from WHO-ISH 1999 Guidelines

Reduction in salt intake
Epidemiologic studies suggest that dietary salt intake is a contributor to blood pressure elevation and to the prevalence of hypertension. The effect appears to be enhanced by a low dietary intake of potassium containing foods. Randomised controlled trials in hypertensive patients indicate that reducing sodium intake by 80-100 mmol (4.7-5.8 g) per day from an initial intake of around 180 mmol (10.5 g) per day will reduce blood pressure by an average of around 4-6 mmHg SBP. However, individuals vary considerably in their responses to changes in dietary salt, with black, obese and elderly subjects the most sensitive. A recent study in older hypertensive patients showed no adverse effects of a reduction in sodium of 40 mmol (2.3 g) per day and after 18 months there was a significant reduction in the need for antihypertensive drug therapy. The aim of dietary sodium reduction should be to achieve an intake of less than 100 mmol (5.8 g) per day of sodium or less than 6 gm per day of sodium chloride. Patients should be advised to avoid added salt, to avoid obviously salted foods, particularly processed foods, and to eat more meals cooked directly from natural ingredients. Counselling by trained dieticians and monitoring of urinary sodium are necessary in most cases. The high sodium – low potassium content of many preserved foods is drawn to the attention of the food industry.