The evidence is clear that for people with high blood pressure, potassium is one dietary factor that exerts a beneficial effect. This is partly because potassium lowers blood pressure and partly because it also protects against stroke and damage to blood vessels when blood pressure is high.
Several studies have shown that groups of people who eat low-potassium diets have an increased incidence of high blood pressure and heart disease. In addition, diets high in potassium and low in sodium can lower blood pressure. An intake of 3.5 g/day of potassium is associated with lower blood pressure and fewer deaths from strokes. All you have to do to get to this level of potassium is eat the five or more servings of fruit and vegetables a day recommended in the Eat for Life guidelines.
Sodium is an essential nutrient, but the amount consumed by most people—mostly in the form of salt (sodium chloride)—well exceeds the amount needed for normal body function. Although the average adult needs no more than several hundred milligrams of sodium a day, surveys show that people consume between 4 and 5.8 g (4000 to 5800 mg) a day.
Although researchers have been studying the relationship of sodium to high blood pressure since the turn of the century, there is still some controversy about the importance of salt in regulating blood pressure. Many studies have shown, for example, that the higher a culture's average salt consumption, the higher the average blood pressure.
The controversy concerns what happens when individual people consume more or less salt—the effect on blood pressure varies tremendously. People differ greatly in their sensitivity to salt. In some, blood pressure is affected to a large extent by the amount of salt they eat. But other people can