We are commonly advised to cut down on salt. The previous version of this review looked at mostly short-term strategies to reduce salt intake. In the present updated version separate analyses of studies with a duration of 2 to 4 weeks or longer were performed. Low salt diets reduced systolic blood pressure by 1% in white people with normal blood pressure and by 3.5% in white people with elevated blood pressure. The effect was similar in trials of 4 weeks or longer. There were increases in some hormones and lipids which could be harmful if persistent over time. However, the studies were not designed to measure long-term health effects. Therefore we do not know if low salt diets improve or worsen health outcomes.
Most of the people who took part in the studies were whites, but in the small number of non-whites the blood pressure reduction was, if anything, greater. More research on reduced salt intake is required, particularly in non-white populations. —Cochrane 2011