Review question/objective

The objective of this review is to establish the effect of modifying dietary sodium intake in normotensive subjects. More specifically, the objectives are to identify the effect of reducing or increasing sodium intake on blood pressure in normotensive subjects with systolic blood pressure <140mmHg, and the effect of sodium reduction or supplementation on arterial function in subjects with baseline systolic blood pressure <140mmHg.

Inclusion criteria

Types of participants

This review will consider studies that include adult subjects with systolic blood pressure <140mmHg and studies conducted in community settings (for example, free living populations) and controlled conditions (for example, metabolic ward, hospital and study centre). This review will exclude studies that include subjects prescribed antihypertensive or vasoactive medications.

Types of interventions

This review will consider studies that evaluate dietary sodium intake for equal to or greater than four weeks duration. This review will consider studies that include two study arms comprising of different levels of sodium intake. This review will consider studies that modify sodium intake via dietary modification, salt reduction, and/or salt supplementation.

Types of outcomes

This review will consider studies that include the following outcome measures: systolic blood pressure, diastolic blood pressure, pulse wave velocity, pulse wave analysis, and flow mediated dilatation by Doppler ultrasound.