DASH diet

Related Terms

Blood pressure, Dietary Approaches to Stop Hypertension, heart attack, kidney failure, stroke.

Background

Dietary Approaches to Stop Hypertension, also known as the DASH diet, is an eating plan designed by the National Heart, Lung, and Blood Institute to reduce blood pressure. The DASH diet encourages individuals to increase the consumption of vegetables, fruits, and low-fat dairy products while decreasing the consumption of total fat, saturated fat, cholesterol, and sodium. The diet is rich in minerals such as magnesium, calcium, and potassium and is also high in protein and fiber. Sweets, junk food, and sodas are not to be consumed on a daily basis and are discouraged overall.
The DASH diet highlights the variety of foods available in this diet plan, rather than focusing on all of the restrictions. DASH diet advocates believe that diets which focus on restriction rather than abundance may deter individuals from choosing to follow the DASH diet.
The DASH diet is based on the U.S. Department of Agriculture (USDA) food pyramid. It has been evaluated in medical trials conducted in the late 1990s and early 2000s and has been shown to reduce blood pressure. The National Heart, Lung, and Blood institute updated the diet specifications after the U.S. Department of Agriculture (USDA) released an updated food pyramid in 2005.
The DASH diet is most commonly used to reduce the likelihood of life-threatening emergencies caused by high blood pressure, such as stroke and heart attack. The primary goal of the DASH diet is to have individuals make dietary changes over time that move them closer to a healthier lifestyle. DASH diet literature provides a variety of tools to help individuals calculate what and how much should be eaten. The tools include lists of foods in different parts of the food pyramids and suggestions of heart-healthy food substitutions. Plans are designed for three different caloric intakes. It is recommended that patients consult with a doctor or nutritionist to determine their current and target caloric intake.
The DASH diet is well studied, approved by most medical experts, and is endorsed by a number of reputable health organizations, including the American Heart Association. The DASH diet was formulated after a number of clinical trials were conducted to evaluate its efficacy in reducing blood pressure and the risk of stroke and heart attack. In one study, patients who followed the DASH diet reduced their blood pressure as much as patients who took antihypertensive (blood pressure lowering) medications.
Some experts believe that following the DASH diet may reduce blood pressure as much as blood pressure lowering prescription medication. As a result, some healthcare practitioners are beginning to recommend the DASH diet instead of antihypertensive medications for patients with high blood pressure who are not in immediate risk of a stroke or heart attack.

Theory / Evidence

High blood pressure is a dangerous condition because the physical changes that may result in a heart attack, stroke, or kidney failure take many years to develop. Because the changes are slow and the symptoms are not obvious without a visit to the doctor, many people do not know how serious high blood pressure can be until they or a loved one experiences a medical emergency.
A patient's blood pressure is recorded as a fraction. The numerator (top number of the fraction) is higher than the denominator (bottom number of the fraction). A person's blood pressure is considered high if the systolic pressure (top number of the fraction) is above 140 and if the diastolic pressure (bottom number of the fraction) is above 90. Patients with blood pressure that is just below these numbers are defined as prehypertensive and should also take steps to lower their blood pressure.
The emphasis on the range of foods that are permitted in the DASH diet is designed to appeal to hypertensive patients who normally are instructed primarily about food restrictions. Experts believe that the focus on abundance rather than adhering to rules will help make individuals more likely to follow the DASH diet plan.
The DASH diet was based in part from data about the lower incidence of certain health problems experienced by vegetarians. It has been found that vegetarians tend to have a lower risk of suffering a stroke, heart attack, or kidney failure due to high blood pressure because individuals who follow a vegetarian diet tend to have lower than average blood pressure. A vegetarian diet also tends to be higher in unsaturated fat, fiber, calcium, potassium, and magnesium than other diets.
Individuals who eat mostly processed foods generally consume too much sodium and not enough potassium, calcium, and magnesium present in foods such as low fat dairy products, vegetables, and fruits. Most prepackaged foods that contain sauce or flavoring packets, pre-mixed ingredients, pre-cooked meats, or pre-cooked meats that are already sliced, diced, or deep fried are considered processed.
Researchers have found that taking calcium, potassium, and magnesium supplements without reducing the amount of processed food in the diet does not help lower blood pressure or reduce the likelihood of heart attack or stroke.
A 2006 trial by Elmer et al. evaluated several behavioral interventions to lower blood pressure and improve lifestyle behaviors of patients with high blood pressure. The length of the trial was six months. Patients who followed the DASH diet showed a statistically significant reduction in weight and sodium and fat intake. In addition, these individuals also statistically increased their intakes of minerals, fiber, dairy, fruits, and vegetables. The authors concluded that patients who undergo and sustain multiple lifestyle modifications, such as those required by the DASH diet, improve their blood pressure readings and may reduce their risk for chronic disease.

Author information

This information has been edited and peer-reviewed by contributors to the Natural Standard Research Collaboration (www.naturalstandard.com).

Bibliography

Azadbakht L, Mirmiran P, Esmaillzadeh A, et al. Beneficial effects of a Dietary Approaches to Stop Hypertension eating plan on features of the metabolic syndrome. Diabetes Care. 2005 Dec;28(12):2823-31.
Conlin PR, Chow D, Miller ER 3rd, et al. The effect of dietary patterns on blood pressure control in hypertensive patients: results from the Dietary Approaches to Stop Hypertension (DASH) trial. Am J Hypertens. 2000 Sep;13(9):949-55.
Elmer PJ, Obarzanek E, Vollmer WM, et al; PREMIER Collaborative Research Group. Effects of comprehensive lifestyle modification on diet, weight, physical fitness, and blood pressure control: 18-month results of a randomized trial. Ann Intern Med. 2006 Apr 4;144(7):485-95.
National Heart, Lung, and Blood Institute. .
Rankins J, Sampson W, Brown B, et al. Dietary Approaches to Stop Hypertension (DASH) intervention reduces blood pressure among hypertensive African American patients in a neighborhood health care center. J Nutr Educ Behav. 2005 Sep-Oct;37(5):259-64.
Sacks FM, Appel LJ, Moore TJ, et al. A dietary approach to prevent hypertension: a review of the Dietary Approaches to Stop Hypertension (DASH) Study. Clin Cardiol. 1999 Jul;22(7 Suppl):III6-10.
Sacks FM, Svetkey LP, Vollmer WM, et al; DASH-Sodium Collaborative Research Group. Effects on blood pressure of reduced dietary sodium and the Dietary Approaches to Stop Hypertension (DASH) diet. DASH-Sodium Collaborative Research Group. N Engl J Med. 2001 Jan 4;344(1):3-10.
Svetkey LP, Sacks FM, Obarzanek E, et al. The DASH Diet, Sodium Intake and Blood Pressure Trial (DASH-sodium): rationale and design. DASH-Sodium Collaborative Research Group. J Am Diet Assoc. 1999 Aug;99(8 Suppl):S96-104.

Diet

The DASH diet recommends making gradual changes to the diet and lifestyle in order to lower blood pressure. Rather than switching from one's normal diet to the DASH diet all at once, individuals are encouraged to slowly adopt and adjust to different parts of the eating plan over a period of time. The theory behind this is that abrupt changes may be too difficult to follow, and as a result, individuals may give up on making positive health changes.
Unlike some other diets designed for individuals with high blood pressure, the DASH diet does not make the levels of sodium in the diet the primary focus. However, salt reduction is an important component of the diet. According to the DASH diet, an individual should consume a maximum of 2,400 milligrams of sodium daily. Individuals are encouraged to pay attention to all of the salt in the diet, including table salt, salt used in cooking, as well as so-called "hidden salts" in fast foods, processed foods, and foods eaten at restaurants. Avoiding or reducing consumption of foods such as canned soups, lunchmeats, and junk foods may significantly decrease a person's sodium intake. As a reference, one teaspoon of salt contains 2,000 milligrams of salt.
Individuals are encouraged to increase consumption of foods rich in potassium, calcium, and magnesium, such as fresh fruits and vegetables. Foods that contain large amounts of calcium include fortified juices, broccoli, spinach, leafy greens (bok choy, chard, collards, turnip greens, mustard greens, beet greens, dandelion greens, endive, escarole, and kale; not including iceberg lettuce), milk, yogurt, and cheese. Foods that contain large amounts of potassium include lean meats, fish, spinach, tomatoes, bananas, potatoes, cantaloupes, and pears. Foods that contain a large amount of magnesium include whole grains, nuts, shrimp, milk, spinach, greens, broccoli, potatoes, and milk.
Individuals are encouraged to decrease the amount of saturated fats, as well as total fat content in their diets. Foods that contain a high level of saturated fat include meats, cheeses, butter, poultry, fast food, and most junk food. Some individuals may not have time to count the saturated fat in their diet, so it is suggested to remember which foods are high in saturated fats and then select alternatives to these foods.
The DASH diet encourages patients to slowly increase their level of physical activity as a part of the diet. Any form of physical activity, from walking to boxing, is acceptable as long as the individual does the activity continuously for at least ten minutes at a time. The physical activity does not need to be intense. Patients who are on the DASH diet are encouraged to exercise 30 minutes every day. If a person exercises in ten-minute spurts, then they should exercise three times daily.
Individuals with high blood pressure who consume more than one or two alcoholic beverages daily are at an increased risk of stroke. The DASH diet encourages individuals to limit alcohol intake to a maximum of two drinks every day. A drink is defined as 12 ounces of beer, 4 ounces of table wine, or 1? ounces of liquor.
Patients who begin to consume more fiber than prior to the DASH diet should make an attempt to drink more water in order to avoid digestive upset.
Individuals on the DASH diet are encouraged to make a number of food substitutions to reach their dietary goals. For instance, low fat dairy products, such as cheese, milk, and yogurt are available as an alternative to regular full-fat dairy products. Typical snacks, such as chips or fast food may be replaced by unsalted pretzels, unsalted nuts, raisins, graham crackers, low-fat, fat-free frozen yogurt and regular yogurt, unsalted plain popcorn with no butter, and raw vegetables. Some individuals enjoy using hummus or low fat or fat free condiments as a substitution for other higher fat dips or spreads that often accompany salty snacks.
Patients are encouraged to add more vegetables, fruit, pasta, and dry beans to the diet. Low-fat or fat-free milk may be consumed at a meal as well.
The DASH diet also encourages patients to limit the intake of some foods. For instance, an individual may use half of the regularly used amount of butter, margarine, or salad dressing or limit the amount of meat they consume to six ounces per day.
Individuals who choose the DASH diet should try to maintain a healthy weight.

Number of recommended servings for different calorie levels

Source: National Heart, Lung, and Blood Institute.

Food servings, sizes, examples, and significance in the dash diet

Source: National Heart, Lung, and Blood Institute.