Managing Hypertension with the DASH Diet

What you eat can help lower your blood pressure and reduce your risk for stroke and heart disease.

One study published in the New England Journal of Medicine showed that following the Dietary Approaches to Stop Hypertension (DASH) diet reduced blood pressure. This diet is low in saturated fat, cholesterol, and total fat and emphasizes fruits, vegetables, and low-fat dairy products.

Another study, published in the Journal of the American Heart Association , showed that the DASH diet also reduces blood levels of homocysteine. High levels of this amino acid may increase the risk for heart disease, stroke, and other vascular diseases.

A third DASH study that also limited sodium (salt) showed even more dramatic reductions in blood pressure, especially in people with hypertension. It was published in the Annals of Internal Medicine.

According to the National Heart, Lung, and Blood Institute (NHLBI), blood pressure can be unhealthy even if it stays only slightly above 120/80 mm Hg. The higher above that level, the greater your health risk. Over time, high blood pressure makes the heart work too hard, which can cause stroke, hardening of the arteries, heart failure, kidney disease, even blindness.

Why this diet works

Why is the DASH diet so effective at reducing blood pressure? "It combines many nutrients that have been shown to be beneficial in lowering blood pressure," says Pao-Hwa Lin, Ph.D., a medical researcher in Durham, N.C., and a coauthor of the DASH studies.

Those nutrients include calcium, potassium, magnesium, protein, and fiber, as well as lower total fat and saturated fat.

"Each of those nutrients alone may not have significant enough impact on blood pressure to be detected in a study," says Dr. Lin. "But if they're together in a whole dietary pattern, such as DASH, their benefits may be additive and more likely to be detected. In fact, studies have shown that if you leave out dairy products and just take calcium supplements, for example, you don't get the same effect on blood pressure."

The DASH diet is naturally low in salt. Recipes for the meals in the DASH diet program have a maximum of 2,400 mg of salt/sodium a day.

Further, following the DASH diet may delay the need to take hypertension medication or prevent you from needing to take it at all. And if you're already on medication, it may help you reduce the amount you take.

Although hypertensive medications have been proven to be effective at lowering blood pressure, having to take them isn't a panacea.

"Most people don't realize that even if the medication they take lowers their blood pressure to a range that's acceptable, their risk for stroke and heart disease is still higher than people who can control their blood pressure with their diet and lifestyle," says Dr. Lin.

Doing the DASH

The DASH diet is a 2,000-calorie diet that includes:

• Seven to eight daily servings of grains and grain products, such as whole-wheat bread, cereal, oatmeal, crackers, unsalted pretzels, and popcorn. A serving size is 1 slice of bread, 1 cup of ready-to-eat cereal, or a half-cup of rice, pasta, or cereal.

• Four to five daily servings of vegetables, the darker in color, the better. A serving size is 1 cup of raw leafy vegetable, half-cup of cooked vegetables, or 6 ounces of vegetable juice.

• Four to five daily servings of fruit. A serving is 1 medium fruit, quarter-cup of dried fruit, half-cup of fresh, frozen or canned fruit, or 6 ounces of fruit juice.

• Two or three daily servings of low-fat or fat-free dairy products. A serving is 8 ounces of milk, 1 cup of yogurt, or 1-1/2 ounces of cheese.

• Two or fewer daily servings of lean meat, poultry, or fish. A serving is 3 ounces of cooked meats, skinless poultry, or fish.

• Four to five servings per week of nuts, seeds, and dry beans. A serving is one-third cup or 1-1/2 ounces of nuts, 1 tablespoon or half-ounce of seeds, or half-cup cooked dried beans.

• Two to three small daily servings of fats and oils, such as olive oil and low-fat salad dressing. A serving is 1 teaspoon soft margarine, 1 tablespoon low-fat mayonnaise, 2 tablespoons light salad dressing, or 1 teaspoon vegetable oil.

• Five servings per week of sweets, such as maple syrup, sorbet, or gelatin. A serving is 1 tablespoon sugar, 1 tablespoon jelly or jam, half-ounce jellybeans, or 8 ounces of lemonade.

Although the DASH diet isn't designed for weight loss, it can easily promote it if you reduce the number of servings you consume, says Dr. Lin. Most of the food the diet features is low in energy density, which means it's big on volume and low in calories.

"It's a healthy diet for the whole family, and it's not hard to follow. Just take one small step at a time, and gradually you'll reach your goal," says Lin.

Still, there are aspects to the DASH diet that may not be easy to replicate. For one, it's packed with dark-colored fruits and vegetables, so be prepared to be choosier at the supermarket. Also, if it's vastly different from what you normally eat, it may be hard to adjust.

If you're serious about following the diet, it's a good idea to work with a registered dietitian (R.D.) for support and guidance. (For the names of R.D.s in your area who are familiar with the DASH diet, visit the American Dietetic Association's Web site, http://www.eatright.org.)

Moving forward

If you decide to go it alone, adopt the DASH diet gradually. By doing so, you'll be more apt to stick to it long-term.

For example, add one more serving of vegetables at lunch and dinner if you only eat one or two servings a day now, or add fruit to meals and snacks if you now only have juice for breakfast. In addition, slowly increase your dairy products to three servings per day— try drinking skim milk with lunch or dinner instead of soda, alcohol, or tea.

To maximize the impact of the DASH, lose weight if you need to and exercise regularly.

"Thirty minutes of moderate exercise, such as brisk walking, swimming, cycling, or golf [if you walk], four to five days a week is a good recommendation for most people," says Dr. Lin.

More dish on the DASH

"The DASH Eating Plan" is a 24-page online guide published by the NHLBI. It offers a reader-friendly explanation of high blood pressure, detailed daily servings charts to help you plan your menus, a week of suggested DASH menus, plus tips to reduce sodium.

For more information about diet and other lifestyle factors to reduce hypertension, visit "Your Guide to Lowering Blood Pressure," another comprehensive NHLBI guide.