Why the DASH Eating Plan Works
Scientific studies show that following DASH and eating less sodium can help you lower your blood pressure and LDL cholesterol.
What you choose to eat affects your chances of developing hypertension, otherwise known as high blood pressure. Blood pressure can be unhealthy even if it stays only slightly above the optimal level of less than 120/80 mmHg. The more your blood pressure rises above normal, the greater the health risk.
Scientists supported by the National Heart, Lung, and Blood Institute (NHLBI) have conducted multiple scientific trials since the Dietary Approaches to Stop Hypertension—or DASH eating plan— was developed more than 20 years ago. Their findings showed that blood pressures were reduced with an eating plan that emphasizes vegetables, fruits, and whole grains and includes fish, poultry, beans, nuts, and healthy oils. It limits foods that are high in saturated fat, such as fatty meats, full-fat dairy products, and tropical oils such as coconut, palm kernel, and palm oils. It is also lower in sodium compared to the typical American diet and reduces sugar-sweetened beverages and sweets.
The DASH eating plan follows heart healthy guidelines to limit saturated fat and trans fat. It focuses on eating more foods rich in nutrients that can help lower blood pressure— mainly minerals (like potassium, calcium, and magnesium), protein, and fiber. It includes nutrient-rich foods so that it also meets other nutrient requirements as recommended by the National Academies of Sciences, Engineering, and Medicine.
DAILY NUTRIENT LEVELS OF THE ORIGINAL DASH EATING PLAN
|Total Fat||27% of calories|
|Saturated Fat||6% of calories|
|Protein||18% of calories|
|Carbohydrate||55% of calories|
* Lower sodium to 1,500 mg for further reduction in blood pressure, if needed
The Science Behind the DASH Eating Plan
The importance of eating more vegetables, fruits, whole grains along with low-fat dairy, poultry, fish, beans, and nuts has been proven in multiple research trials. The combination of the DASH eating plan and reduced sodium creates the biggest benefit, lowering blood pressure significantly.
STUDY 1 Original DASH eating plan
The first DASH trial involved 459 adults with systolic blood pressures of less than 160mmHg and diastolic pressures of 80–95mmHg. About 27 percent of the participants had high blood pressure. About 50 percent were women and 60 percent were African Americans. It compared three eating plans: one that included foods similar to what many Americans regularly eat; one that included foods similar to what many Americans regularly eat plus more fruits and vegetables; and the DASH eating plan. All three plans included about 3,000 milligrams of
sodium daily. None of the plans were vegetarian or used specialty foods.
Results were dramatic. Participants who followed either the plan that included more fruits and vegetables or the DASH eating plan had reduced blood pressure. But the DASH eating plan had the greatest effect, especially for those with high blood pressure. Furthermore, the blood pressure reductions came fast within 2 weeks of starting the plan.
STUDY 2 Varied sodium levels
The second DASH trial looked at the effect on blood pressure of a reduced dietary sodium intake as participants followed either the DASH eating plan or an eating plan typical of what many Americans consume. This trial involved 412 participants. Participants were randomly assigned to one of the two eating plans and then followed for a month at each of the 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 2,300 milligrams per day, and 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 DASH than on the typical American eating plan. The greatest blood pressure reductions were for DASH at the sodium intake of 1,500 milligrams per day. Those with high blood pressure saw the greatest reductions.
STUDY 3 Higher protein or healthy fats
As the science around DASH evolves over time, the overall benefits to heart health continue to be evaluated. The OmniHeart (Optimal Macronutrient Intake Trial for Heart Health) trial studied the effect of replacing some daily carbohydrates— or carbs— with either protein (about half from plant sources) or unsaturated fat. This trial included 164 adults who had systolic blood pressure readings of 120 to 159mmHg. The trial compared three dietary patterns, each containing 2,300 mg of sodium per day— the original DASH plan, substituting 10 percent of daily carbs with protein, and substituting 10 percent of total daily carbs with unsaturated fat.
OmniHeart found that participants who followed either variation of DASH, partially substituting carbs with protein (about half from plant sources) or unsaturated fat, had greater reductions in blood pressure and improvements in blood lipid levels than those who followed the original DASH eating plan.
Success with DASH
DASH along with other lifestyle changes can help you prevent and control high blood pressure. In fact, if your blood pressure is not too high, you may be able to control it entirely by changing your eating habits, losing weight if you are overweight, getting regular physical activity, and cutting down on alcohol. DASH also has other benefits, such as lowering LDL (“bad”) cholesterol, and replacing some carbs with protein or unsaturated fat can have an even greater effect. Along with lowering blood pressure, lower cholesterol can reduce your risk for heart disease.
Making the Move to DASH
- If you now eat one or two servings of vegetables a day, add a serving at lunch and another at dinner.
- If you don’t eat fruit now or have juice only at breakfast, add a serving of fruit to your meals or have it as a snack.
- Gradually increase your use of milk, yogurt, and cheese to three servings a day. For example, drink milk with lunch or dinner, instead of soda, sugar-sweetened tea, or alcohol.
- Choose fat-free or low-fat (1 percent) milk, yogurt, and reduced-fat cheese to reduce your intake of saturated fat, cholesterol, and calories and to increase your calcium.
- Read the Nutrition Facts label on frozen and prepared meals, pizza, and desserts to choose those lowest in saturated fat and trans fat.
Vary your proteins.
- Choose lean cuts of meat and remove skin from poultry.
- Check the labels on ground meats and poultry and select those with lower saturated fat.
- Serve fish instead of meat or poultry once or twice each week.bInclude two or more vegetarian (meatless) meals each week. Aim to fill 1⁄2 your plate with vegetables and fruits, 1⁄4 with whole grains, and 1⁄4 with fish, lean meat, poultry, or beans.
- Add extra vegetables to casseroles, pasta, and stir-fry dishes.
Select nutritious, tasty snacks.
- Fruits offer great taste and variety. Use fruits canned in their own juice or packed in water. Fresh fruits are fast and easy and dried fruits are a good choice to carry with you or to have in the car.
- Try these snack ideas: unsalted rice cakes; nuts mixed with raisins; graham crackers; fat-free and low-fat yogurt; popcorn with no salt or butter added; raw vegetables.
Make healthy substitutions.
- Choose whole grain foods for most grain servings to get more nutrients, such as minerals and fiber. For example, choose whole wheat bread or whole grain cereals.
- If you have trouble digesting milk and milk products, try taking lactase enzyme pills with the milk products. Or, buy lactose-free milk.
- If you are allergic to nuts, use beans or seeds (such as sunflower, flax, or sesame seeds)