Section: Why the DASH Diet?

DASH Evidence

High blood pressure, also known as hypertension, affects nearly one in three adults in the US.  One-third of these adults are unaware they have it.  Don’t let your blood pressure go unchecked.  High blood pressure places a person at greater risk of stroke, heart attack, heart failure and kidney failure. 

The good news is that you can reduce your blood pressure by making and sticking to a few dietary and lifestyle changes.  Research shows that diet plays a role in developing high blood pressure, and, more importantly, that diet plays a role in reducing and preventing high blood pressure.  

Two ground breaking studies funded by the National Institutes of Health looked at the relationship between diet and high blood pressure.  The objective of the first, called the DASH (Dietary Approaches to Stop Hypertension) study, was to determine whether diet could lower high blood pressure in Americans.  

The DASH study was conducted at four academic medical centers in the United States.  It examined the impact of three dietary patterns on a group of 459 subjects with normal to high blood pressure, with 27 percent having hypertension.  The participants included men and women (White and African-Americans) with an average age of 45.  Due to the higher incidence of hypertension in the African-American population, two-thirds of study participants were selected from this group.  About half of the study participants were women.

Participants were randomly assigned to one of three dietary patterns:

  • A diet similar in nutrients to the typical American diet
  • A diet similar in nutrients to the typical American diet, but higher in fruits and vegetables
  • The DASH diet

All three groups consumed about 3,000 mg of sodium daily, which is equivalent to the amount of sodium in about 1 ¼ teaspoons of table salt.  While this number sounds high, it is still about 20% below the average sodium consumption for adults in the US.  Participants were limited to one to two alcoholic beverages per week.

Compared to the other two dietary patterns, the DASH eating plan provided higher amounts of minerals, specifically calcium, magnesium, and potassium, than is typical for adults in the US.

The study results were remarkable.  Reduced blood pressure was seen with both the fruit and vegetable plan and the DASH eating plan.  The greatest effect was seen with DASH, especially for people who began the study with hypertension.  African American participants were particularly sensitive to the dietary changes and experienced significant blood pressure reductions on the DASH eating plan. 

This dramatic decrease in blood pressure is similar to taking one prescription medication for lowering blood pressure.  The DASH study proved that eating a meal pattern high in fruits, vegetables, and lowfat dairy products was very successful in reducing blood pressure.

The second study was a follow-up to the DASH study called DASH-Sodium.  Researchers wanted to further investigate the relationship between sodium intake and blood pressure.  The DASH-Sodium study included 412 participants with normal to high blood pressure, with 41 percent having hypertension.  About 57 percent of participants were women and about 57 percent were African American.  

Participants were randomly assigned to either a typical American diet or the DASH eating plan.  Within each group, participants followed one of three dietary sodium levels:

  • High sodium diet (3,300 mg/day)
  • Intermediate sodium diet (2,400 mg/day)
  • Low sodium diet (1,500 mg/day)

Once again the results showed remarkable decreases in blood pressure with reduced sodium intake for both the typical American diet and the DASH eating plan.  In fact, the lower the sodium level, the lower the blood pressure.  However, the biggest reduction in blood pressure was found in the group that followed the DASH eating plan at the lowest level of sodium intake.

 

The two DASH studies demonstrated the effect of diet on high blood pressure.  Health professionals acknowledge that following the DASH eating plan and lowering sodium intake can help individuals lower their blood pressure.  Further studies have found that following the DASH eating plan and making other lifestyle changes can reduce the risk of many chronic diseases, including certain cancers, diabetes, heart disease, hypertension, obesity, and osteoporosis. 

DASH benefits everyone, not just those with high blood pressure.

 
Be sure to check out the DASH Evidence Resource List.