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Eating Well During National High Blood Pressure
Education Month

This May, in recognition of National High Blood Pressure Education Month, the National Heart, Lung, and Blood Institute (NHLBI) of the National Institutes of Health is encouraging Americans to consume more fruits, vegetables, and low fat diary products, and less salt and dietary sodium. Findings from recent studies demonstrate that these lifestyle changes can decrease blood pressure as well as prevent it from rising.

High blood pressure, or hypertension, increases the risk of stroke, heart disease, heart attacks, congestive heart failure, progression of kidney disease, and death. Blood pressure is considered high when readings are over 140/90 mm Hg.

"NHLBI-funded studies provide solid evidence that Americans should be careful about their diet, especially their daily salt intake," said NHLBI Director Dr. Claude Lenfant. "The results have important implications for preventing high blood pressure, cardiovascular disease, and death as well as for treating those with cardiovascular disease."

Two recent studies in particular found that both individuals with hypertension as well as those with normal blood pressure benefited significantly from reduced salt consumption.

DASH-Sodium Study Results

The DASH (Dietary Approaches to Stop Hypertension)-Sodium study measured the effect of different levels of sodium intake on blood pressure. Researchers found that the less sodium consumed, the lower the blood pressure, regardless of whether the individual had hypertension.

The first study based on the DASH eating pattern examined the effect on blood pressure of whole dietary patterns rather than of individual nutrients. Researchers found that following an eating pattern rich in vegetables, fruit, and low-fat dairy products, and low in total fat and saturated fat, significantly reduces blood pressure. In the DASH-Sodium study, participants followed either a typical U.S. diet (the "control" diet) or the DASH diet at three sodium levels for 30 days each: a higher intake of 3,300 milligrams per day (the average level consumed by Americans); an intermediate intake of 2,400 milligrams per day (the upper limit of current recommendations of the National High Blood Pressure Education Program); and a lower intake of 1,500 milligrams per day.

Lower sodium intake resulted in lower blood pressure for both those on the DASH diet and those on the control diet. The greatest impact was observed among those following the DASH diet at the lowest (1,500 mg) sodium level. Among these individuals, systolic blood pressure (the top number in a blood pressure reading) dropped on average by 11.5 mm Hg in those with hypertension and by 7.1 mm Hg in those without hypertension, compared to their counterparts on the control diet at the highest sodium level. The DASH-Sodium study results were published in the January 4, 2001, issue of the New England Journal of Medicine.

"The combination of following the DASH diet and consuming less dietary sodium has a significant effect - one that is equal to or greater than the result you would expect from treatment with a single hypertension medication," says Dr. Frank Sacks, chair of the DASH-Sodium Steering Committee and Associate Professor of Medicine at Brigham and Women's Hospital and Harvard Medical School.

Salt Sensitivity Findings

Another recent study looked at death rates among people with and without high blood pressure, and among those who were and were not salt sensitive. Salt sensitivity is a measure of how blood pressure responds to a decrease in salt intake.

The results revealed that the risk of dying from cardiovascular disease or other causes 25 years after the start of the study was nearly equal between people with normal blood pressure but who were salt sensitive and people with high blood pressure. Participants in both the salt sensitivity group and the hypertension group had higher death rates than individuals with normal blood pressure and who were not salt sensitive. The study was reported in the February 16, 2001, Council Supplement issue of Hypertension: Journal of the American Heart Association.

Salt sensitivity increases the risk of developing hypertension, conditions such as left ventricular hypertrophy in which the heart's main pumping chamber is enlarged and does not function properly, and kidney disorders.

Based on earlier studies, researchers estimate that 26 percent of Americans with normal blood pressure and 58 percent of those with hypertension are salt sensitive. Because there is no easy way to measure salt sensitivity, the NHLBI recommends that Americans with normal blood pressure follow the Federal recommendation of having no more than 2,400 milligrams of dietary sodium a day to help prevent the development of high blood pressure. Individuals with hypertension are encouraged to consider lowering their sodium intake to 1,500 mg per day. Consult your physician before making changes to your blood pressure management plan.

What You Can Do

To prevent or treat high blood pressure, follow these guidelines:

• Follow a healthy eating plan -- one that emphasizes fruits, vegetables and low fat dairy products as well as one that limits your intake of dietary sodium
• Maintain a healthy weight
• Engage in regular physical activity
• Refrain from drinking excessive amounts of alcohol
• Take medications to treat hypertension as prescribed by your physician.

DASH Eating Plan

The DASH eating plan is a proven, heart-healthy way to lower your blood pressure and your risk of heart disease. Although the number of servings may vary depending on individual caloric needs, the plan's general daily recommendations include:

• 8 to 10 servings a day of fruits and vegetables (fresh, frozen, dried, or unsalted canned)
• 7 to 8 servings of grains and grain products
• 2 to 3 servings of lowfat or fat-free dairy foods
• 2 or fewer servings of meats, poultry, and fish.

In addition, DASH incorporates 4 to 5 servings a week of nuts, seeds, and dry beans.

Tips for Lowering Dietary Sodium

Lowering your dietary sodium intake means making heart-healthy decisions before you reach the kitchen -- only 10 percent of dietary sodium comes from salt added to food at the table. Dr. Eva Obarzanek, an NHLBI nutritionist and Project Officer of the DASH-Sodium study, offers the following tips:

• Buy unsalted varieties of food and condiments
• Eat fewer processed foods (luncheon meats, prepared cheeses, canned vegetables, baked products, etc.), or use lower sodium versions if available
• Read nutrition labels (sodium content and the percent daily value) to choose foods that have less than 5 percent of the daily value for sodium, or 140 mg or less of sodium per serving
• Avoid using salt in food preparation; add flavor to foods instead by using herbs, spices, lemon or lime juice, or vinegar
• Remove salt from the table

For more information on National High Blood Pressure Education Month and how to live a heart-healthy lifestyle year-round, visit the National Heart, Lung, and Blood Institute's Web site at www.nhlbi.nih.gov.