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By David Van Horn, healthAtoZ health editor

"Hold the salt" may not be good advice just for people with high blood pressure. For the first time, medical researchers have found that even people with normal blood pressure are at an increased risk for deadly heart disease if they are sensitive to salt.

About one in four Americans with normal blood pressure is sensitive to salt, and more than half (58 percent) with hypertension are salt sensitive, according to estimates by Myron Weinberger, M.D., professor of medicine and director of the Hypertension Research Center at the Indiana University School of Medicine.

You're more likely to be sensitive to salt if you're elderly, African American or have a family member with hypertension or salt-sensitivity, says Weinberger, the principal investigator in a study published in Circulation: Journal of the American Heart Association.

Salt sensitivity is a measure of how blood pressure responds to salt, and Weinberger's study is the first to show that it may be an independent risk factor for cardiovascular death.

One consequence of this condition is high blood pressure, which increases your risk of developing heart disease, the number one killer of men and women in the United States.

Sensitivity to salt can also increase your risk of developing kidney problems and enlargement of the left ventricle, your heart's main pumping chamber, says the National Heart, Lung, and Blood Institute (NHLBI), which sponsored the study.

Salt sensitivity a new risk factor?

Weinberger and his colleagues did a follow-up investigation of 708 people who participated in a hypertension study in the 1970s. Of the original group, 123 people had died - about half from heart attacks and strokes. Participants with normal blood pressure and no salt sensitivity had a better survival rate than those who had high blood pressure or were salt sensitive.

"Up until now, doctors were telling hypertension patients to lower salt. Now we know that people with normal blood pressure can be salt-sensitive as well and their risk of death can be as high as someone with hypertension," says Winifred Barouch, Ph.D., a health scientist administrator at NHLBI.

Indiana University researchers determined salt sensitivity by giving participants an intravenous salt solution and measuring their blood pressure. Individuals then were given a diuretic drug and told to follow a very low salt diet to reduce their body's salt content. If their subsequent blood pressure reading fell by 10 mm/Hg or more, a person was classified as salt-sensitive. You may wish to talk to your doctor about the availability of such a screening test.

Cutting salt from your diet

Reducing sodium in your diet can significantly reduce your blood pressure, even if you do not have hypertension, according to a NHLMI study.

The average American consumes about 3,300 milligrams of sodium per day, one quarter more than the 2,400 milligrams recommended by the NHLBI's High Blood Pressure Education Program and twice as much as the 1,500-milligram limit in the DASH (Dietary Approaches to Stop Hypertension) diet.

Sodium used as a preservative, curing agent or for flavoring in processed foods is the biggest source of sodium in the American diet. One-third of the sodium in your diet is naturally present in foods, and another one-third comes from table salt, which consists of 40 percent sodium and 60 percent chloride.

Measuring your sodium intake can be very hard, especially when eating prepared foods or dining in restaurants, Barouch says. Here are some tips from the National Heart, Lung, and Blood Institute and the University of Pennsylvania Health System on how to de-salt your diet:

• Read food labels carefully to help you choose foods that are low in sodium. Almost all packaged foods contain sodium, but there are low-, reduced-sodium and no-salt-added versions. What is the difference in these terms? Sodium free is less than 5 milligrams per serving; very low sodium is 35 milligrams or less; low sodium is 140 milligrams or less; and reduced sodium means a 75 percent reduction in the usual level of sodium.

• Buy fresh food. Fresh vegetables, poultry, fish and lean meat are better alternatives than canned or processed foods. You can try rinsing canned foods, such as tuna, to remove some sodium.

• Avoid foods that are high in sodium. Canned and dried foods and processed luncheon meats and cheeses are some common high-sodium foods. Bacon, sausage, corned- beef, hot dogs and pizza are also high in sodium, as are condiments such as ketchup, mustard and soy sauce. Instead, try eating more fruits, vegetables, grains and low-fat dairy foods.

• Put away the saltshaker. Use herbs, spices and salt-free seasonings when cooking. Cook rice, pasta and hot cereals without salt.

• Keep a sodium diary to help you decide which foods to decrease or eliminate. You may be surprised at how much sodium you consume each day.

External Resources: Study Shows New Link Between Salt Sensitivity and Risk of Death, National Heart, Lung, and Blood Institute, Feb. 15, 2001 University of Pennsylvania Health System Watching Salt Intake Isn't Just for Those With High Blood Pressure, American Heart Association,Oct. 25, 2000 Tips to Reduce Salt and Sodium, National Heart, Lung, and Blood Institute, National Institutes of Health Ten Tips to Help You Control Your High Blood Pressure, National Heart, Lung, and Blood Institute, National Institutes of Health

This article was published on 2001-02-22
This article was reviewed on 2003-02-03