definitive long-term trials clearly demonstrating such benefit. There is general (but not complete) agreement on the desirability of reducing sodium intake in those who consume high salt diets (particularly in the setting of an overall poor diet), and as such, the disagreement is not about whether sodium intake should be reduced in some individuals, but in whom, and to what level. Advocates of low sodium intake generally assume a public health perspective, with the emphasis on a population-wide intervention to shift the distribution of sodium intake to the left, which will have very small effects on individuals but potentially large effects at a population level, an approach first proposed by Rose in 1985.[119] However, Rose's approach assumes that the risk associated with the risk factor in question consistently increases with greater exposure, as is the case with, for example, tobacco. This does not apply where the association is J- or U-shaped. Those that oppose a recommendation for low sodium intake[120] and advocate a moderate intake range adopt a more 'clinically' based perspective, in that the evidence level required to make a recommendation for low population-level sodium intake is that it needs to benefit those who consume it, especially when achieving the target is challenging and where observational studies suggest harm. Clinicians in cardiovascular medicine recommend increasing sodium intake in certain patients, such as those with symptomatic orthostatic hypotension or recurrent syncope, so the presence of a clinical J-shaped association is inherent to their clinical practice. In addition, clinicians experience the challenge of recommending a specific target for sodium intake that cannot be measured with convenient testing and is very difficult to achieve for patients. Moreover, in the context of numerous messages to the public regarding health behaviours, there is a risk of diverting resources away from effective interventions by investing in ineffective or unfeasible interventions, with a resultant 'opportunity cost' and risk of a credibility gap if strong public health messages are formulated without robust and consistent evidence to support them.

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