Should dietary salt restriction be a basic component of antihypertensive therapy?

The general intake of salt (sodium chloride) is much higher than the recommended allowances, in part because of added salt in food industry processed food. However, population studies have not been able to show an association between salt intake and unfavorable health outcome. Based on population studies and randomized studies, the effect of an extreme salt reduction of 100 mmol on blood pressure in hypertensive persons is about one third of the effect of antihypertensive medications. This effect-size estimate is based on single measurements of blood pressure and is probably overestimated compared with 24-hour blood pressure measurements. Salt reduction has effects on heart rate and serum levels of renin, aldosterone, catecholamines, and lipids that may be unfavorable. Because of insufficient compliance, extreme salt reduction can only be obtained if salt in food industry processed food is eliminated. The full consequences of such elimination are not known. Other nonpharmacological interventions, such as weight reduction and diets including fruits, vegetables, and low-fat dairy foods, are probably easier to implement and more effective to decrease blood pressure than salt reduction. Furthermore, salt reduction does not seem to add to the effect size when combined with other nonpharmacological interventions. Salt sensitivity due to sodium channel mutations has been shown in a minority of blacks but not in Caucasians. In conclusion, at present, dietary salt restriction should not be a basic component of antihypertensive therapy.