DASH Diet

One of the risk factors for high blood pressure is an unhealthy diet, so if you have high blood pressure, your doctor may recommend the DASH diet (Dietary Approaches to Stop Hypertension). This diet combines healthy foods low in saturated fat and cholesterol while emphasizing fruits, vegetables, and low-fat dairy foods. In clinical studies, combining the DASH diet with a reduced-sodium diet was shown to lower blood pressure by an average of 12/6 mmHg (systolic/diastolic) in those with high blood pressure.

 

DASH Diet: An Overview

Anyone can develop high blood pressure (also known as hypertension). In fact, more than 65 million Americans (nearly 1 in 3) have high blood pressure. Unfortunately, in more than 90 percent of cases, the cause or causes of high blood pressure are not known. But hypertension research scientists have found certain risk factors that increase a person's chance of developing high blood pressure. High blood pressure prevention involves minimizing the high blood pressure risks that can be controlled. One of these risk factors is an unhealthy diet.
 
The DASH eating plan, also known as the DASH diet, is a plan that has been shown in several research studies to lower blood pressure. "DASH" stands for "Dietary Approaches to Stop Hypertension." The DASH diet:
 
  • Combines healthy foods that are low in saturated fat, cholesterol, and total fat
  • Emphasizes fruits, vegetables, and low-fat dairy foods.
     
Combined with low sodium intake, the DASH diet has been shown to be as effective as a single blood pressure medicine in lowering blood pressure.
 

Where Did the DASH Diet Come From?

In the past, researchers tried to find clues about what in the diet affects blood pressure by testing various single nutrients, such as calcium, magnesium, and potassium (see
 Potassium and High Blood Pressure). These studies were done mostly with dietary supplements, and their findings were not conclusive. Then hypertension research scientists conducted two key studies: DASH and DASH-Sodium
 
DASH
The first clinical study was called "DASH," and it tested nutrients as they occur together in food. Its findings showed that blood pressures were reduced with an eating plan that is low in saturated fat, cholesterol, and total fat, and that emphasizes fruits, vegetables, and low-fat dairy foods. This eating plan -- known as the DASH eating plan or DASH diet -- also includes:
 
  • Whole-grain products
  • Fish
  • Poultry
  • Nuts.
     
The DASH diet is reduced in red meat, sweets, and sugar-containing beverages. It is rich in magnesium, potassium, and calcium, as well as protein and fiber.
 
DASH compared three eating plans:
 
  • A plan similar in nutrients to what many Americans consume
  • A plan similar to what Americans consume but higher in fruits and vegetables
  • The DASH diet.
     
All three plans included about 3,000 milligrams of sodium daily. None of the plans were vegetarian or used specialty foods.
 
Results were dramatic: Both the fruits and vegetables plan and the DASH diet reduced blood pressure. But the DASH diet had the greatest effect, especially for those with high blood pressure. Furthermore, the blood pressure reductions came fast -- within 2 weeks of starting the DASH diet.
 
DASH-Sodium
The second study was called "DASH-Sodium," and it looked at the effect on blood pressure of a reduced dietary sodium intake as participants followed either the DASH diet or an eating plan typical of what many Americans consume.
 
Participants were randomly assigned to one of the two eating plans and then followed for a month at each of three sodium levels. The three sodium levels were:
 
  • A higher intake of about 3,300 milligrams per day (the level consumed by many Americans)
  • An intermediate intake of about 2,400 milligrams per day
  • A lower intake of about 1,500 milligrams per day.
     
Results showed that reducing dietary sodium lowered blood pressure for both eating plans. At each sodium level, blood pressure was lower on the DASH diet than on the other eating plan. The biggest blood pressure reductions were for the DASH diet at the sodium intake of 1,500 milligrams per day. Those with hypertension saw the biggest reductions, but those without it also had large decreases.
 
Those on the 1,500-milligram sodium intake eating plan, as well as those on the DASH diet, had fewer headaches. Other than that and blood pressure levels, there were no significant effects caused by the two eating plans or different sodium levels.
 
DASH-Sodium shows the importance of lowering sodium intake, regardless of your eating plan. But for a true winning combination, follow the DASH diet and lower your intake of salt and sodium.
 

Diet Specifics

The following sample DASH diet is based on 2,000 calories a day. The number of daily servings in a food group may vary from those listed, depending on your caloric needs.
 
Food Group
Daily
Servings
(except
as noted)
Serving Size Examples
Grains and grain products
7-8
1 slice bread
1 cup ready-to-eat cereal*
½ cup cooked rice, pasta, or cereal
Vegetables
4-5
1 cup raw leafy vegetable
½ cup cooked vegetable
6 ounces vegetable juice
Fruits
4-5
1 medium fruit
¼ cup dried fruit
½ cup fresh, frozen, or canned fruit
6 ounces fruit juice
Low-fat or fat-free dairy foods
2-3
8 ounces milk
1 cup yogurt
1½ ounces cheese
Lean meats, poultry, and
fish
2 or less
3 ounces cooked lean meats, skinless poultry, or fish
Nuts, seeds, and dry beans
4-5 per week
1/3 cup or 1½ ounces nuts
1 tablespoon or ½ ounce seeds
½ cup cooked dry beans
Fats & oils**
2-3
1 teaspoon soft margarine
1 tablespoon low-fat mayonnaise
2 tablespoons light salad dressing
1 teaspoon vegetable oil
Sweets
5 per week
1 tablespoon sugar
1 tablespoon jelly or jam
½ ounce jelly beans
8 ounces lemonade
 
* Serving sizes vary between 1/2 cup and 1-1/4 cups. Check the product's nutrition label.
** Fat content changes serving counts for fats and oils: For example, 1 tablespoon of regular salad dressing equals 1 serving, 1 tablespoon of a low-fat dressing equals 1/2 serving, and 1 tablespoon of a fat-free dressing equals 0 servings.
 

Getting Started on the DASH Diet

It's easy to adopt the DASH diet. Here are some ways to get started:
 
Change Gradually
Making changes is best done gradually. Don't try to change everything all at once. Suggestions for gradually incorporating the DASH diet into your life include:
 
  • If you now eat one or two vegetables a day, add a serving at lunch and another at dinner.
  • Use only half the butter, margarine, or salad dressing you do now.
  • If you don't eat fruit now or have only juice at breakfast, add a serving to your meals or have it as a snack.
  • Try low-fat or fat-free condiments, such as fat-free salad dressings.
  • Gradually increase dairy products to three servings per day. For example, drink milk with lunch or dinner instead of soda, alcohol, or sugar-sweetened tea. Choose low-fat (1 percent) or fat-free (skim) dairy products to reduce total fat intake.
     
Treat Meat as One Part of the Whole Meal, Instead of the Focus
Many people think of meat as the focus of their meals. While meat can be part of a healthy diet, it's best to treat it as merely one part of the meal. Consider the following tips for eating meat as you make the transition to the DASH diet:
 
  • Buy less meat. If it's not there, you won't eat it.
  • Limit meat to 6 ounces a day (two servings) -- all that's needed. Three to four ounces is about the size of a deck of cards.
  • If you now eat large portions of meat, cut them back gradually -- by a half or a third at each meal.
  • Include two or more vegetarian-style (meatless) meals each week.
  • Increase servings of vegetables, rice, pasta, and dry beans in meals. Try casseroles, pasta, and stir-fry dishes, having less meat and more vegetables, grains, and dry beans.
     
Use Fruits or Low-Fat Foods as Desserts and Snacks
Fruit and other low-fat foods can make up a healthy dessert or snack in a DASH diet. Try these ideas:
 
  • Fruits and low-fat foods offer great taste and variety. Use fruits canned in their own juice. Fresh fruits require little or no preparation. Dried fruits are easy to carry with you.
     
  • Try these snack ideas: unsalted pretzels or nuts mixed with raisins, graham crackers, low-fat and fat-free yogurt and frozen yogurt, plain popcorn with no salt or butter added, and raw vegetables.
     
(Click Salt and High Blood Pressure for ways to reduce salt intake in your diet.)
 

DASH Diet and Weight Loss

The DASH diet was not designed to promote weight loss. But it is rich in lower-calorie foods, such as fruits and vegetables. You can make it lower in calories by replacing higher-calorie foods with more fruits and vegetables -- and that also will make it easier for you to reach your DASH goals.
 

Study Results on the DASH Diet

People with high blood pressure who adhered to the DASH diet at the lowest sodium level had an average systolic pressure reading 11.5 mmHg lower than participants eating the control diet at the highest sodium level. The corresponding number for participants who did not have high blood pressure was a 7.1-mmHg systolic pressure reduction.
 
Detailed analysis showed that the DASH diet and reduced sodium intake reduced blood pressure for all the population subgroups studied. The following list shows the average blood pressure reduction for key subgroups:
 
  • For those with hypertension: 12/6 mmHg (systolic/diastolic); for those without hypertension, 7/4 mmHg
  • For those over age 45, 12/6 mmHg; for those 45 or younger, 6/3 mmHg 
  • For women, 11/5 mmHg; for men, 7/4 mmHg
  • For African Americans, 10/5 mmHg; for non-African Americans, 8/4 mmHg.
     
Other results include:
 
  • Compared with the typical American diet, the DASH diet alone (at the higher sodium level) reduced blood pressure by about 6/3 mmHg for African Americans and by 6/2 mmHg for other races.
     
  • For those with hypertension, reductions from the DASH diet alone were 7/3 mmHg; for those without hypertension, the reductions were 5/3 mmHg.
     
  • The effects of sodium reduction appeared in all subgroups and were greater for those who ate the typical American diet compared with those on the DASH diet. The effects from sodium reduction were particularly great for those with hypertension, African Americans, women, and those over age 45. Sodium reduction in those eating the control diet resulted in lower systolic and diastolic pressures by 8.3 mmHg and 4.4 mmHg, respectively, in people with high blood pressure, and 5.4 and 2.8 mmHg, respectively, in people without hypertension.
     
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Written by/reviewed by: Arthur Schoenstadt, MD
Last reviewed by: Arthur Schoenstadt, MD