Should we all cut back on salt—regardless of our blood pressure level?

Most of the sodium in our diet comes from salt, or sodium chloride. Sodium has many important functions in the body, including:

      *  transmitting nerve impulses

      *  contracting and relaxing muscle fibres

      *  maintaining proper fluid balance.

But Americans get much more than they need—3,400 mg of sodium per day, on average. (See the chart below for recommended intake.)The kidneys regulate the body's sodium level by getting rid of any excess. But if there's too much sodium in the bloodstream, the kidneys can't keep up. Excess sodium in the blood pulls out water from the cells. As this fluid increases so does blood volume. That means more work for the heart, increased pressure in the blood vessels, and often, eventually, stiffened vessel walls, chronic high blood pressure, and an increased risk of heart attack or stroke.

Some people are especially sensitive to sodium—their blood pressure rises and falls directly with their sodium intake. That puts them at increased risk for cardiovascular disease, even if they don't have high blood pressure. It also means that they particularly benefit from restricting sodium intake.

Those most prone to salt sensitivity include:

* the elderly

* African Americans

* people with hypertension

* people with diabetes

* people with chronic kidney disease.