Doctors at the annual meeting of the American Medical Association (AMA) joined the American Heart Association and other health groups to tell us forcefully to stop consuming so much salt. Here's what's behind this story, which made national headlines last week.

Salt intake raises blood pressure, and high blood pressure is a risk factor for strokes, heart attacks, and kidney disease. About one-third of American adults, and a much higher percentage of the elderly, has high blood pressure or hypertension, defined by a systolic blood pressure (the top number) of 140 mm Hg or higher and/or a diastolic pressure (the bottom number) of 90 mm Hg or more.

About 30 percent of people with hypertension don't know they have it, and many millions more have prehypertension, defined as systolic blood pressures between 120 and 139 mm Hg and/or diastolic pressures between 80 and 89 mm Hg, which greatly increases the likelihood that they will develop hypertension.

The AMA made the following resolutions: decrease salt consumption 50 percent over the next decade; reduce salt content in processed foods and in restaurant meals; and remove salt from the list of foods generally considered as safe so that the Food and Drug Administration could regulate the salt content of foods.

Now you might be confused, because some recommendations refer to salt intake while others mention sodium. It's easier to think in terms of dietary sodium rather than salt, especially since food labels list only the sodium, not the salt (sodium chloride, sometimes abbreviated NaCl), content of food. Sodium comprises 40 percent of salt. The goal is to limit dietary sodium, most of which comes from salt.

At more than 4,000 mg per day, the sodium intake of the average American far exceeds the body's requirements for this mineral. Recommendations from the 2005 Dietary Guidelines for Americans limit daily intake of sodium to 2,300 mg (about 1 teaspoon of salt) in healthy people and to 1,500 mg in those with hypertension.

In 2004 the Institute of Medicine recommended even greater restrictions in sodium intake: less than 1,500 mg daily for all adults under age 50, and lower sodium intake with increasing age to less than 1,200 mg for those over 70.

It will take many years before substantial changes are made in the sodium content of the foods we eat. As you'd expect, the food industry has raised serious objections to the AMA recommendations, stating that lowering sodium intake has not been proven to save lives.

But the research is quite clear: even though reducing salt intake lowers blood pressure only modestly in people with hypertension, it's enough to dampen its dangers. And many studies have shown that lowering blood pressure decreases the risk of strokes, kidney disease, and heart attacks.

In the meantime, there's much you can do to limit your own sodium intake:

• Banish salt from the table and in cooking. Of course, the most obvious step is to remove the salt shaker from the table and avoid adding salt during cooking.
• Avoid too much processed food. You may be surprised to learn that less than 15 percent of our sodium intake comes from salt at the table or from cooking. The vast majority comes from the sodium in processed foods. A serving of canned vegetable soup, for example, contains almost 900 mg of sodium. So read the label before you eat (preferably, before you buy).
• Cross these high-sodium foods off your list. Canned fruits and vegetables; cheese; ketchup and soy sauce; microwave popcorn; processed meats like bologna, frankfurters, and cured ham; salted nuts; olives and pickles; smoked or cured fish; salted butter and margarine; and snack foods like potato chips and pretzels.